TITLE OF THE INVENTION
ORAL SPRAY FORMULATIONS AND METHODS FOR ADMINISTRATION OF
SILDENAFIL
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of priority of U.S. Provisional Application Serial
Number 61/566,879, filed December 5, 201 1. The foregoing application is incorporated
herein by reference in its entirety.
FIELD OF THE INVENTION
This present disclosure relates to methods and formulations for delivery of sildenafil,
and derivatives thereof, to the circulatory system by administration via an oral spray
formulation to treat disease, such as pulmonary arterial hypertension and selective serotonin
reuptake inhibitor (SSRI) induced sexual dysfunction.
BACKGROUND OF THE INVENTION
The U.S. Food and Drug Administration (FDA) has approved sildenafil citrate tablets
for the treatment of pulmonary arterial hypertension (WHO Group I) under the brand name
REVATIO . The recommended dose of REVATIO is 20 mg three times a day.
Sildenafil citrate was first approved by the FDA for the treatment of male erectile
dysfunction under the brand name VIAGRA®.
Sildenafil is reported to be a selective inhibitor of cyclic-GMP-specific
phosphodiesterase type 5 (PDE5). Its effects in treating pulmonary arterial hypertension (and
erectile dysfunction) occur by enhancing the downstream effects of nitric oxide (NO)
mediated vasorelaxation. PDE5 is found in pulmonary vascular smooth muscle and the
corpus cavernosum, as well as in tissues such as vascular and visceral smooth muscle and in
platelets. Sildenafil increases cyclic-GMP (cGMP) by inhibiting PDE5. PDE5 is responsible
for degradation of cGMP. As a result, sildenafil increases cGMP within pulmonary vascular
smooth muscle cells. In patients with pulmonary hypertension, this can lead to vasodilation of
the pulmonary vascular bed and, to a lesser degree, vasodilation in the systemic circulation
(see, e.g. , REVATIO product literature).
In addition to its therapeutic benefits in diseases such as pulmonary arterial
hypertension (PAH) and erectile dysfunction, sildenafil is reported to be efficacious in the
treatment of sexual dysfunctions associated with SSRI administration. See, e.g., Stimmel, GL,
"Sexual dysfunction and psychotropic medications" CNS Spectr. (2006) 1l:8(Suppl 9):24-30
and Wang, W-F et al. "Selective serotonin reuptake inhibitors in the treatment of premature
ejaculation" Chin Med J (2007) 120(1 1): 1000-1006. Sexual dysfunctions are a main side
effect of SSRIs, and include difficulties with libido, arousal, delayed or absent orgasm (e.g.,
anorgasmia in women), and delayed ejaculation, anejaculation, or erectile dysfunction in
men. Ibid. In patients suffering from sexual dysfunction as a result of SSRI treatment,
administration of sildenafil as adjunct therapy may improve and sustain arousal, for example,
in the patient by increasing blood flow, and sildenafil is thought to exert an indirect beneficial
effect on other aspects of sexual response via the same mechanism. See, e.g. , Stimmel, GL.
CNS Spectr. (2006) 11:8(Suppl 9):24-30.
Sildenafil has been proposed as a possible therapeutic in the treatment of a number of
other conditions as well. These include female sexual dysfunction, including sexual
dysfunction associated with menopause, such as difficulties with sexual arousal. See, e.g.,
Mattar, CN et al. "Care of women in menopause: sexual function, dysfunction and
therapeutic modalities" Ann Acad Med Singapore (2008) 37:215-223. Other conditions for
which sildenafil may provide a therapeutic benefit include high-altitude illness {see, e.g.,
Luks, AM et al CHEST (2008) 133:744-755), pain, stroke, multiple sclerosis, and irritable
bowl syndrome {see, e.g., Sharma, R Indian J Med Sci (2007) 61:667-679 and Uthayathas, S
et al. Pharmacological Reports (2007) 59: 150-163).
Despite its effectiveness in treating diseases such as PAH and erectile dysfunction, the
administration of solid oral sildenafil dosage forms may also cause undesirable side effects.
At high dosages, the incidence of such side effects increase, for example, abnormal vision
problems (ranging from blue or green halo effects to blurring), dyspepsia, nasal congestion,
blinding headaches, flushing, redness, diarrhea, dizziness, rash, and urinary tract infection.
Other more serious side effects may occur in some cases resulting from a physiological
predisposition, adverse drug interaction or potentiation, or by drug abuse. Such side effects
include syncope (loss of consciousness), priapism (erection lasting 4 hours or more), and
increased cardiac risk (coital coronaries). In particular, hypotension crisis may result from
the combination of sildenafil citrate and organic nitrates, causing death in some cases.
Hence, its administration to patients who are concurrently using organic nitrates (such as
nitroglycerin) in any form is contramdicated. Moreover, the long-term effects of large doses
of sildenafil-containing drugs are unknown (Handy B., "The Viagra® Craze," Time, pp. 50-
57 (May 4, 1998)).
Many drugs exhibit low bioavailabilities owing to extensive first pass metabolism.
Differences in bioavailability may have profound clinical significance. Sildenafil citrate, for
example, exhibits only a 40% bioavailability after oral administration via tablet form, of
which the active metabolite accounts for about one-half.
Compared to the administration of solid oral dosage forms absorbed in the
gastrointestinal tract, the oral cavity presents the possibility for more rapid and efficient drug
delivery because of its rich vascular supply. The oral cavity exhibits a minimal barrier to
drug transport and may result in a rapid rise in serum concentration of drug.
However, the formulation of dosage forms for administration to the oral mucosa often
poses non-trivial problems. For significant drug absorption to occur across the oral mucosa,
the drug must have a prolonged exposure to the mucosal surface and the formulation must be
both chemically stable and pharmaceutically acceptable to patients.
WO 0 1/35926 discloses sildenafil dosage forms for non-oral use, such as nasal
delivery. However, there is currently no commercially available dosage form for oral spray
delivery of sildenafil.
Thus, there is an ongoing need and desire for discreet and convenient sildenafil
dosage forms for the treatment of diseases such as pulmonary arterial hypertension and SSRIinduced
sexual dysfunction, which are both chemically stable and pharmaceutically
acceptable.
SUMMARY OF THE INVENTION
The present disclosure is directed to methods and formulations for treating diseases
such as pulmonary arterial hypertension and/or SSRI-induced sexual dysfunction. In
particular, this disclosure relates to the oral administration of sildenafil or sildenafil citrate.
The disclosure herein is directed to an oral spray formulation for delivery of sildenafil
to treat diseases such as pulmonary arterial hypertension and/or SSRI-induced sexual
dysfunction. The sildenafil oral spray formulation may be a clear, colorless to light yellow,
solution designed to be sprayed directly into the mouth, over or under the tongue.
In one aspect, the oral spray formulation may comprise sildenafil or a
pharmaceutically acceptable salt thereof. In another aspect, the oral spray formulation may
comprise sildenafil citrate.
In yet another aspect, the oral spray formulation comprising sildenafil or a
pharmaceutically acceptable salt thereof may have a pH of about 1.5 to less than 3.0. In some
embodiments, the pH of the formulation is about 2.2 ± 0.5. In a certain embodiment, the pH
of the formulation is about 2.2.
In still another aspect, the oral spray formulation may comprise a polar solvent. The
polar solvent may comprise propylene glycol and ethyl alcohol. In certain embodiments, the
ratio of propylene glycol:ethyl alcohol is about 62.5:37.5 % v/v.
In one aspect, said polar solvent may comprise one or more pH-adjusting agents. The
pH-adjusting agents may be acidifying agents, alkalizing agents, or a combination thereof. In
one aspect, the acidifying agent may be hydrochloric acid (HC1). In a particular embodiment,
the HC1 is present in an amount of about 10% v/v of the formulation. In another aspect, the
alkalizing agent may be sodium hydroxide (NaOH). In a particular embodiment, the NaOH
is present in an amount of about 2.1 % v/v of the formulation.
In one aspect, the oral spray formulation comprising sildenafil or a pharmaceutically
acceptable salt thereof may further comprise a taste-masking agent. In certain embodiments,
the taste-masking agent comprises mint. In some embodiments, the mint is peppermint or
spearmint. In other embodiments, the oral spray formulation further comprises a fruit and/or
chocolate flavor. In some embodiments, the oral spray formulation comprises a sweetener. In
a certain embodiment, the sweetener is sucralose.
In another aspect, the oral spray formulation may further comprise one or more
pharmaceutically acceptable excipients, carriers, or a combination thereof.
The disclosure herein is also directed to a method for treating a disease such as PAH
or SSRI-induced sexual dysfunction, which may comprise administering to a patient in need
thereof a sildenafil oral spray formulation. In some embodiments, the sildenafil exposure in
the patient results in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-t(nglir/
mL) of approximately 299.36. In other embodiments, the sildenafil exposure in the patient
results in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-i(ng-hr/mL) of
approximately 323.16. In yet other embodiments, the sildenafil exposure in the patient
results in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-i (ng-hr/mL) of
approximately 304.98. In some embodiments, the sildenafil exposure in the patient results in
a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-i f(ng-hr/mL) of
approximately 310.60. In other embodiments, the sildenafil exposure in the patient results in
a ln-transformed dose-adjusted to 25 mg geometric mean AUCo (ng-hr/mL) of
approximately 331.22. In yet other embodiments, the sildenafil exposure in the patient
results in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo (ng-hr/mL) of
approximately 3 11.05.
In certain embodiments, the sildenafil is present in an oral spray formulation of the
invention in an amount of about 7 to about 9 % w/v of the formulation. In certain
embodiments, it is present in an amount of about 8.3 1% w/v of the formulation. In other
embodiments, the sildenafil salt is present in an amount of about 10 to about 12 % w/v of the
formulation. In a particular embodiment, the sildenafil salt is present in an amount of about
11.67 % w/v of the formulation.
In some embodiments, the amount of sildenafil in an oral spray formulation of the
invention that is administered per spray is 10 mg. In other embodiments, the amount of
sildenafil administered per spray is 20 mg. In yet other embodiments, the amount of
sildenafil administered per spray is 30 mg.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 (Figure 7.2.6-1-1) is a graph depicting non-dose-adjusted mean plasma
sildenafil concentration (0-24 hours) N=24.
Figure 2 (Figure 7.2.6.2-1) is a graph depicting dose-adjusted mean plasma sildenafil
concentration (0-24 hours) N=24.
Figure 3 (Figure 7.2.6.3-1) is a graph depicting non-dose-adjusted mean plasma Ndesmethylsildenafil
concentration (0-24 hours) N=24.
Figure 4 (Figure 7.2.6.4-1) is a graph depicting dose-adjusted mean plasma Ndesmethylsildenafil
concentration (0-24 hours) N=24.
Figure 5 (Figure 7.2.6.6-1) is a graph depicting mean plasma Ndesmethylsildenafil/
sildenafil ratio (0-4 hours) N=24.
DETAILED DESCRIPTION
Sildenafil is designated chemically as l-[[3-(6,7-dihydro-l-methyl-7-oxo-3-propyllH-
pyrazolo[4,3-d] pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine.
The oral spray formulation disclosed herein comprises sildenafil or a
pharmaceutically acceptable salt thereof. The term "pharmaceutically acceptable salts" refers
to salts prepared from pharmaceutically acceptable non-toxic acids including organic and
inorganic acids. Such acids include acetic, benzenesulfonic, benzoic, camphorsulfonic, citric,
ethane-sulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic,
maleic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic,
sulfuric, tartaric, and p-toluenesulfonic acids.
N-desmethylsildenafil is one known active metabolite of sildenafil.
Sildenafil, administered as the commercially available REVATIO® formulation for
the treatment of pulmonary arterial hypertension (WHO Group I) to improve exercise ability
and delay clinical worsening, is absorbed in the gastrointestinal tract after oral administration,
with absolute bioavailability of about 40%. Based on the REVATIO® manufacturer's
product literature, maximum observed plasma concentrations are reached within 30 to 120
minutes (median 60 minutes) of oral dosing in the fasted state. When the REVATIO®
formulation is taken with a high-fat meal, the rate of absorption is reduced, with a mean delay
Tm of 60 minutes and mean reduction in C x of 29%. The mean steady state volume of
distribution (Vss) for sildenafil is reportedly 105 L, indicating distribution into the tissues.
The oral spray formulation disclosed herein is formulated for delivery via the oral
cavity. The sildenafil oral spray formulation may be delivered transmucosally, sublingually,
via the buccal cavity, via mucosal membranes and/or through the gastrointestinal tract.
The oral spray formulation of the instant application is suitable for use in the
treatment of one or more diseases for which sildenafil administration is considered
efficacious. Examples of such diseases include PAH, SSRI-induced sexual dysfunction, and
erectile dysfunction. In certain embodiments, a sildenafil oral spray formulation of the instant
application is suitable for use in the treatment of HIV-associated PAH; hemolysis associated
PAH; portopulmonary hypertension; PAH in pediatric patients (e.g., idiopathic PAH, post op
congenital heart defect repair, and Eisenmenger syndrome); pulmonary hypertension
associated with heart failure, cardiac surgery, and cardiac transplant; pulmonary
thromboembolic disease; pulmonary fibrosis associated pulmonary hypertension; and/or
altitude-associated pulmonary hypertension. See, e.g. , Barnett, CF et al. Vascular Health and
Risk Management (2006) 2(4):41 1-422. In other embodiments, a sildenafil oral spray
formulation of the instant application is suitable for use in the treatment of female sexual
dysfunction, including sexual dysfunction associated with menopause, such as difficulties
with sexual arousal. In yet other embodiments, a sildenafil oral spray formulation of the
instant application is suitable for use in the treatment of high-altitude illness, pain, stroke,
multiple sclerosis, and/or irritable bowl syndrome.
The oral spray formulation as disclosed may comprise sildenafil base or a
pharmaceutically acceptable salt thereof in an amount of about 6 to about 14% w/v, about 7
to about 13% w/v, or about 8 to about 12% w/v of the formulation. In one aspect, the oral
spray formulation may comprise sildenafil or a pharmaceutically acceptable salt thereof in an
amount of about 8 to about 10% w/v of the formulation.
In another aspect, the oral spray formulation as disclosed may comprise sildenafil
base in an amount of about 6 to about 10% w/v, about 7 to about 9% w/v, or about 8% w/v of
the formulation. In yet another aspect, the oral spray formulation may comprise sildenafil
base in an amount of about 8.3 1% w/v of the formulation.
In one aspect, the oral spray formulation as disclosed may comprise sildenafil citrate
in an amount of about 10 to about 14% w/v, about 11 to about 13% w/v, or about 12% w/v of
the formulation. In another aspect, the oral spray formulation may comprise sildenafil citrate
in an amount of about 11.67% w/v of the formulation.
The oral spray formulation as disclosed may deliver sildenafil base or a
pharmaceutically acceptable salt thereof in an amount (per spray) of about 3 to about 25 mg,
about 6 to about 20 mg, about 8 to about 18 mg, about 10 to about 16 mg, or about 12 to
about 14 mg.
In one aspect, the oral spray formulation may deliver sildenafil base in an amount (per
spray) of about 6 to about 14 mg, or about 8 to about 12 mg. In another aspect, the oral spray
formulation may deliver about 10 mg per spray.
In yet another aspect, the oral spray formulation may deliver sildenafil citrate in an
amount (per spray) of about 10 to about 18 mg, or about 12 to about 16 mg. In still another
aspect, the oral spray formulation may deliver about 14 mg per spray.
In one aspect, one to five sprays of the oral spray formulation may be administered to
a patient. In another aspect, one to three sprays of the sildenafil formulation are delivered to
a patient. In yet another aspect, the spray may deliver about 100 to about 120 mΐ (about 0.1
to about 0.12 mL) of the formulation. In still another aspect, the spray may deliver about 120
mΐ of the formulation. In some embodiments, the spray delivers about 200 to about 250 mΐ of
the formulation. In certain embodiments, the spray delivers about 250 mΐ of the formulation.
The oral spray formulation as disclosed may have a pH of about 1.5 to less than 3.0.
In one aspect, the pH of the oral spray formulation may be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2,
2.3, 2.4, 2.5, 2.6, 2.7, 2.8, or 2.9. In another aspect, the pH of the oral spray formulation of
the may be about 2.2±0.5, or about 2.3±0.5.
Polar solvents of the disclosed oral spray formulation may include, but are not limited
to, ethyl alcohol, propylene glycol, glycerol and polyethylene glycols having a nominal
molecular weight of 200-600 g/mol, N- methyl-2-pyrrolidone, or combinations thereof. In
one aspect, the polar solvent may comprise propylene glycol and dehydrated alcohol (e.g.,
ethyl alcohol). Propylene glycol and dehydrated alcohol may be comprised within the oral
spray formulation at a propylene glycol:alcohol ratio of about 70:30% v/v, about 65:35% v/v,
about 60:40% v/v, about 55:45% v/v, or about 50:50% v/v. In another aspect, the propylene
glycol:alcohol ratio may be about 62.5:37.5% v/v.
In one aspect, propylene glycol is present in an amount of about 55% v/v and ethyl
alcohol is present in an amount of about 33% v/v of the final oral spray formulation.
Formulations as disclosed may comprise one or more pH-adjusting agents. pHadjusting
agents may include acidifying agents or alkalizing agents. Acidifying agents of the
present invention may include, but are not limited to, hydrochloric acid, citric acid, lactic
acid, glycolic acid, acetic acid, glacial acetic acid, malic acid, and proprionic acid. Alkalizing
agents of the present invention may include, but are not limited to, sodium hydroxide, edetol,
potassium carbonate, potassium hydroxide, sodium borate, sodium carbonate, sodium citrate,
sodium lactate, and sodium glycolate. In one aspect, the oral spray formulation may
comprise an acidifying agent, an alkalizing agent, or a combination thereof. The acidifying
agent may be present in the solvent in an amount of about 5 to about 15% v/v of the solvent,
or about 10% v/v of the solvent. The alkalizing agent may be present in the solvent in an
amount of about 1.5 to about 4% v/v of the solvent, or about 2.1% v/v of the solvent.
The Cm obtained after administration of the disclosed oral spray formulation may be,
but is not limited to, about 50 to about 150% of a reference In one aspect, the reference
Cmax may be the Cmax obtained following administration of sildenafil citrate tablets. In
another aspect, the C obtained after administration of the disclosed oral spray formulation
may meet bioequivalence standards, as set forth by the FDA, including that the 90%
confidence interval of the geometric mean ratio of Cmax between the test and reference
product fall within 80-125%.
The AUC obtained after administration of the disclosed oral spray formulation may
be, but is not limited to, about 50 to about 150% of a reference AUC. In one aspect, the
reference AUC may be the AUC obtained following administration of sildenafil citrate
tablets. In another aspect, the AUC obtained after administration of the disclosed oral spray
formulation may meet bioequivalence standards, as set forth by the FDA, including that the
90% confidence interval of the geometric mean ratio of AUC between the test and reference
product fall within 80-125%.
The Tmax obtained after administration of the disclosed oral spray formulation may be,
but is not limited to, about 50 to about 150% of a reference Tmax. In one aspect, the reference
Tmax may be the obtained following administration of sildenafil citrate tablets. In
another aspect, the T x obtained after administration of the disclosed oral spray formulation
may meet bioequivalence standards, as set forth by the FDA, including that the 90%
confidence interval of the geometric mean ratio of Tm x between the test and reference
product fall within 80-125%. The oral spray formulation as disclosed may further comprise
one or more pharmaceutically acceptable excipients, carriers, or a combination thereof.
Excipients may include, but are not limited to, co-solvents and/or solubilizing agents,
penetration enhancers, stabilizing agents, buffering agents, tonicity agents, anti-microbial
agent, and viscosity-modifying agents.
Co-solvents may include, but are not limited to, ethyl alcohol, propylene glycol,
glycerol and polyethylene glycols having a nominal molecular weight of 200-600 g mol, and
N-methyl-2-pyrrolidone.
Solubilizing agents may include, but are not limited to, purified diethylene glycol
monoethyl ether, cyclodextrins, glycerol monostearate, lecithin, poloxomer, polyethylene
alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid
esters, polyoxyethylene stearates, stearic acid, citric acid, and ascorbic acid and the like;
surface active agents such as polysorbates, sorbiton esters, polyvinyl alcohol, benzal konium
chloride, benzithonium chloride, cetrimide, docusate sodium, sodium lauryl sulphate, and
octoxynol.
Solubility enhancers may include, but are not limited to, DL- methionine, caffeine,
nicotinamide, vanillin, benzyl alcohol, ethanol, and Transcutol (diethylene glycol monoethyl
ether). In certain embodiments, a formulation of the invention comprises caffeine as a
solubility enhancer. In further embodiments, caffeine is present in the formulation in an
amount of about 25 mg/mL. In certain embodiments, a formulation of the invention
comprises nicotinamide as a solubility enhancer. In further embodiments, nicotinamide is
present in the formulation in an amount of about 5 % w/w.
Buffering agents may include, but are not limited to, hydrochloric acid, sodium
acetate, glacial acetic acid, orthophosphoric acid, and potassium dihydrogen orthophosphate.
Stabilizing agents may include, but are not limited to, sodium metabisulphite, sodium
bisulphite, disodium EDTA, and ascorbic acid.
Anti-microbial agents may include, but are not limited to, benzyl alcohol,
benzalkonium chloride, phenyl mercuric acetate, and phenylethyl alcohol.
Viscosity-modifying agents may include, but are not limited to, hydroxypropyl
methylcellulose, and poly acrylic acid, or water soluble polymers such as carbopol, sodium
carboxymethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose and various grades
of polyvinylpyrrolidone (e.g., K-15, K-30, K-60, and K-90).
In certain embodiments, it may be desirable to increase the mucosal (e.g., oral
mucosal) residence time of sildenafil that is administered to a patient in an oral spray
formulation as disclosed herein. Accordingly, in certain embodiments, an oral spray
formulation of the instant application may comprise one or more permeation enhancers
and/or mucoadhesives. Examples of suitable permeation enhancers include nicotinamide,
caffeine, peppermint oil, sodium glycocholate, phospholipids, alkyl saccharides, aprotinin,
benzalkonium chloride, ceramides, cetylpyridinium chloride, chitosan, chitosan-4-
thiobutylamidine, cyclodextrins, dextran sulfate, dodecyl azacycloheptyl-2-ketone, ether
lipids (plasmologens), glycerol, glycosylated sphingosines, lauric acid, 23-lauryl ether,
lysophosphatidylcholine, menthol, methoxysalicylate, phosphatidyl choline, l-palmitoyl-2-
glutaroyl-sn-glycero-3-phosphocholine, polycarbophil cysteine, poly-L-arginine,
polyoxyethylene, polyoxyethylene-9-lauryl ether, polysorbate 80, propylene glycol, EDTA,
sodium deoxycholate, sodium glycocholate, sodium glycodeoxycholate, sodium lauryl
sulfate, sodium salicylate, sodium taurocholate, sodium taurodeoxycholate, sodium
taurodihydrofusidate, sphingolipids, and sterols. Examples of suitable mucoadhesives
include hydroxypropyl cellulose, gelatin, crosslinked polyacrylic acid, polymethacrylic acid,
polyhydroxyethyl methacrylic acid, hydroxypropyl methyl cellulose, polyethylene glycol,
sodium carboxymethyl cellulose, hyaluronic acid, chitosan, polycarbophil, pectin, xanthan
gum, alginate, copolymers of dextran, polyacrylamide, acacia, copolymer of caprolactone and
ethylene oxide, carbopol 934, tragacanth, and eudragit.
The oral spray formulation as disclosed may comprise taste-masking or flavoring
agents. Taste-masking or flavoring agents as used herein are agents that may hide or
minimize an undesirable flavor such as a bitter or sour flavor. Examples of taste-masking or
flavoring agents suitable for use in the formulations of the present invention include, but are
not limited to, synthetic or natural peppermint oil, spearmint oil, citrus oil, fruit flavors (e.g.,
citrus, such as orange, lemon, lime; strawberry; cherry; grape; melon; and mixtures thereof),
chocolate, spice (e.g., anise, cinnamon), vanilla, bubblegum, and sweeteners (e.g., sugars,
aspartame, saccharin, and sucralose). In certain embodiments, the oral spray formulation
comprises a sweetener that is sucralose. In certain embodiments, the taste-masking or
flavoring agent is mint. In certain embodiments, the mint is peppermint. In further
embodiments, the mint is a strong mint, e.g., peppermint oil NF. In yet other embodiments, a
formulation of the invention comprises a taste-masking or flavoring agent that is chocolate
mint.
Taste-masking and/or flavoring agents may be evaluated in a formulation of the
invention according to the Flavor Profile Method (see Keane, P. The Flavor Profile Method.
In C. Hootman (Ed.), Manual on Descriptive Analysis Testing for Sensory Evaluation ASTM
Manual Series: MNL 13. Baltimore, MD (1992)), for example, to identify, characterize,
5 and/or quantify sensory attributes of products, e.g., basic tastes, aroma, texture, and
mouthfeel.
In certain embodiments, a formulation of the invention comprises a taste-masking
and/or flavoring agent that achieves an intensity similar to that of a common breath mint
spray. In some embodiments, the buffer strength of the formulation is reduced (e.g., through
10 a reduction in NaOH levels) to achieve a desired balance in formulation taste (e.g., balanced
basic tastes).
The oral spray formulation as disclosed may be packaged in amber Type 1 glass
Schott bottles configured with 100 or 120 mΐ snap-on Pfeiffer pumps, or within any type of
pharmaceutically-acceptable package, container, pump, or bottle.
15 In one aspect, the oral spray formulation as disclosed consists of sildenafil citrate,
propylene glycol, ethyl alcohol, hydrochloric acid, and sodium hydroxide.
In another aspect, the oral spray formulation consists of sildenafil citrate, propylene
glycol, ethyl alcohol, hydrochloric acid, sodium hydroxide, and a taste-masking agent.
In yet another aspect, the oral spray formulation consists essentially of sildenafil
20 citrate, propylene glycol, ethyl alcohol, hydrochloric acid, and sodium hydroxide.
In still another aspect, the oral spray formulation consists essentially of sildenafil
citrate, propylene glycol, ethyl alcohol, hydrochloric acid, sodium hydroxide, and a tastemasking
agent.
The following non-limiting examples will further describe the disclosed oral spray
25 formulation.
EXAMPLE 1
The commercially available, citrate salt form of sildenafil was selected as the active
pharmaceutical ingredient in the development of an oral spray form.
The final solvent system included a combination of 62.5% v/v propylene glycol to
30 37.5% v/v alcohol mixture acidified with 0.5 mL dilute HCl and pH adjusted to 2.0 or less
using 5N NaOH. This combination was able to solubilize 12 to 14% w/v sildenafil citrate and
keep the API in solution.
Table Composition of the formulation vehicle designed to deliver 14 mg citrate salt
(10 mg base equivalent) per 0.12 mL spray
Ingredient Concentration Target amounts in 250
mL
Sildenafil citrate 11.67% w/v 29. 1 5 g
Propylene glycol/ethanol -70% v/v 175 mL
Mixture
62.5%/37.5% v/v or
68.4%/31.6%w/w
Diluted HCL (10%v/v) 10% v/v 25 mL
5N NaOH 2.1% v/v 5.25 mL
Propylene glycol/ethanol Qs 250 mL
mixture
The sildenafil citrate solution (having a salt concentration of 11.67% w/v ( 11.67
mg/mL)) may be administered to a patient in a commercially available pump spray designed
to deliver 14 mg salt/120 mΐ of spray (or 10 mg base/120 mΐ of spray).
The formulation vehicle was stable when stored 25°C/60% R and 40°C/75% R for
six months.
EXAMPLE 2
Subjects are provided sildenafil citrate in an oral spray dosage form as a part of a
single-dose study. One subset of subjects is administered one spray of an oral spray sildenafil
formulation comprising 14 mg sildenafil citrate per spray (providing a total administered
amount equivalent to 10 mg sildenafil base). A second subset of subjects is administered two
sprays of an oral spray sildenafil formulation comprising 14 mg sildenafil citrate per spray
(providing a total administered amount equivalent to 20 mg sildenafil base). A third subset of
subjects is administered three sprays of an oral spray sildenafil formulation comprising 14 mg
sildenafil citrate per spray (providing a total administered amount equivalent to 30 mg
sildenafil base).
EXAMPLE 3
A relative bioavailability study of sildenafil oral spray at 10 mg, 20 mg, and 30 mg doses
versus 25 mg VIAGRA tablets underfasting conditions
Objective
This study assessed the relative bioavailability of sildenafil oral spray compared to
that of VIAGRA®tablets by Pfizer Labs following a single oral dose [1 x 14 mg/0.12 mL
sildenafil citrate oral spray (equivalent to 10 mg sildenafil base), 2 x 14 mg/0.12 mL
sildenafil citrate oral sprays (equivalent to 20 mg sildenafil base), 3 x 14 mg/0.12 mL
sildenafil citrate oral sprays (equivalent to 30 mg sildenafil base), or 1 x 25 mg tablet] in
healthy adult subjects when administered under fasting conditions.
Secondary objectives were to assess the relative safety of the sildenafil oral spray
following single oral dose administration compared to that of VIAGRA® tablets.
Assessments include evaluation of changes in orthostatic hypotension, oral irritation, vital
sign assessments, 12-lead electrocardiogram (ECG), and clinical assessments.
STUDY DESIGN
This was an open-label, single-dose, randomized, four-period, four-treatment
crossover study under fasting conditions. The total number of healthy adult male subjects
enrolled in the study was twenty-four (24). The total duration of the study, screening through
study exit, was approximately nine weeks with at least a three-day washout period between
doses. At study check-in, the subjects reported to the clinical site at least 36 hours prior to
Day 1 dosing for Period I and at least 12 hours prior to Day 1 dosing for Periods II, III, and
IV. Subjects were required to stay for at least 24 hours after each treatment period.
Following each washout period, subjects returned to the clinical facility to be dosed
with the alternative treatments as per the randomization. Blood sample collection was
obtained within 90 minutes, but no later than 30 minutes, prior to dosing (0 hour) and after
dose administration at 0.083,0.167,0.25,0.33,0.50,0.75,1, 1.5,2,3,4,6,8, 10, 12, 16, and 24
hours. The actual time of sample collection was documented. During each study period, a
total of 18 blood samples were collected for a total of 72 samples and 432 mL total volume.
The actual time of sample collection was documented.
Bioanalytical Sample Analyses
The sildenafil and N-desmethylsildenafil plasma concentrations were measured using
a validated bioanalytical method and according to the standard operating procedures and
FDA Guidelines. The validated detection range for sildenafil is 1 to 300 ng/mL in human
plasma. The validated detection range for N-desmethylsildenafil is 0.25 to 75 ng/mL in
human plasma.
Pharmacokinetic Data Analyses
Pharmacokinetic parameters for plasma sildenafil and N-desmethylsildenafil
concentration were calculated using standard noncompartmental approaches as indicated
below:
AUC„.t The area under the plasma concentration versus time curve, from time 0 to the
last measurable concentration, as calculated by the linear trapezoidal method.
AUC0.i The area under the plasma concentration versus time curve from time 0 to infinity.
AUCo is calculated as the sum of the AUC0 t plus the ratio of the last measurable
plasma concentration to the elimination rate constant.
AUC„.,/AUC„. The ratio of AUC„.t to Au< .
Cmax Maximum measured plasma concentration over the time span specified.
Time of the maximum measured plasma concentration. If the maximum value
occurs at more than one time point, Tmax is defined as the first time point with
this value.
Kel Apparent first-order terminal elimination rate constant calculated from a semi¬
log plot of the plasma concentration versus time curve. The parameter will be
calculated by linear least-squares regression analysis in the terminal log-linear
phase (three or more non-zero plasma concentrations).
T½ The apparent first-order terminal elimination half-life will be calculated as
0.693/Kel.
Ratio The ratio of metabolite/parent will be assessed at each concentration as well for
Metabolite/Parent PK parameters Cm„ , AUC . and A .
No value of Kel, AUCo-inf, or T½ will be reported for cases that do not exhibit a terminal loglinear
phase in the concentration versus time profile. Other pharmacokinetic parameters may
be calculated if deemed necessary.
Statistical Analyses
Arithmetic means, standard deviations and coefficients of variation were calculated
for the parameters listed above. Additionally, geometric means were calculated for AUCo-i,
Analyses of variance (ANOVA) were performed on the ln-transformed
pharmacokinetic parameters AUCo-i, AUCo-inf d C m . The ANOVA model includes
sequence, formulation and period as fixed effects and subject nested within sequence as a
random effect. Sequence is tested using subject nested within sequence as the error term. A
10% level of significance is used to test the sequence effect. Each analysis of variance
includes calculation of least-squares means, the difference between adjusted formulation
means and the standard error associated with this difference. The above statistical analyses
were performed using the appropriate SAS® procedure.
In agreement with the two one-sided test for bioequivalence, 90% confidence
intervals for the difference between drug formulation least-squares means (LSM) were
calculated for the parameters AUCo-i, AUCo-inf, and C m using ln-transformed data. The
confidence intervals are expressed as a percentage relative to the LSM of the reference
formulation.
Ratios of means were calculated using the LSM for ln-transformed AUCo-i, AUCo-inf,
and Cmax. The geometric mean values are reported. Ratios of means are expressed as a
percentage of the LSM for the reference formulation.
Bioequivalence is based on the 90% confidence intervals for sildenafil.
Mouth Preparation
Between 1.25 hours (study hour -1.25) and 1 hour (study hour -1) prior to dosing,
including Period I Day - 1 placebo dose, subjects brushed their teeth and tongue with
5 toothpaste provided by the clinical site. After completing the brushing, subjects immediately
rinsed their mouths three times with approximately 80 mL of room temperature water to total
240 mL (8 fluid ounces).
Saliva pH Assessments
Saliva pH was measured at 2300 hours (± 30 minutes) on Day -1, and on Day 1 within
10 30 minutes prior to teeth and tongue brushing, within 30 minutes of completion of teeth and
tongue brushing, and within 15 minutes prior to dosing. For the placebo dose (Day - 1 of
Period I), the saliva pH was measured at 2300 hours (± 30 minutes) on Day -2, and on Day - 1
within 30 minutes prior to teeth and tongue brushing, within 30 minutes of completion of
teeth and tongue brushing, and within 15 minutes prior to placebo dosing. The pH was
15 measured using pH test strips with a range of 5 - 9. Any subject that had a pH of 5 was
additionally tested with pH test strips with a range of 0 - 6.
Oral Spray Administration
Within 30 minutes prior to administration, the spray product bottle was primed by
actuating five sprays according to priming instructions provided by the sponsor prior to study
20 start. A new spray bottle was used for each subject for each dose.
At the time of dosing, subjects were instructed to open their mouths and place their
relaxed tongues against their bottom rows of teeth. Study staff then administered the
appropriate number of sprays according to the randomization schedule.
After dosing, subjects were instructed to close their mouths and place their tongues
25 against their bottom row of teeth for two minutes. Subjects were instructed not to swallow or
swish around the product in their mouth during the two minutes. After two minutes, the
subjects were instructed to swallow and any deviation from this time was recorded. After
swallowing was complete, an objective oral irritation assessment (soft tissue irritation within
the labial or buccal mucosa and tongue) was performed.
30 Reference Product Administration
A single 25 mg dose of Viagra® Tablets ( 1 x 25 mg) was administered on Day 1
dosing with approximately 240 mL (8 fluid ounces) of room temperature water. Site
personnel ensured the entire dose and fluid were swallowed.
Post-Dose Questionnaire
Immediately after dosing was completed and at one hour after dosing, subjects were
queried on the following regarding the test product:
• Taste of the product
• Willingness to take the product again
• Any presence of excessive salivation
If oral irritation persisted beyond one hour, subjects were queried at all irritation
evaluations after one hour with the following: "How does your mouth feel?"
STUDY PROCEDURES
Study Check-In (Day -2 of Period I)
At study check-in, the subjects reported to the clinical site at least 36 hours prior to
Day 1 dosing and were required to stay for 24 hours after Day 1 dosing. The subjects were
evaluated to assess if they continued to meet the study inclusion/exclusion and restriction
criteria. Water was allowed ad libitum during fasting. Supine and standing blood pressure and
heart rate, and an electrocardiogram were collected. A urine sample was collected for a drug
abuse screen.
Subjects began fasting at least ten hours prior to dosing on Day -1. Throughout the
study, standardized meals and beverages were served. Meals were the same in content and
quantity during each confinement period. At 2300 hours (± 30 minutes), saliva pH was
measured prior to nighttime teeth brushing. Subjects were instructed to go to bed after
completing this assessment.
On Day - 1 of Period I only, subjects received three sprays of the placebo test product
at 24 hours prior to Period I Day 1 dosing. Dose preparation and administration were
identical to the test product procedures.
Study Check-In (Day -1 of Periods II, III, & IV)
At study check-in, the subjects reported to the clinical site at least 12 hours prior to
Day 1 dosing and were required to stay for 24 hours after Day 1 dosing. The subjects were
briefly evaluated to assess if they continued to meet the study inclusion/exclusion and
restriction criteria. Water was allowed ad libitum during fasting. Supine and standing blood
pressure and heart rate, and an electrocardiogram were collected. A urine sample was
collected for a drug abuse screen. Subjects began fasting at least ten hours prior to dosing on
Day 1. Throughout the study, standardized meals and beverages were served. Meals were the
same in content and quantity during each confinement period. At 2300 hours (± 30 minutes),
saliva H was measured prior to nighttime teeth brushing. Subjects were instructed to go to
bed after completing this assessment.
Study Day Procedures (Day -1 of Period I)
Prior to placebo dosing, the following activities were completed:
• Measured saliva pH before subject brushed their teeth and the tongue
• Subjects brushed their teeth and tongue prior to dose administration
• Measured saliva pH after subject brushed their teeth and tongue
• Measured saliva pH within 15 minutes prior to dose administration
• Assessed the oral cavity for baseline oral irritation prior to placebo administration
• No fluid was allowed from one hour prior to dose administration until one hour after
dosing.
At 24 hours prior to Day 1 dosing, each subject was dosed sequentially with one dose
(three sprays) of placebo oral spray during Period I for a total of one dose per subject.
After placebo dosing, the following activities were completed:
• Both objective and subjective oral irritation assessments were performed
immediately after dosing and at one hour after placebo dose administration.
• A fast was maintained until at least four hours after placebo dosing. During the study
confinement period, fluid consumption resumed at no sooner than one hour after dose
administration. When fluids are not restricted, they were allowed ad libitum.
• Subjects were not allowed to brush their teeth and tongue for the first two hours after
dosing.
• Lunch was provided at study hour 4.25 after placebo dose administration.
• Dinner was provided at study hour 10.25 after placebo dose administration.
• An evening snack was provided at 10.5 hours prior to dose administration on Day 1.
• At 2300 hours (± 30 minutes), saliva pH was measured prior to nighttime teeth and
tongue brushing. Subjects were instructed to go to bed after completing this
assessment.
• Subjects began fasting at least ten hours prior to dosing on Day 1.
Day l
Prior to dosing, the following activities were completed:
• Collected supine and standing blood pressure and heart rate.
• Measured saliva pH before subject brushed their teeth and the tongue.
• Subjects brushed their teeth and tongue prior to dose administration.
• Measured saliva H after subject brushed their teeth and tongue.
• Collected a pre-dose 0 hour blood sample for pharmacokinetic analysis.
• Measured saliva pH within 15 minutes prior to dose administration.
• Assessed the oral cavity for baseline oral irritation.
• No fluid, except that given with reference drug administration, was allowed from
one hour prior to dose administration until one hour after dosing.
Each subject was dosed sequentially with one dose ( 1 x 14 mg/0.12 mL oral spray, 2 x
14 mg/0.12 mL oral spray, 3 x 14 mg/0.12 mL oral spray, or I x 25 mg tablet) in each of the
four dosing periods for a total of four doses per subject.
After dosing, the following activities were completed:
• Both objective and subjective oral irritation assessments were performed
immediately after dosing and at one hour after dose administration.
• A fast was maintained until at least four hours after dosing. During the study
confinement period, fluid consumption resumed no sooner than one hour after dose
administration. When fluids were not restricted, they were allowed ad libitum.
• Subjects were not allowed to brush their teeth and tongue for the first two hours after
dosing.
• Subjects were closely supervised and within sight of study personnel for four hours
after receiving their initial dose.
• The subjects remained seated upright for the first four hours after dosing, except as
otherwise required for study procedures or personal needs. Subjects were not allowed
to lie down (except as directed by Clinical staff secondary to adverse events) for the
first four hours after dosing. Subjects did not engage in any strenuous activity while
confined to the clinic and followed the rules governing their activities as set forth by
the clinic.
• Lunch was provided at study hour 4.25.
• Dinner was provided at study hour 10.25
• An evening snack was provided at study hour 14.25.
• Blood sample collections were obtained as per the profile.
• Supine and standing blood pressure and heart rate were measured at approximately
one hour after each dose.
• An electrocardiogram was measured at approximately one hour after each dose.
• All subjects were evaluated for the presence of any adverse events.
Day 2
• Blood sample collections were obtained as per the profile.
• Supine and standing blood pressure and heart rate was measured at approximately
24 hours after each dose.
• All subjects were evaluated for the presence of any adverse events prior to release
from the study site.
• Prior to release, subjects were evaluated to ensure it was safe for them to be released
from the study site.
• Subjects were released from the study site at approximately 24 hours after dose
administration.
ORAL IRRITATION ASSESSMENTS
Immediately prior to the first dose (0 hour) of each oral spray treatment, including
placebo administration and at time intervals as specified below, each volunteer's oral cavity
was assessed for local irritation. Local irritation was evaluated relative to the zero hour
observation. Whenever possible, the same evaluator performed all of the evaluations for a
single subject throughout all study periods. If irritation was found, a specific description
defining the location, degree, and extent of irritation was given. Irritation assessment
information and time to irritation resolution was recorded in the CRF.
Irritation Assessment Schedule
Irritation assessments were collected at the following time points: Prior to each oral
spray administration, immediately after swallowing (2 minutes), and at 1 hour post
administration.
If any irritation persisted beyond the one hour assessment, assessments continued every two
hours until resolution up to ten hours post-dose. If irritation was still reported at ten hours, the
subject was assessed by the Investigator as to whether the subject should be discontinued
from the study. Any assessments after one hour also included a subjective evaluation
question.
Irritation Assessment
The examination consisted of a visual inspection/evaluation of the soft tissue for
irritation of the labial and buccal mucosa and tongue. The time and date of these
examinations was recorded. A small flashlight or other similar device was used to facilitate
the examinations. The oral mucosa surfaces, right and left, and labial junctions and tongue
were examined for irritation and graded according to the following classification system.
Irritation Assessment Scale
Numerical Grade Erythema - Oral Mucosa (Left and Right) and Tongue
0 No erythema
1 Very slight erythema (barely perceptible)
2 Slight erythema (edges of area well defined by definite raising)
3 Moderate erythema (raised approximately 1.0 mm)
4 Severe erythema (raised more than 1.0 mm extending beyond the area of
exposure)
STUDY SUBJECTS
Disposition of Subjects
Twenty-eight (28) volunteers checked in for Period I and a total of 24 subjects were
enrolled. The study was conducted with 24 (23 completed) healthy adult males.
Subjects checked into the clinical facility on 30 July 2010 for Period I, on 06 August
2010 for Period II, on 13 August 2010 for Period III, and on 20 August 2010 for Period IV.
Check-in occurred two days prior to dose administration for Period I and one day prior to
dose administration for Periods II, III, and IV. The subjects remained confined at the clinical
facility until after the 24-hour blood sample collection of each period.
Table 6.1-1 presents all discontinued subjects, the reason(s) for discontinuation, and time
points during the study at which each subject was discontinued.
Table 6.1-1 Discontinued Subjects
Table 6.1-2 presents the number of subjects who were randomized according to each
treatment sequence and the post-randomization discontinuation that occurred over the
of the study.
Table 6.1-3 presents the summary of subject disposition by study period.
Table 6.1-2 Summary of Subject Disposition by Sequence
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
5 Treatment D: Viagra® tablets 25 mg
Table 6.1-3 Summary of Subject Disposition by Study Period
PHARMACOKINETIC EVALUATIONS
Data Sets Analyzed
Twenty-four (24) subjects were enrolled in the study and all subjects were healthy
10 adults.
Twenty-four (24) subjects began the study and 23 subjects completed the clinical portion of
the study in its entirety.
Data for all 24 subjects were used in the statistical analysis for sildenafil and N-
15 desmethylsildenafil for the Test Product A ( 1 Spray; 10 mg) versus Reference Product D ( 1
Tablet, 25 mg) comparisons and Test Product C (3 Sprays; 30 mg) versus Reference Product
D ( 1 Tablet, 25 mg) comparisons. Subject 24 elected to withdraw from the study prior to
Period IV check-in due to a schedule conflict. Data for 23 of 24 subjects were used in the
statistical analysis for sildenafil and N-desmethylsildenafil for the Test Product B (2 Sprays;
20 20 mg) versus Reference Product D ( 1 Tablet, 25 mg) comparisons. Actual times were used
in the calculation of pharmacokinetic parameters.
Bioanalytical Method Summary
The bioanalytical laboratory of Cetero Research - Toronto determined the sildenafil
25 and N-desmethylsildenafil plasma concentrations. The analysis was performed on a
Micromass Quattro Ultima LC/MS/MS system, equipped with Z-spray. The positive ions
were measured in MRM mode. The analyte was quantitated using a liquid-liquid extraction
procedure. Following extraction, a 20 aliquot was injected onto an LC/MSBVIS system.
The data was acquired by, and calculated on, Micromass "Mass lynx" software version 4.1.
Linear regression with 1/x2 weighting was used to obtain the best fit of the data for the
calibration curve. The lower limit of quantitation (LLOQ) was 1.000/0.2500 ng/mL and the
upper limit of quantitation (ULOQ) was 300.0/75.00 ng/mL for sildenafill Ndesmethylsildenafil.
Calibration curve standards and quality control (QC) samples for
sildenafil and N-desmethyl sildenafil met the acceptance criteria for the runs used for the final
data, demonstrating satisfactory performance of the method during the analysis of study
subject samples.
Pharmacokinetic Results and Tabulations of Individual Subject Data
Statistical Analytical Issues
The pharmacokinetic parameters were calculated using WinNonlin®, Version 5.0.1,
software designed specifically for analyzing pharmacokinetic data. WinNonlin® Model 200
for extravascular input was utilized.
An Analysis of Variance (ANOV A) was performed on each of the pharmacokinetic
parameters using SAS® software. The ANOV A model containing factors for sequence of
products, subjects within sequence, periods and products was utilized in comparing the
effects between the test and reference products.
Handling of Dropouts or Missing Data
Plasma level data from subjects who completed the study were included in the final data
analysis. Plasma level data from subjects who withdrew or were discontinued for any reason
were not used in the final analysis. Data from subjects with missing concentration values
(e.g., missed blood draws, lost samples, samples unable to be quantified) were used if
pharmacokinetic parameters could be estimated using remaining data points; otherwise, data
from these subjects were excluded from the final analysis.
Pharmacokinetic Results
Sildenafil (Non-Dose-Adjusted)
Table 7.2.6.1-1 summarizes the non-dose-adjusted sildenafil pharmacokinetic parameters for
each product using noncompartmental analysis.
Table 7.2.6.1-1 Summary Statistics and Pharmacokinetic Parameter Values for Non-
Dose-Adjusted Sildenafil Data for the Noncompartmental Analysis
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Overall, plasma sildenafil concentrations were well characterized at the 10 mg, 20
mg, and 30 mg oral spray doses and at the 25 mg oral tablet dose, and declined in a
monoexponential manner following oral sprays and oral tablet administration in healthy adult
male volunteers.
In general, when oral spray sildenafil 10 mg, 20 mg, and 30 mg test products were
administered to healthy adult males, the overall extent of sildenafil exposure and peak plasma
concentrations, as assessed by mean AUC and Cm , respectively, increased proportionally
with increasing doses from 10 mg to 30 mg. For all treatments, maximum sildenafil
concentrations tended to be rapidly reached by approximately 1.00 hour after dose. The mean
terminal half-lives values were, in general, similar for all four treatments, with estimated
mean half-lives between 2.25 and 3.14 hours.
Tables 7.2.6.1-2, 7.2.6.1-3, and 7.2.6.1-4 summarize the results of the analyses
performed on the pharmacokinetic parameters for non-dose-adjusted sildenafil.
Table 7.2.6.1-2 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Non-Dose Adjusted Sildenafil Data for Test Product
A (1 Spray; 10 mg) versus Reference Product D (2 mg); (N = 24)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment D: Viagra@ tablets 25 mg
Table 7.2.6.1-3 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Non-Dose Adjusted Sildenafil Data for Test Product
B (2 Sprays; 20 mg) versus Reference Product D (25 mg); ( = 23)
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.1-4 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Non-Dose Adjusted Sildenafil Data for Test Product
C (3 Sprays; 30 mg) versus Reference Product D (25 mg); (N = 24)
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
When PK parameters AUC and Cm for oral spray products Test A (10 mg), Test B
(20 mg), and Test C (30 mg) were not dose-adjusted to the Reference D tablet (25 mg), the
relative bioavailability of sildenafil in the test oral spray products as compared to the
reference tablet product demonstrated that:
• The non-dose adjusted AUCs of sildenafil for the 2 spray (20 mg dose) Test B
product were comparable to the 25 mg tablet Reference D product. The point estimate for
Cm was approximately 15% lower than the 25 mg Reference D tablet and the lower limit of
the 90% CI for Cmax was only slightly below the lower acceptance range at 75.40%.
• As expected, the AUCs and C values for the 1 spray (10 mg dose) Test A product
were significantly lower, and for the 3 spray (30 mg dose) Test C product were
significantly higher than the Reference D product (25 mg tablet).
Sildenafil (Dose-Adjusted)
Table 7.2.6.2-1 presents a summary of the dose-adjusted sildenafil pharmacokinetic
parameters for each product using noncompartmental analysis.
Table 7.2.6.2-1 Summary Statistics and Pharmacokinetic Parameter Values for Dose-
Adjusted Sildenafil Data for the Noncompartmental Analysis
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
The dose-adjusted C for the sildenafil oral spray products Test A (10 mg), Test B
(20 mg), and Test C (30 mg) was comparable to the Reference D tablet (25 mg), whereas
overall extent of sildenafil exposure as assessed by dose-adjusted AUC was consistently
higher than the Reference D tablet (25 mg) with AUCo range of 328 to 344 ng-hr/mL for the
oral spray compared to 294 ng-hr/mL for the reference 25 mg tablet and with AUC o range
of 334 to 356 ng-hr/mL for the oral spray compared to 301 ng-hrlmL for the reference 25 mg
tablet.
The peak plasma concentrations, as assessed by „ , were comparable across all test
doses (oral spray of 10 mg, 20 mg, and 30 mg) to the reference dose (oral tablet of 25 mg).
For all treatments, the peak plasma concentrations ranged from 103.26 ng/mL - 111 .19
ng/mL.
Tables 7.2.6.2-2, 7.2.6.2-3, and 7.2.6.2-4 summarize the results of the analyses
performed on the pharmacokinetic parameters for dose-adjusted sildenafil.
Table 7.2.6.2-2 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Dose-Adjusted Sildenafil Data for Test Product A
(1 Spray; 10 mg) versus Reference Product D (25 mg); (N = 24)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.2-3 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Dose-Adjusted Sildenafil Data for Test Product B
(2 Sprays; 20 mg) versus Reference Product D (25 mg); (N = 23)
Treatment B: Sildenafil Citrate Oral Spray .55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Treatment C: Sildenafil Citrate Oral Spray .55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
When PK parameters AUC and Cm for oral spray products Test A (10 mg), Test B
(20 mg), and Test C (30 mg) were dose-adjusted to the Reference D tablet (25 mg), the
relative bioavailability of sildenafil in the test oral spray products as compared to the
reference tablet product demonstrated that:
• The dose-adjusted C x values of sildenafil for the 10 mg, 20 mg, and 30 mg oral
spray products were comparable to the Reference D product (25 mg tablet) and all
were within the 90% CI.
• The Test/Reference ratio point estimates for the dose-adjusted AUCo for all the
sildenafil oral spray doses were approximately 114 % to 121 %. The upper limit of the
90 % CI was 124 % for Test A (10 mg) and Test C (30 mg) doses, just below the
125% upper limit. The Test/Reference ratio point estimates for the dose-adjusted
AUCo for all the sildenafil oral spray doses were approximately 112 % to 121%. The
upper limit of the 90 % CI was 123 % for Test A (10 mg) and 125 % for Test C (30
mg) doses. For the Test B (20 mg) oral spray, the point estimates for AUCs were
approximately 21% higher and the 90% CI for AUCs were above the upper
acceptance range at 132 %.
These data indicate that the overall systemic sildenafil exposure for the oral spray test
product is more systemically bioavailable than the 25 mg oral tablet reference product, likely
due to avoiding first pass metabolism through transmucosal absorption.
N-desmethylsildenafil (Non-Dose- Adjusted)
Table 7.2.6.3-1 presents a summary of the non-dose-adjusted N-desmethylsildenafil
pharmacokinetic parameters for each product using noncompartmental analysis.
Table 7.2.6.3-1 Summary Statistics and Pharmacokinetic Parameter Values for Non-
Dose-Adjusted N-desmethylsildenafil Data for the Noncompartmental
Analysis
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
In general, the overall extent of N-desmethylsildenafil exposure and peak plasma
concentrations for oral spray products Test A (10 mg), Test B (20 mg), and Test C (30 mg),
as assessed by mean AUCs and Cm , increased proportionally with increasing doses from 10
mg to 30 mg. For all doses of the sildenafil oral spray treatments, the time to reach maximum
N-desmethylsildenafil concentrations was slightly slower than the oral tablet reference
product Tm of 0.75 hours; however, the ranges of T x for all test sildenafil oral sprays and
the reference oral tablet were similar. The mean terminal half-life values were, in general,
similar for all four treatments.
Tables 7.2.6.3-2, 7.2.6.3-3, and 7.2.6.3-4 summarize the results of the analyses
performed on the pharmacokinetic parameters for non-dose-adjusted N-desmethylsildenafil.
Table 7.2.6.3-2 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil Data for Test Product A (1
Spray; 10 mg) versus Reference Product D (25 mg); (N - 24)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.3-3 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil Data for Test Product B (2
Sprays; 20 mg) versus Reference Product D (25 mg); (N = 23)
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.3.4 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil Data for Test Product C (3
Sprays; 30 mg) versus Reference Product D (25 mg); (N = 24)
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
When N-desmethylsildenafil PK parameters AUC and Cmili for oral spray products
Test A (10 mg), Test B (20 mg), and Test C (30 mg) were not dose-adjusted to the Reference
D tablet (25 mg), the relative bioavailability of N-desmethylsildenafil in the test oral spray
products as compared to the reference tablet product demonstrated that:
• The point estimates for non-dose-adjusted AUCs of N-desmethylsildenafil between
the 10 mg, 20 mg, and 30 mg test oral spray doses were, in general, comparable to the
difference to the 25 mg reference tablet.
• The point estimates for Cmax between the 10 mg, 20 mg, and 30 mg test oral spray
doses were generally less than the difference to the 25 mg reference oral tablet.
N-desmethylsildenafil (Dose- Adjusted)
Table 7.2.6.4-1 presents a summary of the dose-adjusted N-desmethylsildenafil
pharmacokinetic parameters for each product using noncompartmental analysis.
Table 7.2.6.4-1 Summary Statistics and Pharmacokinetic Parameter Values for Dose-
Adjusted N-desmethylsildenafil Data for the Noncompartmental
Analysis
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to to mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
After dose-adjusting the PK parameters AUC and Cmili of N-desmethylsildenafil for
oral spray products Test A (10 mg), Test B (20 mg), and Test C (30 mg) to the Reference D
tablet (25 mg), the overall extent of exposure of N-desmethylsildenafil, as assessed by AUC,
shows a trend to slightly increase with increasing doses from 10 mg to 30 mg. However, the
dose-adjusted peak N-desmethylsildenafil plasma concentrations, as assessed by C x, were
similar for the test oral spray doses of 20 mg and 30 mg, but slightly less for the test oral
spray dose of 10 mg. For all four products, the peak plasma concentrations ranged from 21.94
ng/niL - 29.04 ng/niL.
Tables 7.2.6.4-2, 7.2.6.4-3, and 7.2.6.4-4 summarize the results of the analyses performed on the
pharmacokinetic parameters for dose-adjusted N-desmethylsildenafil.
Table 7.2.6.4-2 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Dose-Adjusted Ln-Transformed N-desmethylsildenafil Data for Test
Product A (1 Spray; 10 mg) versus Reference Product D (25 mg);
(N= 24)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.4-3 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Dose-Adjusted N-desmethylsildenafll Data for Test
Product (2 Sprays; 20 mg) versus Reference Product D (25 g);
( = 23)
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.4-4 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed Dose-Adjusted N-desmethylsildenafil Data for Test
Product C (3 Sprays; 30 mg) versus Reference Product D (25 mg);
( = 24)
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
After dose-adjusting the PK parameters AUC and Cma of N-desmethylsildenafil for
oral spray products Test A (10 mg), Test B (20 mg), and Test C (30 mg) to the Reference D
tablet (25 mg), the PK and statistical results demonstrated that, with the exception of the C
for the test oral spray 10 mg and 20 mg doses, the AUCs and C values were all within the
90 % CI criteria of 80 %-125 %.
Dose Proportionality
The results for dose proportionality at doses of single 10 mg, 20 mg, and 30 mg oral
spray administrations of sildenafil demonstrate that, while the AUCi„f increases linearly with
dose, it does not do so in exactly a dose proportional manner; specifically, a slightly greater
than dose-proportional increase is observed. As the results in the Table 7.2.6.5-1 demonstrate,
a mean 2.24 and 3.13 fold increase in AUCi„f is observed from 1 to 2 sprays and 1 to 3
sprays, respectively. Similar greater than non-proportional dose results following single oral
dose administration of sildenafil tablets in healthy male volunteers have been reported by
Nichols et al. and, as noted in that study and in this study, the extent of this nonproportionality
is unlikely to be clinically significant.
Table 7.2.6.5-1 Dose Proportionality for Sildenafil Test Oral Spray
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w (1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil)
Metabolite/ Parent Ratio (N-desmethylsildenafil/Sildenafil Ratio)
Table 7.2.6.6-1 summarizes the Metabolite/ Parent Ratio (N-desmethylsildenafil/
Sildenafil) pharmacokinetic parameters for each treatment test product.
Table 7.2.6.6-1 Summary Statistics and Pharmacokinetic Parameter Values for
Metabolite/ Parent Ratio (N-desmethylsildenafil/ Sildenafil)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Tables 7.2.6.6-2, 7.2.6.6-3, and 7.2.6.6-4 summarize the results of the analyses
performed on the pharmacokinetic parameters for N-desmethylsildenafil/Sildenafil Ratio.
Table 7.2.6.6-2 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil/ Sildenafil Ratio for Test
Product A (1 Spray; 10 mg) versus Reference Product D (25 mg);
( = 24)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.6-3 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil/ Sildenafil Ratio for Test
Product B (2 Sprays; 20 mg) versus Reference Product D (25 mg);
(N = 23)
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Table 7.2.6.6-4 Geometric Means, Ratios of Means, and 90% Confidence Intervals of
Ln-Transformed N-desmethylsildenafil/ Sildenafil Ratio for Test
Product C (3 Sprays; 30 mg) versus Reference Product D (25 mg);
(N = 24)
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Overall, the results of metabolite to parent (M/P) ratios analysis demonstrated that the
formation of the metabolite, as assessed by the M/P ratios for the Test A (10 mg) and Test B
(20 mg) oral spray doses were less than the M/P ratio of the Reference D (25 mg) tablet,
whereas the M/P ratios for the Test C (30 mg) oral spray dose were comparable to the M/P
ratios observed for the Reference D (25 mg) tablet.
The M/P ratio for each concentration time point was calculated for each treatment and
plotted versus time to visually assess the rate of formation of metabolite. This was done up to
four hours post-dose. This plot is shown in Figure 7.2.6.6-1. It can be noted that there was an
immediate peak in the M/P ratio for the reference oral tablet, whereas the M/P ratio with time
for all doses of the test oral spray doses were significantly slower than the reference tablet.
This observation indicates that there is a marked decrease in the rate of metabolite formation
in the test oral spray products compared to the reference oral tablet product and indicative
that the test oral spray is, for the most part, bypassing first pass metabolism due to
transmucosal absorption.
Saliva pH Assessments
The transmucosal absorption of drugs may be dependent on the pH of the oral cavity
when administered to patients. Therefore, in this study saliva pH was measured in healthy
male adult volunteers at 2300 hours (± 30 minutes) on Day - 1 and on Day 1 within 30
minutes prior to teeth and tongue brushing. There was minimal change in saliva pH pre- and
post-teeth and tongue brushing. Saliva pH was then measured within 30 minutes of
completion of teeth and tongue brushing (~ 45 minutes pre-dose), and within 15 minutes prior
to dosing. The pH was measured using pH test strips with a range of 5-9. No subject had a pH
of 5, therefore, there was no additional testing with pH test strips with a range of 0-6. There
were no appreciable differences found in saliva pH between treatments or periods at 45
minutes and 15 minutes prior to dose administration, as shown in the Table 7.2.7-1.
Table 7.2.7-1 Summary of Mean Saliva pH by Treatment and by Period
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil);
Treatment D: Viagra® tablets 25 mg
Post-Dose Questionnaire
Immediately after dosing was completed (2 minutes) and at 1 hour after dosing,
subjects were queried on the following regarding the test product (oral spray):
• Taste of the product
• Willingness to take the product again
• Any presence of excessive salivation
Table 7.2.8-1 Summary of Taste Questionnaire Results
Test A (1 Spray) Test B (2 Sprays) Test C (3 Sprays)
After 1 hour After 1 hour After 1 hour
swallowing post-dose swallowing post-dose swallowing post-dose
Mean taste score ( 1 = bad: 5 = very good)
2.2 3.0 1.9 3.0 1.8 2.9
Willingness to take the product again (%Affirmative responses)
79% 92% 74% 87% 63% 75%
Presence of any excessive salivation [Affirmative responses (%)]
6 of 4 (25%) 3 of 24 (12.5%) 9 of 23 (39%) 3 of 23 (13%) 12 of 24 (50%) 2 of 24 (8%)
Treatment A: Sildenafil Citrate Oral Spray 11.55% w/w ( 1 spray, equivalent to 10 mg sildenafil);
Treatment B: Sildenafil Citrate Oral Spray 11.55% w/w (2 sprays, equivalent to 20 mg sildenafil);
Treatment C: Sildenafil Citrate Oral Spray 11.55% w/w (3 sprays, equivalent to 30 mg sildenafil)
Oral Irritation Assessment
The examination consisted of a visual inspection/evaluation of the soft tissue for
irritation of the labial and buccal mucosa and tongue. The oral mucosal surfaces, right and
left, and labial junctions and tongue were examined for irritation and graded according to the
following classification system described below.
Numerical Grade Erythema - Oral Mucosa (Left and Right) and Tongue
0 No erythema
1 Very slight erythema (barely perceptible)
2 Slight erythema (edges of area well defined by definite raising)
3 Moderate erythema (raised approximately 1.0 mm)
4 Severe erythema (raised more than 1.0 mm extending beyond the area of
exposure)
Evaluation of soft tissue irritation within the labial or buccal mucosa and of the
tongue were done after both active and placebo dosing. Irritation assessments were collected
at the following time points: Prior to each oral spray administration, immediately after
swallowing (2 minutes), and at 1 hour post administration. If any irritation persisted beyond
the one hour assessment, assessments continued every two hours until resolution up to ten
hours post-dose. If irritation was still reported at ten hours, the subject was assessed by the
Investigator as to whether the subject should be discontinued from the study. Any
assessments after one hour also included a subjective evaluation question.
The results of the oral irritation assessment found no oral irritation following
administration of placebo (3 sprays). Additionally, no oral irritation was found following
administration of Test A ( 1 spray), Test B (2 sprays), or Test C (3 sprays), when observed
immediately after administration (held for two minutes, then swallowed), and when observed
at 1 hour post-dose.
DISCUSSION
The dose-adjusted C values of sildenafil for oral spray products Test A (10 mg),
Test B (20 mg), and Test C (30 mg) were, in general, comparable to the Reference D (25 mg)
oral tablet. The Test/Reference ratio point estimates for the dose-adjusted AUCs for all the
sildenafil oral spray doses were approximately 112 % to 121 % and the 90 % CI for AUCs
were 124 % to 132 % with an upper acceptance range of 125 %. In addition, the non-doseadjusted
point estimates for AUCs for the Test B 2 spray dose (20 mg) oral spray were
approximately 97 %, demonstrating comparable bioavailability to the Reference D (25 mg)
oral tablet. These data indicate that the overall sildenafil exposure for the test oral spray
product is more systemically bioavailable than the reference oral tablet, likely due to avoiding
first pass metabolism through transmucosal absorption.
Sildenafil is known to be metabolized to its major metabolite N-desmethyl sildenafil
through first pass metabolism by more than 50 % [absolute bioavailability is 4 1 % (range 25-
63 %)]. The pharmacokinetic and statistical results following administration of the sildenafil
oral spray in healthy adult male subjects demonstrated increased systemic exposure that can
reasonably be attributed to oral transmucosal absorption processes.
The assessment of M/P ratio (metabolite (N-desmethylsildenafil) to parent (sildenafil)
ratio) for the oral spray products Test A (10 mg), Test B (20 mg), and Test C (30 mg) as
compared to the Reference D (25 mg) oral tablet demonstrated differences in the rate of
formation of the metabolite indicative of trans mucosal absorption.
There was minimal change found in the mean saliva pH between treatments and
periods in this study, therefore subject saliva pH was not likely a contributing factor in the
apparent transmucosal absorption observed following the oral spray administration.
There was no oral irritation observed in any of the subjects following administration
of sildenafil oral spray placebo or active doses (up to 3 sprays, 30 mg dose).
Overall, sildenafil citrate was well tolerated in doses of 10 mg, 20 mg, 30 mg, and
was well tolerated as a single oral dose of 25 mg ( 1 x 25 mg tablet) administered to healthy
adult subjects under fed conditions.
EXAMPLE 4
OBJECTIVE
The objective of the following was to evaluate the partial AUC exposures of sildenafil
in the first, fourth, twelfth and twenty-fourth hour (AUCo-i, AUC0 AUCo and AUCo
for the 10, 20 and 30 mg Test oral spray products to that of the 25 mg tablet Reference
product of sildenafil.
STUDY DESIGN
A randomized, four-way crossover design was used in this study to compare the
relative bioavailability (rate and extent of absorption) of one test product at three different
dose levels (10 mg, 20 mg, and 30 mg) with one reference product under fasting conditions.
In this study, one test formulation at three different dose levels (10 mg, 20 mg, and 30 mg of
an oral dose of Sildenafil Citrate Oral Spray 14 mg/0.12 mL were compared with VIAGRA®
25 mg Tablets.
Twenty-four healthy male adult subjects and no alternates were randomly assigned to
one of four sequences of the following products:
Test Product (A): Sildenafil Citrate Oral Spray 11.55% w/w;
( 1 Spray; 10 mg)
Test Product (B): Sildenafil Citrate Oral Spray 11.55% w/w;
(2 Spray; 20 mg)
Test Product (C): Sildenafil Citrate Oral Spray 11.55% w/w;
(3 Spray; 30 mg)
Reference Product (D): Viagra® tablets 25 mg;
The four sequences were as follows:
Sequence 1 = ABC D
Sequence 2 = B D A C
Sequence 3 = CAD B
Sequence 4 = D C B A
A single oral dose of test or reference product was administered to volunteers on four
separate occasions under fasting conditions with at least a 3-day washout period between
doses. Food and fluid intake were controlled during each confinement period.
The pharmacokinetic parameters for both non-dose adjusted and dose adjusted AUC o-
AUC AVC d AUC of sildenafil and its metabolite, N-desmethylsildenafil
were calculated using WinNonlin®, Version 5.0.1, software designed specifically for
analyzing pharmacokinetic data. WinNonlin® Model 200 for extravascular input was
utilized.
An analysis of variance (ANOVA) was performed on each ofthe partial AVC
AUC AUC and AUC pharmacokinetic parameters using SAS® software. The
ANOVA model containing factors for sequence of products, subjects within sequence,
periods and products was utilized in comparing the effects between the test and reference
products. AUCo calculation for majority of the subjects could not be calculated due to BLQ
concentration values at hour 24.
PHARMACOKINETIC RESULTS AND DISCUSSION
Table 1 presents a summary of the sildenafil pharmacokinetic parameters for each
product using noncompartmental analysis.
Table 1 Summary Statistics and Partial AUC Values for Non-Dose Adjusted
Sildenafil
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 1.1.1 - 1.1.4
In general, when oral spray sildenafil 10, 20 and 30 mg Test products were
administered to healthy adult males, the partial extent of sildenafil exposure as assessed by
non-dose adjusted AUC -i , AUC and AUC increased proportionally with increasing
doses.
The non-dose adjusted partial, AUCs of sildenafil Oral Spray and the Reference
Tablet as presented in Table 1 demonstrates that partial AUC AUC AUC d AUC
is consistent with the AUCo-tand AUCo (Table 7.2.6.1-1) difference observed between
the oral spray and reference tablet with the 2 spray 20 mg dose having essential the same
AUC as the 25 mg reference tablet.
Tables 2, 3, and 4 summarize the statistical results of the analyses performed on the
partial AUC intervals for non-dose adjusted sildenafil.
Table 2 Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product A
1 S ra 10 m vs. Reference Product 25 m
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 1.2.1
Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product B
2 S ra 20 m vs. Reference Product 25 m
· * Not calculated due to BLQ at th 24 hour time point
Source: Tables 1.2.2
Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product C
3 S r a 30 m vs. Reference Product 25 m
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 1.2.3
When PK parameters AUC o-i, AUC AUC for oral spray products Test A (10
mg), Test B (20 mg), and Test C (30 mg) were not dose-adjusted to the Reference D tablet
(25 mg), statistical results for partial extent of sildenafil exposure from 0 to 1, 4, 12 and 24
hours in the test oral spray products as compared to the reference tablet product demonstrated
that:
- there was a significant difference for partial AUC AUC AUC for nondose
adjusted Test product A ( 1 oral spray, 10 mg dose) of sildenafil as compared
to the 25 mg tablet Reference D product. The extent of sildenafil exposure as
calculated to one hour (AUC was approximately 63 % lower while AUC
calculated to 4 and 12 hours were approximately 55 % lower, respectively, than
the Tablet Reference product consistent with the dose difference. (Refer to Table
2).
- the extent of exposure as calculated to 4 and 12 hrs (for non-dose adjusted AUC
AUC Test product B (2 oral sprays, 20 mg dose) were comparable to the
25 mg tablet Reference D product as these values were within the 90 % CI.
However, partial AUC calculated to 1 hr was not contained within the 90 % CI,
although the point estimate was only slightly lower at approximately 10 %. (As
presented in Table 3).
- for Test Product C, 30 mg oral spray product, the non-dose adjusted partial
AUC AUC AUC of sildenafil was in general, reflective of the
difference in dose from the 25 mg tablet Reference product (approximately 16,34
and 37 % higher, respectively) and all the values calculated for partial AUC from
0 to 1, 4 and 12 hrs were not within the 90 % CI (Refer to Table 4).
Sildenafil (Dose Adjusted)
Table 5 presents a summary of the dose adjusted sildenafil pharmacokinetic
parameters for each product using noncompartmental analysis.
Table 5 Summary Statistics and Partial AUC Values for Dose- Adjusted to
25 mg Sildenafil
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 2.1.1 -2.1.4
Statistical results presented in Table 5 for dose-adjusted partial PK parameters AUC
AUC AUC and AUC demonstrates that:
» the dose adjusted AUC for the sildenafil oral spray 10, 20 and 30 mg were in
general comparable to the 25 mg Reference Tablet Sildenafil
» in general partial AUC calculated from 0 to 12 hrs for all 3 oral spray Test
products of sildenafil was slightly higher than the 25 mg Reference tablet
product (by approximately 11 to 19%. respectively).
» these results indicate that the partial extent of sildenafil exposure calculated for
the first hour (AUC o-i) were lower and for the next 4 hours (AUC0 -4) comparable
but then higher when calculated to 12 hrs (AUCo-12) for all the oral spray Test
products as compared to the oral tablet Reference product.
Tables, 6, 7 and 8 summarize the results ofthe analyses performed on the
pharmacokinetic parameters for dose adjusted sildenafil.
Tabic 6 Summary of Statistical Analysis Partial AUC Dose Adjusted Test
Product A
1 S ra 10 m vs. Reference Product 25 m
* Not calculated due to BLQ at the 24 hour time point
Source: Tables 2.2.1
Summary of Statistical Analysis Partial AUC Dose Adjusted Test
ProductB
(2 Spray; 20 mg) vs. Reference Product (25 mg)
Not calculated due to BLQ at the 24 hour time point
Source: Tables 22.2
Summary of Statistical Analysis Partial AUC Dose Adjusted Test
Product C.
(3 Spray; 30 mg) vs. Reference Product (25 mg)
** Not calculated due to BL at the 24 hour time point
When PK parameters partial AUC AUC and AUC for sildenafil were dose
adjusted to the 25 mg Reference Tablet formulation the partial systemic exposure of
sildenafil in the oral spray products as compared to the Reference 25 mg tablet formulation
demonstrated that (refer to Tables 6 to 8):
~ the values of dose adjusted AUC calculated from 0 to 4 and to 12 hours of
sildenafil for the 10 mg and 30 mg oral spray products were in general,
comparable to the 25 mg tablet Reference product and were within the 90 % CI.,
The 20 mg Test product B which was slightly higher compared to the 25 mg
tablet Reference product and was not within the 90% CI.
~ the values obtained for partial AUC calculated from 0 to 1 hr were, in general,
not within the 90 % CI indicating that partial extent of sildenafil exposure
calculated to 1 hour for all oral spray Test products were not comparable to the
25 mg tablet Reference product.
~ as the % Test / Reference point estimates indicate, the partial systemic sildenafil
exposure at AUC AUC and AUC for the 20 mg oral spray (Test Product
B) was slightly more systemically bioavailable than the oral 25 mg reference
tablet ( 112 % vs 119.5% vs 121.3 %, respectively).
N-desmethylsildenafil Partial AUC (Non-Dose Adjusted)
Table 9 presents a summary of the N-desmethylsildenafil partial AUC for each
product using noncompartmental analysis.
Table 9 Summary Statistics and Partial AUCValuesfor Non-Dose Adjusted
N-desmethylsildenafil
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 3.1.1 -3.1.4
Statistical results as presented in Table 9 for non-dose adjusted partial AUC
parameters AUC o-i, AUC o-4, AUC 0-12 and AUC 0-24 of the metabolite Ndesmethylsildenafil,
demonstrates that :
~ in general, for all doses of the sildenafil oral spray product, the extent of
N-desmethylsildenafil exposure as assessed by partial AUC calculated from 0 to
4 and 12 hours, increased proportionally with increasing doses from 10 to 30 mg.
~ in general the differences found between the N-desmethylsildenafil partial AUC
were consistent with the dose difference of the oral spray and 25 mg reference
tablet.
Tables 10, 11, and 12 summarize the results of the analyses performed on the partial
AUC parameters for non-dose adjusted N-desmethylsildenafil.
Table 10 Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product
1 S ra 10 m vs. Reference Product 25 m
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 3.2.1
Table 11 Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product
2 S ra 20 m vs. Reference Product 25 m
Source: Tables 3.2.2
Table 12 Summary of Statistical Analysis Partial AUC Non-Dose Adjusted Test
Product
3 S ra 30 m vs. Reference Product 25 m
Source: Tables 3.2.3
The non-dose adjusted to the 25 mg reference tablet N-desmethylsildenafil partial
AUC AUC AUC d AUC of the oral spray doses as compared to the
Reference 25 mg tablet formulation demonstrated that:
» the point estimates for non-dose adjusted partial AUC as calculated from 0 to
1 hour (AUC0-1) of N-desmethylsildenafil for the 10, 20 and 30 mg oral spray
doses were in general, lower to the difference in doses to the 25 mg tablet
reference tablet
» the point estimates for partial AUC as calculated to 4, 12 and 24 hours for the
10 mg and 20 mg oral spray doses were generally consistent with the difference
in mg dose to the 25 mg oral tablet
N-desmethylsildenafil Partial AUC (Dose Adjusted)
Table 13 presents a summary of the dose adjusted N-desmethylsildenafil
pharmacokinetic parameters for each product using noncompartmental analysis.
Table 13 Summary Statistics and Partial AUC Values for Dose- Adjusted to
25 mg N-desmethylsildenafil
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 4.1.1 -4.1.4
After dose adjusting the partial AUC0-1for the 10, 20 and 30 mg oral spray doses,
were found to be less than the 25 mg oral tablet dose.
The dose- adjusted AUCs calculated from 0 to 4 and 12 hours for the metabolite of
Test products A, B and C were in general, comparable while no specific trend was observed
for AUCo for all the oral spray Test products to the Reference Tablet product.
Tables 14, 15, 16 summarize the results of the analyses performed on the partial AUC
for dose adjusted N-desmethylsildenafil.
Summary of Statistical Analysis Partial AUC Dose Adjusted Test
Product A
1 S ra 10 m vs. Reference Product 25 m
" * Not calculated due to BLQ at the 24 hour time point
Source: Tables 4.2.1
Summary of Statistical Analysis Partial AUC Dose Adjusted Test
Product B
2 S ra 20 m vs. Reference Product 25 m
Source: Tables 42.2
Table 16 Summary of Statistical Analysis Partial AUC Dose Adjusted Test
Product C
3 S ra 30 m vs. Reference Product 25 m
Source: Tables 4.2.3
When comparing the dose adjusted partial AUC o-i, AUC o-4, AUC 0-12 and AUC 0-24
N-desmethylsildenafil for the oral spray doses, the pharmacokinetic and statistical results
for the N-desmethylsildenafil demonstrated that:
~ for the 1 spray (10 mg dose), 2 spray (20 mg dose) and 3 spray (30 mg dose) the
AUC values ofthe metabolite as calculated to 4 and 12 hours were in general, all
within the 90 % CI criteria of 80-125 % and therefore considered comparable to
the 25 mg tablet Reference product.
~ the values obtained for partial AUC calculated to the first hour demonstrated
that, in general for all oral spray Test products, values for AUCo-iwere
substantially lower than the tablet Reference product.
Metabolite/Parent Ratio Partial AUC (N-desmethylsiidenafil/Sildenafil Ratio)
Table 17 presents a summary of the Metabolite/Parent Ratio (Ndesmethylsildenafil/
Sildenafil) pharmacokinetic parameters for each product.
Summary Statistics and Partial AUC Values for Metabolite/Parent
Ratio (N-desmethylsildenafil/Sildenafil)
· * Not calculated due to BLQ at the 24 hour time point
Source: Tables 5.1.1 -5.1.4
Tables 18, 19, and 20 summarize the results ofthe analyses performed on the
pharmacokinetic parameters for N-desmethly1sildenafil/Sildenafil Ratio.
Table 18 Summary of Statistical Analysis Partial AUC M/P Ratio Test Product
1 S ra 10 m vs. Reference Product 25 m
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 5.2.1
Table 19 Summary of Statistical Analysis Partial AUC M/P Ratio Test Product
2 S ra 20 m vs. Reference Product 25 m
** Not calculated due to BLQ at the 24 hour time point
Source: Tables 5.2.2
Source: Tables 5.2.3
Overall, the formation of the metabolite as assessed by the M/P ratio for the 10, 20
and 30 mg oral spray doses demonstrates that the most substantive difference was seen for
AUC (0-1) interval. These differences were also essentially independent of the Test as dose
( 1 spray, 2 sprays and 3 sprays) as only minimal differences were seen between numbers of
sprays. There was essentially no difference in partial AUC M/P ratio seen for the AUC and
AUC hour intervals.
DISCUSSION
The partial AUC assessment indicates that the most substantive difference between
the sildenafil OS and the reference Viagra® tablet occurs at AUC (0-1) interval. There are
then no substantive differences found in the partial AUC intervals 0-4, 0-12 and 0-24
between
the test OS and the reference tablet. This was again demonstrated with the ratio of
metabolite/parent where the most substantive difference is seen for AUC (0-1) interval.
These differences were also essentially independent ofthe sildenafil OS dose ( 1 spray, 2
sprays and 3 sprays).
REFERENCES
Food and Drug Administration. Guidance for Industry: Bioavailability and
Bioequivalence Studies for Orally Administered Drug Products - General Considerations.
Center for Drug Evaluation and Research, March 2003.
Chow, S.C. and. J.P. Liu. Design and Analysis of Bioavailability and Bioequivalence
Studies, Second Edition, Revised and Expanded. New York: Marcel Dekker, Inc., 2000.
Pharsight Corporation. WinNonlin® User's Guide. Pharsight Corporation, 1998-2005.
SAS Institute, Inc. SAS OnlineDoc®, Version 9.1. Cary, NC: SAS Institute, Inc.,
2002-2006.
5 Pharmacokinetics of sildenafil after single oral doses in healthy male subjects:
absolute bioavailability, food effects and dose proportionality. Donald J. Nichols, Gary J.
Muirhead, Jane A. Harness Br. J. Clin Pharmaeo, Vol 53 supp. pages: 5S-12S, Feb2002
Comparative human pharmacokinetics and metabolism of single-dose oral and
intravenous sildenafil authors: Gary J. Muirhead, David J. Ranee, Br. J. Clin Pharmaeo, Vol
10 53 supp. Pages, 13S-20S, Mar 2002.
* * *
Having thus described in detail preferred embodiments of the present invention, it is
to be understood that the invention defined by the above paragraphs is not to be limited to
particular details set forth in the above description as many apparent variations thereof are
15 possible without departing from the spirit or scope of the present invention.
The terms "include," "includes," or "including" shall be deemed to be followed by the
words "without limitation" unless otherwise indicated.
Each patent, patent application, and publication cited or described in the present
application is hereby incorporated by reference in its entirety as if each individual patent,
20 patent application, or publication was specifically and individually indicated to be
incorporated by reference.
WHAT IS CLAIMED IS:
1. An oral spray formulation for the treatment of pulmonary arterial hypertension
and/or SSRI-induced sexual dysfunction, comprising sildenafil base or a pharmaceutically
acceptable salt thereof, wherein the pH of the formulation is about 1.5 to less than 3.0.
2. The oral spray formulation of claim 1, wherein the sildenafil base is present in
an amount of about 7 to about 9 % w/v of the formulation.
3. The oral spray formulation of claim 2, wherein the sildenafil base is present in
an amount of about 8.3 1 % w/v of the formulation.
4. The oral spray formulation of claim 1, wherein the sildenafil salt is present in
an amount of about 10 to about 12 % w/v of the formulation.
5. The oral spray formulation of claim 4, wherein the sildenafil salt is present in
an amount of about 11.67 % w/v of the formulation.
6. The oral spray formulation of claim 4 or claim 5, wherein the sildenafil salt is
sildenafil citrate.
7. The oral spray formulation of claim 1, wherein the pH of the formulation is
about 1.5 to less than 3.0.
8. The oral spray formulation of claim 1, wherein the formulation comprises a
polar solvent.
9. The oral spray formulation of claim 8, wherein the polar solvent comprises
propylene glycol and ethyl alcohol.
10. The oral spray formulation of claim 9, wherein the ratio of propylene
glycokethyl alcohol is about 62.5:37.5 % v/v.
11. The oral spray formulation of claim 1, wherein the formulation comprises one
or more pH-adjusting agents.
12. The oral spray formulation of claim 11, wherein the pH-adjusting agents may
be acidifying agents, alkalizing agents or combinations thereof.
13. The oral spray formulation of claim 12, wherein the acidifying agent is
hydrochloric acid (HC1).
14. The oral spray formulation of claim 13, wherein the HC1 is present in an
amount of about 10% v/v of the formulation.
15. The oral spray formulation of claim 12, wherein the alkalizing agent is sodium
hydroxide (NaOH).
16. The oral spray formulation of claim 15, wherein the NaOH is present in an
amount of about 2.1 % v/v of the formulation.
17. The oral spray formulation of claim 1, wherein the formulation comprises a
taste -masking agent.
18. The oral spray formulation of claim 1, wherein the formulation comprises one
or more pharmaceutically acceptable excipients, carriers or a combination thereof.
19. The oral spray formulation of claim 1, wherein the pH of the formulation is
about 2.2 ± 0.5
20. The oral spray formulation of claim 19, wherein the pH of the formulation is
about 2.2.
2 1. A method for the treatment of pulmonary arterial hypertension and/or SSRIinduced
sexual dysfunction, comprising administering to a patient an oral spray formulation
comprising sildenafil base or a pharmaceutically acceptable salt thereof, wherein the pH of
the formulation is about 1.5 to less than 3.0.
22. The method of claim 21, wherein the sildenafil base is present in an amount of
about 7 to about 9 % w/v of the formulation.
23. The method of claim 22, wherein the sildenafil base is present in an amount of
about 8.31 % w/v of the formulation.
24. The method of claim 21, wherein the sildenafil salt is present in an amount of
about 10 to about 12 % w/v of the formulation.
25. The method of claim 24, wherein the sildenafil salt is present in an amount of
about 11.67 % w/v of the formulation.
26. The method of claim 24 or claim 25, wherein the sildenafil salt is sildenafil
citrate.
27. The method of claim 2 1, wherein the pH of the formulation is about 1.5 to less
than 3.0.
28. The method of claim 21, wherein the formulation comprises a polar solvent.
29. The method of claim 28, wherein the polar solvent comprises propylene glycol
and ethyl alcohol.
30. The method of claim 29, wherein the ratio of propylene glycokethyl alcohol is
about 62.5:37.5 % v/v.
31. The method of claim 2 1, wherein the formulation comprises one or more pHadjusting
agents.
32. The method of claim 31, wherein the pH-adjusting agents may be acidifying
agents, alkalizing agents or combinations thereof.
33. The method of claim 32, wherein the acidifying agent is HC1.
34. The method of claim 33, wherein the HCl is present in an amount of about 10
% v/v of the formulation.
35. The method of claim 32, wherein the alkalizing agent is NaOH.
36. The method of claim 35, wherein the NaOH is present in an amount of about
2.1 % v/v of the formulation.
37. The method of claim 21, wherein the formulation comprises a taste-masking
agent.
38. The method of claim 21, wherein the formulation comprises one or more
pharmaceutically acceptable excipients, carriers or a combination thereof.
39. The method of claim 21, wherein the pH of the formulation is about 2.2 ± 0.5
40. The method of claim 39, wherein the pH of the formulation is about 2.2.
4 1. The method of claim 2 1, wherein the amount of sildenafil administered per
spray is 10 mg.
42. The method of claim 21, wherein the amount of sildenafil administered per
spray is 20 mg.
43. The method of claim 21, wherein the amount of sildenafil administered per
spray is 30 mg.
44. The method of claim 41, wherein the sildenafil exposure in the patient results
in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-t(ng-mVmL) of
approximately 299.36.
45. The method of claim 42, wherein the sildenafil exposure in the patient results
in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-t(ng-mVmL) of
approximately 323.16.
46. The method of claim 43, wherein the the sildenafil exposure in the patient
results in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-t (ng-hr/mL) of
approximately 304.98.
47. The method of claim 41, wherein the sildenafil exposure in the patient results
in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-i f(ng-hr/mL) of
approximately 310.60.
48. The method of claim 42, wherein the sildenafil exposure in the patient results
in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo-inf (ng-hr/mL) of
approximately 33 1.22.
49. The method of claim 43, wherein the sildenafil exposure in the patient results
in a ln-transformed dose-adjusted to 25 mg geometric mean AUCo- (ng-hr/mL) of
approximately 3 1.05.
50. The oral spray formulation of claim , wherein the amount of sildenafil
administered per spray is 1 mg.
51. The oral spray formulation of claim 1, wherein the amount of sildenafil
administered per spray is 20 mg.
52. The oral spray formulation of claim 1, wherein the amount of sildenafil
administered per spray is 30 mg.
53. The oral spray formulation of claim 7, wherein the taste-masking agent
comprises mint.
54. The oral spray formulation of claim 53, wherein the mint is peppermint or
spearmint.
55. The oral spray formulation of claim 53 or claim 54, further comprising a fruit
and or chocolate flavor.
56. The method of claim 37, wherein the taste-masking agent comprises mint.
57. The method of claim 53, wherein the mint is peppermint or spearmint.
58. The method of claim 53 or claim 54, further comprising a fruit and/or
chocolate flavor.
59. The oral spray formulation of claim 53, further comprising a sweetener.
60. The ora spray formulation of claim 59, wherein the sweetener is sucralose.
6 . The method of claim 55, further comprising a sweetener.
62. The method of claim 1, wherein the sweetener is sucralose.