CONTROL OF CCI-779 DOSAGE FORM STABILITY THROUGH
CONTROL OF DRUG SUBSTANCE IMPURITIES
BACKGROUND OF THE INVENTION
Rapamycin 42-ester with 3-hydroxy-2-(hydroxymethyl)-2-methylpropionic
acid (CCI-779) has potential as an antitumor agent. This compound is now known
generically under the name temsirolimus (Wyeth). The preparation and use of
hydroxyesters of rapamycin, including temsirolimus, are described in US Patent Nos.
5,362,718 and 6,277,983.
The intravenous dosage form includes a solution of CCI-779, -tocopherol,
citric acid, and ethanol in propylene glycol. Rapamycin and related compounds may
be susceptible to oxidative and hydrolytic degradation during synthesis and
purification of the drug substance or when formulated as a dosage form. Oxidation
generally begins via peroxidation of unsaturated carbons in the 1-7 carbon polyene
region of rapamycin and its derivatives, such as CCI-779. The initial peroxidation
generally proceeds to form a number of oxide, hydroxide and aldehyde degradation
products.
Collectively, these degradation products or impurities are referred to as "group
IT' or "oxidative and hydrolytic" degradation products or impurities. The presence of
these impurities/degradation products can catalyze degradation of the drug and
thereby destabilize the drug when present in sufficiently high amounts.
Addition of antioxidants to both the drug substance, during processing, and in
the final drug product may inhibit degradation caused by the degradation products or
impurities. However, when these degradation/impurity levels reach a critical value,
further degradation of drug product is difficult to inhibit by practical means. This is
especially a limitation for parenteral products because the levels of antioxidants and
other stabilizers used in a formulation is often limited by safety concerns and their
levels in new products may be limited by previous human safety experience.
Because of the negative influence of oxidative/hydrolytic degradation products on the
potency and purity of drug product, it is advantageous to limit their amount in the
composition of the final drug product.

US Patent No. 6,605,613 B2 discusses stabilization of macrolides using
various antioxidants. The primary focus of that patent is to stabilize drug during its
preparation and final isolation.
Because of the variety of degradation pathways that occur during oxidation
and hydrolysis of rapamycin derivatives as well as the ability of rapamycin and
related compounds to form various isomers, the isolation and quantitation of
oxidative/hydrolytic degradation products/impurities as individual substances is
difficult to achieve. For this reason, it is often necessary to quantitate
oxidative/hydrolytic degradation products as a group rather than as single, individual
compounds.
What is needed in the art are alternate methods for preparing rapamycin
compositions that have less degradation impurities.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a method of preparing a
rapamycin composition having increased potency.
In another aspect, the present invention provides a method for preparing a
rapamycin composition having increased potency by formulating a rapamycin
compound having not more than 1.5% oxidative and hydrolytic rapamycin impurities
with an antioxidant and optional excipients.
Other aspects and advantages of the invention will be readily apparent from
the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is an LC/UV chromatogram of an exemplary temsirolimus (CCI-779)
sample preparation which is corrected for solvent.
Fig. 2 is an LC/MS chromatogram of an exemplary temsirolimus (CCI-779)
sample preparation. More particularly, this HPLC/MS Chromatogram for oxidative /
hydrolysis degradants has a time in column (TIC) Range: m/z 1044.7 to 1076.7.
Fig. 3 is a plot of total nonoxidative degradants and oxidative/hydrolysis
degradants vs. time for a parenteral drug product of temsirolimus (CCI-779) prepared
with drug substance that contained 0.5, 1, or 2% initial oxidative/hydrolysis

degradants. In this figure, "OD" refers to the percent (%) oxidative/hydrolysis
degradants initially in the drug substance.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides methods of preparing rapamycin compositions
having increased stability. The term "increased stability" as used herein refers to a
rapamycin composition whereby the concentration of the rapamycin compound
contained therein decreases to a lesser extent over time and has fewer or lower levels
of degradation products as compared to rapamycin compositions in the art. Desirably,
the rapamycin compositions of the present invention show minimal degradation after
storage at 25 °C or 40 °C compared to compositions where the oxidative/hydrolytic
impurities in the starting material are not controlled.
As used herein, the term rapamycin compound defines a class of
immunosuppressive compounds that contain the basic rapamycin nucleus as shown
below.

The rapamycin compounds of this invention include compounds that are
chemically or biologically modified as derivatives of the rapamycin nucleus, while
still retaining immunosuppressive properties. Accordingly, the term rapamycin
compound includes rapamycin, and esters, ethers, carbamates, oximes, hydrazones,
and hydroxylamines of rapamycin, as well as rapamycins in which functional groups
on the rapamycin nucleus have been modified, for example through reduction or
oxidation.
The term rapamycin compound also includes 42- and/or 31-esters and ethers
of rapamycin as described in the following patents, which are all hereby incorporated

by reference: alkyl esters (US Patent No. 4,316,885); aminoalkyl esters (US Patent
No. 4,650,803); fluorinated esters (US Patent No. 5,100,883); amide esters (US Patent
No. 5,118,677); carbamate esters (US Patent No. 5,118, 678); silyl esters (US Patent
No. 5,120,842); aminodiesters (US Patent No. 5,162,333); sulfonate and sulfate esters
(US Patent No. 5,177,203); esters (US Patent No. 5,221,670); alkoxyesters (US Patent
No. 5,233,036); O-aryl, -alkyl, -alkenyl, and -alkynyl ethers (US Patent No.
5,258,389); carbonate esters (US Patent No. 5,260,300); arylcarbonyl and
alkoxycarbonyl carbamates (US Patent No. 5,262,423); carbamates (US Patent No.
5,302,584); hydroxyesters (US Patent No. 5,362,718); hindered esters (US Patent No.
5,385,908); heterocyclic esters (US Patent No. 5,385,909); gem-disubstituted esters
(US Patent No. 5,385,910); amino alkanoic esters (US Patent No. 5,389,639);
phosphorylcarbamate esters (US Patent No. 5,391,730); carbamate esters (US Patent
No. 5,411,967); carbamate esters (US Patent No. 5,434,260); amidino carbamate
esters (US Patent No. 5,463,048); carbamate esters (US Patent No. 5,480,988);
carbamate esters (US Patent No. 5,480,989); carbamate esters (US Patent No.
5,489,680); hindered N-oxide esters (US Patent No. 5,491,231); biotin esters (US
Patent No. 5,504,091); O-alkyl ethers (US Patent No. 5,665,772); and PEG esters of
rapamycin (US Patent No. 5,780,462). The preparation of these esters and ethers is
disclosed in the patents listed above.
Further included within the definition of the term rapamycin compound are
27-esters and ethers of rapamycin, which are discussed in US Patent No. 5,256,790.
Also described are C-27 ketone rapamycins which are reduced to the corresponding
alcohol, which is in turn converted to the corresponding ester or ether. The
preparation of these esters and ethers is discussed in the patents provided above. Also
included are oximes, hydrazones, and hydroxylamines of rapamycin as discussed in
US Patent Nos. 5,373,014; 5,378,836; 5,023,264; and 5,563,145. The preparation of
these oximes, hydrazones, and hydroxylamines is discussed in the above-listed
patents. The preparation of 42-oxorapamycin is discussed in US Patent No.
5,023,263.
The term rapamycin compound also refers to any combination of different
rapamycins or chemical compounds that contains rapamycin or any derivative thereof.

Specific examples of rapamycin compounds that can be used in the invention
include, without limitation, rapamycin, CCI-779, norrapamycin, deoxorapamycin,
desmethylrapamycin, desmethoxyrapamycin, or the rapamycins described in US
Patent Publication No. 2006-0135549 (claiming priority from US Provisional
Application No. 60/637,666) and US Patent Publication No. 2006-013550 Al,
(claiming priority from US Provisional Application No. 60/638,004), which are
hereby incorporated by reference, or pharmaceutically acceptable salts, prodrugs, or
metabolites thereof, among others.
The term "desmethylrapamycin" refers to the class of rapamycin compounds
which lack one or more methyl groups. Examples of desmethylrapamycins that can
be used according to the present invention include 3-desmethylrapamycin (US Patent
No. 6,358,969), 7-O-desmethyl-rapamycin (US Patent No. 6,399,626), 17-
desmethylrapamycin (US Patent No. 6,670,168), and 32-O-desmethylrapamycin,
among others.
The term "desmethoxyrapamycin" refers to the class of rapamycin compounds
which lack one or more methoxy groups and includes, "without limitation, 32-
desmethoxyrapamycin.
The rapamycin compositions of the invention include the rapamycin
compound at an amount sufficient to treat the conditions and diseases identified
below. Specifically, the rapamycin compound is present in the rapamycin
compositions at about 0.1 to 30 wt%, 0.5 to 25 wt%, 1 to 20 wt%, 5 to 15 wt%, or 7 to
12 wt% (wt/wt). Desirably, the rapamycin compound is present at an amount of 2 to
about 500 mg, 5 mg to 250 mg, 10 mg to 100 mg, 15 mg to 50 mg, or about 20 mg to
25 mg.
The rapamycin compound of the invention can be in a micronized or
nonmicronized form and can also include tautomeric forms of the rapamycin
compound. The present invention also includes derivatives of rapamycin, including,
but not limited to, esters, carbamates, sulfates, ethers, oximes, carbonates, and the
like.
The rapamycin compound can also encompasses "metabolites" which are
unique products formed by processing rapamycin by the cell or patient. Desirably,
metabolites are formed in vivo.

It is also desirable that the rapamycin compound in the compositions of the
invention degrades less than the rapamycin compound in the compositions in the art.
Of course, it is most desirable that the concentration of the rapamycin compound in
the compositions of the present invention be maintained. However, it is desirable that
the concentration of the rapamycin compound in the compositions of the invention
degrades less than about 2 % after storage for 3-5 months at 25 °C or 1 month at 40
°C, more desirably less than about 1 %.
The inventors found that more potent rapamycin compositions are obtained
when the rapamycin compound utilized therein contained less than 1.5% (i.e., 0 or
0.01, 0.01 to 1.5%) oxidative and hydrolytic impurities in the starting material. In
fact, by utilizing rapamycin compounds containing 0.5 to 1% or less oxidative and
hydrolytic impurities, degradation of the rapamycin was significantly reduced or
eliminated. More desirably, the rapamycin compound contains less than about 1%,
less than about 0.5%, less than about 0.4%, less than about 0.3%, less than about
0.2%, or about 0.1% oxidative impurities. Most desirably, the rapamycin contains
less than about 0.5% oxidative impurities.
The term "oxidative and hydrolytic impurities of rapamycin", or variations
thereof as used herein, refers to chemical compounds that form in rapamycin •
compositions. These impurities can include a group of oxygen addition compounds
involving the C1-6 region of rapamycin or its analogs identified below. These
impurities can therefore include aldehydes, epoxides, hydroxides, and combinations
thereof of rapamycin or rapamycin derivatives. These impurities can also include
ring-opened forms of rapamycin or rapamycin analogs that contain the oxygen
addition modifications described above for the C1-6 region.

The presence of these oxidative and hydrolytic impurities is typically
measured using high performance liquid chromatography (HPLC) with ultraviolet

(UV) or mass spectrometric (MS) detection. Specifically, the oxidative and
degradation impurities can be quantitated using either HPLC/UV or HPLC/MS. More
specifically, the oxidative and hydrolytic impurities may be quantitated as a mixture
of co-eluting materials over a specified range of retention times (HPLC/UV). For
example, in one embodiment, the retention time of the CCI-779 Isomer B peak should
be between 18 and 24 minutes using a suitable chromatograph column (e.g., a reverse
phase column). Alternatively quantitation by analyzing the extent of one oxygen, two
oxygen, 3 oxygen, one oxygen plus water, and water incorporation, based on the m/z
of the addition product, is employed.
The method of the invention thereby includes preparing a rapamycin
composition by selecting a rapamycin compound as noted above for use therein.
Desirably, the rapamycin compound has less than 1.5% oxidative and hydrolytic
rapamycin impurities. After selection of the desired rapamycin compound, it is
formulated with one or more of an antioxidant.
Antioxidants that can be used in the rapamycin compositions of the present
invention include, but are not limited to, citric acid, alpha tocopherol, BHA, BHT
(2,6-di-tert-butyl-4-methylphenol), monothioglycerol, Vitamin C, and propyl gallate.
In one embodiment, Vitamin C is ascorbic acid. However, one of skill in the art may
substitute a pharmaceutically acceptable salt thereof for the ascorbic acid. D.esirably,
the antioxidant is d,l--tocopherol. In one embodiment, the antioxidant may be used
in concentrations ranging from 0.0005 wt% to 3 wt%, and desirably from 0.001 wt%
to 3 wt%.
The rapamycin compositions of the invention may also contain suitable
excipients including, without limitation, water soluble polymers, pH modifying
agents, chelating agents, surfactants, fillers, binders, disintegrants, and the like. Any
given rapamycin composition useful in the invention may contain multiple ingredients
of each class of component. For example, some compositions may contain one or
more antioxidant.
pH modifying agents include, but are not limited to, citric acid, sodium citrate,
acetic acid, lactic acid, dilute HC1, and other mild acids or bases capable of buffering
a solution containing the rapamycin compound to a pH in the range of about 4 to
about 6.

Chelating agents, and other materials capable of binding metal ions, can be
included in the rapamycin compositions of the invention. Desirably, the chelating
agent enhances the stability of the rapamycin compound. In certain embodiments, the
antioxidant component of the formulation of the invention can exhibit cheiating
activity. Examples of chelating agents include, without limitation, citric acid and
ascorbic acid (which may function as both a classic antioxidant and a chelating agent
in the present formulations). Other chelating agents include such materials as are
capable of binding metal ions in solution, such as ethylene diamine tetra acetic acid
(EDTA), its salts, or amino acids such as glycine, which are capable of enhancing the
stability of the rapamycin compound. Typically, chelating agents are used in the
lower end of the range of concentrations for the antioxidant component provided
herein. In one example, citric acid is utilized at a concentration of less than 0.01%
w/v. Additionally, such chelating agents may be used in combination with other
antioxidants as part of the antioxidant component of the invention. For example, an
acceptable formulation may contain both citric acid and d,l--tocopherol. Optimal
concentrations for the selected antioxidant(s) can be readily determined by one of skill
in the art, based upon the information provided herein.
Surfactants may include polysorbate 80, polyoxyethylene fatty acid esters,
sodium lauryl sulfate, sodium dodecyl sulfate, salts of bile acids (taurocholate,
glycocholate, cholate, deoxycholate, etc.) that may be combined with lecithin,
Vitamin E TPGS, and/or poloxamers. The surfactant can be present in the rapamycin
compositions at 0.5 to 10 wt%, 1 to 8 wt%, or 3 to 5 wt% (wt/wt), or can be present in
amounts from the lower or higher end of these ranges up to about 50 wt%.
Binders, fillers, and disintegrants can include sucrose, lactose, microcrystalline
cellulose, croscarmellose sodium, magnesium stearate, gum acacia, cholesterol,
tragacanth, stearic acid, gelatin, casein, lecithin (phosphatides),
carboxymethylcellulose calcium, carboxymethylcellulose sodium, methylcellulose,
hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethycellulose
phthalate, noncrystalline cellulose, cetostearyl alcohol, cetyl alcohol, cetyl esters wax,
dextrates, dextrin, lactose, dextrose, glyceryl monooleate, glyceryl monostearate,
glyceryl palmitostearate, polyoxyethylene alkyl ethers, polyethylene glycols,

polyoxyethylene castor oil derivatives, polyoxyethylene stearates, and polyvinyl
alcohol.
Typical water soluble polymers include, but are not limited to,
polyvinylpyrrolidone (PVP), hydroxypropylmethylcellulose (HPMC), poiyethylene
glycol (PEG), and cyclodextrin or mixtures thereof. Desirably, the water-soluble
polymer is PVP and has a molecular weight of between 2.5 and 60 kilodaltons.
The rapamycin compositions described herein can be formulated in any form
suitable for the desired route of delivery using a pharmaceutically effective amount of
the rapamycin compound. For example, the compositions of the invention can be
delivered by a route such as oral, dermal, transdermal, intrabronchial, intranasal,
intravenous, intramuscular, subcutaneous, parenteral, intraperitoneal, intranasal,
vaginal, rectal, sublingual, intracranial, epidural, intratracheal, or by sustained release.
Suitable oral formulations for the rapamycin compositions can be prepared as
described for CCI-779, as described in International Patent Publication No. WO
2004/026280 and US Patent Application Publication No. US 2004-0077677 A1,
which are hereby incorporated by reference. In one embodiment, the composition
contains 0.1 to 30 wt%, 0.5 to 25 wt%, 1 to 20 wt%, 5 to 15 wt%, or 7 to 12 wt%
(wt/wt) of a rapamycin compound and 0.001 wt% to 1 wt%, 0.01 wt% to 1 wt%, or
0.1 wt% to 0.5 wt% (wt/wt) of an antioxidant. The compositions can optionally
contain 0.5 to 50 wt%, 1 to 40 wt%, 5 to 35 wt%, 10 to 25 wt%, or 15 to 20 wt%
(wt/wt) of a water soluble polymer and 0.5 to 10 wt%, 1 to 8 wt%, or 3 to 5 wt%
(wt/wt) of a surfactant. However, other embodiments may contain more, or less, of
these components.
Oral formulations may include any conventionally used oral forms,
including tablets, capsules, buccal forms, troches, lozenges and oral liquids,
suspensions or solutions. Capsules may contain mixtures of the rapamycin compound
with inert fillers and/or diluents such as the pharmaceutically acceptable starches (e.g.
com, potato or tapioca starch), sugars, artificial sweetening agents, powdered
celluloses, such as crystalline and microcrystalline celluloses, flours, gelatins, gums,
etc. Useful tablet formulations may be made by conventional compression, wet
granulation or dry granulation methods and utilize pharmaceutically acceptable
diluents, binding agents, lubricants, disintegrants, surface modifying agents (including

surfactants), suspending or stabilizing agents, including, but not limited to,
magnesium stearate, stearic acid, talc, sodium lauryl sulfate, microcrystalline
cellulose, carboxymethylcellulose calcium, polyvinylpyrrolidone, gelatin, alginic
acid, acacia gum, xanthan gum, sodium citrate, complex silicates, caicium carbonate,
glycine, dextrin, sucrose, sorbitol, dicalcium phosphate, calcium sulfate, lactose,
kaolin, mannitol, sodium chloride, talc, dry starches and powdered sugar. Surface
modifying agents can include nonionic and anionic surface modifying agents.
Representative examples of surface modifying agents include, but are not limited to,
poloxamer 188, benzalkonium chloride, calcium stearate, cetostearyl alcohol,
cetomacrogol emulsifying wax, sorbitan esters, colloidal silicon dioxide, phosphates,
sodium dodecylsulfate, magnesium aluminum silicate, and triethanolamine. Oral
formulations herein may utilize standard delay or time release formulations to alter
the absorption of the rapamycin. The oral formulation may also include water or a
fruit juice, containing appropriate solubilizers or emulsifiers as needed.
In some cases it may be desirable to administer the rapamycin composition
directly to the airways in the form of an aerosol.
The rapamycin compositions may also be administered parenterally or
intraperitoneally. Solutions or suspensions of the rapamycin compound as a free base
or pharmacologically acceptable salt can be prepared in water suitably mixed with a
surfactant such as hydroxy-propylcellulose. Dispersions can also be prepared in
glycerol, liquid polyethylene glycols and mixtures thereof in oils. Under ordinary
conditions of storage and use, these preparations contain a preservative to prevent the
growth of microorganisms.
The pharmaceutical forms suitable for injectable use include sterile aqueous
solutions or dispersions and sterile powders for the extemporaneous preparation of
sterile injectable solutions or dispersions. In all cases, the form must be sterile and
must be fluid to the extent that easy syringability exists. It must be stable under the
conditions of manufacture and storage and must be preserved against the
contaminating action of microorganisms such as bacteria and fungi. The carrier can
be a solvent or dispersion medium containing, for example, water, ethanol, polyol
(e.g., glycerol, propylene glycol and liquid polyethylene glycol), suitable mixtures
thereof, and vegetable oils.

Particularly suitable injectable formulations containing the rapamycin
compound can be prepared in a manner similar to those described in International
Patent Publication No. WO 2004/011000 and US Patent Application Publication No.
US 2004-0167152 A1, which are hereby incorporated by reference. In this
embodiment, the injectable formulation useful in the invention provides a rapamycin
composition cosolvent concentrate containing a parenterally acceptable solvent and an
antioxidant as described above and a parenteral formulation containing a rapamycin
compound, a parenterally acceptable cosolvent, an antioxidant, a diluent solvent, and
a surfactant. For example, a parenterally acceptable solvent can include a non-
alcoholic solvent, an alcoholic solvent, or mixtures thereof. Examples of suitable
non-alcoholic solvents include, without limitation, dimethylacetamide,
dimethylsulfoxide, or mixtures thereof. Examples of alcoholic solvent include,
without limitation, one or more alcohols as the alcoholic solvent component of the
formulation. Examples of solvents useful in the formulations invention include,
without limitation, ethanol, propylene glycol, polyethylene glycol 300, polyethylene
glycol 400, polyethylene glycol 600, polyethylene glycol 1000, or mixtures thereof.
Further, ethanol and propylene glycol can be combined to produce a less flammable
product. These latter two cosolvents are particularly desirable because degradation via
oxidation and lactone cleavage occurs to a lower extent for these cosolvents. Larger
amounts of ethanol in the mixture generally result in better chemical stability. A
concentration of 30 to 100% v/v of ethanol in the mixture is desirable.
The stability of the rapamycin compound in the parenterally acceptable
alcoholic cosolvent can be enhanced by addition of an antioxidant to the formulation.
Generally, the parenteral formulation useful in the invention will contain an
antioxidant component(s) in a concentration of 0.001% to 3% w/v or 0.01% to 0.1%
w/v, of the cosolvent concentrate, although lower or higher concentrations may be
desired. Of the antioxidants, d,l--tocopherol is particularly desirable and is used at a
concentration of 0.01 to 0.1% w/v with a concentration of 0.075% w/v of the
cosolvent concentrate being most desirable.
Dosage regimens are expected to vary according to the route of administration.
For example, dosages for oral administration are often up to five to tenfold greater
than for intravenous (i.v.) administration. In one embodiment, a dosage of the

rapamycin compound may be about 2 to about 500 mg/day, 5 mg/day to 75 mg/day,
10 mg/day to 50 mg/day, 15 mg/day to 35 mg/day, or about 20 mg/day to 25 mg/day
for an adult. However, this dosage can be adjusted upwardly or downwardly by one
of skill in the art, depending upon the indication being treated, the size of the patient,
and other factors which are known those of skill in the art.
In certain embodiments of the parenteral formulations useful in the invention,
precipitation of the rapamycin compound upon dilution with aqueous infusion
solutions or blood is prevented through the use of a surfactant contained in the diluent
solution. The most important component of the diluent is a parenterally acceptable
surfactant. One particularly desirable surfactant is polysorbate 20 or polysorbate 80.
However, one of skill in the art may readily select other suitable surfactants from
among salts of bile acids (taurocholate, glycocholate, cholate, deoxycholate, etc.)
which are optionally combined with lecithin. Alternatively, ethoxylated vegetable
oils, such as a pegylated castor oil (e.g., such as PEG-35 castor oil which is sold, e.g.,
under the name Cremophor EL, BASF), vitamin E tocopherol propylene glycol
succinate (Vitamin E TGPS), and polyoxyethylene-polyoxypropylene block
copolymers can be used in the diluent as a surfactant, as well as other members of the
polysorbate family such as polysorbate 20 or 60. Other components of the diluent
may include water, ethanol, polyethylene glycol 300, polyethylene 400, polyethylene
600, polyethylene 1000, or blends containing one or more of these polyethylene
glycols, propylene glycol and other parenterally acceptable cosolvents or agents to
adjust solution osmolarity such as sodium chloride, lactose, mannitol or other
parenterally acceptable sugars, polyols and electrolytes. It is expected that the
surfactant will include at least 5% w/v, at least 10% w/v, or at least 5% w/v of the
diluent solution. Desirably, the surfactant will include 2 to 100% w/v, 5 to 80% w/v,
10 to 75% w/v, or 15 to 60 % w/v of the diluent solution.
A parenteral formulation useful in the invention can be prepared as a single
solution, or desirably can be prepared as a cosolvent concentrate containing the
rapamycin compound, an alcoholic solvent, and an antioxidant, which is subsequently
combined with a diluent that contains a diluent solvent and suitable surfactant. Prior
to use, the cosolvent concentrate is mixed with a diluent comprising a diluent solvent,
and a surfactant. When rapamycin compound is prepared as a cosolvent concentrate

according to this invention, the concentrate can contain concentrations of the
rapamycin compound from 0.05 mg/mL, from 2.5 mg/mL, from 5 mg/mL, from 10
mg/mL or from 25 mg/mL up to approximately 50 mg/mL. The concentrate can be
mixed with the diluent up to approximately 1 part concentrate to 1 part diluent, to give
parenteral formulations having concentrations of the rapamycin compound from 1
mg/mL, from 5 mg/mL, from 10 mg/mL, from 20 mg/mL, up to approximately 25
mg/mL. For example the concentration of the rapamycin compound in the parenteral
formulation may be from about 2.5 to 10 mg/mL. This invention also covers the use
of formulations having lesser concentrations of the rapamycin compound in the
cosolvent concentrate, and formulations in which one part of the concentrate is mixed
with greater than 1 part of the diluent, e.g., concentrate: diluent in a ratio of about
1:1.5, 1:2, 1:3,1:4 ,1:5, or 1:9 v/v and so on, to rapamycin compound parenteral
formulations having a rapamycin compound concentration down to the lowest levels
of detection. Typically the antioxidant may include from about 0.0005 to 0.5% w/v of
the formulation. The surfactant may for example include from about 0.5 % to about
10% w/v of the formulation. The alcoholic solvent may for example include from
about 10% to about 90% w/v of the formulation.
The parenteral formulations useful in this invention can be used to produce a
dosage form that is suitable for administration by either direct injection or by addition
to sterile infusion fluids for intravenous infusion.
Transdermal administrations include all administrations across the surface of
the body and the inner linings of bodily passages including epithelial and mucosal
tissues. Such administrations may be carried out using the present compounds, or
pharmaceutically acceptable salts thereof, in lotions, creams, foams, patches,
suspensions, solutions, and suppositories (rectal and vaginal). Transdermal
administration may be accomplished through the use of a transdermal patch
containing the active compound and a carrier that is inert to the active compound, is
non toxic to the skin, and allows delivery of the agent for systemic absorption into the
blood stream via the skin. The carrier may take any number of forms such as creams
and ointments, pastes, gels, and occlusive devices. The creams and ointments may be
viscous liquid or semisolid emulsions of either the oil-in-water or water-in-oil type.
Pastes comprised of absorptive powders dispersed in petroleum or hydrophilic

petroleum containing the active ingredient may also be suitable. A variety of
occlusive devices may be used to release the active ingredient into the blood stream
such as a semi-permeable membrane covering a reservoir containing the active
ingredient with or without a carrier, or a matrix containing the active ingredient.
Other occlusive devices are known in the literature.
Suppository formulations may be made from traditional materials, including
cocoa butter, with or without the addition of waxes to alter the suppository's melting
point, and glycerin. Water soluble suppository bases, such as polyethylene glycols of
various molecular weights, may also be used.
The rapamycin compound of the invention may be formulated for any suitable
delivery route and vehicle and assembled in the form of a kit of parts.
Thus, the rapamycin compositions of the invention can be useful as an
antineoplastic agent, and therefore in the treatment of solid tumors, including
sarcomas and carcinomas; and more particularly against astrocytomas, prostate
cancer, breast cancer, colon cancer, small cell lung cancer, and ovarian cancer; and
adult T-cell leukemia/lymphoma. The rapamycin compound-containing compositions
are also useful in the treatment or inhibition of transplantation rejection such as
kidney, heart, liver, lung, bone marrow, pancreas (islet cells), cornea, small bowel,
and skin allografts, and heart valve xenografts; in the treatment or inhibition of graft
vs. host disease; in the treatment or inhibition of autoimmune diseases such as lupus,
rheumatoid arthritis, diabetes mellitus, myasthenia gravis, and multiple sclerosis; and
diseases of inflammation such as psoriasis, dermatitis, eczema, seborrhea,
inflammatory bowel disease, pulmonary inflammation (including asthma, chronic
obstructive pulmonary disease, emphysema, acute respiratory distress syndrome,
bronchitis, and the like) and ocular uveitis; adult T-cell leukemia/lymphoma; fungal
infections; hyperproliferative vascular diseases such as restenosis; graft vascular
atherosclerosis; and cardiovascular disease, cerebral vascular disease, and peripheral
vascular disease, such as coronary artery disease, cereberovascular disease,
arteriosclerosis, atherosclerosis, nonatheromatous arteriosclerosis, or vascular wall
damage from cellular events leading toward immune mediated vascular damage, and
inhibiting stroke or multiinfarct dementia.

The following examples are illustrative only and are not intended to be a
limitation on the present invention.
EXAMPLES
Example 1 - General Procedures for Evaluation of Oxidative Impurities Present in
CCI-779 Samples
The oxidative and hydrolytic impurities in a CCI-779 sample may be
quantitated as a mixture of co-eluting materials over a specified range of retention
times. The method used is a reverse phase gradient HPLC/UV procedure. The
chromatographic conditions are outlined below.



Table 2
With reference to Table 1 above, the following table provides further details
relating to the gradients used with mobile phase A (MP-A) and mobile phase B (MP-
B). During "linear change", the gradient is changed at a uniform rate. During
"isocratic hold", the solvent phase remains constant. During "step change", an
incremental change in the solvent is introduced.


As an alternative to HPLC/UV, the CCI-779 in the sample was quantitated by
analyzing the extent of one oxygen, two oxygen, 3 oxygen, one oxygen plus water,
and water incorporation, based on the m/z of the addition product.



Example 2 - Varying Levels of Impurities
In this example, three rapamycin compositions, each of which contains CCI-
779 2.5%, d,l-alpha-tocopherol 0.075%, anhydrous citric acid 0.0025%, dehydrated
alcohol 39.5%, and propylene glycol q.s., with varying levels of oxidative impurities,
were monitored over a period of about 3 to 5 months to determine their stabilities at
various temperatures and humidities. These batches contained about 0.5%, about 1%
and about 2% of oxidative/hydrolysis impurities, respectively.
Aliquots of the formula were subdivided into glass vials, stoppered, sealed
and stored at 5°C, 25°C/60% relative humidity (RH), or 40°C/75% RH. Samples
were monitored for (i) appearance and description, (ii) moisture, (iii) strength, total
related compounds (nonoxidative), (iv) oxidative/hydrolysis impurities, and (v) -
tocopherol content. The data illustrates that for samples initially containing about
0.5% impurities, there was a slight increase in total (nonoxidative) degradation and
oxidative/hydrolytic degradation after 1 month at 40°C. After 3 and 5 months at 25°C
the formulation was stable, i.e., the potency remained the same as did total
degradation.
For the sample initially containing about 1% impurities, there was an increase
in oxidative/hydrolytic degradation products to about 1.94% after three months. This
trend continued out to 5 months at 25 °C, with increases in total nonoxidative and
oxidative/hydrolytic degradation products to 1.65 and 2.3% respectively.

For the sample initially containing about 2% impurities, the total nonoxidative
degradation and oxidative/hydrolytic degradation increased after 1 month 40 °C/75%
RH to 8 and 4.3% respectively. After three months, both total nonoxidative
degradation and oxidative/hydroiytic degradation products increased for the samples
at 25°C/60%RH to 3.3 and 4.2% respectively. Figure 3 illustrates the effect of initial
oxidative/hydrolysis degradant levels contributed by the input drug raw material on
the stability of CCI-779 after 1 and 3 month storage.
In summary, it was found that higher initial concentrations of the
oxidative/hydrolytic impurities adversely affected the stability of the CCI-779
samples. In fact, the greatest stability of samples containing CCI-779 occurred when
the initial concentration of the oxidative impurities in the rapamycin composition was
0.5% or less. Therefore, reducing the initial oxidative impurities significantly
enhances the shelf-life of the formulated CCI-779 product.
Example 3 - Varying a-Tocopherol Concentration
To further investigate the effect of the oxidative impurities in rapamycin
compositions, studies were conducted by varying concentrations of -tocopherol in
the rapamycin compositions.
Samples of CCI-779 containing 0.2%, 0.5% and 1% d,l--tocopherol (Eisai)
were placed in 2 mL flint glass vials and stoppered with 13 mm West Teflon Faced
4432/50 stoppers. The effect of increased a-tocopherol concentrations on the
rapamycin compositions was monitored over 1 month at 40°C. Samples were stored
upright at about 5°C or about 40°C.
After 1 month at 40°C, the data illustrate that in all of the samples, the -
tocopherol concentration dropped significantly. However, for the samples containing
0.2% and 0.5% of a-tocopherol, the concentration of the oxidative impurities
remained essentially unchanged, i.e., the concentration of oxidative impurities did not
increase. However, there was an overall loss of potency of the samples due to the
formation of other degradation products.
For samples containing 1% a-tocopherol, the presence of the oxidative
impurities drastically increased to 8.42%.

In summary, increasing the concentration of -tocopherol in the samples to 0.2
and 0.5% slowed the growth of oxidative impurities, but did not inhibit degradation of
the CCI-779 via other mechanisms when the oxidative impurity levels were 3% or
more. As indicated in the previous example, inhibition of the non-oxidative
impurities was controlled by limiting the initial amount of oxidative/hydrolysis
impurities in the drug substance.
All documents listed in this specification are incorporated herein by reference.
While the invention has been described with reference to particular embodiments, it
will be appreciated that modifications can be made without departing from the spirit
of the invention. Such modifications are intended to fall within the scope of the
appended claims.

WHAT IS CLAIMED IS:
1. A method of preparing a rapamycin composition having increased
potency, said method comprising the steps of:
selecting a rapamycin compound having less than 1.5% oxidative and
hydrolytic rapamycin impurities; and
formulating the selected rapamycin with an antioxidant and optional
excipients.
2. The method according to claim 1, wherein the selecting step comprises
screening the rapamycin in a high performance liquid chromatography assay.
3. The method according to claim 1 or 2, wherein the antioxidant is
selected from the group consisting of a tocopherol, vitamin C, 2,6-di-tert-butyl-4-
methylphenol, and mixtures thereof.
4. The method according to claim 3, wherein the antioxidant is -
tocopherol.
5. The method according to any one of claims 1 to 4, wherein the selected
rapamycin has less than 0.5% oxidative impurities.
6. The method according to any one of claims 1 to 5, wherein the selected
rapamycin is formulated for parenteral delivery.
7. The method according to any one of claims 1 to 6, wherein the selected
rapamycin is formulated as a liquid concentrate.
8. The method according to claim 7, wherein the selected rapamycin is
formulated with d,l--tocopherol, anhydrous citric acid, dehydrated alcohol, and
propylene glycol.

9. The method according to any one of claims 1 to 5, wherein the selected
rapamycin is formulated for oral delivery.
10. A method of preparing a rapamycin composition having increased
potency, said method comprising the steps of:
selecting a rapamycin compound having less than 1.5% oxidative and
hydrolytic rapamycin impurities;
formulating the selected rapamycin with at least two antioxidants and
optional excipients.
11. The method according to claim 10, wherein at least one of the
antioxidants is vitamin C or 2,6-di-tert-butyl-4-methylphenol.
12. The method according to claim 10, wherein said at least two
antioxidants are vitamin C and 2,6-di-tert-butyl-4-methylphenol.
13. The method according to any one of claims 1 to 12, wherein said
rapamycin is selected from the group consisting of rapamycin and CCI-779.

A method of preparing a rapamycin composition having increased potency is provided. The method involves selecting a rapamycin compound having less than 1.5% oxidative and hydrolytic rapamycin impurities and formulating the selected
rapamycin with an antioxidant and optional excipients.