DESCRIPTION
THERAPEUTIC OR PROPHYLACTIC AGENT FOR DIABETES
TECHNICAL FIELD
[0001]
The present invention relates to a therapeutic or prophylactic agent for
diabetes, with a reduced side effect.
BACKGROUND ART
[0002]
Diabetes is a group of diseases whose main symptom is chronic
hyperglycemia accompanied by insufficiency of the action of insulin, and involves
various characteristic metabolic disorders. The number of patients suffering from
diabetes shows a worldwide tendency to increase, and, due to changes in the lifestyle
such as consumption of high-fat diets and lack of exercise, patients suffering from
type 2 diabetes, which is a diseased state associated with risk factors such as obesity,
hypertriglyceridemia, low HDL cholesteremia, glucose metabolism disorder and/or
hypertension and occurs with the metabolic syndrome, are especially increasing.
Since it is known that insulin resistance (insufficiency of the action of insulin) is
strongly involved in the increase in the number of patients, development of a
therapeutic agent for type 2 diabetes having an action to improve insulin resistance
has been especially strongly demanded.
[0003]
Peroxisome proliferator-activated receptor gamma (PPAR-?) agonists, which
are nuclear receptors, are recently developed therapeutic agents for type 2 diabetes,
and known to improve insulin resistance and thereby exert a hypoglycemic action,
which is effective for prophylaxis and therapy of diabetes.
[0004]
As PPAR-? agonists, only pioglitazone hydrochloride and rosiglitazone
maleate are currently commercially available, but agents such as Isaglitazone,
Rivoglitazone, Bardoxolone, Aleglitazar, Lobeglitazone, ZYH-1, AVE-0897,
Chiglitazar, THR-0921, GFT-505, Indeglitazar, GSK-376501 and Inoglitazone are
now being developed and drawing attention as agents effective for therapy of type 2
diabetes.
[0005]
On the other hand, since PPAR-? agonists are likely to cause characteristic
side effects such as edema and body weight gain, their use is restrictive. For
example, PPAR-? agonists cannot be used for patients suffering from heart failure
and patients with a history of heart failure, and the body weight needs to be
appropriately controlled. Since obesity is one of the risk factors for diabetes, body
weight gain is a side effect which diabetics want to avoid, so that reduction of the
side effects of PPAR-? agonists has been strongly demanded.
[0006]
In view of this, a method has been disclosed in which a highly safe and
effective therapeutic effect for diabetes is exerted by using a PPAR-? agonist in
combination with another therapeutic agent or prophylactic agent for diabetes having
a different action mechanism (e.g., a-glycosidase inhibitor, sulfonylurea agent,
biguanide, aldose reductase inhibitor, statin compound, squalene synthesis inhibitor,
fibrate compound, LDL catabolism promoter or angiotensin converting enzyme
inhibitor) (Patent Document 1).
[0007]
It has been disclosed that an IP agonist such as a prostaglandin I2 derivative
has the actions of vasodilation, platelet aggregation inhibition, smooth-muscle
proliferation inhibition, vascular endothelium protection and inflammatory cytokine
inhibition and is effective as a therapeutic agent for diabetes in cases where it is used
alone (Patent Document 2, Non-patent Document 1), and that an IP agonist is
effective for therapy or prophylaxis of diabetes when combined with a PPAR-?
agonist (Patent Document 3). However, in Patent Document 3, the PPAR-? agonist
is merely listed as one of many arbitrary components and there is no particular
description at all suggesting or supporting a combined effect with an IP agonist.
Further, the fact that cicletanine, which is known as an endogenous prostacyclin
inducer, exerts a synergistic therapeutic effect for diabetes when used in combination
with a PPAR-? agonist (Patent Document 4), and expected matters on lipid
metabolism, control of edema and reduction of hepatotoxicity of PPAR-? agonists
are described (Patent Document 5). However, these reports do not describe that an
IP agonist suppresses body weight gain due to a PPAR-? agonist.
[0008]
An IP agonist beraprost sodium has been widely employed as an orally-
available stable prostaglandin I2 derivative for basic research and clinical applications,
to be used as a therapeutic agent for chronic artery obstruction (Non-patent
Document 2) or primary pulmonary hypertension (Non-patent Documents 3 and 4).
Since beraprost sodium and its derivatives have a platelet aggregation inhibition
action, those are suggested to have possibilities to be useful as antithrombotic agents,
and also reported to have an anti-hyperlipemic action (Patent Documents 6 and 7).
Further, it has been discovered that beraprost sodium is effective for diabetic
complications such as arterial sclerosis, diabetic nephropathy, diabetic
microangiopathy, diabetic neuropathy, diabetic retinopathy and diabetic
macroangiopathy (Patent Document 8), and that the combination of beraprost sodium
and an antidiabetic drug enables amelioration of decrease in the functions of the
motor nerve and the sensory nerve, which have not been able to be sufficiently
treated with conventional antidiabetic drugs, by improvement of the nerve
conduction velocity. In view of this, a therapeutic method for diabetic neuropathy
using the combination of these drugs is disclosed (Patent Document 9). However,
the target diseases are different in these reports, and the reports do not describe a
therapeutic effect for diabetes by the combination of beraprost sodium and an
antidiabetic drug. Further, it is disclosed that beraprost sodium is effective for
therapy or prophylaxis of diabetes when it is used in combination with pioglitazone
hydrochloride (Patent Document 3), but beraprost sodium and pioglitazone
hydrochloride are merely listed as one of many combinations of IP agonist drugs and
PPAR-? agonist drugs, and there is no particular description at all suggesting or
supporting the combined effect.
[0009]
However, it has not been known so far that IP agonists can be therapeutic
agents or prophylactic agents which not only suppress the side effect of PPAR-?
agonists, that is, the body weight-increasing action, but also have an excellent
hypoglycemic action
PRIOR ART DOCUMENTS
[Patent Documents]
[0010]
[Patent Document 1] JP 2007-191494 A
[Patent Document 2] JP 2-167227 A
[Patent Document 3] JP 2006-199694 A
[Patent Document 4] Japanese Translated PCT Patent Application Laid-open
No. 2006-523668
[Patent Document 5] WO2006/034510
[Patent Document 6] JP 1-53672 B
[Patent Document 7] JP 62-286924 A
[Patent Document 8] WO99/13880
[Patent Document 9] JP 10-251146 A
[Non-patent Documents]
[0011]
[Non-patent Document 1] Paolisso et al., Diabetes Care, 18, 200-205, 1995
[Non-patent Document 2] Melian et al., Drugs, 62, 107-133, 2002
[Non-patent Document 3] Hashida et al., Angiology, 49, 161-164, 1998
[Non-patent Document 4] Miyata et al., J. Cardiovasc. Pharmacol., 27, 20-26,
1996
DISCLOSURE OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0012]
The present invention aims to provide a therapeutic or prophylactic agent for
diabetes comprising as an effective component a PPAR-? agonist, which agent shows
a reduced side effect of the PPAR-? agonist.
MEANS FOR SOLVING THE PROBLEMS
[0013]
As a result of intensive study to solve the above-described problems, the
present inventors discovered that, by employing an IP agonist at a dose at which no
effective hypoglycemic action is exerted in combination with a PPAR-? agonist at a
dose at which no effective hypoglycemic action is exerted but characteristic side
effects, especially an action to increase the body weight, occur, a sufficiently
effective hypoglycemic action and glucose tolerance-improving action, which are not
exerted by single-agent administration of each of these agents, are exerted and the
side effects of the PPAR-? agonist can be reduced, thereby completing the present
invention.
[0014]
That is, the present invention is as follows.
(1) A therapeutic or prophylactic agent for diabetes, comprising a combination of
an IP agonist and a PPAR-? agonist.
(2) The therapeutic or prophylactic agent according to (1), wherein the IP agonist
is a prostaglandin I2 derivative represented by General Formula (I):
[0015]

[0016]
(wherein
Rl represents a pharmaceutically acceptable cation or hydrogen;
R2 represents hydrogen or C2-C10 acyl;
R3 represents hydrogen or C2-C10 acyl;
R4 represents hydrogen, methyl or ethyl;
R5 represents C1-C5 linear alkyl;
A represents
i) —CH2—CH2—; or
ii) trans —CH=CH—; and
X represents trans —CH=CH—).
[0017]
(3) The therapeutic or prophylactic agent according to (2), wherein the
prostaglandin I2 derivative represented by General Formula (I) is beraprost sodium.
[0018]
(4) The therapeutic or prophylactic agent according to any of (1) to (3), wherein
the PPAR-? agonist is a thiazolidine derivative.
[0019]
(5) The therapeutic or prophylactic agent according to (4), wherein the
thiazolidine derivative is pioglitazone or a pharmaceutically acceptable salt thereof.
[0020]
(6) The therapeutic or prophylactic agent according to any of (1) to (5), wherein
each of the IP agonist and PPAR-? agonist is used at a dose at which a therapeutic or
prophylactic effect for diabetes is not exerted by single-agent administration thereof.
[0021]
Further, the following parts in the above description are preferred in the
present invention.
(1)' A therapeutic or prophylactic agent for diabetes, comprising a combination of
a prostaglandin I2 derivative represented by General Formula (I):
[0022]

[0023]
(wherein
R represents a pharmaceutically acceptable cation or hydrogen;
R2 represents hydrogen or C2-C10 acyl;
R3 represents hydrogen or C2-C10 acyl;
R4 represents hydrogen, methyi or ethyl;
R5 represents C1-C5 linear alkyl;
A represents
i) — CH2—CH2—; or
ii) trans —CH=CH—; and
X represents trans —CH=CH—)
and a thiazolidine derivative.
[0024]
(2)' The therapeutic or prophylactic agent according to (1)', wherein, in the
General Formula (I), both R2 and R3 are hydrogen, both R4 and R5 are methyl, and A
is —CH2~CH2—.
[0025]
(3)' The therapeutic or prophylactic agent according to (2)', wherein the
prostaglandin I2 derivative represented by General Formula (I) is beraprost sodium.
[0026]
(4)' The therapeutic or prophylactic agent according to any of (1)' to (3)', wherein
the thiazolidine derivative is pioglitazone or a pharmaceutically acceptable salt
thereof.
EFFECT OF THE INVENTION
[0027]
Since the therapeutic or prophylactic agent of the present invention shows a
sufficiently effective hypoglycemic action and glucose tolerance-improving action
without causing side effects characteristic to PPAR-? agonists (e.g., body weight
gain), the agent is useful as a highly safe and effective therapeutic or prophylactic
agent for diabetes.
BEST MODE FOR CARRYING OUT THE INVENTION
[0028]
In the present invention, "IP agonist" is a general term for agents which bind
to prostaglandin I2 (IP) receptors on the cell membrane to exert actions such as
vasodilation, platelet aggregation inhibition, smooth-muscle proliferation inhibition,
vascular endothelium protection and inflammatory cytokine inhibition. The IP
agonist is preferably a prostaglandin I2 derivative represented by the General Formula
(I), and the IP agonist is especially preferably beraprost, which is a compound
described in JP 1-53672 B, or beraprost sodium, which is the sodium salt thereof; or
Compound 1:
[0029]

which is an isomer constituting beraprost, or
[0030]
Compound 2:
[0031]
which is the sodium salt thereof.
[0032]
The prostaglandin I2 derivatives represented by the General Formula (I)
include d-isomers, 1-isomers and dl-isomers, and also include mixtures of compounds
represented by the General Formula (I).
[0033]
Preferred examples of the IP agonist also include octimibate (DE 3504677 B)
and the compounds described in this specification; ataprost (JP 54-130543 A) and the
compounds described in this publication; CS-570 (JP 54-95552 A) and the
compounds described in this publication; cicaprost (JP 59-157050 A) and the
compounds described in this publication; OP-2507 (JP 61-30519 A) and the
compounds described in this publication; clinprost (JP 59-137445 A) and the
compounds described in this publication; pimilprost (JP 59-141536 A) and the
compounds described in this publication; TY-11223 (JP 03-246252 A) and the
compounds described in this publication; samixogrel (JP 03-005457 A) and the
compounds described in this publication; epoprostenol sodium (JP 52-136161 A) and
the compounds described in this publication; treprostinil sodium (US 4306075 B)
and the compounds described in this specification; iloprost (JP 55-057559 A) and the
compounds described in this publication; ibudilast(JP 48-097898 A) and the
compounds described in this publication; ozagrel sodium (JP 55-000313 A) and the
compounds described in this publication; isbogrel (JP 58-219162 A) and the
compounds described in this publication; TRA-418 (WO 00/07992) and the
compounds described in this literature; phthalazinol (JP 50-70380 A) and the
compounds described in this publication; and NS-304 (WO 02/088084) and the
compounds described in this literature. Either a single type or a combination of 2 or
more types of IP agonist(s) may be used.
[0034]
In the prostaglandin I2 derivatives represented by the General Formula (I),
examples of the "pharmaceutically acceptable cation" include metal cations and
amine cations.
[0035]
The metal cations are those induced from alkaline metals (e.g., lithium,
sodium and potassium) and alkaline earth metals (e.g., magnesium and calcium).
Cations induced from other metals such as aluminum, zinc and iron are of course
included in the present invention.
[0036]
The amine cations are those induced from primary amines, secondary amines
and tertiary amines. Examples of suitable amines include: (1) aliphatic, alicyclic
and aromatic amines and heterocyclic amines, such as methylamine, dimethylamine,
triethylamine, ethylamine, dibutylamine, triisopropylamine, N-methylhexylamine,
decylamine, dodecylamine, allylamine, crotylamine, cyclopentylamine,
dicyclohexylamine, benzylamine, dibenzylamine, a-phenylethylamine, (3-
phenyl ethyl amine, ethylenediamine, di ethyl enetri amine, 1 -methylpiperidine, 4-
ethylmorpholine, 1-isopropylpyrrolidine, 2-methylpyrrolidine, 1,4-
dimethylpiperazine and 2-methylpiperidine; (2) water-soluble amines and amines
having a hydrophilic group(s), such as mono-ethanolamine, di-ethanolamine, tri-
ethanolamine, ethyIdiethanolamine, N-butylethanolamine, 2-amino-l-butanol, 2-
amino-2-ethyl-l,3-propanediol, tris(hydroxymethyl)aminomethane and N-
phenylethanolamine; and (3) basic amino acids, such as lysine and arginine.
[0037]
The "C1-C5 linear alkyl" is methyl, ethyl, propyl, butyl or pentyl. Examples
of the "C2-C12 acyl" include acetyl, propionyl, pentanoyl, hexanoyl and decanoyl.
[0038]
In the present invention, prostaglandin I2 derivatives represented by the
General Formula (I), especially beraprost sodium, are preferred among IP agonists.
Since beraprost sodium is physicochemically stable for a long period and has high
oral bioavailability, effective therapy of diabetes can be realized by use of beraprost
sodium in combination. Further, since beraprost sodium has been used in many
clinical cases, its long-term safety in cases of administration to human has been
established, so that beraprost sodium is especially preferably used.
[0039]
Beraprost sodium is already commercially available and its production
method is well known. Beraprost sodium can be produced by, for example, the
method described in JP 1-53672 B. Further, in the present invention, a
commercially available beraprost sodium may also be preferably used. Beraprost
sodium is normally used together with a pharmaceutically acceptable carrier or
vehicle, in the form of a common oral pharmaceutical formulation such as a tablet,
capsule, powder, granules or liquid, but the dosage form is not restricted thereto.
[0040]
Prostaglandin I2 derivatives represented by General Formula (I) other than
beraprost sodium can also be produced by, for example, the method described in JP
1-53672 B.
[0041]
Compounds 1 and 2 can be produced by, for example, the method described
in a known literature (Heterocycles, Vol.53, No.5, p. 1085-1110, 2000) or a
salification method which is commonly used. These are normally used together
with a pharmaceutically acceptable carrier or vehicle, in the form of a common oral
pharmaceutical formulation such as a tablet, capsule, powder, granules or liquid, but
the form is not restricted thereto.
[0042]
In the present invention, "PPAR-? agonist" is a general term for agents which
act on a nuclear receptor, peroxisome proliferator-activated receptor gamma (PPAR-
y), to enhance the insulin sensitivity. Preferred examples of the PPAR-? agonist
include pioglitazone hydrochloride and rosiglitazone maleate, which are currently
commercially available; and Isaglitazone, Rivoglitazone, Bardoxolone, Aleglitazar,
Lobeglitazone, ZYH-1, AVE-0897, Chiglitazar, THR-0921, GFT-505, Indeglitazar,
GSK-376501 and Inoglitazone, which are currently being developed. Among
PPAR-? agonists, thiazolidine derivatives are preferred. "Thiazolidine derivatives"
herein means a group of compounds having thiazolidinedione as a partial structure.
Among thiazolidine derivatives, pioglitazone, which is a compound described in US
4,687,777 B and commercially available, and pharmaceutically acceptable salts
thereof are especially preferred. Examples of the pharmaceutically acceptable salts
include inorganic salts such as hydrochloric acid salt, nitric acid salt, hydrobromic
acid salt, sulfuric acid salt, boric acid salt and phosphoric acid salt; organic acid salts
such as acetic acid salt, maleic acid salt, fumaric acid salt, tartaric acid salt, succinic
acid salt, malic acid salt, lactic acid salt, citric acid salt, malonic acid salt, benzoic
acid salt, paratoluene sulfonic acid salt and methane sulfonic acid salt; and acid
addition salts including those to which an amino acid such as lysine, glycine,
phenylalanine, asparagine or glutamic acid is added. Either a single type or a
combination of 2 or more types of PPAR-? agonist(s) may be used.
[0043]
Pioglitazone hydrochloride is an excellent insulin sensitizer, and, by
recovering the function of damaged insulin receptors, it normalizes the intracellular
localization of glucose transporters and normalizes enzyme systems playing central
roles in glucose metabolism, such as glucokinase, or lipid metabolism-related
enzyme systems, such as lipoprotein lipase. This results in not only improvement of
insulin resistance and glucose tolerance, but also reduction of neutral fat and free
fatty acids. In addition, since pioglitazone hydrochloride has been used in many
clinical cases, its long-term effectivity in human has been established, so that
pioglitazone hydrochloride is especially preferably used.
[0044]
The production methods of pioglitazone and its pharmaceutically acceptable
salts are well known, and the production can be carried out by, for example, the
methods described in JP 55-22636 A and JP 61-267580 A. Commercially available
products may also be preferably used. Pioglitazone or its pharmaceutically
acceptable salt is normally used together with a pharmaceutically acceptable carrier
or vehicle, in the form of a common oral pharmaceutical formulation such as a tablet,
capsule, powder, granules or liquid, but the form is not restricted thereto.
[0045]
In the present invention, the combination of a compound represented by the
General Formula (I), especially beraprost sodium, among IP agonists, and especially
pioglitazone hydrochloride among PPAR-? agonists is most preferred.
[0046]
In the present invention, "therapeutic or prophylactic agent for diabetes" also
includes an agent which is a therapeutic agent as well as a prophylactic agent for
diabetes.
[0047]
The dose of the therapeutic or prophylactic agent of the present invention may
be determined according to the doses of the individual agents, and may be
appropriately selected depending on the age, body weight and symptoms of the
subject to whom the agent is to be administered; administration time; dosage form;
administration method; combination of agents; and the like.
[0048]
In cases where the IP agonist in the present invention is used for human, it is
preferred to administer the IP agonist in an amount of, for example, 1 to 1000
ug/adult/administration, preferably 5 to 500 ug/adult/administration in terms of the
amount of a prostaglandin I2 derivative represented by the General Formula (I) as an
effective component, which is preferably administered at one time or dividedly in
about 2 to 4 times for not less than lday, especially not less than 3 days. In cases
where the IP agonist is applied to a non-human mammal, the dose is preferably 0.1
ug/kg to 100 mg/kg, more preferably 1 ug/kg to 50 mg/kg in terms of the amount of a
prostaglandin I2 derivative represented by the General Formula (I) as an effective
component, which is administered at one time or dividedly in about 2 to 4 times for
not less than lday, especially not less than 3 days.
[0049]
The dose of the PPAR-? agonist in the present invention may be selected, in
the cases of oral administration, within the range of 0.01 to 10 mg/kg body weight,
which is the clinical dose (preferably 0.05 to 10 mg/kg body weight, more preferably
0.05 to 5 mg/kg body weight), and, in the cases of parenteral administration, within
the range of 0.005 to 10 mg/kg body weight (preferably 0.01 to 10 mg/kg body
weight, more preferably 0.01 to 1 mg/kg body weight). The administration is
usually carried out 1 to 3 times a day.
[0050]
Surprisingly, as concretely described in the Examples below, an excellent
therapeutic or prophylactic effect for diabetes is exerted by combined use of the IP
agonist and the PPAR-? agonist even in cases where the dose of each of these
agonists is one at which a therapeutic or prophylactic effect for diabetes is not
exerted by single-agent administration. In addition, although the PPAR-? agonist
causes side effects such as body weight gain even at such a dose, the IP agonist
reduces the side effects of the PPAR-? agonist. Therefore, in the present invention,
by using the IP agonist and the PPAR-? agonist such that each of these is
administered at a dose at which a therapeutic or prophylactic effect for diabetes is not
exerted by single-agent administration and at which the IP agonist reduces side
effects of the PPAR-? agonist, an excellent therapeutic or prophylactic effect can be
achieved while reduction of the side effects and reduction of the cost of therapy can
be achieved (reduction of the dose of the agent, of course, results in a lower cost),
which is preferred. Such a dose of the IP agonist is, in the cases of oral
administration, 5 to 500 ug/adult/administration, preferably 5 to 250
ug/adult/administration, which is preferably administered at one time or dividedly in
about 2 to 4 times for not less than lday, especially not less than 3 days. The dose
of the PPAR-? agonist may be selected, in the cases of oral administration, within the
range of 0.05 to 1.0 mg/kg body weight, preferably 0.05 to 0.5 mg/kg body weight,
and, in the cases of parenteral administration, within the range of 0.025 to 1.0 mg/kg
body weight, preferably 0.025 to 0.5 mg/kg body weight. The administration is
usually carried out 1 to 3 times a day.
[0051]
The administration method is not restricted and may be selected from, for
example, oral administration, subcutaneous administration, intravenous or
intravascular administration, intramuscular administration, pulmonary administration,
intraduodenal administration and intraperitoneal administration. A more preferred
dosage form is oral administration.
[0052]
In the present invention, the IP agonist, for example, a prostaglandin h
derivative represented by the General Formula (I), may be formulated as appropriate
using a pharmaceutically acceptable additive which is necessary for the formulation.
More particularly, examples of a vehicle which may be contained in the formulation
include sugars such as lactose, mannitol, xylitol and dextrin; starches such as corn
starch, hydroxypropyl starch and partially-alphanized starch; cellulose derivatives
such as crystalline cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose
and sodium carboxymethylcellulose; polyvinylpyrrolidone; polyethylene oxide
5000K; and mixtures composed of 2 or more of these. Examples of a binder which
may be contained in the formulation include hydroxypropyl cellulose (HPC),
hydroxypropyl methylcellulose (HPMC), methyl cellulose (MC), sodium
carboxymethylcellulose (CMCNa), polyvinylpyrrolidone (PVP), polyethylene glycol
(PEG), starch, Macrogol 6000, L-glutamic acid, magnesium stearate, and mixtures
composed of 2 or more of these.
[0053]
In the present invention, the IP agonist, such as a formulation containing a
prostaglandin I2 derivative represented by the General Formula (I), may be
administered either orally or parenterally.
[0054]
In the cases of oral administration, the prostaglandin I2 derivative represented
by the General Formula (I) may be formulated into a tablet, powder, fine granules,
granules, tablet, liquid, syrup, capsule, pill or spray. In such cases, the shaped
product may be coated with a film, coated with sugar or filled in a capsule.
Formulation into a tablet, fine granules, granules, powder or liquid is especially
preferred. Alternatively, when a prostaglandin I2 derivative represented by the
General Formula (I) is formulated, the effective component may be included in a
food to prepare a formula meal. Such a formula meal may be in the form of a solid,
semifluid or solution.
[0055]
In the cases of parenteral administration, the IP agonist, such as a
prostaglandin I2 derivative represented by the General Formula (I), may be
formulated into various injection solutions or suppository. In such cases, another
solute such as sodium chloride or glucose enough to make the solution isotonic may
be used, or the formulation may be prepared into a sustained-release formulation by a
known method such as use of a hydrogel.
[0056]
The administration route of the PPAR-? agonist used in the present invention
is commonly oral administration. The unit dosage form is not restricted as long as it
is prepared by a normal formulation technique, and examples thereof include
powders, granules, tablets and capsules.
[0057]
These various formulations may be prepared according to conventional
methods using known auxiliary materials which may be normally used in the field of
formulation of pharmaceuticals, such as vehicles, binders, disintegrators, lubricants,
solubilizers, correctives and coating agents.
[0058]
For example, as a carrier used for shaping into a tablet, those known in the art
may be widely used, and specific examples of the carrier include vehicles such as
lactose, saccharose, sodium chloride, glucose, urea, starch, calcium carbonate, kaolin,
crystalline cellulose and silicic acid; binders such as water, ethanol, propanol, simple
syrup, glucose solutions, starch solutions, gelatin solutions, carboxymethyl cellulose,
shellac, methyl cellulose, potassium phosphate and polyvinyl pyrrolidone;
disintegrators such as dry starch, sodium alginate, agar powder, laminaran powder,
sodium hydrogen carbonate, calcium carbonate, polyoxyethylene sorbitan fatty acid
esters, sodium lauryl sulfate, stearic acid monoglyceride, starch and lactose;
disintegration suppressing agents such as saccharose, stearin, cacao butter and
hydrogenated oil; absorption enhancers such as quaternary ammonium base and
sodium lauryl sulfate; moisturizers such as glycerin and starch; adsorbents such as
starch, lactose, kaolin, bentonite and colloidal silicic acid; and lubricants such as
purified talc, stearate, boric acid powder and polyethylene glycol. The tablet may be
prepared as a tablet with a normal coating, such as a sugar-coated tablet, gelatin-
coated tablet, enteric-coated tablet or film-coated tablet, or a bilayer tablet or
multilayer tablet.
[0059]
As a carrier used for shaping into a pill, those known in the art may be widely
used, and specific examples of the carrier include vehicles such as glucose, lactose,
starch, cacao butter, hydrogenated vegetable oil, kaolin and talc; binders such as gum
arabic powder, powdered tragacanth, gelatin and ethanol; and disintegrators such as
laminaran agar. Further, as required, a coloring agent, preservative, perfume,
flavoring agent, sweetener and/or another drug may be contained..
[0060]
The amount of the PPAR-7 agonist contained in the pharmaceutical
formulation is not restricted and may be appropriately selected from a wide range,
and the amount is usually 1 to 70% by weight, preferably 1 to 30% by weight with
respect to the total amount of the composition.
[0061]
The therapeutic or prophylactic agent of the present invention may be
administered in the form of a combination drug. Alternatively, a plurality of
individual agents may be administered at the same time. Alternatively, the
individual agents may be administered at appropriate intervals. The intervals
acceptable for allowing an effect caused by administration of the drug to be achieved
can be confirmed clinically or by an animal experiment. Each single agent is
formulated into a form appropriate for the compound, and then administered. The
administration route may be different among the agents.
[0062]
In the therapeutic or prophylactic agent of the present invention, in cases
where a side effect, especially body weight gain, was observed as a result of
administration of a PPAR-? agonist, the dose of the PPAR-? agonist may be reduced
as appropriate to within the range whose upper limit is a dose at which a clinically
acceptable minor side effect occurs.
[0063]
Further, in the present invention, a known antidiabetic agent may be used in
combination. Examples of the known antidiabetic agent include PPAR-a agonists,
PPAR- 5 agonists, retinoid RXR agonists, p3-adrenaline receptor agonists, 11 (3-
hydroxysteroid dehydrogenase inhibitors, protein tyrosine phosphatase-IB (PTP-1B)
inhibitors, AMP-activated protein kinase (AMPK) activators, acetyl-CoA
carboxylase (ACC) inhibitors, cannabinoid receptor 1(CB1) antagonists, insulin
secretagogues (ATP-dependent potassium channel inhibitors (sulfonylurea drugs,
sulfonamide drugs, phenylalanine derivatives and the like)), biguanides, a-
glucosidase inhibitors, insulin formulations, insulin analogues, dipeptidyl peptidase
IV inhibitors, glucagon-like peptide 1 (GLP1) agonists and GLP1. These known
antidiabetic agents may also be administered in the form of a combination drug.
Alternatively, a plurality of individual agents may be administered at the same time.
Alternatively, the individual agents may be administered at appropriate intervals.
[0064]
Examples of the method of evaluation of the therapeutic or prophylactic effect
for diabetes in the present invention include blood glucose measurement, the glucose
tolerance test and the hyperinsulinemic euglycemic glucose clamp method, and, in
particular, blood glucose measurement and the glucose tolerance test are employed as
diagnostic methods for diabetes.
[0065]
The present invention will now be described more concretely by way of
Examples below, but the present invention is not restricted to these Examples.
EXAMPLES
[0066]
Example 1
Combined Effect of Beraprost Sodium (BPS) and Pioglitazone Hydrochloride on
Blood Glucose Level and Body Weight of KKAy Mice
For the experiment, male KKAy mice (CLEA Japan, Inc.) were used. KKAy
mice show obesity and high blood glucose from 7 or 8 weeks old, and are commonly
used as model mice for type 2 diabetes. The KKAy mice were purchased when they
were 5 weeks old, and, from immediately thereafter, fed with CMF feed (Oriental
Yeast Co., Ltd.) for 3 weeks under free food/water intake conditions, before being
subjected to the experiment. For continuous subcutaneous administration of a
solvent (physiological saline, 6 uL/day) or BPS (1 mg/kg/day, commercially
available product from Toray Industries, Inc.), a minipump for sustained release
(Alzet micro osmotic pump model 1002, Alzet osmotic pumps company) was
subcutaneously placed in each KKAy mouse. The continuous administration of
physiological saline or BPS was carried out until the end of the experiment. From 3
days after the placement (beginning of the subcutaneous continuous administration),
oral administration of a solvent (0.5% methyl cellulose (MC) solution, 10 mL/kg) or
pioglitazone hydrochloride (product synthesized in Toray Industries, Inc.) was started.
Pioglitazone hydrochloride was administered as a suspension in 0.5% MC solution.
The 0.5% MC solution and pioglitazone hydrochloride were administered for 10 days,
during which the administration was carried out once per day in the evening. The
mice were divided into the following experimental groups,
[0067]
(1) Control group (n=8): physiological saline (6 uL/day) + 0.5% MC solution (10
mL/kg)
(2) BPS group (n=6): BPS (1 mg/kg/day) + 0.5% MC solution (10 mL/kg)
(3) Pioglitazone hydrochloride 3 mg group (n=6): physiological saline (6 uL/day)
+ pioglitazone hydrochloride (3 mg/kg)
(4) BPS/pioglitazone hydrochloride 3 mg-combined-use group (n=6): BPS (1
mg/kg/day) + pioglitazone hydrochloride (3 mg/kg)
(5) Pioglitazone hydrochloride 30 mg group (n=6): physiological saline (6
uL/day) + pioglitazone hydrochloride (30 mg/kg)
[0068]
The body weight and the casual blood glucose level were measured on the day
before starting of the continuous administration of physiological saline or BPS (these
correspond to the data shown in the "Before administration" columns in Tables 1 and
2). The body weight was measured when 0.5% MC solution or pioglitazone
hydrochloride was finally administered, and the casual blood glucose level was
measured about 18 hours after the final administration (these correspond to the data
shown in the "After administration" columns in Tables 1 and 2). The casual blood
glucose level was measured by collecting about 5 uL of blood from the tail vein and
subjecting the blood to measurement with a simplified blood glucose meter
(Medisense Precision Xceed, ABBOTT JAPAN Co., LTD.).
[0069]
As a result, as shown in Table 1, the BPS group and the pioglitazone
hydrochloride 3 mg group showed no change in the casual blood glucose level
compared to the value observed before the beginning of drug administration. On
the other hand, the BPS/pioglitazone hydrochloride 3 mg-combined-use group and
the pioglitazone hydrochloride 30 mg group showed significant decrease in the casual
blood glucose level compared to the value observed before the beginning of drug
administration, and the extent of the action was similar between these groups.
[0070]
In terms of the action on the body weight, as shown in Table 2, the
pioglitazone hydrochloride 3 mg group and the pioglitazone hydrochloride 30 mg
group showed significant increase in the body weight compared to the value observed
before the beginning of drug administration. On the other hand, the
BPS/pioglitazone hydrochloride 3 mg-combined-use group showed no change in the
body weight compared to the value observed before the beginning of drug
administration.
[0071]
Thus, it was revealed that, by combined administration of BPS at a dose at
which a sufficiently effective hypoglycemic action is not exerted by single-agent
administration and 3 mg of pioglitazone hydrochloride, an action to decrease the
casual blood glucose level is exerted to almost the same extent as in the case of
administration of 30 mg/kg pioglitazone hydrochloride, and the body weight-
increasing action, which is observed after single-agent administration of 3 mg/kg
pioglitazone hydrochloride, can be suppressed.
[0072]
Table 1. Casual blood glucose levels observed before and after administration of
drugs (in KKAy mice)
**p<0.01, paired t-test for data obtained before and after administration of each drug
Each value in the table represents the mean±standard error among individuals.
[0073]
Table 2. Body weights observed before and after administration of drugs (in KKAy
mice)
**p<0.01, paired t-test for data obtained before and after administration of each drug
Each value in the table represents the mean±standard error among individuals.
[0074]
Example 2
Combined Effect of Beraprost Sodium (BPS) and Pioglitazone Hydrochloride on
Glucose Tolerance of KKAy Mice
For the experiment, male KKAy mice (CLEA Japan, Inc.) were used. The
KKAy mice were purchased when they were 5 or 7 weeks old, and, from
immediately thereafter, fed with CMF feed (Oriental Yeast Co., Ltd.) for 2 to 4
weeks under free food/water intake conditions, before being subjected to the
experiment. After dividing the mice into groups, oral administration of a solvent
(0.5% methyl cellulose (MC) solution, 10 mL/kg) or pioglitazone hydrochloride
(product synthesized in Toray Industries, Inc.) was started. Pioglitazone
hydrochloride was administered as a suspension in 0.5% MC solution. The MC
solution and pioglitazone hydrochloride were administered for 20 days, during which
the administration was carried out once per day in the evening. Six days after the
beginning of administration of the MC solution and pioglitazone hydrochloride, for
continuous subcutaneous administration of a solvent (physiological saline, 6 uL/day)
or BPS (1 mg/kg/day, commercially available product from Toray Industries, Inc.), a
minipump for sustained release (Alzet micro osmotic pump model 1002, Alzet
osmotic pumps company) was subcutaneously placed in each KKAy mouse. The
continuous administration of physiological saline or BPS was carried out until the
end of the experiment. The experimental groups were as follows.
[0075]
(1) Control group (n=6): physiological saline (6 uL/day) + 0.5% MC solution (10
mL/kg)
(2) BPS group (n=5): BPS (1 mg/kg/day) + 0.5% MC solution (10 mL/kg)
(3) Pioglitazone hydrochloride 3 mg group (n=5): physiological saline (6 uL/day)
+ pioglitazone hydrochloride (3 mg/kg)
(4) BPS/pioglitazone hydrochloride 3 mg-combined-use group (n=6): BPS (1
mg/kg/day) + pioglitazone hydrochloride (3 mg/kg)
(5) Pioglitazone hydrochloride 30 mg group (n=6): physiological saline (6
uL/day) + pioglitazone hydrochloride (30 mg/kg)
[0076]
After the final oral administration of 0.5% MC solution and pioglitazone
hydrochloride, a glucose tolerance test was carried out. This glucose tolerance test
was carried out by fasting the mice for not less than 17 hours and performing forced
oral administration of an aqueous glucose solution (1.5 g/10 mL/kg) under
unanesthetized conditions. The blood glucose level was measured immediately
before the administration of glucose (this timing is regarded as "0 minute") and 15,
30, 60 and 120 minutes after the administration of glucose. The blood glucose level
was measured by collecting about 5 uX of blood from the tail vein and subjecting the
blood to measurement with a simplified blood glucose meter (Glutest Ace R,
ARKRAY, Inc./Sanwa Kagaku Kenkyusho Co., Ltd.). The increase in the blood
glucose level at each timing relative to the blood glucose level observed immediately
before the administration of glucose (0 minute) was defined as Ablood glucose level.
The length of time (minutes) after the administration of glucose was plotted along the
abscissa and Ablood glucose level (mg/dL) was plotted along the ordinate, to
calculate the area under the Ablood glucose level-time curve from 0 minute to 120
minutes (AAUC0-120).
[0077]
As a result, as shown in Table 3, the BPS group and the pioglitazone
hydrochloride 3 mg group showed no change in AAUC0.120 compared to the control
group. On the other hand, the BPS/pioglitazone hydrochloride 3 mg-combined-use
group showed significant decrease in AAUC0-120 compared to the control group, so
that a glucose tolerance-improving action was observed. The amount of decrease in
the value was significantly larger than that observed in the pioglitazone
hydrochloride 30 mg group.
[0078]
Thus, it was revealed that, by combined use of BPS and pioglitazone
hydrochloride, each at a dose at which a hypoglycemic action is not exerted by
single-agent administration, a glucose tolerance-improving action is exerted in KKAy
mice to almost the same or a higher extent compared to the case of administration of
30 mg/kg pioglitazone hydrochloride, indicating that the combination shows a
sufficient effect as a therapeutic and prophylactic agent for diabetes.
[0079]
Table 3. The area under the Ablood glucose level-time curve (AAUC0-120) in the
glucose tolerance test after administration of a drug (in KKAy mice)

*p<0.05, t-test against the control group
#p<0.05, t-test against the pioglitazone hydrochloride 30 mg group
Each value in the table represents the mean±standard error among individuals.
INDUSTRIAL APPLICABILITY
[0080]
By the present invention, it was confirmed that combined administration of an
IP agonist, especially a prostaglandin I2 derivative represented by the General
Formula (I), with a PPAR-? agonist enhances the hypoglycemic action of the PPAR-?
agonist, reduces side effects (especially body weight gain), and allows a glucose
tolerance-improving action. Therefore, the therapeutic or prophylactic agent of the
present invention by combination of an IP agonist and a PPAR-? agonist can be
expected to be an excellent therapeutic or prophylactic agent for diabetes, in which
side effects of the PPAR-? agonist are reduced.
We Claim:
1. A therapeutic or prophylactic agent for diabetes, comprising a combination of
a prostaglandin I2 derivative represented by General Formula (I):

(wherein
R1 represents a pharmaceutically acceptable cation or hydrogen;
R2 represents hydrogen or C2-C10 acyl;
R3 represents hydrogen or C2-C10 acyl;
R4 represents hydrogen, methyl or ethyl;
R5 represents C1-C5 linear alkyl;
A represents
i) ~-CH2—CH2—; or
ii) trans — CH=CH—; and
X represents trans —CH=CH—)
and a thiazolidine derivative.
2. The therapeutic or prophylactic agent according to claim 1, wherein, in said
General Formula (I), both R and R3 are hydrogen, both R4 and R5 are methyl, and A
is —CH2—CH2—.
3. The therapeutic or prophylactic agent according to claim 2, wherein said
prostaglandin I2 derivative represented by General Formula (I) is beraprost sodium.
4. The therapeutic or prophylactic agent according to any one of claims 1 to 3,
wherein said thiazolidine derivative is pioglitazone or a pharmaceutically acceptable
salt thereof.

ABSTRACT

A therapeutic or prophylactic agent for diabetes comprising a thiazolidine
derivative as a PPAR-γ agonist as an effective component, which agent shows a
reduced side effect of the PPAR-γ agonist, is disclosed. The therapeutic or
prophylactic agent for diabetes comprises a particular IP agonist such as beraprost
sodium (BPS), and a thiazolidine derivative such as pioglitazone or a
pharmaceutically acceptable salt thereof. Since the therapeutic or prophylactic
agent of the present invention shows a sufficiently effective hypoglycemic action
without being accompanied by side effects characteristic to PPAR-γ agonists (e.g.,
body weight gain), the agent is useful as a highly safe and effective therapeutic or
prophylactic agent for diabetes.