JPH10203966A - Sustained release microcapsule and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sustained release microcapsule of an acetylcholine esterase inhibitor suitable for prevention and treatment of dementia, having high content and excellent in release controllability by including the acetylcholine esterase inhibitor with an in vivo degradable polymer. SOLUTION: The preparation includes an acetylcholine esterase inhibitor, an in vivo degradable polymer and an organic solvent, and preferably obtained by microcapsulating the components by dispersing an oil phase containing the components in water phase to form O/W type emulsion and drying the dispersoid in water. The acetylcholine esterase inhibitor is preferably a piperidine derivative having nonpeptide free base, especially 8-[1-oxo-3-[1-(phenylmethyl) piperidin-4-yl]propyl]-2,3,4,5-tetrahydro-1H-1-benzazepine. The in vivo degradable polymer is a lactic acid-glycolic acid polymer or a copolymer having about (100/0) to (50/50) of the ratio of lactic acid/glycolic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sustained-release microcapsule of an acetylcholinesterase inhibitor useful as a therapeutic agent for dementia and a method for producing the same.

[0002]

2. Description of the Related Art A prophylactic / therapeutic drug for Alzheimer's dementia mediated by the choline system is
Muscarinic receptor agonists and acetylcholinesterase inhibitors are roughly classified.

[0003] Acetylcholinesterase inhibitors administered as prophylactic and / or therapeutic agents to patients with dementia such as Alzheimer's disease (mainly the elderly) have dementia symptoms when administration is stopped. Administration is required. During this time, related to the administration or taking of the drug,
The effort forced on the person or caregiver is enormous. Therefore, with the expectation of improving the convenience and certainty (compliance) of drug administration, it is desired to develop sustained-release preparations for preventive and therapeutic drugs for dementia. For sustained release formulations of acetylcholinesterase inhibitors, see WO 95/0305.
No. 2 discloses oral administration of tacrine comprising a tacrine composition adjusted so that the osmotic pressure inside the skin is always higher than the osmotic pressure in the gastrointestinal tract, in a semi-permeable skin having an outlet. A sustained-release pellet for use is described, and in this oral preparation, after administration, tacrine dissolved by body fluid permeated through the skin in the gastrointestinal tract is gradually released from the release port by a difference in osmotic pressure between the inside and outside of the preparation. Features. W09 / 00
No. 065 describes an oral caplet containing a quick-release and sustained-release tacrine-containing core pellet as a controlled release formulation of tacrine. Israel Patent No. 777
No. 33 discloses a method for producing a sustained-release preparation for transdermal application of physostigmine.

However, sustained-release preparations reported on acetylcholinesterase inhibitors have a sustained-release period of less than several days after a single administration, and are intended for transdermal or oral administration. And the convenience of medication is still not sufficient. Therefore, as a therapeutic agent which is easier to administer, a preparation for sustained release of the drug for 2 weeks to several months after administration, particularly an injection, is desired. On the other hand, it has been reported that continuous injection of an acetylcholinesterase inhibitor is much more effective than continuous administration of a solution in a study on animal models of learning disability [Journal of Pharmacology and Experimental Therapy. (J. Pharmacol. Exp.
Ther.) 248, 825-835, 1989], and the development of long-term sustained release formulations is very important. However, since a sustained-release injection is a drug storage (depot) type and its dose per dose is limited, a formulation with a high drug content is desirable to ensure a sufficient blood concentration for onset of drug efficacy. It is. In addition, sustained-release injections tend to cause excessive drug release from sustained-release preparations called bursts in the early stage after administration, and in order to prevent peripheral side effects of drugs, it has been an issue to suppress bursts as much as possible. However, some acetylcholinesterase inhibitors are particularly necessary because some of them exhibit salivation, liver toxicity and the like as side effects. However,
A sustained-release injection of an acetylcholinesterase inhibitor satisfying these conditions is not known.

[0005]

In view of such circumstances, the present inventors have conducted intensive studies for the purpose of developing a sustained-release injection of an acetylcholinesterase inhibitor over a long period of time, and considered the dissociation state of the drug. When prepared by an in-water drying method from an oil-in-water (O / W) emulsion using a lactic acid-glycolic acid copolymer (PLGA), the initial release of the acetylcholinesterase inhibitor is low,
It has been clarified that a sustained-release preparation having a high drug content and exhibiting good sustained-release properties over a long period of time can be obtained. As a result of further intensive studies based on this finding, the present invention has been completed. That is, the present invention provides (1) a sustained-release microcapsule containing an acetylcholinesterase inhibitor and a biodegradable polymer, (2) the microcapsule according to (1), wherein the acetylcholinesterase inhibitor is a free base,
(3) the microcapsule according to (1), wherein the acetylcholinesterase inhibitor is non-peptidic; (4) the microcapsule according to (1), wherein the acetylcholinesterase inhibitor is a piperidine derivative; (5) acetylcholinesterase inhibition If the agent is 8- [1-oxo-3-
[1- (phenylmethyl) piperidin-4-yl] propyl] -2,3,4,5-tetrahydro-1H-1-benzazepine, the microcapsule according to the above (1), and (6) an acetylcholinesterase inhibitor. 1-benzyl-4-
[(5,6-dimethoxy-1-oxoindan-2-yl) methyl] piperidine according to (1), wherein the biodegradable polymer has a lactic acid / glycolic acid ratio of about 100/0. A microcapsule according to the above (1), which is a lactic acid-glycolic acid polymer or copolymer of about 50/50 (mol%); (8) a lactic acid-glycolic acid polymer or copolymer having a molecular weight of 5,000 to 20,000 The microcapsule according to the above (7), which is

(9) A preparation containing the microcapsules according to (1), (10) A preparation according to (9), which is an injection, and (11) A preparation according to (9), which is a therapeutic agent for dementia. (12) the preparation according to (11), wherein the dementia is Alzheimer's dementia, non-Alzheimer's degenerative dementia or cerebrovascular dementia, (13) acetylcholinesterase inhibitor, biodegradable polymer and organic solvent A method for producing sustained-release microcapsules, comprising removing an organic solvent from a solution or dispersion containing
4) Sustained-release microcapsules comprising dispersing an oil phase containing an acetylcholinesterase inhibitor, a biodegradable polymer and an organic solvent in an aqueous phase to prepare an O / W emulsion, and subjecting the emulsion to drying in water. (15) The method according to (13) or (14), wherein the acetylcholinesterase inhibitor is a salt with a weak acid having a pKa of 4.0 or more.
(16) The method according to (13) or (14), wherein the acetylcholinesterase inhibitor is a free base.

[0007] The acetylcholinesterase inhibitor used in the present invention is not particularly limited as long as it inhibits the enzymatic activity of acetylcholinesterase, and may be either a peptidic compound or a non-peptidic compound. Peptide acetylcholinesterase inhibitors are preferred. In the case of a compound having one or more asymmetric carbon atoms in the molecule, two or more kinds of optical isomers are present, and such optical isomers and a mixture thereof are also included in the present invention. Examples of non-peptide acetylcholinesterase inhibitors include stacofyllin
e), Metrifonate, Diflocillone (Zi
frosilone), galanthamine, tacrine and its analogs (eg, ipidacrine), physostigmine and its derivatives (eg, eptastigmine, etc.), piperidine derivatives (eg, donepezil [1-benzyl-4-[(5,6- Dimethoxy-1-oxoindane-2-
Yl) methyl] piperidine; Journal of Medicinal Chemistry (J. Med. Chem.) 38, 4821, 199
5 years], CP-118954 [Annu. Drug Data Per 17 (11), 984
, 1995], etc., and particularly preferred are derivatives having a 1-benzylpiperidine structure), and carbamoyloxybenzene derivatives (eg, SDZ-ENA-713 [Arch. Int. Pharmacody]
n. 323, 85, 1993], Ro-46-5934 [Annu. Drug Pata Re
p. 17 (4), p. 327, 1995], etc.) Amyridine [JP-B 63-63]
22520].

Further, the piperidine derivative includes:
For example, a group of compounds described in JP-A-5-1490149 is preferably exemplified, and among them, 8- [1-oxo]
-3- [1- (Phenylmethyl) piperidin-4-yl] propyl] -2,3,4,5-tetrahydro-1H-1-benzazepine (hereinafter sometimes referred to as compound 1) is known for its pharmacological activity. It is a particularly preferred object. The compound or a salt thereof (especially a fumarate thereof) is useful as a therapeutic agent for senile dementia of the Alzheimer type having acetylcholinesterase inhibitory activity, but remains free when used in the sustained-release microcapsules of the present invention. Or in the form of a salt of a weak acid. By the way, it is known that Compound 1, unlike physostigmine, which is also used for the treatment of glaucoma and myasthenia, has a long action time and shows a reliable central effect at a dose that does not show an effect on peripheral nerves. I have. Donepezil or a weak acid salt thereof is also preferably used. These compounds can be produced by a method known per se. As such a method, specifically, in the case of the above-mentioned piperidine derivative, for example, Japanese Patent Application Laid-Open No. 5-1490149 or J. Med. Chem. Or a method analogous thereto. Other non-peptidic acetylcholinesterase inhibitors can also be produced, for example, by the methods described or cited in the above documents. The non-peptide acetylcholinesterase inhibitor (hereinafter sometimes simply referred to as a drug) may be acidic, neutral or basic, but preferably has basicity.

The biodegradable polymer used in the present invention preferably has an acidic group in the molecule from the viewpoint of biocompatibility. More preferably, it is a biodegradable polymer having a free carboxyl group at a terminal. The biodegradable polymer having a free carboxyl group at the terminal used in the present invention is a gel permeation chromatograph (hereinafter referred to as GP).
This is a biodegradable polymer in which the number average molecular weight by measurement and the number average molecular weight by terminal group quantification are almost the same. The number average molecular weight by terminal group quantification is calculated as follows. About 1 to 3 g of the biodegradable polymer is mixed with acetone (25 ml) and methanol (5 ml).
And the carboxyl group in this solution was quickly titrated with a 0.05N alcoholic potassium hydroxide solution with stirring at room temperature (20 ° C.) using phenolphthalein as an indicator. Is calculated. Number average molecular weight by terminal group quantification = 20,000 × A / B A: mass of biodegradable polymer (g) B: amount of alcoholic potassium hydroxide solution added by the end of titration (ml) For example, one or more kinds In a polymer synthesized from α-hydroxy acids by a noncatalytic dehydration polycondensation method and having a free carboxyl group at a terminal, the number average molecular weight by GPC measurement and the number average molecular weight by terminal quantification are almost the same. On the other hand, in a polymer synthesized from a cyclic dimer by a ring-opening polymerization method using a catalyst and having substantially no free carboxyl group at the terminal, the number average molecular weight determined by the terminal group is determined by the GPC measurement. Significantly above average molecular weight. By this difference, a polymer having a free carboxyl group at a terminal can be clearly distinguished from a polymer having no free carboxyl group at a terminal.

[0010] While the number average molecular weight determined by terminal group quantification is an absolute value, the number average molecular weight determined by GPC is determined by various analysis and analysis conditions (for example, the type of mobile phase, the type of column, the reference material, and the slice width). Selection, baseline selection, etc.). For this reason, it is difficult to associate the two with unique numerical values.
The number average molecular weight determined by the PC measurement and the number average molecular weight determined by the terminal group quantification substantially match when the number average molecular weight determined by the terminal group quantification is about 0.4 to about 2 times, preferably about 0 times the number average molecular weight determined by the GPC measurement. The range is from about 0.5 to about 2 times, more preferably from about 0.8 to about 1.5 times. Also, the expression that the number average molecular weight determined by the terminal group determination greatly exceeds the number average molecular weight determined by the GPC measurement means that the number average molecular weight determined by the end group determination exceeds about twice the number average molecular weight determined by the GPC measurement.

Specific examples of the biodegradable polymer having a free carboxyl group at the terminal include, for example, α-hydroxycarboxylic acids (eg, glycolic acid, lactic acid, hydroxybutyric acid, etc.) and hydroxydicarboxylic acids (eg, malic acid, etc.) ), A polymer synthesized by non-catalytic dehydration polycondensation from at least one kind of hydroxytricarboxylic acid (eg, citric acid, etc.),
Copolymers or mixtures thereof, poly-α-cyanoacrylates, polyamino acids (eg, poly-γ-benzyl-L-glutamic acid), maleic anhydride-based copolymers (eg, styrene-maleic acid copolymers) And the like). The biodegradable polymer is preferably an aliphatic polyester, such as α-hydroxycarboxylic acids (eg,
Polymers synthesized from one or more of glycolic acid, lactic acid, hydroxybutyric acid, etc.), hydroxydicarboxylic acids (eg, malic acid, etc.), hydroxytricarboxylic acids (eg, citric acid, etc.) by non-catalytic dehydration polycondensation, Examples thereof include polymers and mixtures thereof. The form of polymerization is random,
Any of a block and a graft may be used. When the α-hydroxy acids, hydroxydicarboxylic acids, and hydroxytricarboxylic acids have an optically active center in the molecule, any of D-, L-, and DL-forms can be used. The biodegradable polymer having a free carboxyl group at the terminal is preferably (1) lactic acid-glycolic acid polymer or copolymer or (2) (A) glycolic acid and a compound of the formula [II]

Embedded image (Wherein, R represents an alkyl group having 2 to 8 carbon atoms) with a hydroxycarboxylic acid represented by the formula (B):
Biodegradable polymer mixed with polylactic acid. The biodegradable polymer having a free carboxyl group at a terminal is particularly preferably a lactic acid-glycolic acid copolymer.

When a lactic acid-glycolic acid polymer or copolymer is used as the biodegradable polymer, its composition ratio (lactic acid / glycolic acid) (mol%) varies depending on the sustained release period. In the case of weeks to 3 months, preferably 2 weeks to 1 month, it is about 100/0 to 50/50. The weight average molecular weight of the lactic acid-glycolic acid polymer or copolymer is generally 5,000
0 to 20,000. The weight average molecular weight is more preferably from 8,000 to 19,000, particularly preferably from 10,000 to 18,000. The dispersity (weight average molecular weight / number average molecular weight) of the lactic acid-glycolic acid polymer or copolymer is preferably about 1.2.
From about 4.0. The degree of dispersion is more preferably from about 1.5 to about 3.5. The lactic acid-glycolic acid polymer or copolymer can be produced by a known production method, for example,
It can be produced according to the production method described in JP-A 1-258521.

In the above formula [II], the linear or branched alkyl group having 2 to 8 carbon atoms represented by R is:
For example, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 1-ethylpropyl, hexyl, isohexyl, 1,1-dimethylbutyl,
Examples thereof include 2,2-dimethylbutyl, 3,3-dimethylbutyl, and 2-ethylbutyl. Preferably, a linear or branched alkyl group having 2 to 5 carbon atoms is used. Specific examples include, for example, ethyl, propyl, isopropyl, butyl, isobutyl and the like. Particularly preferably,
R is ethyl. Examples of the hydroxycarboxylic acid represented by the formula (II) include 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxycaproic acid, 2-hydroxyisocaproic acid, And hydroxycapric acid. In particular, 2-
Hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxy-3
-Methylbutyric acid and 2-hydroxycaproic acid are preferred. The hydroxycarboxylic acid of the formula (II) is particularly preferably 2-hydroxybutyric acid. These hydroxycarboxylic acids may be any of D-form, L-form and D, L-form, but the D-form / L-form (mol%) is about 75/25 to about 2 / mol.
Those having a range of 5/75 are preferred. More preferably,
D-form / L-form (mol%) is about 60/40 to about 40 /
A range of 60 hydroxycarboxylic acids. Particularly preferred is a hydroxycarboxylic acid having a D-form / L-form (mol%) in the range of about 55/45 to about 45/55.

In a copolymer of glycolic acid and a hydroxycarboxylic acid represented by the formula (II) (hereinafter abbreviated as glycolic acid copolymer (A)), the copolymerization mode is random, block or graft. Either may be used. Preferably, it is a random copolymer. One or more hydroxycarboxylic acids represented by the formula (II) may be used in an appropriate ratio. The composition ratio of glycolic acid to the hydroxycarboxylic acid represented by the formula (II) in the glycolic acid copolymer (A) is preferably such that glycolic acid is about 10 to about 75 mol% and the remainder is hydroxycarboxylic acid. More preferably, the glycolic acid is from about 20 to about 75 mole%, the balance being hydroxycarboxylic acid. Particularly preferred is when the glycolic acid is about 40 to about 70 mol%, the balance being hydroxycarboxylic acid. These glycolic acid copolymers have a weight average molecular weight of about 2,000 to about 50,000. The weight average molecular weight is preferably from about 3,000 to about 40,000. The weight average molecular weight is more preferably from about 8,000 to about 30,000. The degree of dispersion (weight average molecular weight / number average molecular weight) of these glycolic acid copolymers is preferably about 1.2 to about 4.0. The degree of dispersion is particularly preferably from about 1.5 to about 3.5. The glycolic acid copolymer (A) can be produced according to a known production method, for example, a method described in JP-A-61-28521.

The polylactic acid may be any of L-form, D-form and a mixture thereof, but those having a D-form / L-form (mol%) in the range of about 75/25 to about 20/80. Is preferred. More preferably, D-form / L-form (mol%)
Is in the range of about 60/40 to about 25/75. Particularly preferably, the D-form / L-form (mol%) is about 5%.
Polylactic acid in the range of 5/45 to about 25/75.
The weight average molecular weight of the polylactic acid is preferably about 1,50.
0 to about 30,000. The weight average molecular weight is more preferably from about 2,000 to about 20,000.
The weight average molecular weight is particularly preferably from about 3,000 to about 15,000. The polylactic acid preferably has a degree of dispersion of about 1.2 to about 4.0. The degree of dispersion is particularly preferably from about 1.5 to about 3.5. As a method for producing polylactic acid, a method of ring-opening polymerization of lactide, which is a dimer of lactic acid, and a method of dehydrating and polycondensing lactic acid are known.
In order to obtain a relatively low molecular weight polylactic acid used in the present invention, a method of directly dehydrating and polycondensing lactic acid is preferred. The production method is described in, for example, JP-A-61-28521.

The glycolic acid copolymer (A) and the polylactic acid (B) are used in a mixing ratio (% by weight) represented by (A) / (B) in the range of about 10/90 to about 90/10. Is done. The mixing ratio (% by weight) is preferably about 20 /
80 to about 80/20. The mixing ratio (% by weight)
More preferably, it is about 30/70 to about 70/30. In the present specification, the weight average molecular weight and the degree of dispersion mean the molecular weight in terms of polystyrene measured by GPC using polystyrene as a reference substance and the degree of dispersion calculated. GPC column KF804Lx2 (manufactured by Showa Denko), RI
Monitor SE-61 (Showa Denko KK) was used, and chloroform was used as a mobile phase.

The sustained-release microcapsules of the present invention can be produced by removing an organic solvent from a solution or dispersion containing a drug, a biodegradable polymer (hereinafter sometimes referred to as a polymer) and an organic solvent. Can be. In the present invention, in particular, by using a basic drug in a free base state or as a weak acid salt, by imparting an electrostatic interaction between an acidic group of the polymer and a basic group of the drug, a high drug content can be obtained. In addition, a sustained-release preparation or a microcapsule having a small initial release can be prepared. In the present invention, the sustained release microcapsules may be fine particles (microspheres) containing a drug and a polymer, and specific examples thereof include, for example, microcapsules containing one drug core in one particle. Examples include polynuclear microcapsules containing a large number of drug cores in one particle, and fine particles in which a drug is dissolved or dispersed in a polymer as a solid solution in molecular form. The weak acid used herein does not inhibit the interaction between the above-mentioned biodegradable polymer, for example, a lactic acid-glycolic acid copolymer (hereinafter sometimes referred to as PLGA) and a drug, that is, the terminal carboxyl group of the polymer used. Any acid that has a pKa greater than pKa and that can form a salt with an acetylcholinesterase inhibitor may be used. Specifically, the pKa of the terminal carboxyl group of PLGA (about 4.0)
It is preferable to use the above acids. The acid having a pKa of 4.0 or more may be any of an inorganic acid and an organic acid. Examples of the inorganic acid include carbonic acid, bicarbonate, and boric acid. As the organic acid, a monocarboxylic acid, especially a lower (C _{1) -3} ) Alkane monocarboxylic acids are preferred, for example, acetic acid, propionic acid and the like. These weak acids are more preferably acids having a pK of about a4.5 or more, and
a about 13 or less, especially those with a pKa of about 9 or less are preferred. More preferably, a basic drug is used as a free base.

The organic solvent is preferably an organic solvent having a solubility in water of 3% (W / W) or less at room temperature (20 ° C.). Further, the boiling point of the organic solvent is preferably 120 ° C. or lower. Examples of such organic solvents include halogenated hydrocarbons (eg, dichloromethane, chloroform, chloroethane, trichloroethane, carbon tetrachloride, etc.), alkyl ethers having 3 or more carbon atoms (eg, isopropyl ether, etc.), and fatty acid alkyls (eg, isopropyl ether). Examples thereof include esters (eg, having 4 or more carbon atoms) (eg, ethyl acetate, butyl acetate, etc.), aromatic hydrocarbons (eg, benzene, toluene, xylene, etc.), alcohols (eg, ethyl alcohol), and acetonitrile. These may be used as a mixture of two or more kinds at an appropriate ratio. The organic solvent is more preferably a halogenated hydrocarbon (eg, dichloromethane, chloroform, chloroethane, trichloroethane, carbon tetrachloride, etc.). The organic solvent is particularly preferably dichloromethane.

In the production method of the present invention, as a method for producing an organic solvent solution containing (a) a drug and (b) a polymer, (a) and (b) are finally dissolved in a solvent system or homogeneously. Any method can be used as long as it becomes a suitable dispersion. As the method, for example, (a) in a solution or dispersion state with a solvent and (b) in a solution or dispersion state with a solvent are mixed, and (a) is a solution or dispersion in a solvent. Mixing the state and (b),
(B) a solution or dispersion in a solvent;
(A) and (a), (b) and a solvent,
A method in which (a) and (b) are made into a solution state in a solvent system is exemplified. The above-mentioned solvents are appropriately selected so that, after mixing the respective solvents, a solvent system capable of bringing (a) and (b) into a dissolved state. Specifically, the above-mentioned solvent is mixed with, for example, a solvent obtained by mixing one or more of the above-mentioned organic solvents at an appropriate ratio to such an extent that the dissolution of (a) and (b) is not inhibited. The added solvent is used. The amount of the drug or its weak acid salt varies depending on the type of the drug and the desired duration of the duration, but the concentration in the solution is about 0.5.
001% to about 200% (W / W), more preferably 0.001% to 100% (W / W), particularly preferably 0.01% to 50% (W / W). The amount of the drug varies depending on the type of the drug, the desired pharmacological effect and the duration of the effect.
It is used from about 0.01 to about 60% (w / w) based on the base biodegradable polymer. Preferably, about 0.1 to about 55% (w / w) is used. Particularly preferably, about 1 to about 50% (w / w) is used.

The concentration of the polymer depends on the molecular weight of the polymer,
Although it depends on the type of the solvent, it is preferably about 0.01 to about 80% (W / W). More preferably, it is about 0.1 to about 70% (W / W). Particularly preferred is about 1 to about 60% (W / W). Next, the organic solvent is removed from the thus-produced solution or dispersion of the drug and the polymer to produce the microcapsule of the present invention. Specifically, a known microencapsulation method, for example, a method of microencapsulation by an underwater drying method, a phase separation method, or a spray drying method, or a solid obtained by removing the organic solvent of the oil phase by a jet mill or the like A gas pulverization method of pulverization into fine particles using a method or a method equivalent thereto is used.

In the case of producing microcapsules by the phase separation method, a coacervating agent is gradually added to an organic solvent solution of a drug and a polymer under stirring at a constant speed to precipitate and solidify the polymer. The coacervation agent is added in a volume of about 0.01 to about 1,000 times the volume of the organic solvent solution of the drug and the polymer. More preferably, the volume is about 0.05 times to about 500 times.
Particularly preferably, the volume is about 0.1 to about 200 times. The coacervation agent may be a polymer-based, mineral oil-based or vegetable oil-based compound that is miscible with the polymer solvent and does not dissolve the polymer. Specifically, for example, silicon oil, sesame oil, soybean oil, corn oil,
Cottonseed oil, coconut oil, linseed oil, mineral oil, n-hexane, n-heptane and the like. These may be used as a mixture of two or more. The microcapsules thus obtained are filtered and collected, and then repeatedly washed with heptane or the like to remove the coacervation agent. Further, the free drug and the solvent are removed by the same method as the below-mentioned in-water drying method.

In the production by the in-water drying method and the coacervation method, an anti-agglomeration agent may be added to distilled water as a washing liquid in order to prevent agglomeration of particles during washing. Examples of the coagulation inhibitor include water-soluble polysaccharides such as mannitol, lactose, glucose, starches (eg, corn starch), proteins such as glycine, fibrin and collagen, and inorganic salts such as sodium chloride and sodium hydrogen phosphate. No. When manufacturing microcapsules by the spray drying method, an organic solvent solution or dispersion of a drug and a polymer is sprayed into a drying chamber of a spray dryer (spray dryer) using a nozzle, and atomized in a very short time. The organic solvent in the droplet is volatilized to prepare microcapsules. As the nozzle, a two-fluid nozzle type,
A pressure nozzle type, a rotating disk type and the like can be mentioned. At this time, it is also effective to spray an aqueous solution of the above-mentioned anti-agglomeration agent from another nozzle simultaneously with the organic solvent solution or dispersion of the drug and the polymer simultaneously with the purpose of preventing aggregation of the microcapsules. The microcapsules thus obtained are further subjected to removal of water and an organic solvent from the microcapsules under heating and reduced pressure conditions as described above, if necessary.

In the present invention, drying in water is preferred. The drying in water is usually carried out by dispersing an oil phase containing an acetylcholinesterase inhibitor, a biodegradable polymer and an organic solvent in an aqueous phase to form an O / W emulsion,
This is performed by removing the solvent in the oil phase. The volume of the aqueous phase is generally from about 1 to about 10,000 of the oil phase volume.
Selected from double. Preferably, from about 2 to about 5,000
Selected from double. More preferably, from about 5 to about 2,
000 times. Particularly preferably, about 50 to about 10
It is 00 times. The temperature of the aqueous phase may be adjusted in advance to, for example, about 5 ° C to about 30 ° C, preferably about 10 ° C to about 25 ° C, more preferably about 10 ° C to about 20 ° C. An emulsifier may be added to the aqueous phase. The emulsifier,
In general, any material may be used as long as it can form a stable O / W emulsion. Specifically, for example, anionic surfactants (sodium oleate, sodium stearate, sodium lauryl sulfate, etc.), nonionic surfactants (polyoxyethylene sorbitan fatty acid ester [Tween 80, Tween] 60, Atlas Powder Co., Ltd.], polyoxyethylene castor oil derivatives (HCO-60, HCO-50, Nikko Chemicals, etc.), polyvinylpyrrolidone, polyvinyl alcohol, carboxymethylcellulose, lecithin, gelatin, hyaluronic acid and the like. One of these emulsifiers or a combination of some of them may be used. As the emulsifier, polyvinyl alcohol is preferably used. The concentration of the emulsifier when used is about 0.001 to about 20% (W / V)
Can be appropriately selected from the range. More preferably about 0.0
It is used in the range of 1 to about 10% (W / V). Particularly preferably, it is used in the range of about 0.05 to about 5% (W / V). Osmotic pressure regulators such as saccharides such as mannitol and salt and salts may be added to the aqueous phase. In this case, the osmotic pressure is adjusted to about 0.5 to 3 times, preferably about 2 to about 2 times the osmotic pressure of the physiological saline.

The method of removing the organic solvent can be performed according to a method known per se. For example, a method of evaporating the organic solvent at normal pressure or gradually reducing the pressure while stirring with a propeller-type stirrer or a magnetic stirrer, a method of evaporating the organic solvent while adjusting the degree of vacuum using a rotary evaporator, and the like. Can be When the O / W emulsion is dried in water, the organic solvent is volatilized and the microcapsules are solidified to determine the structure of the microcapsules. At this time, by using the drug as a free base or a salt of a weak acid and allowing the drug to interact with the terminal acidic group of the polymer, a high content of the drug can be encapsulated. Also, the initial drug release from the microcapsules prepared by this method is low. The sustained-release microcapsules thus obtained are separated by centrifugation or filtration, and the free drug, drug-retaining substance, emulsifier, etc. attached to the surface of the microcapsules are distilled several times with distilled water. Wash repeatedly, re-disperse in distilled water and freeze-dry.

At the time of freeze-drying, an anticoagulant may be added. Examples of the coagulation inhibitor include water-soluble polysaccharides such as mannitol and starches (eg, corn starch), inorganic salts, amino acids, proteins and the like. Of these, mannitol is preferred. The mixing ratio (weight ratio) of the microcapsules and the anti-agglomeration agent is about 50: 1 to about 1: 1, preferably about 20: 1 to about 1: 1,
More preferably, it is from about 10: 1 to about 5: 1. In order to prevent aggregation of particles during washing, an aggregation inhibitor may be added to distilled water as a washing liquid. As the anticoagulant,
Examples thereof include water-soluble polysaccharides such as mannitol, lactose, glucose, and starches (eg, corn starch), proteins such as glycine, fibrin and collagen, and inorganic salts such as sodium chloride and sodium hydrogen phosphate. The anti-agglomeration agent is preferably mannitol. Further, after freeze-drying, by further heating under reduced pressure, moisture and an organic solvent in the sustained-release preparation or microcapsules may be further removed to improve sustained-release properties. If the heating temperature is lower than the glass transition temperature of the biodegradable polymer used as the base, there is no effect of improving the initial release of an excessive amount of the drug, and if the temperature is too high, fusion of the microcapsules, deformation, decomposition of the drug, The risk of deterioration etc. increases. The heating temperature can not be generally specified, but the physical properties (eg, molecular weight, stability, etc.) of the biodegradable polymer used as the base, the drug, the average particle size of the microcapsules, the heating time, the degree of drying of the microcapsules, the heating It can be appropriately determined in consideration of the method and the like. Organic solvent is 1000pp
m, preferably less than 500 ppm, more preferably less than about 100 ppm.

Preferably, the microcapsules are heated and dried at a temperature not lower than the glass transition temperature of the biodegradable polymer used as the base material and at such a level that the particles of the microcapsules do not adhere to each other. More preferably, the glass transition temperature of the biodegradable polymer used as the base is about 30 ° C. above the glass transition temperature.
Heat and dry within a high temperature range. In particular, when a lactic acid-glycolic acid polymer or copolymer is used as the biodegradable polymer, the temperature is not lower than the glass transition temperature and not higher than 10 ° C. and higher than the glass transition temperature, preferably not lower than the glass transition temperature and not lower than 5 ° C. When dried by heating at a high temperature or lower (especially a temperature 3 to 4 ° C. higher than the glass transition temperature), the sustained release property is improved. Here, the glass transition temperature means a midpoint glass transition temperature (Tmg) obtained when the temperature is raised at a heating rate of 10 or 20 ° C. per minute using a differential scanning calorimeter (DSC). The heating and drying time also varies depending on the heating temperature, the amount of the microcapsules to be treated, and the like, but generally it is preferably about 24 to about 120 hours after the temperature of the microcapsules themselves reaches a predetermined temperature. About 4 more
8 to about 120 hours are preferred. Especially about 48 to about 96
Time is preferred. In particular, regarding the upper limit, the heating time may be any time as long as the remaining organic solvent and moisture are below the allowable value, but under the condition of the glass transition temperature or higher, the microcapsules are softened, and the physical contact between the microcapsules is caused. Or it is deformed by the load at the time of laminating the microcapsules. Therefore, it is desirable that the heating and drying be completed as soon as the remaining amount of the organic solvent and water becomes less than the allowable value. The heating method is not particularly limited, but any method may be used as long as the microcapsules are uniformly heated. As a preferred specific example of the heating and drying method, for example, a method of heating and drying in a constant temperature bath, a fluidized bath, a moving tank or a kiln, a method of heating and drying with a microwave, and the like are used. Among these, the method of drying by heating in a thermostat is preferred.

Sustained-release microcapsules are formulated into various dosage forms as they are or by using the microcapsules as a raw material, and parenteral preparations (eg, injections or implants for intramuscular, subcutaneous, organ, etc., nasal cavity, rectum) , Uterus, etc.), oral preparations (eg, capsules (eg, hard capsules, soft capsules, etc.), solid preparations such as granules and powders, syrups, emulsions, suspensions, etc.) Liquid etc.]. For example, in order to make sustained-release microcapsules an injection, the microcapsules must be dispersed (eg,
n 80, HCO-60, carboxymethylcellulose (including sodium carboxymethylcellulose), sodium alginate, etc., preservatives (eg, methylparaben, propylparaben, etc.), tonicity agents (eg, sodium chloride, mannitol, sorbitol, glucose, etc.) ), Or dispersed in vegetable oils such as sesame oil and corn oil to give sustained-release injections that can be used as oily suspensions. The particle size of the microcapsules may be, for example, in the case of being used as a suspension injection, in a range that satisfies the degree of dispersion and needle penetration. For example, the average particle size may be in the range of about 0.1 to about 500 μm. No. Preferably, the particle size ranges from about 1 to about 300 μm. More preferably, the average particle size ranges from about 2 to about 200 μm. Further, by adding the osmotic pressure adjusting agent to the aqueous phase as described above, the shape of the microcapsule can be made into a more suitable spherical shape through the needle. Examples of the method for making the microcapsules into a sterile preparation include, but are not particularly limited to, a method of sterilizing the entire production process, a method of sterilizing with gamma rays, and a method of adding a preservative.

The preparation of the present invention can be used in mammals (eg,
Human, cow, pig, dog, cat, mouse, rat, rabbit, etc.)
Can be used safely. The dosage of the sustained-release preparation depends on the type and content of the drug, the dosage form, the duration of drug release,
It varies depending on the target disease (eg, Alzheimer's dementia, senile dementia, etc.), the target animal, etc., but may be any effective amount of the drug. The dose per dose of the drug
For example, when the sustained release preparation is a one-month preparation, it can be appropriately selected from the range of about 0.01 mg to about 30 mg / kg body weight per adult. Preferably, it can be appropriately selected from the range of about 0.05 mg to about 20 mg / kg body weight. More preferably, it can be appropriately selected from the range of about 0.5 mg to about 10 mg / kg body weight. The dosage of the sustained-release preparation per dose is about 0.1 mg to about 300 mg per adult.
/ Kg body weight. Preferably, it can be appropriately selected from the range of about 0.5 mg to about 200 mg / kg body weight. The number of administrations is appropriately selected depending on the type and content of the drug, the dosage form, the duration of drug release, the target disease, the target animal, etc., such as once every several weeks, once a month, or once every several months. be able to. The preparation of the present invention has an acetylcholinesterase inhibitory action and has an action of improving passive avoidance learning disorder and the like in basal forebrain-disrupted rats.Therefore, by increasing acetylcholine levels in the local brain, senile dementia, It is used for improving and treating symptoms such as Alzheimer's dementia, non-Alzheimer's dementia, and cerebrovascular dementia. In the preparation of the present invention, the administration interval is greatly extended, so that the burden on the patient or family in taking and administering for a long period can be greatly reduced, and improvement in compliance is expected. In addition, in the preparation of the present invention, excessive release immediately after administration is suppressed, so that a large amount of acetylcholine inhibitor is not ingested at once, and there is no fear of peripheral side effects (salivation, etc.), and it is safe. Can be used.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples and Experimental Examples, but these are not intended to limit the present invention. In the following Examples, Comparative Examples and Experimental Examples, "%" indicates% by weight unless otherwise specified.

[0030]

【Example】

Example 1 8- [1-oxo-3- [1- (phenylmethyl) piperidin-4-yl] propyl] -2,3,4,5-tetrahydro-1H-1-benzazepine (hereinafter referred to as compound 1) ) 200mg and lactic acid-
Glycolic acid copolymer (hereinafter abbreviated as PLGA) (manufactured by Wako Pure Chemical, Lot. No. K1030, lactic acid / glycolic acid composition ratio (mol%): 75/25, GPC weight average molecular weight:
13000) A solution of 2.0 g dissolved in 2 ml of dichloromethane was cooled to 16-18 ° C.
The solution was poured into 500 ml of a 0.1% aqueous solution of polyvinyl alcohol (EG-40, manufactured by Nippon Synthetic Chemical Industry) cooled to １８18 ° C., and stirred using a turbine homomixer (manufactured by Tokushu Kika).
An O / W emulsion was obtained at 000 rpm. O / W obtained
The emulsion was stirred at room temperature for 3 hours to evaporate dichloromethane and solidify the oil phase, and then centrifuged at 1500 rpm. After re-dispersing the obtained precipitate in distilled water, the dispersion was further centrifuged to remove the free drug by washing. The obtained microcapsules were redispersed in a small amount of distilled water and freeze-dried to obtain microcapsules as powder. The drug content in the microcapsules is 9.25%, and the trap rate is 101.7.
%Met. The drug content was 25 mg of microcapsules in 60% acetonitrile-containing phosphate buffer (pH 7).
The measurement was performed by quantifying a sample dissolved in 10 ml by an HPLC method.

Comparative Example 1 8- [1-oxo-3- [1- (phenylmethyl) piperidin-4-yl] propyl] -2,3,4,5-tetrahydro-1H-
Microcapsules were obtained in the same manner as in Example 1 except that 1-benzazepine fumarate (a fumarate of compound 1; referred to as compound 2) was used. Since compound 2 did not completely dissolve in the oil phase, it was prepared in an S / O / W system. Since fumaric acid (pKa1 = 2.9) inhibits the interaction between the drug and the acidic group of the polymer to prepare a microcapsule with a high drug content, the drug content in the microcapsule is 6.47%, and the trap rate is 71.2%. there were. Comparative Example 2 Microcapsules were prepared in the same manner as in Comparative Example 1 except that ethanol (2 ml) was added to the oil phase in order to completely dissolve the drug (compound 2) in the oil phase. The drug content in the microcapsules was 4.78%, and the trap rate was 52.6%. In Comparative Examples 1 and 2, a significant decrease in the trapping rate was observed as compared with Example 1.

Example 2 800 mg of Compound 1 and PLGA (Lot. N, manufactured by Wako Pure Chemical Industries, Ltd.)
o. K1030, lactic acid / glycolic acid composition ratio (mol%):
75/25, GPC weight average molecular weight: 13000) 2.
A solution of 0 g in 6 ml of dichloromethane was added to 16
After cooling to -18 ° C, a 0.1% aqueous solution of polyvinyl alcohol 500 previously cooled to 16-18 ° C
Injected into a ml, turbine type homomixer (made by special machine)
To obtain an O / W emulsion at 7000 rpm. Thereafter, microcapsules were collected in the same manner as in Example 1. The drug content in the microcapsules was 27.5%, the trap rate was 96.2%, and the drug was incorporated into the microcapsules at a high content.

Example 3 1.5 g of Compound 1 and PLGA (Wako Pure Chemical Industries, Lot.
890324, lactic acid / glycolic acid composition ratio (mol%):
75/25, GPC weight average molecular weight: 13000) 4.
A solution of 5 g in 9 ml of dichloromethane was added to 16
After cooling to -18 ° C, a 0.1% aqueous solution of polyvinyl alcohol 500 previously cooled to 16-18 ° C
Injected into a ml, turbine type homomixer (made by special machine)
To obtain an O / W emulsion at 8000 rpm. The obtained O / W emulsion was stirred at room temperature for 3 hours to evaporate dichloromethane and solidify the oil phase, and then centrifuged at 1500 rpm using a centrifuge. After re-dispersing the obtained precipitate in distilled water, the dispersion was further centrifuged to remove the free drug by washing. The obtained microcapsules were redispersed in a small amount of distilled water and freeze-dried to obtain microcapsules as powder. The drug content in the microcapsules is 21.
The trap rate was 56.0% and the trap rate was 86.0%. Example 4 Microscopy was performed in the same manner as in Example 3 except that PLGA (Wako Pure Chemical Industries, Lot. No. K1030, lactic acid-glycolic acid composition ratio (mol%): 75/25, GPC weight average molecular weight: 13000) was used. Capsules were prepared. The drug content in the microcapsules was 24.2%, and the trap rate was 96.8%.

Experimental Example 1 62.8 mg (equivalent to 30 mg / kg body weight as a drug) of the microcapsules obtained in Example 3 was added to 0.5 ml of a dispersion medium (2.5 mg of carboxymethylcellulose, 1.0 m).
g of polysorbate 80, 25.0 mg of mannitol in distilled water), and administered subcutaneously to the back of 10-week-old male SD rats with a 22G injection needle. After the administration, the rats are sacrificed at regular time intervals, and the microcapsules remaining at the administration site are taken out. The amount of the drug in the taken out microcapsules is quantified, and the residual ratio to the dose is shown in [Table 1].

Table 1 Time after administration Drug residual rate 1 week 85.4% 2 weeks 60.7% 3 weeks 8.4% 4 weeks 1.0% As shown in [Table 1], obtained by the production method of the present invention. The resulting microcapsules have a low initial drug release and sustained release over 4 weeks.

Experimental Example 2 278.9 mg of the microcapsules obtained in Example 4
2.8 (equivalent to 150 mg / kg body weight as drug dose)
The mixture was dispersed in 10 ml of a dispersing medium, and administered subcutaneously to the back of 10-week-old male SD rats using a 22G injection needle in three parts (n
= 5). Thereafter, blood was collected over time and the amount of drug in the serum was quantified by the HPLC method. The results are shown in [Table 2].

Table 2 Time after administration Blood concentration (ng / ml) 1 day 67.9 1 week 44.2 2 weeks 38.2 3 weeks 21.0 4 weeks 10.2.5 5 weeks 7.9 6 weeks 4.9

Experimental Example 3 Drug Efficacy Experiment A passive avoidance reaction test was performed 10 days after administration of the microcapsules obtained in Example 4 using rats in which the basal forebrain was destroyed by injecting ibotenic acid. Rats with basal forebrain destruction showed significantly shorter latencies in the retention test performed 24 hours after the acquisition trial than in the untreated control group.
In rats to which the microcapsules obtained in the above were administered at doses equivalent to 3 mg and 30 mg / kg body weight as drug amounts, the latency was extended in a dose-dependent manner, and an improving effect on learning disability was confirmed.

[0037]

According to the production method of the present invention, a sustained-release microcapsule containing a high content of an acetylcholinesterase inhibitor can be easily prepared, and a sustained-release preparation containing the microcapsule can be provided. The sustained-release preparation obtained by the present production method can be easily administered, for example, by injection, and enables sustained release of an acetylcholinesterase inhibitor over a long period of time.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI A61K 47/30 A61K 47/30 C

Claims (16)

[Claims] 1. A sustained-release microcapsule containing an acetylcholinesterase inhibitor and a biodegradable polymer. 2. The microcapsule according to claim 1, wherein the acetylcholinesterase inhibitor is a free base. 3. The microcapsule according to claim 1, wherein the acetylcholinesterase inhibitor is non-peptidic. 4. The microcapsule according to claim 1, wherein the acetylcholinesterase inhibitor is a piperidine derivative. 5. The method of claim 5, wherein the acetylcholinesterase inhibitor is 8
-[1-oxo-3- [1- (phenylmethyl) piperidine-4
-Yl] propyl] -2,3,4,5-tetrahydro-1H-1
The microcapsule according to claim 1, which is benzazepine. 6. The method of claim 1, wherein the acetylcholinesterase inhibitor is 1-
Benzyl-4-[(5,6-dimethoxy-1-oxoindane-
2. The microcapsule according to claim 1, which is 2-yl) methyl] piperidine. 7. The microparticle according to claim 1, wherein the biodegradable polymer is a lactic acid-glycolic acid polymer or copolymer having a lactic acid / glycolic acid ratio of about 100/0 to about 50/50 (mol%). capsule. 8. The microcapsule according to claim 7, wherein the lactic acid-glycolic acid polymer or copolymer has a molecular weight of 5,000 to 20,000. 9. A preparation containing the microcapsule according to claim 1. 10. The preparation according to claim 9, which is an injection. 11. The preparation according to claim 9, which is a therapeutic agent for dementia. 12. The preparation according to claim 11, wherein the dementia is Alzheimer-type dementia, non-Alzheimer-type degenerative dementia or cerebrovascular dementia. 13. A method for producing sustained-release microcapsules, comprising removing an organic solvent from a solution or dispersion containing an acetylcholinesterase inhibitor, a biodegradable polymer and an organic solvent. 14. An O / W emulsion is prepared by dispersing an oil phase containing an acetylcholinesterase inhibitor, a biodegradable polymer and an organic solvent in an aqueous phase, and subjecting it to drying in water. Method for producing conductive microcapsules. 15. The method of claim 15, wherein the acetylcholinesterase inhibitor is pK
The process according to claim 13 or 14, wherein the salt is a salt with a weak acid of 4.0 or more. 16. The method according to claim 13, wherein the acetylcholinesterase inhibitor is a free base.