KR20210054660A - Sustainable Microspheres for Initial Release Control of Drugs and Method for Preparing the same - Google Patents

Abstract

The present invention relates to a method for manufacturing sustained-release microspheres with easy sustained release control. When microspheres are manufactured by using the present invention, a temperature-sensitive polymer gelled while capturing an active drug forms particles in the microspheres made of biodegradable polymers, so that it is possible to manufacture sustained-release microspheres containing drugs which have excellent sustained-release properties that stably and continuously release the drug at an effective concentration for a long period of time.

Description

Sustainable Microspheres for Initial Release Control of Drugs and Method for Preparing the same}

The present invention relates to a method for producing microspheres for sustained-release easy to control sustained-release, and more specifically, a sol-gel of a temperature-sensitive polymer containing a drug in encapsulating a drug in a microsphere made of a biodegradable polymer. gel) Based on the phase transition, a gelled polymer carrying a drug is encapsulated in a biodegradable polymer carrier, thereby suppressing the initial over-release of hydrophilic or hydrophobic drugs, as well as preventing the use of organic solvents that are essential in the existing manufacturing process. The present invention relates to a method for producing microspheres for sustained release that eliminates the problem caused by residual solvents by excluding them.

In a drug delivery system using medical materials, it is very important to effectively control and design the drug release so that the drug can maintain a minimum effective concentration in the blood and minimize side effects due to toxicity. Existing sustained-release formulations mainly prefer constant drug release such as zero-order release, but they are not always effective in all cases, and new paradigm drug delivery methods such as external control or self-control drug delivery or smart drug delivery system are continuously required. have.

As a type of sustained-release drug-release system, research on a microsphere-based sustained-release drug-release system is also actively underway. However, most of the microsphere-based sustained-release drug release systems have disadvantages in that it is difficult to have a constant drug release rate or that drugs are rapidly released within a relatively short time due to initial release. Conventionally, typical methods of manufacturing microspheres for drug delivery using polymers include coacervation, melt extrusion, spray drying, and solvent extraction. Among the solvent extraction methods, the double emulsification method (W/O/W; water/ oil/water) and a single emulsification method (o/w; oil/water) are most commonly used. However, there is a disadvantage in that it is difficult to solve the toxicity problem due to the residual solvent because an organic solvent such as dichloromethane (DCM) is used as a solvent used in these microsphere production methods.

Therefore, there is a need to develop a formulation capable of suppressing the rapid initial release of drugs, enabling continuous drug release, and solving the toxicity problem caused by residual solvents.

MR Kim, TG Park, J Control Rel, 80, 69 (2002) T lnoue, G Chen, K Nakamae, et al., Polymer Gels Network, 5, 561 (1997)

As a result of intensive research efforts to solve the above-described problems in the prior art, the present inventors did not use an organic solvent, so that there is no toxicity problem due to residual solvents, yet a method for producing a microsphere for sustained release capable of controlling the initial release of the drug And completed the present invention.

Accordingly, it is an object of the present invention to provide a novel drug for sustained-release microspheres and a method for producing the same.

According to one aspect of the present invention, the present invention provides a method for producing microspheres for sustained release of a drug comprising the following steps:

(a) preparing a biodegradable polymer solution containing an organic acid and a biodegradable polymer;

(b) preparing a temperature-sensitive polymer solution containing an aqueous solvent, a temperature-sensitive polymer, and a drug;

(c) preparing an emulsion by mixing the biodegradable polymer solution and the temperature-sensitive polymer solution; And

(d) generating microspheres by spraying the emulsion onto the dispersion solvent being stirred.

Hereinafter, the manufacturing method of the present invention will be described for each step.

Step (a): preparing a biodegradable polymer solution containing an organic acid and a biodegradable polymer

This step is a step of first preparing a biodegradable polymer solution for constituting the biodegradable microspheres of the present invention, characterized in that the biodegradable polymer is dissolved in an organic acid instead of an organic solvent such as dichloromethane.

In one embodiment of the present invention, the biodegradable polymer is a conventional polymer used in the manufacture of microspheres that can be used as a drug delivery system, and is self-degrading in vivo and has biocompatibility.

Examples of the biodegradable polymer include proteins such as gelatin and collagen; Polysaccharide-based natural polymers such as alginate and hyaluronic acid; Biodegradable synthetic polymers such as polylactic acid derivatives can be used.

As the polylactic acid derivative, a biocompatible and biodegradable polylactic acid derivative used in the art related to the production of polymer microspheres may be used without limitation. Specifically, the polylactic acid derivative is polylactic acid, polylactide, polylactic-co-glycolic acid, polylactide-co-glycolide (PLGA), a copolymer of lactic acid and caprolactone, polycaprolactone, lactic acid and amino acid The copolymer of, or a mixture thereof, but is not limited thereto.

In a specific embodiment of the present invention, the biodegradable polymer may have an intrinsic viscosity of 0.1 to 0.6 dL/g. In the present invention, if the viscosity of the biodegradable polymer is less than 0.1 dL/g, the microspheres are not formed properly or the drug encapsulation rate is significantly reduced, and if it exceeds 0.6 dL/g, the size of the microspheres may be large. .

In the present specification, the term "organic acid" refers to an organic compound having acidity, and an organic compound containing a carboxyl group and a sulfone group is representative. The "organic acid" is simply an acid (eg, hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ )), nitric acid (HNO ₃ ), phosphoric acid ( H ₃ PO ₄ )) It is meant to exclude acids other than "inorganic acid", but does not limit the organic acid in a specific range.

In one embodiment of the present invention, the organic acid is formic acid, acetic acid, lactic acid, tartaric acid, malic acid, citric acid, succinic acid, fumaric acid, or a mixture thereof, preferably formic acid, acetic acid, or a mixture thereof, but limited thereto. It is not.

According to a specific embodiment of the present invention, the biodegradable polymer in step (a) is at a concentration of 10 mg to 150 mg per mL of organic acid, preferably 25 mg to 125 mg, more preferably 50 mg to 100 It dissolves in mg concentration. When the concentration of the biodegradable polymer is low, the viscosity of the polymer solution decreases and the particle size tends to decrease when forming a dispersed phase in the form of droplets, whereas when the concentration exceeds 150 mg/mL, the viscosity of the polymer solution increases. Depending on the size of the microspheres tend to increase.

In a specific embodiment of the present invention, in step (a), the mixing temperature is maintained at 20 to 60° C. to be prepared. The mixing temperature is preferably 25 to 50°C. When the mixing temperature is less than 20° C., the sol-gel transition of the temperature-sensitive polymer is not easily induced, so that the possibility that the drug is not stably collected in the biodegradable polymer microspheres increases, and the initial release may be accelerated.

In addition, when the temperature is higher than 60°C, the molecular chain movement is faster than the glass transition temperature (Tg) of the biodegradable polymer, so the viscosity of the polymer decreases and the instability in the solution increases. May not appear.

Step (b): Aqueous solvent , Temperature- Sensitivity Containing a polymer, and a drug Temperature sensitivity Step of preparing a polymer solution

This step is a step of preparing a temperature-sensitive polymer solution for preparing a temperature-sensitive polymer in which an effective drug is collected, which is enclosed in the microparticles made of the biodegradable polymer of the present invention.

In one embodiment of the present invention, the temperature-sensitive polymer is polyethylene oxide-polypropylene oxide copolymer, polyethylene oxide-polylactic acid copolymer, polyethylene oxide-glycolic acid copolymer, polyethylene oxide-polylactic glycolic acid copolymer , A polyethylene oxide-polycaprolactone copolymer and a polyethylene oxide-polydioxanone copolymer, and more preferably a polyethylene oxide-polypropylene oxide copolymer may be used.

Polyethylene oxide-polypropylene oxide copolymer exhibits a temperature-dependent sol-gel transition when the aqueous solution concentration is 16% or more (MR Kim, TG Park, Temperature-responsive and degradable Hyaluronic acid. /Pluronic composite hydrgels for controlled release of human growth hormone, J Control Rel, 80, 69 (2002); T lnoue, G Chen, K Nakamae, et al., Temperature sensitivity of a hydrogel network containing different LSCT oligomers grafted to thehydrogel backbone, Polymer Gels Network, 5, 561 (1997)).

In one embodiment of the present invention, the concentration of the temperature-sensitive polymer solution is 10-35% by weight, 13-35% by weight, 16-35% by weight, 10-30% by weight so that the sol-gel transition can easily occur. %, 13-30% by weight, 16-30% by weight, 10-25% by weight, 13-25% by weight, or 16-25% by weight. When the concentration of the temperature-sensitive polymer solution is less than 10% by weight, sol-gel transition of the temperature-sensitive polymer does not occur, and in step (d), microspheres are not produced and aggregates are formed.

In addition, the temperature-sensitive polymer solution is 1-10 ℃, 1-7 ℃, 1-5 ℃, 1-4 ℃, 2-10 ℃, 2-7 ℃, 2-5 ℃, or 2-4 ℃ It is preferably maintained at temperature.

In a specific embodiment of the present invention, when the temperature-sensitive polymer is a polyethylene oxide-polypropylene oxide copolymer, the concentration of the solution is preferably 16-25% by weight. When the concentration of the temperature-sensitive polymer solution is less than 16% by weight, sol-gel transition of the temperature-sensitive polymer does not occur, and in step (d), microspheres are not produced and aggregates are formed.

The aqueous solvent used in the present invention is sterile purified water, physiological saline, or water for injection, but is not limited thereto.

Any drug used in the present invention may be used as long as it has physical properties that can be contained within the biodegradable microspheres in the manufacturing process according to the present invention. The drugs are, for example, non-steroidal anti-inflammatory drugs, such as acetaminophen, acetylsalicylic acid, ibuprofen, fenbuprofen, fenoprofen, flubiprofen, indomethacin, naproxen, etololac, ketoprofen, dec Sibuprofen, piroxicam, aceclofenac; Examples of immunosuppressants or atopic dermatitis treatments include cyclosporine, tacrolimus, rapamycin, mycophenylate, and pimecrolimus. In addition, as a calcium channel blocker, nifedipine, nimodipine, nitrendipine, nilbadipine, felodipine, amlodipine, isradipine; Angiotensin II antagonists including valsartan, eprosartan, irbesartan, candersartan, telmisartan, olmesartan, and losartan as a cholesterol synthesis inhibitory treatment for hyperlipidemia; Atorvastatin, lovastatin, simvastatin, fluvastatin, rosuvastatin, pravastatin; Gemfibrozil, fenofibrate, etofibrate, bezafibrate as treatments for cholesterol metabolism and secretion-promoting hyperlipidemia; As a therapeutic agent for diabetes, pioglitazone, rosiglitazone, metformin; Itraconazole, amphotericin ratio, terbinafine, nystatin, glyceofulvin, fluconazole, ketoconazole as antifungal agents; Hepatoprotective agents including biphenyldimethyldicarboxylate, silymarin, ursodeoxycholic acid as a therapeutic agent for digestive system diseases; Sofalcon, omeprazole, pantoprazole, famotidine, itopride, mesalazine; Platelet aggregation inhibitors including cilostazol clopidogrel as a therapeutic agent for osteoporosis; Antiviral agents including raloxifene, acyclovir, famcyclovir, lamivudine, and oseltamivir as antibiotics; Clarithromycin, ciflofloxacin, cefuroxime; Testosterone, prednisolone, estrogen, cortisone, hydrocortisone, dexamethasone as hormonal agents; Paclitaxel, docetaxel, paclitaxel derivatives, doxorubicin, adriamycin, daunomycin, campotecin, etoposide, teniposide, busulfan, leuprolide, tryptorelin as antitumor agents; As a psychotropic drug, drugs such as haloperidol, flufentixol, flofenazine, jucropetixol, pipethiazine, paliperidone, olanzapine, ecitalopram, donepezil, naltrexone, risperidone, or pharmaceutically acceptable salts thereof And, protein or peptide drugs such as insulin, testosterone, estradiol, somatropin, octreotide, etc. may be used, but the present invention is not limited thereto.

The temperature-sensitive polymer solution in step (b) of the present invention is a suspension in which a drug is added to an aqueous solvent in which a temperature-sensitive polymer is dissolved.

That is, in the step (b) of the present invention, the above-described temperature-sensitive polymer is mixed or dissolved in an aqueous solvent, and a hydrophilic or poorly soluble drug is added to the prepared solution, followed by stirring to prepare a suspension.

Step (c): the biodegradable polymer solution and the temperature Sensitivity Mixing a polymer solution to prepare an emulsion

In this step, the biodegradable polymer solution for preparing microspheres prepared in step (a) and the temperature-sensitive polymer solution containing the drug prepared in step (b) are mixed so that the biodegradable polymer solution and the temperature-sensitive polymer solution are emulsified with each other. This is the step of preparing an emulsion that forms a shape.

As described above in steps (a) and (b), the biodegradable polymer solution is maintained at 20-60°C, and the temperature-sensitive polymer solution is maintained at 1-10°C. Therefore, when the two solutions are mixed and stirred, a low temperature temperature-sensitive polymer solution is gelled by mixing with a relatively high temperature biodegradable polymer solution to prepare an emulsion. The gelation proceeds at a faster rate as the temperature of the biodegradable polymer solution increases. Therefore, it is advantageous for the production of microspheres that the temperature of the biodegradable polymer solution during mixing is maintained at a temperature of 25°C or higher, 30°C or higher, and preferably 50°C or higher.

In one embodiment of the present invention, the step (c) is to prepare an emulsion by stirring the two solutions at 150 to 400 rpm.

According to a specific embodiment of the present invention, the stirring is 150 to 400 rpm, 150 to 350 rpm, 150 to 300 rpm, 200 to 400 rpm, 200 to 350 rpm, 200 to 300 rpm, 250 to 400 rpm, 250 to 350 rpm, 250 to 300 rpm, 300 to 400 rpm, 300 to 350 rpm, or 350 to 400 rpm.

When the emulsion is dispersed in the dispersion solution of the next step (d), a suspension in which the microspheres of the present invention are dispersed is prepared.

Step (d): Agitation By spraying the emulsion on the dispersion solvent being Microspheres Steps to generate

This step is a step of spraying the emulsion of the biodegradable polymer solution and the temperature-sensitive polymer solution prepared in step (c) onto a dispersion solvent to generate the microspheres of the present invention. The microspheres produced in this step have not yet been cured.

In one embodiment of the present invention, the dispersion solvent is an aqueous solvent containing a hydrophilic emulsifier.

The aqueous solvent of the present invention is sterile purified water, physiological saline, or water for injection, but is not limited thereto.

The aqueous solvent of the present invention may contain a hydrophilic emulsifier. The content of the hydrophilic emulsifier is in the range of 0.1 g to 10 g, 1 g to 10 g, 3 g to 10 g, 0.1 g to 7 g, 1 g to 7 g, or 3 g to 7 g per 1 L of solvent. That is, 0.1-10%(w/v), 1-10%(w/v), 3-10%(w/v), 0.1-7%(w/v), 1-7%(w/v ), or 3-7 (w/v)%.

In one embodiment of the present invention, the hydrophilic emulsifier is polyvinyl alcohol, polyethylene glycol, polysorbate, poloxamer, span 80, polyoxyethylene hydrogenate castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene Fatty acid esters, or mixtures thereof, but are not limited thereto.

In one embodiment of the present invention, the injection is performed by a syringe or an injection tool having a nozzle of a similar type, and the method of injection is performed without limitation such as injection into a solvent or dripping.

In one embodiment of the present invention, the injection is performed on a dispersion solvent using a syringe, but the thickness of the injection needle may be 19, 21, 23, 25, 30G (gauge), etc., but is not limited thereto. .

In one embodiment of the present invention, in the step (b), a polymer solution for preparing microspheres is sprayed into the dispersion solution while stirring the dispersion solvent at 150 to 400 rpm.

According to another specific embodiment of the present invention, the stirring is 150 to 400 rpm, 150 to 350 rpm, 150 to 300 rpm, 200 to 400 rpm, 200 to 350 rpm, 200 to 300 rpm, 250 to 400 rpm, 250 to 350 rpm, 250 to 300 rpm, 300 to 400 rpm, 300 to 350 rpm, or 350 to 400 rpm. If the stirring speed is 100 rpm or less, fine spheres are not well formed, and if higher than 400 rpm, the fine spheres are not well dispersed in the dispersion solution.

In one embodiment of the present invention, the present invention may additionally include the following steps.

Step (e): created in step (d) Fine grain Disperse solvent until cured Agitating step

In this step, the uncured microspheres dispersed in the suspension of step (d) are cured, and at the same time, the organic acid contained in the microspheres is evaporated to substantially form microspheres.

According to an embodiment of the present invention, step (d) is performed by stirring the suspension at 4 to 35° C. for 1 to 18 hours.

In a specific embodiment of the present invention, the stirring time is 1 to 18 hours, 1 to 16 hours, 1 to 14 hours, 1 to 12 hours, 1 to 10 hours, 1 to 8 hours, 1 to 6 hours, 1 to 4 Hours, 2 to 18 hours, 2 to 16 hours, 2 to 14 hours, 2 to 12 hours, 2 to 10 hours, 2 to 8 hours, 2 to 6 hours, 2 to 4 hours, 3 to 18 hours, 3 to 16 hours Hours, 3 to 14 hours, 3 to 12 hours, 3 to 10 hours, 3 to 8 hours, 3 to 6 hours, 3 to 4 hours, 4 to 16 hours, 4 to 14 hours, 4 to 12 hours, 4 to 10 Time, 4 to 8 hours, 4 to 6 hours, 6 to 18 hours, 6 to 16 hours, 6 to 14 hours, 6 to 12 hours, 6 to 10 hours, or 6 to 8 hours, but limited thereto It is not.

In particular, the upper limit of the stirring time (18 hours) means that even if the stirring is performed for 18 hours or longer, the hardening of the microspheres does not proceed further, so stirring for 18 hours or more means that the economic value is low, and is prepared by stirring for 18 hours or longer. Even if it does, it does not mean that it is excluded from the scope of the present invention.

The stirring temperature is 4 to 35 ℃, 10 to 35 ℃, 15 to 35 ℃, 20 to 35 ℃, 25 to 35 ℃, 30 to 35 ℃, 4 to 30 ℃, 10 to 30 ℃, 15 to 30 ℃, 20 To 30°C, 25 to 30°C, 4 to 25°C, 10 to 25°C, 15 to 25°C, 20 to 25°C, 4 to 20°C, 10 to 20°C, or 15 to 20°C, but limited thereto It does not become.

In a specific embodiment of the present invention, the agitation is 1-8 hours, 1-7 hours, 1-6 hours, 1-5 hours, 1-4 hours, 1-3 hours, 2-8 at 15 to 25 ℃ Hours, 2-7 hours, 2-6 hours, 2-5 hours, 2-4 hours, 2-3 hours, 3-8 hours, 3-7 hours, 3-6 hours, 3-5 hours, or 3- It is preferable in terms of the efficiency of encapsulating the drug to be performed for 4 hours.

The manufacturing method of the present invention may additionally include the following steps subsequently.

Step (f): the cured Microspheres Separating steps

In the step (c), after curing of the particulate matter is completed, the solvent in the suspension remaining is removed, and the particulate matter is separated and recovered therefrom. The method of removing the solvent may be used without limitation such as suction, evaporation, discharge, and filtration.

In addition, the manufacturing method of the present invention may additionally include the following steps.

Step (g): the separated Microspheres Steps to wash and dry

This step relates to a post-treatment process of the separated and recovered microspheres, and is a step of removing organic acids that may remain inside the microspheres by washing several times with an aqueous solvent such as distilled water. Since the organic acid of the present invention is excellent in water solubility, when washing with an aqueous solvent, the organic acid is easily eluted into the solvent and does not remain.

Upon completion of this step, subsequent processes such as freeze-drying for preservation and sieving and sorting by particle size may be performed.

According to another aspect of the present invention, the present invention provides microspheres for sustained-release drug containing biodegradable polymer particles.

In one embodiment of the present invention, the biodegradable polymer particles include particles containing a temperature-sensitive polymer and a drug inside the particles.

The microparticles of the present invention are prepared by the method for producing microparticles for sustained release of the drug. Therefore, the biodegradable polymer, the temperature-sensitive polymer, and the drug, which are constituents of the microparticles of the present invention, are as described above in the method for preparing the microparticles.

According to one embodiment of the present invention, the weight ratio of the biodegradable polymer and the temperature-sensitive polymer is 1:1 to 1:5.

According to a specific embodiment of the present invention, the weight ratio of the biodegradable polymer and the temperature-sensitive polymer is 1:1 to 1:5, 1:1 to 1:4.5, 1:1 to 1:4, 1:1 to 1 :3, 1:1 to 1:2.5, or 1:1 to 1:2, and most preferably 1:2.5 to 1:3, but is not limited thereto. When the weight ratio of the biodegradable polymer and the temperature-sensitive polymer is 1:1 or less, that is, 1:0.5, 1:0.3, etc., only aggregates are formed and the microspheres of the present invention are not formed. In addition, when the weight ratio of the biodegradable polymer and the temperature-sensitive polymer exceeds 1:5, the production yield of microspheres is drastically lowered.

The microspheres of the present invention may be manufactured by the method of manufacturing the microspheres described above, but the present invention is not limited thereto.

On the other hand, the microspheres of the present invention are spherical bodies having a porous matrix inside, and effective drugs in the microspheres can be stably encapsulated. In the microspheres of the present invention, it is assumed that the temperature-sensitive polymer temporarily gels while trapping the effective drug to form a porous matrix in the microspheres made of biodegradable polymers (see FIG. 1).

In addition, since the microspheres of the present invention release the effective drug enclosed in the microspheres sustainedly, the conventionally low bioavailability and the number of times of administration of the drug can be continuously released at an effective concentration over a long period of time, so that it can be usefully used as a sustained-release preparation. I can.

Accordingly, according to another aspect of the present invention, the present invention provides a composition for drug delivery comprising the microspheres.

When the microspheres of the present invention, or a composition for drug delivery including the same, are prepared as a pharmaceutical composition, the pharmaceutical composition of the present invention may include a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier is commonly used in the formulation, lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum acacia, calcium phosphate, alginate, gelatin, calcium silicate, microcrystalline cellulose, Polyvinylpyrrolidone, cellulose, water, syrup, methylcellulose, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate, mineral oil, and the like, but are not limited thereto.

The pharmaceutical composition of the present invention may further include a lubricant, a wetting agent, a sweetening agent, a flavoring agent, an emulsifying agent, a suspending agent, a preservative, and the like in addition to the above components. Suitable pharmaceutically acceptable carriers and formulations are described in detail in Remington's Pharmaceutical Sciences (19th ed., 1995).

In a specific embodiment of the present invention, the pharmaceutical composition of the present invention is sucrose, mannitol, sorbitol, glycerin, trehalose, excipients of polyethylene glycols, and cyclodextrins (alpha, beta, gamma-cyclodextrin, hydroxycyclo Excipients such as dextrin to cyclodextrin derivatives, etc.) are additionally included. The excipient is added to the particles, which are active ingredients of the pharmaceutical composition, functions as a cryoprotectant or an osmotic pressure regulator, and is formulated by lyophilization, solvent evaporation, and the like.

The pharmaceutical composition of the present invention can be administered orally or parenterally. In the case of parenteral administration, intravenous administration, subcutaneous administration, intradermal administration, intramuscular administration, intranasal administration, intramucosal administration, intrathecal administration, intraperitoneal administration It can be administered by administration, intraocular administration, etc., and specifically intravenous administration.

The pharmaceutical composition of the present invention is prepared in unit dosage form by formulating using a pharmaceutically acceptable carrier and/or excipient according to a method that can be easily carried out by a person skilled in the art. Or it can be prepared by incorporating it into a multi-dose container. In this case, the formulation may be in the form of a solution, suspension or emulsion in an oil or aqueous medium, or may be in the form of an extract, powder, granule, tablet or capsule, and may additionally include a dispersant or a stabilizer.

The features and advantages of the present invention are summarized as follows:

(a) The present invention provides a solution to the problem of residual toxic solvents found in conventional microsphere formulations by using an organic acid, unlike a manufacturing method using a halogenated alkane solvent such as dichloromethane.

(b) The present invention provides microspheres having a uniform size suitable for injection through simple spraying rather than a complicated manufacturing process such as a spray drying method or a double emulsion/solvent evaporation method.

In the case of producing microspheres using the present invention, the temperature-sensitive polymer gelled while collecting the effective drug forms particles in the microspheres made of biodegradable polymers, and has excellent sustained-release properties that stably and sustainably release the drug at an effective concentration for a long period of time. It is possible to prepare microspheres for sustained-release containing drugs.

1 is a view showing a micrograph in Example 1 according to the present nickname.
2 is a scanning electron microscope photograph of Examples 1 to 4 and Comparative Examples 1 and 2 according to the present invention. [a) Example 1, b) Example 2, c) Example 3, d) Example 4, e) Comparative Example 1, f) Comparative Example 2]
3 and 4 are graphs showing the dissolution rates at 37° C. of Examples and Comparative Examples according to the present invention over time.
5 is a view showing a microscopic photograph (ab) and a macroscopic photograph (c) of residual microspheres after 35 days of the dissolution test of Example 1 according to the present invention.
6 is a view showing a macroscopic photograph (a), a scanning electron microscope (SEM) photograph (b), and a microscopic photograph (cd) of the remaining microspheres after 63 days of the dissolution test of Example 3 according to the present invention.
7 is a scanning electron microscope (SEM) photograph (a) of the remaining microspheres after 63 days of the dissolution test of Example 3 according to the present invention, an enlarged photograph (b), and a SEM photograph of the cross section of the remaining microspheres (c ) And an enlarged photograph (d).
8 is a simple schematic diagram according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for describing the present invention in more detail, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention. .

Example

Throughout this specification, "%" used to indicate the concentration of a specific substance is (weight/weight)% for solids/solids, (weight/volume)% for solids/liquids, and Liquid/liquid is (vol/vol) %.

Example 1: dexamethasone long-acting Microspheres Produce

As a biodegradable polymer, 100 mg of polylactic acid was dissolved in 2 mL of formic acid to prepare a biodegradable polymer solution, and the temperature of the preparation solution was maintained at 50°C.

Next, as a temperature-sensitive polymer, a poloxamer-based polymer (manufactured by BASF, product name: Pluronic F-127) was prepared by dissolving in water so that the polymer concentration was 25% (w/w).

20 mg of dexamethasone was mixed with the temperature-sensitive polymer solution at 4°C, and a suspension in which dexamethasone was dispersed in the temperature-sensitive polymer solution was prepared, and kept cold at 4°C. The suspension was added to the polylactic acid solution at 50° C. and stirred rapidly at 300 rpm to obtain an emulsion.

Thereafter, the emulsion was aspirated into a syringe, and an aqueous solution of 10 mL of 2% (w/v) polyvinyl alcohol (PVA) as a dispersion solvent was maintained at 4° C. and sprayed with rapid stirring at 300 rpm to form microspheres. With the hood turned on, the aqueous solution was slowly stirred for 8 hours or more to harden the formed microspheres and evaporate the organic acid. Next, the aqueous solution was centrifuged at 1500 rpm for 10 minutes to recover the cured microspheres. The recovered microspheres were washed three or more times with distilled water to remove the remaining organic acid, and the precipitate was freeze-dried. A small amount of the freeze-dried powder was taken and suspended in 100 μL of distilled water, placed on a slide glass, and the formation and shape of microspheres were confirmed through a microscope (Leica microsystem) (FIG. 1).

As shown in FIG. 1, it was confirmed that the temperature-sensitive polymer, which collected the drug in the microspheres made of the biodegradable polymer, gelled to form small particles.

Example 2 to 4: long-lasting dexamethasone Microspheres Produce

Example 2

In Example 2, the recovered microspheres were washed with distilled water and the precipitate was vacuum-dried instead of freeze-dried to prepare microspheres in the same manner as in Example 1.

Example 3

In Example 3, a microsphere was prepared in the same manner as in Example 1, except that the temperature of the biodegradable polymer solution containing polylactic acid was changed to 25°C instead of 50°C.

Example 4

In Example 4, the recovered microspheres were washed with distilled water and the precipitate was vacuum-dried instead of freeze-dried to prepare microspheres in the same manner as in Example 3.

Example 5

In Example 5, microspheres were prepared in the same manner as in Example 1, except that 2% (w/v) polyvinyl alcohol (PVA) as a dispersion solvent was maintained at room temperature to cure the microspheres.

Example 6

In Example 6, microspheres were prepared in the same manner as in Example 1, except that the microspheres were cured for 4 hours in 2% (w/v) polyvinyl alcohol (PVA) as a dispersion solvent.

Example 7

In Example 7, microspheres were prepared in the same manner as in Example 1, except that 2% (w/v) polyvinyl alcohol (PVA) as a dispersion solvent was maintained at room temperature to cure the microspheres for 4 hours.

Comparative example 1: biodegradable polymer PLGA , O/W type using dexamethasone Microspheres Produce

160 mg of biodegradable polymer PLGA and 40 mg of dexamethasone were added to 5 ml of dichloromethane as an organic solvent, followed by vigorous stirring for 1 hour to dissolve. Disperse at 16,000 rpm using a homogenizer (IKA, ULTRA-TURRAX T8) while pouring the uniformly dissolved solution into 20 ml of 2% (w/v) polyvinyl alcohol aqueous solution and over 2 minutes O/W emulsion Got it. After that, the emulsion was stirred strongly with a magnetic stirrer (900 rpm) for 5 hours at room temperature and pressure to form microspheres, centrifuged at 1500 rpm for 10 minutes to collect the cured microspheres, and washed 2-3 times with distilled water. .

Comparative example 2

In Comparative Example 2, microspheres were prepared in the same manner as in Example 1, except that the temperature-sensitive polymer, poloxamer-based polymer, was not added.

Experimental example

Experimental example One: Microsphere Check shape and particle size distribution

About 5 mg of the microspheres prepared in Example 1 were coated with platinum for 4 minutes using a coater (Quorum Q150 TES, 10 mA), and then the microspheres were treated with a scanning electron microscope (Tescan Mira 3, LMU FEG-SEM). The morphology and particle size were observed. The measurement results are shown in Figure 2, a) is Example 1, b) is Example 2, c) is Example 3, d) is Example 4, e) is Comparative Example 1, f) is Comparative Example 2 to be.

According to the above results, in each of Examples 1-7, relatively homogeneous microspheres having a size of about 20 μm and smooth particle surfaces were identified. However, in the case of Example 5, it was confirmed that when the curing was performed at room temperature for more than 8 hours, an aggregate was formed as time passed.

In Comparative Example 1, microspheres having a size of about 10 μm were identified, and Comparative Example 2 was confirmed to be prepared in the form of aggregates rather than microspheres.

Experimental example 2: Microsphere Sealing efficiency And yield measurement

After accurately weighing 5 mg of microspheres containing dexamethasone prepared in Examples 1 to 4 and Comparative Example 1, completely dissolve in 10 mL of DMSO (Dimethyl Sulfoxide, Sigma Aldrich) and dilute 10 times with a mobile phase, and then filter a 0.45 μm syringe. 10 μL of the filtrate filtered through was injected into HPLC (Agilent 1260 Infinity) and quantified. For this experiment, a C18 (100mm x 4.6 mm I.D., 5 μm) column was used as an analysis column, and the encapsulation efficiency (%) and drug content (%) of the drug were calculated using the following Equations 1 and 2.

Equation 1

Drug encapsulation efficiency (%) = (Drug encapsulation amount (mg)/Drug injection amount (mg)) X 100

Equation 2

Drug content (%) = (Drug enclosed amount (mg)/particulate sphere weight (mg)) X 100

Table 1 shows the encapsulation efficiency and drug content of each drug according to Equations 1 and 2 above.

division Drug encapsulation efficiency (%) Drug content (%) Example 1 54.53 9.09 Example 2 47.07 7.84 Example 3 36.30 6.05 Example 4 42.50 7.08 Example 5 28.75 2.61 Example 6 72.88 12.15 Example 7 94.75 15.79 Comparative Example 1 38.94 7.79

Experimental example 3: Microsphere Measurement of drug release behavior in vitro

In order to measure the drug release behavior of dexamethasone-containing microspheres as a sustained-release ophthalmic solution, the microspheres prepared in the above Examples and Comparative Examples were weighed so that the amount of drug in the particles was 700 μg, and then a dialysis bag ( MW cut-off 8 kDa), and the elution test was carried out while stirring at 37° C. and 100 rpm in 30 mL of physiological saline. 25 mL of the solution was recovered every 7 days, replaced with 25 mL of a new physiological saline solution, diluted 10 times with an HPLC mobile phase, and 10 μL of the filtrate filtered with a 0.45 μm syringe filter was added to HPLC (Agilent 1260 Infinity). It was quantified by injection. As an analysis column for this experiment, a C18 (100mm x 4.6 mm I.D., 5 μm) column was used. The amount of the drug released for each time slot relative to the total amount of drug in each particle sample was calculated as a cumulative percentage, and the measurement results are shown in FIG. 3.

3 is a graph showing the results of measuring in vitro drug release behavior of microspheres prepared in Examples 1, 2 and Comparative Example 1 according to the present invention. Compared to Comparative Example 1 prepared by the conventional single emulsification method (o/w), the initial release of the microspheres of Examples 1 and 2 was not observed, and the delayed release effect was high as time passed. there was. This is expected to be due to the fact that PF-127, a temperature-sensitive gel containing a drug, was present in a solution at 4 °C and then gelled while collecting the drug while being mixed with a polylactic acid solution at 50 °C to form small particles in the biodegradable microspheres. It was confirmed that there was no significant difference in the dissolution rate between Examples 1 and 2 according to the drying method of the recovered microspheres.

4 is a graph showing the results of measuring in vitro drug release behavior of microspheres prepared in Example 3 and Example 4 according to the present invention. Compared with the results of FIG. 3, the dissolution rate when the temperature of the biodegradable polymer solution containing polylactic acid was changed to 25° C. was higher than that of Example 1 or Example 2. However, it can be seen that the microspheres of Examples 3 and 4 also show an initial release suppression and delayed release effect compared to Comparative Example 1. It is expected that the elution of PF-127, a temperature-sensitive polymer, was relatively accelerated as the gelation proceeded slowly at a temperature of 25°C. It was confirmed that there was no significant difference in the elution rate by the drying method of the recovered microspheres.

In addition, as a result of comparing Examples 5-6, it was confirmed that when curing at room temperature for more than 8 hours (Example 5), aggregates were formed as time passed, and the drug encapsulation efficiency was significantly lowered. As a result of comparing Examples 6-7, it was confirmed that the drug encapsulation efficiency was more excellent when the temperature of the dispersion solvent was maintained at room temperature (Example 7).

Experimental example 4: Microsphere Measurement of drug release behavior in vitro

FIG. 5 shows the results of visual confirmation and microscopic observation by recovering residual microspheres after 35 days of elution in an in vitro dissolution experiment of microspheres prepared in Example 1. FIG. A significant amount of microspheres remained on the 35th day, and it was confirmed that the microspheres were hardened in an aggregated form. As a result of microscopic observation, a number of small particles that were expected to contain the drug in the microsphere aggregate were identified, and as a result of analyzing the content of dexamethasone in the remaining microspheres by HPLC, it was confirmed that 53.5% of the amount remained compared to the initial dose.

6 is a result of visual confirmation and microscopic observation by recovering residual microspheres after 63 days of elution in an in vitro dissolution experiment of microspheres prepared in Example 3. FIG. A significant amount of microspheres remained even on the 63rd day, and unlike Example 1, it was confirmed that the particle size was increased to 200-400 μm while maintaining the shape of the microspheres. As a result of observation with a scanning electron microscope in FIG. 7, a number of small particles expected to contain a drug in the microsphere aggregate could be confirmed.

Claims (15)

A method for producing microspheres for sustained release of a drug comprising the following steps:
(a) preparing a biodegradable polymer solution containing an organic acid and a biodegradable polymer;
(b) preparing a temperature-sensitive polymer solution containing an aqueous solvent, a temperature-sensitive polymer, and a drug;
(c) preparing an emulsion by mixing the biodegradable polymer solution and the temperature-sensitive polymer solution; And
(d) generating microspheres by spraying the emulsion onto the dispersion solvent being stirred. The method of claim 1, wherein the biodegradable polymer solution in step (a) is maintained at a temperature of 20°C to 60°C. The method of claim 1, wherein the temperature-sensitive polymer solution in step (b) is a suspension in which a drug is added to an aqueous solvent in which the temperature-sensitive polymer is dissolved. The method of claim 1, wherein the temperature-sensitive polymer solution in step (b) is maintained at a temperature of 1°C to 10°C. The method of claim 1, further comprising agitating the dispersion solvent until the microspheres produced in step (d) are cured. The method of claim 5, wherein the stirring is performed at 4 to 35°C for 1 to 18 hours. The method of claim 5, further comprising the step of separating the cured microspheres. The method of claim 7, further comprising washing and drying the separated microspheres. The method of claim 1, wherein the organic acid is formic acid, acetic acid, lactic acid, tartaric acid, malic acid, citric acid, succinic acid, fumaric acid, or a mixture thereof. The method of claim 1, wherein the biodegradable polymer is polylactic acid, polylactide, polylactic-co-glycolic acid, polylactide-co-glycolide (PLGA), a copolymer of lactic acid and caprolactone, polycaprolactone, It is a copolymer of lactic acid and an amino acid, or a mixture thereof, the production method. The method according to claim 1, wherein the dispersion solvent is an aqueous solvent containing a hydrophilic emulsifier. The method of claim 11, wherein the hydrophilic emulsifier is polyvinyl alcohol, polyoxyethylene hydrogenate castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, or a mixture thereof. The method of claim 11, wherein the aqueous solvent is sterile purified water, physiological saline, or water for injection. In the microspheres for sustained-release drug containing biodegradable polymer particles, wherein the biodegradable polymer particles include particles containing a temperature-sensitive polymer and a drug in the particles. The method of claim 14, wherein the microspheres are produced by the method of any one of claims 1 to 12.

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