KR20140094119A - A process for the preparation of polymeric microparticles - Google Patents

Abstract

Provided by the present invention is a manufacturing method which: manufactures frozen DMSO/polyester polymer microparticles by dropping the dimethylsulfide (DMSO) of a polyester polymer in fine droplets into hydrocarbon solution of C_5-10 of -20 to 0 °C at a dropping speed of 0.1-1.0 ml/min/syringe through a thin injection needle of 25-30 gauge which vibrates in the range of vibration number 1,000-15,000 rpm and vibration width 1-30 mm; and obtains polyester polymer microparticles in an eco-friendly way without an harmfulness to a human body at a high yield by dissolving and removing the DMSO by putting the obtained frozen microparticles into salt solution and washing with distilled water.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a process for preparing polymer microparticles,

The present invention relates to an improved method for producing polymeric microparticles. More specifically, a polymer solution obtained by dissolving a polyester-based polymer in dimethyl sulfoxide (hereinafter referred to as "DMSO") as a solvent is dropped dropwise through a syringe needle (needle), and vibration is given to the injection needle The present invention also relates to a method for producing polymer microparticles by dissolving DMSO in water after freezing the droplets of the small polymer solution in a low temperature hydrocarbon solution.

Porous biodegradable polymer scaffolds are widely used as templates for various tissue regeneration. The support requires a porous structure with good intercellular connectivity to promote nutrient and oxygen supply for sufficient cell adhesion density, cell proliferation and differentiation.

Porous biodegradable polymer scaffolds can be prepared by various methods. Among them, porogen leaching is the most widely used method. The void-forming particles are various particles such as salts, foamable salts, carbohydrates, hydrocarbon waxes, etc., and the voids are formed by selectively dissolving or foaming the void-forming particles in the polymer / solvent / void forming particle mixture. Other methods such as emulsification / freeze drying, phase separation, expansion of a critical liquid phase, and three-dimensional ink jet printing have also been used (AG Mikos, G. Sarakinos, SM Leite, JP Vacanti, R. Langer, Biomaterials, 14 A. Park, B. Wu, LG Griffith, J. Biomater Sci., Pp. 333-330; Z. Ma, C. Gao, Y. Gong, J. Biomed. Polym. Ed., 9 (1998) 89-110).

Such a porous polymer scaffold induces adhesion and differentiation of cells, and thus can be useful for bone, cartilage, and liver regeneration. However, these scaffolds are transplanted into the body through surgical operations, which are both physically and economically burdensome to the patient. Therefore, a method of injecting a biodegradable polymer scaffold into a scanning mold has been developed to minimize patient inconvenience. This is a method of injecting a polymer solution containing cells and forming a hydrogel by photo-crosslinking or sol-gel phenomenon (J. J Marler, A. Guha, J. Rowley, R. Koka, D. Monney, J. Upton, J. Engl., AG Mikos, Biomaterials, 21 (2000) 2389-2394), J. Heim, MJ Yaszemski, AW Yasko, PS Engel, Plast. Reconstr. Surg. 105 (2000) 2049-2058; .

However, these hydrogels do not provide an ideal environment for cells requiring adhesion to a solid surface, and the mechanical strength is so weak that it is difficult to protect the cells enclosed therein. To overcome these disadvantages, a wide range of natural and synthetic microparticles, including microparticles made of gelatin with a porous structure, such as Cultispher, have been used for animal cell culture but have poor biocompatibility and poor mechanical strength There are disadvantages.

The presently used method of producing fine particles of injected particles is an emulsification-solvent evaporation method. Among them, the W / O / W double emulsification method has two emulsification steps, and the porous structure is determined according to the stability of the W / O emulsion, which is the first emulsification step. Since the emulsion is in a thermodynamically unstable state, it is difficult to manufacture because the aqueous phase and the organic phase are separated from each other through processes such as coalescence, fusion, and creaming (M. Kanouni, HL Rosano , N. Naouli, Adv. Colloid Interface Sci. 99 (2002) 229-254, AJ Webster, ME Cates, Langmuir, 14 (1998) 2068-2079).

Also, a fine powder including a W / O / W double emulsification step of forming a W / O emulsion by adding an aqueous solution in which a foamable salt is dissolved to an organic phase in which an aliphatic polyester polymer is dissolved and redispersing and emulsifying in an aqueous solution containing a hydrophilic surfactant (See Korean Patent No. 801194). The particulate carrier has characteristics such as biodegradability, high porosity, and excellent interconnectivity between pores, but has a weak mechanical strength and difficulty in mass production process.

Recently, biodegradable polymer microparticles were prepared by dissolving biodegradable polymers in dimethylsulfoxide (DMSO), injecting them into a low-temperature hydrocarbon solution to freeze the DMSO / polymer solution, and then removing DMSO from the low- Is a method for producing biodegradable polymer fine particles (see Korean Patent No. 1105292). In the injection process, which is the most important process in the manufacturing process, the viscous DMSO / polymer solution and the air are injected together through the nozzle at a low temperature In this case, the hydrocarbon bubbles flow into the air along with the air, which can cause a considerable amount of hydrocarbons to be lost, which can damage the environment and the human body. In addition, since it is an air jet method, there is a disadvantage that the particle size distribution of the desired size is lowered because the size distribution of the generated fine particles is large.

Therefore, it has been required to develop a manufacturing process capable of mass production of polymer microparticles excellent in biocompatibility, biodegradability, porosity, mechanical strength, cell affinity, etc. in a more environmentally friendly process and a high production yield.

Accordingly, the inventor of the present invention has been studying to develop a method capable of overcoming the technical disadvantages of the conventional microparticle manufacturing process. While the polymer solution is being vibrated through the thin needle, The present invention has been completed. In the present invention, since it is not an air injection method, it is an eco-friendly process because there is no loss of hydrocarbon bubbles harmful to the environment and human body. In addition, fine particles of desired grain size can be manufactured with high yield.

In order to achieve the above object,

A dimethylsulfoxide (DMSO) solution of a biodegradable polyester polymer is added to a hydrocarbon solution having a carbon number of 5 to 10 (C ₅ to C ₁₀ ) at a temperature below the melting point of DMSO, that is, at -20 ° C to 0 ° C at a frequency of 1,000 to 15,000 rpm, The frozen DMSO / polymer microparticles were prepared by dropping them into fine droplets with a syringe at a dropping rate of 0.1 to 1.0 ml / min / syringe through a vibrating needle at a vibration amplitude ranging from 1 to 30 mm, DMSO is dissolved in an aqueous solution, removed, and washed with distilled water to prepare biodegradable polymer microparticles.

Hereinafter, the present invention will be described in detail.

As shown in FIG. 1, the biodegradable polymer microparticles of the present invention are prepared by vibrating a biodegradable polyester polymer dissolved in DMSO into a hydrocarbon solution having a low carbon number of 5 to 10 (C ₅ to C ₁₀ ) through a syringe The frozen DMSO / polymer microparticles were prepared by dropping droplets with a syringe through a needle at a dropping rate of 0.1 to 1.0 ml / min / syringe. The DMSO / polymer microparticles were then dissolved in a low-temperature salt aqueous solution to dissolve DMSO, And then removing it.

Since the porosity is determined according to the concentration of the polymer dissolved in DMSO, it is easy to control the porosity and the size of the fine particles can be easily controlled by controlling the dropping speed, vibration width and vibration speed of the DMSO solution in which the polymer is dissolved .

More specifically, the method for producing biodegradable polymer microparticles of the present invention comprises:

A dimethylsulfoxide (DMSO) solution of a biodegradable polyester polymer is added to a hydrocarbon solution having a carbon number of 5 to 10 (C ₅ to C ₁₀ ) at a temperature below the melting point of DMSO, that is, at -20 ° C to 0 ° C at a frequency of 1,000 to 15,000 rpm , The vibrating width is 1 to 30 mm, and the droplets are dropped into fine droplets by a syringe at a dropping rate of 0.1 to 1.0 ml / min / s to prepare frozen DMSO / polymer microparticles. The obtained frozen fine particles DMSO is dissolved and removed in an aqueous salt solution, and washed with distilled water to prepare biodegradable polymer microparticles.

First, a DMSO (Dimethyl Sulfoxide) solution of a biodegradable polyester polymer will be described.

In the present invention, the biodegradable polyester-based polymer is an aliphatic polyester-based polymer including, but not limited to, polylactic acid (PLA), polyglycolic acid (PGA), poly (D, L-lactic acid-co Poly (lactic-co-glycolic acid), PLGA), polycaprolactone (PCL), poly (valerolactone), poly (hydroxybutyrate), poly (hydroxyvalerate) Or a derivative thereof, which may be used singly or in a mixture of two or more components. Preferably PLA, PGA, PLGA, PCL or a mixture thereof, more preferably PLA, PLGA or PCL. These are preferably polymers having an average molecular weight of 10,000 to 250,000. However, since the method of producing biodegradable polymer microparticles of the present invention is characterized by being capable of easily producing spherical fine particles and easily controlling the size of fine particles, it is possible to control the fine particle size by the average molecular weight It is not limited.

In the present invention, the biodegradable polyester polymer solution may be prepared by dissolving the polymer in DMSO (Dimethyl Sulfoxide) to a concentration of 1% -25% (w / v) The porosity of biodegradable porous microparticles can be controlled. When the concentration of the polymer solution is less than 1%, the mechanical strength of the fine particles is weak, resulting in poor practicality. When the concentration exceeds 25%, the viscosity is too high to form a fiber.

In the present invention, the organic solvent used for dissolving the aliphatic polyester-based polymer is required to use DMSO (Dimethyl Sulfoxide) which has a high freezing point and forms phase separation with hydrocarbons.

Next, a DMSO solution of the polyester polymer thus obtained is added to a hydrocarbon solution having a carbon number of 5 to 10 (C ₅ to C ₁₀ ) at a temperature below the melting point of DMSO, that is, at -20 ° C to 0 ° C, at a frequency of 1,000 to 15,000 rpm, The frozen DMSO / polymer microparticles are prepared by dropping into fine droplets with a syringe at a dropping rate of 0.1-1.0 ml / min / syringe through a vibrating needle in the range of 1 to 30 mm.

In the present invention, the hydrocarbon solution is a hydrocarbon having a carbon number of 5 to 10 (C ₅ to C ₁₀ ), for example, Pentane, Hexane, Heptane or the like, which is not frozen at a temperature of minus 0 ° C and is phase- Saturated hydrocarbons such as octane, nonane, decane and petroleum ether, and mixtures thereof, preferably using n-hexane, which is volatile, good. Due to the high volatility of n-hexane, it can eventually be easily removed during the drying process. Hydrocarbons having less than 5 carbon atoms are too volatile to be difficult to manufacture, and hydrocarbons having 10 or more carbon atoms are less practical. The temperature of the hydrocarbon solution is lower than the melting point of DMSO for freezing of DMSO, and a temperature of less than about 18 캜 is preferable for 1 atm. More preferably -20 째 C to 0 째 C, and most preferably -10 째 C to -5 째 C in order to facilitate freezing of DMSO and formation of fine particles.

The fine droplet forming method of the aliphatic polyester-based polymer solution used in the present invention can be used without limitation as long as it can form fine droplets by dropping a polymer solution while vibrating a fine needle of 25 to 30 gauge (G) .

The frequency used in the present invention can be varied in a range from 1,000 rpm to 15,000 rpm, preferably from 2,000 rpm to 7,000 rpm, more preferably from 3,000 rpm to 5,500 rpm. When the frequency is 1,000 rpm or less, And a large droplet is formed. If it is more than 15,000 rpm, the motor and the manufacturing apparatus are burdened. The size of the fine particles can be easily controlled by varying the vibration width in the range of 1 to 30 mm, preferably 3 to 10 mm, and more preferably 4 to 8 mm. If the vibration width is less than 1 mm, the polymer solution can not be efficiently dropped from the injection needle. If the vibration width is more than 30 mm, the polymer solution dropping from the injection needle spreads too widely, so that the freezing tank for freezing the particle becomes unnecessarily large, And an unreasonable force is required for the manufacturing apparatus. In addition, the dropping rate can be variously controlled within a range of 0.1 to 1.0 ml / min / syringe, preferably at a dropping rate of 0.2 to 0.5 ml / min / syringe. If the dropping rate is less than 0.1 ml, the productivity is too low to be realistic. If the dropping rate is more than 1.0 ml, it is difficult to form droplets of fine polymer solution.

Then, the prepared frozen DMSO / polymer microparticles are added to the aqueous salt solution to dissolve and remove DMSO, and then washed with water to obtain the polyester polymer microparticles of the present invention.

In the present invention, it is preferable that the aqueous salt solution is maintained in a frozen state at 0 DEG C or lower. Water may be used for the removal of DMSO. However, it is preferable to remove DMSO in a solution of 0 ° C or less in order to maintain the stability of fine particles at the time of production. Therefore, an aqueous solution of NaCl or CaCl _{2 at a} concentration of 5% to 30% . Preferably, the aqueous salt solution may be a 20% to 25% sodium chloride (NaCl) solution, and is preferably used at -20 ° C to 0 ° C. After removal of the DMSO with the aqueous salt solution, the removal of the salt may be accomplished by washing with excess water, preferably deionized distilled water (DDW), to remove residual DMSO and salts.

The biodegradable polymer microparticles can be prepared by such a method. The manufacturing method of the present invention is simple and efficient compared with the conventional method and solves problems (such as human hazard and emission of pollutants) caused by an emergency of hydrocarbon bubbles generated by injection, So that injection into the living body can be made possible.

The biodegradable polymer microparticles of the present invention thus produced had a yield of 80% or more and a diameter of 30 탆 to 1,000 탆. The diameter of the biodegradable polymer microparticles of the present invention can be appropriately adjusted according to the dropping rate, vibration width and vibration speed of the polymer solution into the hydrocarbon solution, and the lower the dropping rate of the polymer solution, Fine particles having a diameter can be obtained.

1A is a conceptual diagram of a polymer fine particle production apparatus,
1B is a schematic view of an apparatus for producing polymer microparticles.
2 is a photograph of the microparticles prepared according to the method of the present invention observed with an electron microscope. (X 200: Polymer solution dropping rate: 0.2 ml / min / syringe: oscillation width: 4 mm; )
3 is a photograph of the microparticles prepared according to the method of the present invention observed with an electron microscope. (X 400: polymer solution dropping rate: 0.2 ml / min / syringe: vibration width: 8 mm; )
4 is a photograph of the microparticles prepared according to the method of the present invention observed with an electron microscope (X 2,000; polymer solution dropping rate: 0.2 ml / min / syringe; oscillation width: 8 mm; oscillation speed: 5,400-5,500 rpm )
5 is a photograph of the microparticles prepared according to the method of the present invention observed with an electron microscope (X 200: Polymer solution dropping rate: 0.5 ml / min / syringe: oscillation width: 8 mm; vibration velocity: 3,000-3,100 rpm )
6 is a photograph of the microparticles prepared according to the method of the present invention observed with an electron microscope (X 500: polymer solution dropping rate: 0.5 ml / min / syringe: vibration width: 8 mm; vibration velocity: 5,400-5,500 rpm )

Hereinafter, the present invention will be described in detail with reference to examples.

However, the following examples are illustrative of the present invention, and the present invention is not limited to the following examples.

Example  1-5

1. A 5% (w / v) polymer solution was prepared by dissolving 2.5 g of polylactic acid (PLA) having an average molecular weight of 110,000 in 50 ml of DMSO (Dimethyl Sulfoxide). The polymer solution is divided into five 10 ml Luer lock syringes (30 G 1/2 "), and five syringes are mounted on the fine particle production apparatus (see FIG. 1).

While dropping the polymer solution at a rate of 0.2 ml / min / syringe in n-hexane cooled to -10 ° C, shake the syringe needle at a vibration amplitude of 4 mm and a frequency of 3,000 rpm. At this time, the fine droplets of the polymer solution that have fallen are frozen in a spherical form at a low temperature of n-hexane.

The frozen fine particles are obtained and dissolved in 100 ml of a 25% (w / v) NaCl aqueous solution cooled to -10 ° C for 48 hours to dissolve the DMSO component, followed by filtration to obtain DMSO-free polymer microparticles. This was further washed with 500 ml of distilled water to remove residual DMSO and NaCl, and then lyophilized to complete the biodegradable polymer microparticles of the present invention.

2. In addition, biodegradable polymer microparticles were prepared in the same manner as in Method 1 except that the polymer solution dissolved in DMSO was dropped to n-hexane under the conditions of a vibration amplitude of 8 mm and a frequency of 3,000 rpm.

3. The biodegradable polymer microparticles were prepared in the same manner as in the above 1 except that the polymer solution dissolved in DMSO was dropped to n-hexane under the conditions of a vibration amplitude of 8 mm and a frequency of 5,500 rpm.

4. The polymer solution dissolved in DMSO was dropped to n-hexane at a vibration amplitude of 8 mm and a frequency of 3,000 rpm while dropping the polymer solution at a rate of 0.5 ml / min / syringe, thereby obtaining a biodegradable polymer Fine particles were prepared.

5. The polymer solution dissolved in DMSO was dropped to n-hexane at a vibration amplitude of 8 mm and a frequency of 5,500 rpm while dropping the polymer solution at a rate of 0.5 ml / min / syringe to obtain a biodegradable polymer Fine particles were prepared.

Experimental Example

In order to confirm the characteristics of the biodegradable polymer microparticles prepared in Examples 1 to 5, the size and production yield of the biodegradable polymer microparticles were measured. At this time, the size of the fine particles was measured by taking an electron microscope photograph, and the production yield was calculated by measuring the amount of the fine particles finally obtained with respect to the amount of introduced polymer.

As a result, as shown in Figs. 2 to 6 and Table 1, it was found that the size of the fine particles was inversely proportional to the vibration width and the vibration speed in proportion to the dropping rate of the polymer solution. The size of the microparticles prepared according to the preparation method of the present invention was a size suitable for administration into the body, and it was judged to be economical in terms of yield.

Manufacturing conditions Fine particle size
(탆) yield
(%) 5% (w / v) polymer solution dropping rate ( ml / min /syringe) Vibration Width
( mm ) Vibration speed
( rpm ) 0.2 4 3,000-3,100 300-500 87 8 3,000-3,100 100-300 84 8 5,400-5,500 Below 100 82 0.5 8 3,000-3,100 300-800 84 8 5,400-5,500 50-200 81

Industrial Applicability The present invention is an industrially advantageous invention due to its manufacturing conditions and yield characteristics.

Claims (3)

A dimethylsulfoxide (DMSO) solution of a polyester polymer is added to a C _5-10 hydrocarbon solution at -20 ° C to 0 ° C in the range of 25-30 gauge vibrating at a frequency of 1,000 to 15,000 rpm and a vibration amplitude of 1 to 30 mm DMSO / polyester polymer microparticles were prepared by dropping with fine droplets through a fine needle at a dropping rate of 0.1 to 1.0 ml / min / syringe, and the obtained frozen fine particles were dissolved in a salt aqueous solution to dissolve and remove DMSO And washing with distilled water. The method according to claim 1, wherein the polymer has a frequency of 2,000 to 7,000 rpm, a vibration width of 3 to 10 mm, and a dropping rate of 0.2 to 0.5 ml / min / syringe. The method according to claim 1 or 2, wherein the vibration frequency is 3,500 to 5,500 rpm and the vibration width is 4 to 8 mm.

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