Biodegradable particle and method for producing the same

a spherical particle, biodegradable technology, applied in the direction of extracellular fluid disorder, drug composition, surgery, etc., can solve the problems of clogging, inability to carry to the desired site, and high viscosity, so as to achieve effective indwelling or aimed functions, low strength

Inactive Publication Date: 2009-12-17
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0051]According to the present invention, as explained in the following, it is possible to provide a particle capable of not clogging by an aggregation in a micro diameter tube of devices such as a catheter, needle or syringe mainly used in pharmaceutical and medical applications or in a blood vessel and capable of recovering to original shape after passing the tube, and furthermore, not depending on indwelled site or indwelled environment, capable of being smoothly degraded after passing a specified period of time so that degraded component can finally be absorbed or discharged in vitro.
[0052]The biodegradable particle of the present invention is a particle degradable by a chemical decomposition represented by hydrolysis or by an enzyme produced by a cell or a microorganism. Mainly, a hydrolyzable one is preferable. As starting materials used for the biodegradable particle, it is not especially limited, but may be any one of a natural polymers or an artificially synthesized polymers, and polyesters, polyethers, polyacid anhydrides, polypeptides, poly(α-cyanoacrylate)s polyacrylamides, poly(ortho esters), polyphosphazenes, polyamino acids, biodegradable polyurethanes, polycarbonates, polyiminocarbonates, nucleic acids, polysaccharides or the like are mentioned, and as concrete representative examples, gelatin, chitin, chitosan, dextran, gum ababic, alginic acid, starch, polylactic acid (hereafter, referred to as PLA), polyglycolic acid (hereafter, referred to as PGA), polylactic acid glycolic acid copolymer (hereafter, referred to as PLGA), hydroxy terminal poly(ε-caprolactone)-polyether, polycaprolactone, n-butyl cyanoacrylate, copolymer consisting of the above-mentioned polymer, etc., are mentioned.
[0053]As the first embodiment of the biodegradable particle of the present invention, since it is preferable that a material having an elasticity capable of passing through a micro diameter tube smaller than the particle size and capable of keeping a necessary strength in catheter tube or in blood vessel, etc., it is good that a compressive mo

Problems solved by technology

However, there are following problems in the microparticle carrier consisting of polymer particle or the embolization material.
(2) In a tube of pharmaceutical and medical application devices such as catheter, needle or syringe, it may aggregate or its viscosity may increase to clog the tube.
In particular, the clogging frequently occurs when a particle smaller than inner diameter of the catheter is passed through.
(3) It may not be able to be carried to a desired site since it aggregates or its viscosity increases in a normal blood vessel on the way to an affected region.
(4) In case where it is used as an embolization material, since its material quality is hard and does not fit to cross-sectional shape of a blood vessel, although it may decrease blood flow, it may not be able to perfectly emb

Method used

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Examples

Experimental program
Comparison scheme
Effect test

synthesis example 1

[0136]Under nitrogen flow, L-lactide (produced by Purac Biochem Ltd.) 4.96 g, glycolide (produced by Boehringer Ingelheim Co.) 1.66 g and dehydrated PEG (Sunbright DKH-20T produced by Nihon Yushi Kogyo Co.) 2.88 g were mixed in a flask and after dissolved and mixed at 150° C., a toluene solution 460 μL in which tin dioctanoate (produced by Wako Pure Chemical Industries, Ltd.) was dissolved so that its concentration was 0.1 mol / L was added and reacted to thereby obtain a water insoluble polymer having PLGA-PEG-PLGA structure of which water-soluble polymer weight ratio is 30.3%. This water insoluble polymer was dissolved in chloroform and dropped into a greatly excessive amount of diethyl ether / acetone mixed liquid to obtain a white precipitate. Weight average molecular weight according to the above-mentioned GPC method was 22,000.

[0137]The obtained purified polymer was dissolved in dichloromethane so that its concentration was 30 wt %. Said solution was poured into a laboratory dish ...

synthesis example 2

[0138]Under nitrogen flow, L-lactide (produced by Purac Biochem Ltd.) 1.92 g, glycolide (produced by Boehringer Ingelheim Co.) 0.96 g and dehydrated PEG (Sunbright MEH-20T produced by Nihon Yushi Kogyo Co.) 2.88 g were mixed in a flask and dissolved, mixed and reacted in the same way as Synthesis example 1, to thereby obtain a water insoluble polymer having PLGA-PEG structure of which water-soluble polymer weight ratio is 50.0%. From this water insoluble polymer, a white precipitate was obtained in the same way as Synthesis example 1. Weight average molecular weight according to the above-mentioned GPC method was 14,000.

[0139]By using the obtained purified polymer, a film forming was carried out in the same way as Synthesis example 1, and obtained a film of 20 μm thickness. When this was immersed in pure water at room temperature, water content became constant in about 3 hours. When a tensile test was carried out under the wet condition, tensile modulus of the film was 2.1 MPa.

TABLE...

example 1

[0140]The water insoluble polymer obtained in Synthesis example 1 and the water insoluble copolymer obtained in Synthesis example 2 were mixed in a weight ratio of 70:30 and dissolved in dichloromethane. This was dropped into aqueous solution of 1 wt % polyvinyl alcohol (Cat. No. 360627, produced by Aldrich Corp.) to carry out a drying-in-O / W liquid, and a spherical particle dispersion was obtained.

[0141]Subsequently, after a wet fractionation by nylon sieves (cut off particle diameter: 65 μm, 185 μm, 260 μm, 360 μm and 540 μm), it was vacuum dried to obtain dried spherical particles with no aggregation or cohesion. Among the above-mentioned cut off particle diameters, respective 40 mg particles collected by sieves of the 4 kinds of size except 540 μm were dispersed in PBS 1 mL, respectively, and average particle diameter and particle size distribution were determined, and it was found to be, for the respective particles collected by the sieves of the 4 kinds of size, 125±60 μm, 220...

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Abstract

The present invention aims to provide a biodegradable particle capable of being molded without an aggregation or cohesion of the particles, capable of being carried or injected without clogging by an aggregation in a micro diameter tube such as of a catheter, needle or syringe mainly used in pharmaceutical and medical applications of which inner diameter is smaller than the particle size or in a blood vessel and capable of being smoothly degraded in a specified period of time so that degraded component can finally be absorbed or discharged in vitro. As means for solving the problem, the present invention provides a biodegradable particle characterized in that a compressive modulus of the particle in water saturated state is 10 MPa or less.

Description

TECHNICAL FIELD[0001]The present invention relates to a biodegradable spherical particle which can be carried through tubes having a micro diameter smaller than the particle size, such as of catheter, needle or injector which are pharmaceutical and medical devices.BACKGROUND ART[0002]In medical field, safety of therapy or minimum invasive therapy which is light in patient's pain has become important. Along with that, techniques for designing or synthesizing safer materials or techniques for administration in vivo have been developed. One of them is technique of therapy or administration of drug through a tube of small inner diameter. By being the inner diameter of the tube small, it became unnecessary to incise patient's body, and a pain accompanied by inserting the tube into body was also greatly reduced. Therapy by catheter is a marked example of that. Another one is a technology relating to a biodegradable or bioabsorbable material which is not left in the body. A sewing thread o...

Claims

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Application Information

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IPC IPC(8): A61K9/14A61K47/30
CPCA61K9/0019A61L2430/36A61L24/0042A61L24/046A61L31/06A61L31/148C08J3/12C08J2367/04C08L67/04C08L71/02A61K9/14C08L2666/22A61P7/04
Inventor TANAHASHI, KAZUHIRONAKANISHI, MEGUMI
Owner TORAY IND INC
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