Biodegradable particle and method for producing the same

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.

1 . (canceled) 
   
   
       2 . A biodegradable particle containing a water-soluble polymer and a biodegradable polymer characterized in having a substrate of which containing ratio of said water-soluble polymer to said biodegradable polymer is 0.60 to 0.70. 
   
   
       3 . A biodegradable particle according to  claim 2  characterized in having a degradability in phosphate buffered saline at 37° C. 
   
   
       4 . A biodegradable particle according to  claim 2  characterized in that its average particle diameter is 100 μm or more and, in water saturated state, a particle diameter after passing through a catheter having an inner diameter of 60% or more and 85% or less of said particle diameter is larger than the inner diameter of said catheter. 
   
   
       5 . A biodegradable particle according to  claim 2  characterized in that a compressive modulus of the particle in water saturated state is 10 MPa or less. 
   
   
       6 . A biodegradable particle according to  claim 2  characterized in that said water-soluble polymer is a polyalkylene glycol or a derivative thereof. 
   
   
       7 . A biodegradable particle according to  claim 6  characterized in that a weight average molecular weight of said polyalkylene glycol is 200 or more and 40,000 or less. 
   
   
       8 . A biodegradable particle characterized in being a particle of which particle diameter is 5 μm or more and coated with a polyalkylene glycol or a derivative thereof. 
   
   
       9 . A biodegradable particle according to  claim 2  characterized in being coated with a polyalkylene glycol or a derivative thereof. 
   
   
       10 . A biodegradable particle according to  claim 8  characterized in that a weight average molecular weight of said polyalkylene glycol is 1,000 or more and 40,000 or less. 
   
   
       11 . A biodegradable particle according to  claim 8  characterized in that said polyalkylene glycol is a polyethylene glycol. 
   
   
       12 . A biodegradable particle according to  claim 8  characterized in that a particle diameter is 5 to 2000 μm. 
   
   
       13 . A biodegradable particle according to  claim 12  characterized in that a particle size distribution is within ±60% of its average particle diameter. 
   
   
       14 . A biodegradable particle according to  claim 13  characterized in that the particle is spherical. 
   
   
       15 . A biodegradable particle according to  claim 8  characterized in that said biodegradable polymer contains α-hydroxy acid unit. 
   
   
       16 . A biodegradable particle according to  claim 8  characterized in that a weight average molecular weight of water insoluble copolymer comprising said water-soluble polymer and said biodegradable polymer is 1,000 to 100,000. 
   
   
       17 . A biodegradable particle according to  claim 2  characterized in being used in pharmaceutical and medical applications. 
   
   
       18 . A biodegradable particle according to  claim 8  characterized in being used as an indwelling device. 
   
   
       19 . A biodegradable particle according to  claim 18  characterized in being used for embolization therapy. 
   
   
       20 . A production method of biodegradable particle characterized in that the particle is obtained by blending a water insoluble polymer A of which film has a tensile modulus of 1 MPa or more and less than 50 MPa in water saturated state and a water insoluble polymer B of which film has a tensile modulus of 50 MPa or more in water saturated state. 
   
   
       21 . A production method of biodegradable particle according to  claim 20  characterized in that a blend ratio of said water insoluble polymer B is 20 wt % or more. 
   
   
       22 . A production method of a biodegradable particle obtainable from a water-soluble polymer and a biodegradable polymer characterized in that the particle is obtained by blending a water insoluble polymer C of which weight ratio of the water-soluble polymer is 50% or more and a water insoluble polymer D of which weight ratio of the water-soluble polymer is less than 50%. 
   
   
       23 . A production method of biodegradable particle according to  claim 22  characterized in that a blend ratio of said water insoluble polymer D is 20 wt % or more. 
   
   
       24 . A production method of biodegradable particle according to  claim 23  characterized in that said water insoluble polymer is a copolymer in which the water-soluble polymer and the biodegradable polymer is chemically bonded. 
   
   
       25 . A biodegradable particle containing a water-soluble polymer and a biodegradable polymer and having a substrate of which containing ratio of said water-soluble polymer to said biodegradable polymer is 0.60 to 0.70,
 characterized by being made by the production method of biodegradable particle according to  claim 24 .