Patent ID: 6030636
Filing Date: 2000-02-29
Classification: A61K,A61L,Y10S

Abstract:
A bioresorbable composition shaped as a cylinder or a cube and having a controllable dissolution rate, wherein said composition comprises calcium sulfate and is prepared by the process comprising:(a) mixing powder consisting essentially of alpha-calcium sulfate hemihydrate and, optionally, powder consisting essentially of beta-calcium sulfate hemihydrate with a solution comprising water to form a mixture, and(b) forming said mixture into a composition shaped as a cylinder or a cube,wherein said powder consisting essentially of alpha-calcium sulfate hemihydrate has a purity greater than 98 wt. % calcium sulfate hemihydrate, a BET surface area in the range of from about 0.4 m.sup.2 /g to about 0.9 m.sup.2 /g, a density in the range of from about 2.73 to about 2.80 g/cm.sup.3, a mean particle size of about 16 .mu.m to about 22 .mu.m, andwherein 90-95 wt. % of the powder consisting essentially of alpha-calcium sulfate hemihydrate has a particle size distribution from about 1 .mu.m to about 45 .mu.m,wherein said powder consisting essentially of beta-calcium sulfate hemihydrate has a purity greater than 98 wt. % calcium sulfate hemihydrate, a BET surface area in the range of from about 4.5 m.sup.2 /g to about 7.5 m.sup.2 /g, a density in the range of from about 2.5 g/cm.sup.3 to about 2.6 g/cm.sup.3, and a mean particle size in the range of from about 10 .mu.m to about 15 .mu.m, andwherein the dissolution rate is controlled by varying the weight ratio of the powder consisting essentially of beta-calcium sulfate hemihydrate to the powder consisting essentially of alpha-calcium sulfate hemihydrate from 0 to about 3.