CONTROLLED RELEASE OF LASTET, AN ANTICANCER DRUG, FROM POLY(3-HYDROXYBUTYRATE) MICROSPHERES CONTAINING ACYLGLYCEROLS

Poly(3-hydroxybutyrate) (PHB) microspheres containing 10wt% of lastet, an anticancer drug, were prepared by a solvent-evaporation process. The release rate of lastet from PHB microspheres in vitro (in 0.01M phosphate buffer) was significantly increased by incorporating glycerol tristearate as an additive. The significant difference in the surface characteristics was found between two types of PHB microspheres with and without glycerol tristearate by the scanning electron micropgraphs. In the surface of PHB microspheres containing 25wt% of glycerol tristearate, large holes of about 5-mu-m were detected together with small holes of about 1-mu-m diameter. It has been proposed that lastet is released through a number of internal channels in PHB microspheres.