POLY(PALMITOYL-L-HYDROXYPROLINE ESTER) MICROSPHERES AS POTENTIAL ORALCONTROLLED DRUG-DELIVERY SYSTEM

A new type of carrier using poly(palmitoyl-L-hydroxyproline ester) (PP H) [IUPAC name: ly((1-palmitoyl-4,2-pyrrolidinediyl)carbonyloxy)], a p oly(amino acid) is described. The polymer is synthesized by convention al method and the microspheres were prepared by solvent evaporation te chnique for application in drug delivery system. Microspheres with dif ferent sizes were prepared by varying certain formulation and technolo gical parameters and their distributive stabilities under physiologica l conditions were studied. The microspheres were characterized by DSC, optical and laser particle size analysis. A model drug, rifampicin (a ntituberculosis drug) was entrapped in the microspheres and the in vit ro release studies were performed in pH 7.4 and pH 1.5 buffer media. T he pH value seemed to have some influence on the dissolution rate of t he rifampicin-containing microspheres. Dissolution experiments using r ifampicin indicated the possibility of using PPH microspheres with oth er hydrophobic drugs. (C) 1997 Elsevier Science B.V.