OBJECTIVETo prepare pravastatin sodium-loaded chitosan microspheres to allow sustained drug release.

METHODSThe drug-loaded chitosan microspheres were prepared by using genipin as the cross-linker. The influences of molecular weight of chitosan, volume ratio of oil and water, reaction temperature, and stirring speed on the formation of chitosan microspheres were investigated. The morphology of the microspheres was observed using scanning electron microscopy. The encapsulation efficiency, swelling ratio under different pH conditions, and in vitro drug release were measured.

RESULTSThe in vitro release of pravastatin sodium could last for at least 31 days. The drug release rate varied with the reaction condition. The drug entrapment efficiency of the microsphere was 54.7%. The optimal processing conditions were as follows: chitosan viscosity of 200-400 mPa·s, oil-water proportion of 10:1, stirring speed of 850 r/min, and reaction temperature at 40 degrees celsius;.

CONCLUSIONThe pravastatin sodium-loaded microspheres show good sustained drug release property, and the drug release rate can be modified by controlling the cross-linking time.