CLONAZEPAM MICROENCAPSULATION IN POLY-D,L-LACTIDE-CO-GLYCOLIDE MICROSPHERES

The work is aimed at the preparation and characterization of biodegrad able microspheres of poly-D,L-lactide-co-glycolide (PLGA), for the con trolled release of clonazepam. The solubility characteristics of this drug make it an interesting example to evaluate the performances of th e two most widely used microencapsulation techniques, emulsification s olvent evaporation and spray-drying. Several biodegradable PLGA copolp mers have been evaluated (RG 502H, RG 503H, RG 503, Boerhinger Ingelhe im). They differ in terms of molecular weight and physico-chemical cha racteristics. The microspheres obtained have been characterized for th eir morphology, physico-chemical properties (DSC) and in vitro dissolu tion behaviour. Between the two preparation methods, only spray-drying was suitable for the microencapsulation of clonazepam in PLGA microsp heres. In vitro dissolution tests highlight that more sustained releas e of drug is achieved with the higher (molecular weight) polymer.