Influence of formulation variables on the morphology of biodegradable microparticles prepared by spray drying.

The preparation of microparticles of the biodegradable poly-DL-lactide (PLA) and polylactide-co-glycolide (PLGA) polymers using spray-drying technology was studied. Formulation parameters investigated include polymer type, polymer molecular weight, polymer concentration, and viscosity. Microparticles were characterized using electron microscopy, particle size analysis, and gel permeation chromatography. Kinematic viscosity was determined for each of the sprayed polymer solutions. Polymer molecular weight and polymer concentration were found to be important parameters when preparing PLA and PLGA microparticles using spray-drying technology.