EVALUATION OF SPRAY-DRYING AS A METHOD FOR POLYLACTIDE AND POLYLACTIDE-CO-GLYCOLIDE MICROSPHERE PREPARATION

Polylactide and polylactide-co-glycolide microspheres containing a lip ophilic model drug (vitamin D3) were prepared by spray drying. The pur pose of this work is to evaluate the efficacy of spray drying as a met hod for microsphere preparation. The study was carried out on five dif ferent polymers of lactide class: poly-L-lactide 57000 MW, poly-D,L-la ctide 209000 MW, 109000 MW, 16000 MW, and polylactide-co-glycolide 220 00 MW. The process conditions were experimentally assessed for each po lymer used. The microspheres obtained were characterized for their sha pe, size and drug content, and the influence of the polymer on microsp here characteristics was evaluated. Results show that polymer type, po lymer molecular weight and its concentration in the spraying solution greatly affect microsphere characteristics. In vitro dissolution tests performed with the rotating bottle method resulted in different relea se profiles depending on type of polymer and on microsphere morphology .