RESUMO
Poly(DL-lactide-co-glycolide) (PDLLGA) and poly(L-lactide-co-glycolide) (PLLGA) copolymers were prepared by bulk ring opening polymerization of lactide and glycolide and characterized by GPC, FTIR, 1H NMR and DSC. Copolymers with different molar masses at a constant lactide/glycolide ratio were used for preparation of bovine serum albumin (BSA)-loaded microparticles by the double emulsion w/o/w method. The influence of the copolymer molar mass and composition on the microparticle morphology, size, yield, degradation rate, BSA-loading efficiency and BSA release profile were studied. For microparticles prepared from PDLLGA copolymers, a biphasic profile for BSA release was found and for those made from PLLGA copolymers the release profile was typically triphasic; both of them were characterized by high initial burst release. Possible reasons for such behavior are discussed.
Assuntos
Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/farmacocinética , Ácido Láctico/síntese química , Ácido Láctico/farmacocinética , Tamanho da Partícula , Ácido Poliglicólico/síntese química , Ácido Poliglicólico/farmacocinética , Polímeros/síntese química , Polímeros/farmacocinética , Animais , Bovinos , Química Farmacêutica/métodos , Portadores de Fármacos/síntese química , Portadores de Fármacos/farmacocinética , Emulsões , Glicolatos/síntese química , Glicolatos/farmacocinética , Ácido Láctico/classificação , Ácido Poliglicólico/classificação , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros/classificação , Soroalbumina Bovina/química , Soroalbumina Bovina/farmacocinética , Tecnologia Farmacêutica/métodosRESUMO
Biodistribution studies of radiolabelled 131I-BSA loaded gelatin microspheres were carried out on BALB/c mice after peroral administration. To two groups, radiolabelled 131I-BSA gelatin microspheres of different particle size, 1.2 +/- 1.1 microm and 7.0 +/- 1.2 microm, were administered orally. To the control group, a solution of 131I-BSA was administered orally as well. Biodistribution was followed periodically within 15 days as the percent of total radioactivity present in the stomach and small intestine with Peyer's patches and mesentery, in colon with Peyer's patches, appendix and mesentery, in liver, spleen, blood, kidney, lungs and heart. Preliminary in vitro biodegradation and drug release studies confirmed the potential of gelatin microspheres to protect the antigen of interest from enzymatic degradation in the gut, and to release it in a controlled manner. The biodistribution data confirmed that particle uptake into Peyer's patches and passage to the liver and spleen via the mesentery lymph supply and nodes increased with decreasing particle size.
