Effect of various formulation variables on the encapsulation and stability of dibucaine base in multilamellar vesicles.

Formulation of local anesthetics in liposomal topical drug delivery system could provide a sustained and localized anesthesia. The aim of this study was to develop a liposomal dibucaine base (DB) local anesthetic delivery system. DB-loaded multilamellar vesicles (MLVs) were prepared through varying lipid composition, induced charge and pH of the hydration medium. Liposomes were characterized for morphology, size, entrapment efficiency (EE), in vitro drug release and stability including leakage stability. The percentage of drug entrapped in liposomes was found to be hydration medium pH dependent and charge dependent and more pronounced for negatively charged liposomes prepared using hydration medium of pH 9. In vitro release studies of liposomes have shown a sustained release of entrapped dibucaine compared to control solution. Results revealed that adjusting the various formulation variables of dibucaine base MLVs could yield stable and effective topical liposomal local anesthetic formulations.