ABSTRACT
Multilamellar vesicles [noisome] of polyoxyethylene alkyl ether surfactants [Brij 52, 72, 76 and 92] were prepared using classic film hydration method. Vesicle formation ability of the surfactants was assessed in presence or absence of cholesterol. All used surfactants formed vesicles in the absence of cholesterol. Recombinant human insulin was used as a model protein drug to investigate encapsulation efficiency and release characteristics of the vesicles. The amount of insulin released in simulated intestinal fluid [SIF] and simulated gastric fluid [SGF] from Brij 92 vesicles was lower than the other ones. These vesicles also showed the highest protection of insulin against proteolytic enzymes, pepsin and trypsin. Diabetes was induced by IP injection of streptozotocin [65 mg/kg] in male wistar rats. Animals treated with oral niosome [Brij 52 and 92]-encapsulated insulin [100 IU/kg] showed decreased levels of blood glucose and elevation of serum insulin, which in the case of Brij 92 niosomes the hypoglycemic effect was significant [P< 0. 05]