Abstract
It is well established through the last decade that niosomes have potential applications as drug carriers either to improve drug permeation across membranes or targeting to specific tissues. Having a considerable ability to improve the permeability of drugs through lipoid membranes, niosomes have been utilized as carriers to enhance atenolol absorption from the gastrointestinal tract. Two methods have been adopted to prepare niosomes, the proniosome- derived method (A) and the conventional film hydration method (B). The products from the two methods were compared in terms of their morphology, vesicle size, drug encapsulation efficiency, in vitro drug release and enhancement effect on drug permeation across the intestinal membrane using an everted sac technique. Proniosome- derived niosomes were smoother and exhibited a smaller (5 pm) vesicle size compared to those prepared by conventional methods 12 mu m). High encapsulation efficiencies of 98.6% and 93.4% were achieved by methods A and B, respectively. In vitro drug release has been significantly retarded from both types of niosomes. Comparing to pure drug, which dissolved completely in 15 min, only 8.9% and 9.9% of the entrapped drug was released in the same time period. The drug release kinetics showed non-Fickian (anomalous) behavior. Permeation through an everted intestinal sac showed a significant enhancement effect (more than 4 fold) for both types of niosomes compared to untrapped drug; however, the difference between the two types of niosomes was not significant.