Non-ionic surfactant based Proniosome Gels of naproxen sodium, an cox II inhibitor, were prepared by coacervation phase separation method. The prepared systems were characterised for encapsulation efficiency, shape, size and in vitro drug release. Stability study was carried out to investigate the leaching of drug from the proniosomal system during storage. The results showed that naproxen in all the formulations was successfully entrapped and a substantial change in release rate and an alteration in the encapsulation efficiency of naproxen from proniosomes were observed upon varying the type of surfactant and cholesterol content. The encapsulation efficiency of proniosomes prepared with Span 40:60 was superior to that prepared with all Span prepration . A preparation with Span 40: 60, cholesterol and lecithin gave maximum encapsulation efficiency (84.61%) and release results (Q24h= 81%) as compared to other compositions. Proniosomal formulations showed fairly high retention of naproxen inside the vesicles at refrigerated temperature (4-8oC) up to 1 month.
Keywords: Naproxen, proniosomes, Niosomes, encapsulation efficiency, drug delivery.