Formulation and characterisation of valsartan proniosomes

Non-ionic surfactant vesicles of valsartan, an angiotensin 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 valsartan in all the formulations was successfully entrapped and a substantial change in release rate and an alteration in the encapsulation efficiency of valsartan from proniosomes were observed upon varying the type of surfactant and cholesterol content. The encapsulation efficiency of proniosomes prepared with Span 60 was superior to that prepared with Span 40. A preparation with 9:2:9 ratio of Span 60, cholesterol and lecithin gave maximum encapsulation efficiency (71.50%) and release results (Q24h= 75%) as compared to other compositions. Proniosomal formulations showed fairly high retention of valsartan inside the vesicles at refrigerated temperature (4-8oC) up to 1 month