Proniosomal transdermal therapeutic system of losartan potassium: development and pharmacokinetic evaluation

The purpose of the current study was to investigate the feasibility of proniosomes as transdermal drug delivery system for losartan potassium. Different preparations of proniosomes were fabricated using different nonionic surfactants, such as Span 20, Span 40, Span 60, Span 80, Tween 20, Tween 40, and Tween 80. Different formulae were prepared and coded as PNG-1 (proniosomal gel-1) to PNG-7. The best in vitro skin permeation profile was obtained with proniosomal formulation PNG-2 in 24 h. The permeability parameters such as flux, permeability coefficient, and enhancement ratio were significant for PNG-2 compared with other formulations (P<0.05). This optimized PNG-2 was fabricated in the form of transdermal patch using HPMC gel as a suitable base. Proniosomal transdermal therapeutic system (PNP-H) was found to be the optimized one as it gave better release of drug and better permeation in a steady-state manner over a desired period of time, that is, 24 h through rat skin. In vivo pharmacokinetic study of PNP-H showed a significant increase in bioavailability (1.93 times) compared with oral formulation of losartan potassium. The formulation appeared to be stable when stored at room temperature (30+/-2 degrees C) and at refrigeration temperature (4+/-2 degrees C) for 45 days.