Candesartan cilexetil microemulsions for transdermal delivery: formulation, in-vitro skin permeation and stability assessment.

The work investigates the formulation and evaluation of microemulsions containing olive oil, Tween 80 and isopropyl alcohol for transdermal candesartan cilexetil delivery. The pseudoternary phase diagram was constructed to determine composition of microemulsions. These formulated microemulsions were evaluated for in vitro skin permeation and stability. The microemulsion containing 72 % olive oil, 8 % water, 15 % Tween 80, and 5 % isopropylalcohol showed maximum viscosity of 29.54±0.32 mPas, average small droplet size of 180.90 nm, smaller polydispersity index of 0.37, zeta potential of -12.20 and maximum candesartan cilexetil permeation flux of 0.49±0.05 μg/cm2/h through excised porcine skin. The degradation of candesartan cilexetil microemulsions after 3 months storage was found low and its shelf-life was calculated as 3.92 years at room temperature.