Fabrication and Evaluation of Hydrogel Thickened Microemulsion of Ibuprofen for Topical Delivery

Abstract:

The objective of present study was to formulate hydrogel thickened ibuprofen transdermal formulation. Eutectic mixture of camphor and menthol was chosen as oily phase, solvent for ibuprofen and powerful penetration enhancer. Tween 80, ethanol (90% v/v) and carbopol 940 were selected as surfactant, co-surfactant and hydrogel thickening agent respectively. Ternary phase diagrams were constructed to obtain the concentration range of eutectic mixture, surfactant and co-surfactant for microemulsion formulation. Hydrogel thickened microemulsions were characterized for pH, viscosity, spreadability, irritation study and in vitro drug transport study with excised rat skins. The average drug transport rate of optimized hydrogel thickened microemulsion containing 1% w/w ibuprofen, 31.84% w/w eutectic mixture of camphor and menthol, 27.21% w/w tween 80, 13.61% w/w ethanol, 23.84% w/w water, 1.5% w/w carbopol 940 and 1% w/w triethanolamine through rat skin was 1.94 μg/ml*h*cm². The percentage in vitro drug transport of optimized hydrogel thickened microemulsion through rat skin was 0.12 times higher than that obtained in human cadaver skin at the end of 12 h. Short term stability study of the optimized hydrogel thickened microemulsion demonstrated no considerable difference in performance characteristics.

Key words: Hydrogel thickened microemulsion, Ibuprofen, Eutectic mixture, Carbopol 940, Short term stability study