Effect of some penetration enhancers on the permeation of glibenclamide and glipizide through mouse skin

The purpose of this investigation was to study the effect of some penetration enhancers on in vitro permeation of glibenclamide and glipizide through mouse skin. Ethanol in various concentrations, N-methyl-2-pyrrolidinone, transcutol, propylene glycol and terpenes like citral, geraniol and eugenol were used as penetration enhancers. The in vitro skin permeation experiments were conducted by both simultaneous application of drug and enhancer solution and by pretreatment of the skin with neat enhancer. At the end of the experiment drug retained in the skin was estimated. The flux values (microg/cm2/h) of both drugs significantly (p < 0.05) increased in the presence of penetration enhancers, except transcutol and propylene glycol. The glibenclamide flux values ranged from 1.42 +/- 0.09 without enhancer, to 18.25 +/- 1.21 in a combination of 50% ethanol and 5% eugenol. Glipizide flux values ranged from 3.21 +/- 0.51 without enhancer, to 57.21 +/- 5.25 in a combination of 50% ethanol and 5% eugenol. Skin retention and solubility of both drugs increased with all penetration enhancers compared to control (except propylene glycol). As the target permeation rates for glibenclamide and glipizide were calculated to be 193.8 and 184.8 microg/h respectively, the present study showed that the required permeation rates for both drugs could be achieved with the aid of enhancers by increasing the area of application in an appreciable range.