| Hydroxyzine HC1 is a first generation Antihistaminic. The antihistaminic properties are being investigated in the treatment of allergic conditions like Urticaria, Atopic Dermatoses, Contact Dermatoses and Histamine mediated Pruritis. The studies were undertaken to develop, screen and evaluate various topical formulations of Hydroxyzine HC1 for optimum drug release and permeation through the skin.;Various formulations containing 0.5%Drug were developed using Nonionic, Anionic, Cationic emulsion based systems along with HPMC and Carbomer gel based systems. Also ,The formulations were evaluated with the penetration enhancers:Dimethylsulfoxide(DMSO), Propylene Glycol(PG), Diethyleneglycol monoethylether (DGME) at 5%,10%,15% levels of concentrations to study their effect on permeation through the skin. The studies were carried out using Franz diffusion cell with cellulose membrane and human cadaver skin as the diffusion barriers for a period of 2hrs. The optimum formulation with maximum drug release through cellulose membrane was then chosen for studies through the human cadaver skin. Studies were performed for the optimum formulation at various and evaluated after a period of 30 days to determine the stability of the formulation. Studies with cellulose membrane gave the drug release profile as: HPMC gel>Cationic emulsion >Non Ionic emulsion. Among all the samples evaluated Cationic formulation containing 15%DMSO showed 31.26% release after 12 hrs. The drug release from this system was then studied through human cadaver skin for 12 hrs. Here, the drug release pattern remained similar to cellulose membrane, but the amount of total drug diffused was reduced as expected. The data obtained was then treated to determine various physical parameters that influence drug diffusion. Interestingly, the values for the steady state flux and diffusion coefficient were found to be the highest from the optimum formulation, and the values for the lag time and partition coefficient were the lowest.;The diffusion studies support well as a technique to evaluate various dermatological formulations and optimize the drug release. Cationic emulsion with 0.5% drug, 15%DMSO gave the optimum drug release profile. This study suggests that with proper vehicle system, it is possible to develop a topical formulation with optimal drug release. |
