Formulation and In Vitro Evaluation of Transdermal Patches of Metformin Hydrochloride Using Hydrophilic and Hydrophobic Polymer Complex.

The aim of present research work was to prepare and evaluate transdermal drug delivery (TDDS) of metformin hydrochloride. Metformin hydrochloride is an agonist at �2 –adrenergic receptor sites. The drug undergoes rapid first pass metabolism (approximately 95% of dose) which necessitates its frequent dosing by oral route. Transdermal drug delivery system of metformin hydrochloride was prepared using combinations of a hydrophobic polymer, ethyl cellulose and hydrophilic polymer, polyvinyl pyrrolidone in different ratios (1:2, 1:4, 1:6, 1:8, 2:1, 4:1, 6:1 and 8:1 w/w) by solvent evaporation technique. Polyvinyl alcohol was used to prepare the backing membrane and dibutyl phthalate as plasticizer. The prepared polymeric films were characterized for various physiochemical parameters like film thickness, tensile strength, moisture content, moisture uptake, water vapour transmission rate. Permeation studies were carried out for patches through commercial semi-permeable membrane as well as mouse epidermis using Keshary-Chien diffusion cell. Formulation F6 showed 94.83% drug release from the patch within 24 h in in vitro diffusion cell and was selected for ex vivo skin permeation and drug release data of selected patch showed good fit into Higuchi equation. The effect of storage on in vitro release and physiochemical parameters of selected patch was found within the acceptable limits.