Physicochemical Analysis: In Vitro and Ex Vivo Permeation of Smart Polymeric Transdermal Patches of Antispasmodic Drug

The present work was performed to develop and evaluate transdermal patches of antispasmodic drug tizanidine hydrochloride. Different concentration of ethanol and double distilled water with polyvinyl alcohol was used to prepared and optimize the backing membrane. Eudragit and polyvinyl pyrollidone were selected as matrix material to suspend the drug in the continuous thickness of the patch. The equal ratio of chloroform and methanol was used as solvent and the propylene glycol was selected as plasticizer. The effect of five different permeability enhancers such as dimethyl sulfoxide, isopropyl myristate, Tween 20, eucalyptus oil and clove oil was used to investigate the release and permeation of the drug from the subjected patches. In order to evaluate the physicochemical characterization, patch thickness, weight variation, folding endurance, content uniformity and moisture uptake capacity were investigated. The formulated patches were subjected to evaluation of the release of a drug by in vitro means of dissolution method. The permeation of antispasmodic drug was conducted by Franz diffusion cell technique. Effects of different enhancers were estimated on the release and permeation of drug. The formulation SC3 having dimethyl sulfoxide as permeation enhancer showed maximum amounts of drug release 97.4 +/- 0.5 at the end of 24 h dissolution study. SC3 also showed maximum permeation of drug 5264 mu g after 24 h permeation study through rabbit skin mounted on Franz cell. The patches having no enhancer in the formulation also showed some drug release and permeation due to the presence of plasticizer. The results of the study suggested that new controlled release transdermal formulations of antispasmodic drug can be suitably developed as an alternative to conventional dosage forms.