Transdermal patch incorporating salbutamol sulphate: In vitro and clinical characterization.

Eudragit patches containing salbutamol sulphate were prepared and evaluated as a rate-controlling membrane for transdermal use. The effect of different Eudragit polymers and various plasticizers on the permeability and mechanical properties of the prepared patches were studied. Drug patches of Eudragit polymers were prepared by a casting method employing methanol as a solvent and dibutylphthalate, polyethylene glycol 400, Propylene glycol, and triacetin as plasticizers. These patches were evaluated for weight and thickness uniformity, swelling index, tensile strength, percentage of elongation, and moisture absorption capacity. In vitro release characteristics of these patches were studied and analyzed. The patches were found to have a uniform thickness. Patches prepared using Eudragit RS 100 (T(8)) as well as RS100 + L100 in a ratio of 3:1 (T(15)) plasticized with triacetin were found to have a tensile strength lower than that of other patches. Permeability characteristics of selected patches were studied. Patch formulations T(8) and T(15) containing 10% oleic acid and 5% dimethyl formamide as penetration enhancers, respectively, displayed the highest permeability to salbutamol sulphate. These two formulations were selected for further clinical investigation and although both resulted in improvement in respiratory function tests, only the first formulation resulted in significant improvement.