FORMULATION AND CHARACTERIZATION OF METHIMAZOLE-LOADED TRANSDERMAL PATCHES FOR CONTROLLED SYSTEMIC DELIVERY

Methimazole is an antithyroid agent widely prescribed for the management of hyperthyroidism; however, conventional oral administration is associated with frequent dosing, variable bioavailability, and systemic adverse effects. The present study aimed to formulate and characterize methimazole-loaded transdermal patches for controlled systemic delivery to improve therapeutic efficacy and patient compliance. Prior to formulation, pre-formulation studies were performed to evaluate the physicochemical properties of methimazole, including organoleptic characteristics, solubility profile, melting point, partition coefficient, drug identification, and compatibility with selected polymers using Fourier Transform Infrared (FTIR) spectroscopy. The transdermal patches were prepared by the solvent-casting technique using suitable film-forming polymers, plasticizers, and permeation enhancers. The formulated patches were characterized for Physio chemical and pharmaceutical properties, including appearance, thickness, weight uniformity, folding endurance, tensile strength, percentage moisture content, moisture uptake, drug content uniformity, surface pH, and flatness. In vitro drug release studies were carried out using a suitable diffusion medium, while ex vivo permeation studies were performed across biological membrane models to assess transdermal drug transport. Release kinetics were analysed using mathematical models to determine the mechanism of drug release. The optimized methimazole transdermal patch demonstrated acceptable physio chemical properties, uniform drug distribution, sustained drug release, satisfactory permeation characteristics, and good stability throughout the study period. The findings suggest that the developed transdermal system has the potential to provide controlled systemic delivery of methimazole, reduce dosing frequency, and enhance patient adherence, making it a promising alternative to conventional oral therapy for the long-term management of hyperthyroidism. Keywords: Methimazole, Transdermal Patch