Formulation and In Vitro Characterization of Clonidine HCl Transdermal Drug Delivery System

The present study aims to formulate and evaluate matrix-type transdermal patches of Clonidine Hydrochloride (Clonidine HCl) to achieve sustained drug release, enhanced bioavailability, and improved patient compliance in the treatment of hypertension. Transdermal patches were developed using solvent casting technique with polymers such as Carboxy Methyl Chitosan and Hydroxypropyl Methylcellulose (HPMC 5 cps), in combination with plasticizers like PEG 400. Six different formulations (F1–F6) were prepared and evaluated for physicochemical parameters including thickness, weight variation, tensile strength, folding endurance, and drug content uniformity. In vitro drug release was studied using a Franz diffusion cell over 12 hours. Release kinetics were analyzed using Zero-order, First-order, Higuchi, and Korsmeyer-Peppas models. FTIR spectroscopy was used to assess drug-excipient compatibility. All formulations showed satisfactory physical characteristics. Among them, formulation F4 exhibited optimal properties with uniform drug content (97.32 ± 1.64%) and maximum cumulative drug release (99.34% in 12 hours). The drug release followed Zero-order kinetics, indicating a controlled release mechanism. FTIR analysis confirmed no significant interaction between drug and excipients