Fabrication of polyisobutene based matrix patches for transdermal delivery of atenolol

One of the possible routes for local and systemic delivery of hypertensive drugs has been identified as transdermal administration. Monolithic drugs in adhesive patches have the advantages of being relatively simple to manufacture and having limited dimensions of both thickness and surface area. Polyisobutene is a pressure-sensitive adhesive polymer often used in transdermal patch preparation. Polyisobutenes with varying molecular weight distributions have differing viscosities, which can affect drug release. In the current study, Atenolol transdermal patches were made with different proportions of low and high molecular weight polyisobutene and ethyl cellulose as a thickening agent. Prepared patches were evaluated for their physicochemical properties like thickness, weight variation, folding endurance, tensile strength, moisture content, drug content and in- vitro permeation rate. Based on tensile strength (1.92kg/mm²), folding endurance (343) and in-vitro permeation rate (85.79%) at the end of 30^th hour, F1 formulation was found to be optimum. Ex vivo permeation study was carried out using rat skin and 67.09% drug permeated at the end of 30^th hour. Formulations were subjected to stability studies for 60 days and were found to be stable. Thus, an ideal combination of polyisobutenes in the ratio 3:1 (High Molecular Weight: Low Molecular Weight) and ethyl cellulose (200mg) would serve as the best choice for fabrication of Atenolol patches for its sustained effect.