Formulation and In Vitro Evaluation of a Matrix Type Transdermal Patch for the Sustained Delivery of Sparteine

Abstract

This study aimed to formulate and evaluate matrix-type transdermal patches of Sparteine to enhance drug permeation, ensure skin compatibility, and assess stability under accelerated conditions. Sparteine patches (F1–F7) were prepared using polymeric matrices with plasticizers and permeation enhancers. Ex vivo permeation across excised rat skin was studied using Franz diffusion cells, and cumulative drug release, flux, and permeability coefficients were calculated. Skin irritation potential of the optimized patch was evaluated in albino rabbits using the Draize scoring system. Stability studies were conducted under accelerated conditions (40 ± 2°C, 75 ± 5% RH) for 90 days according to ICH guidelines. Ex vivo permeation showed formulation-dependent drug release, with F7 exhibiting the highest cumulative permeation (365.2 ± 14.1 µg/cm²), flux (15.6 ± 0.7 µg/cm²/h), and permeability coefficient (1.56 ± 0.07 ×10⁻³ cm/h). Skin irritation scores remained ≤1 at all-time points, indicating the optimized patch was non-irritant. Stability studies demonstrated that the patch maintained its physical appearance, thickness, moisture content, drug content, and in vitro release over 90 days, confirming chemical and mechanical stability. The optimized Sparteine transdermal patch (F7) provides sustained drug release, is safe for dermal application, and exhibits excellent stability, highlighting its potential as a viable alternative for controlled transdermal delivery of Sparteine.