Formulation, Optimization and Evaluation of a Ribavirin-Loaded Liposomal Emulgel for Targeted Topical Antiviral Delivery

Abstract

The skin’s stratum corneum act as major barrier and to overcome it while reducing the systemic toxicities associated with conventional dosage forms, this study is aimed to develop, optimize and evaluate a novel ribavirin-loaded liposomal emulgel for localized antiviral therapy minimizing systemic exposure. Ribavirin-loaded liposomes were prepared using a thin-film hydration technique and optimized using a Central Composite Design (CCD) to assess the effects of phospholipid and cholesterol concentrations on drug encapsulation and release. After optimization an ideal formulation contained 741.5 mg of phospholipid and 201.6 mg of cholesterol, which yielded a high entrapment efficiency of 82.3±0.38% and a cumulative in vitro release of 83.4±0.33% over 12h was selected. Scanning electron microscopy (SEM) revealed a smooth, spherical vesicular morphology with a zeta potential value of −35 mV, indicating good colloidal stability.an emugel was prepared by combining these optimized liposomes into a Carbopol 934. The resulting emulgel exhibited good dermatological properties, with a skin-compatible pH of 5.9±0.10, a viscosity of 12,580±0.79 cP, and a spreadability of 7.86±0.12 g⋅cm/s. The emulgel exhibited linear, zero-order release kinetics (83.52±0.62% over 420 min) and ex vivo skin permeation studies using excised goat skin showed good dermal retention with minimal flux into systemic circulation. These results show that the developed carrier system successfully crossed the epidermal barrier to establish a controlled therapeutic reservoir within target tissues, giving a stable and efficient formulation for the localized antiviral thrapy.