The effectiveness of Acyclovir ointment in treating herpes simplex virus infections can be limited by its moderate efficacy, particularly in severe cases. This limitation is partly attributed to the slow absorption of the drug through the skin’s epidermal layer. Consequently, there is considerable interest in developing improved formulations to enhance the topical delivery of Acyclovir. Nanoemulsions, colloidal dispersions of oil and water stabilized by surfactants, offer a promising approach to improve drug penetration.
In this study, we aimed to develop and characterize a nanoemulsion-based transdermal patch for enhanced delivery of Acyclovir. Screening of surfactants, oils, and co-surfactants based on solubility studies guided the formulation process. Pseudoternary phase diagrams helped determine optimal concentrations of Smix and oils for nanoemulsion preparation. Three formulations were evaluated for particle size, encapsulation efficiency, and zeta potential, with the optimized formulation selected for incorporation into the transdermal patch.
The patch was formulated using 4% polyvinyl alcohol and 1% polyvinyl pyrrolidine as suitable polymers. Evaluation of drug content and diffusion across a membrane confirmed successful incorporation of the nanoemulsion. In vitro release studies demonstrated zero-order release kinetics with sustained drug release over 2 hours for all formulations and up to 7 hours for the patch. Importantly, the nanoemulsion-based transdermal patches exhibited enhanced drug diffusion and permeation compared to pure drug formulations.
Overall, this study highlights the potential of nanoemulsion-based transdermal patches as a promising strategy for improving the delivery of Acyclovir, offering extended release, reduced administration frequency, and enhanced therapeutic efficacy in treating herpes simplex virus infections.