A Novel Transethosomal Gel Formulation for Sustained Capsaicin Delivery in Post-Herpetic Neuralgia Treatment

Objectives: The study aims to develop a novel capsaicin loaded transethosomal gel for the treatment of Post-Herpetic Neuralgia (PHN) for sustained capsaicin delivery. Materials and Methods: Transethosomes were formulated by ethanol injection method and were optimized by 32 factorial design. The concentration of soya lecithin and ethanol were selected as independent variables, Vesicle size (VS) and Entrapment Efficiency (EE) have been assessed in relation to the individual and combined effects of independent factors. Transethosomes were analyzed for particle size, encapsulation effectiveness, zeta potential, and cumulative percent drug release. Xanthum gum was used as a polymer for preparing Capsaicin-loaded transethosomal gel. Results: The optimized formulation (F1) exhibited a vesicle size of 61.57 nm and an entrapment efficiency of 73%. The homogeneous and spherical surfaces of Transethosomes were validated using Transmission Electron Microscopy (TEM) analysis. The in vitro drug release of transethosomal gel (84%) was more when compared with the capsaicin ointment (49%) and capsaicin plain gel (29%) and these studies were demonstrated a biphasic burst release profile, extending over 24 hr. The transformation of transethosomes into a gel using xanthan gum resulted in desired physical properties suitable for topical application. In vitro diffusion studies revealed sustained release of capsaicin from the transethosomal gel, indicating its potential for topical pain management. Ex vivo permeation studies shows that optimized transethosomal formulation is the highest drug permeation through porcine skin. The capsaicin-loaded transethosomal gel that has been developed presents a highly promising therapeutic strategy for the treatment of post-herpetic neuralgia. This gel combines the benefits of transethosomal administration with the analgesic properties of capsaicin. Conclusion: The results obtained demonstrated that this novel formulation presents a significant advancement in the management of post-herpetic neuralgia, addressing the need for effective and sustained pain relief, ultimately improving patient outcomes.