Formulation Optimization and Evaluation of Nanocochleate Gel of Famciclovir for the Treatment of Herpes Zoster

Background: Herpes zoster is a viral infection triggered due to the reactivation of the varicella- zoster virus in the posterior dorsal root ganglion. Herpes zoster infections occur mostly in the facial, cervical and thoracic regions of the body, beginning with pain and resulting in the vesicular eruption. Recently, this infection was observed during the Covid-19 pandemic and also after the induction of mRNA-based vaccine for coronavirus at an extended level. Nanocochleates are cylindrical (cigarshape) microstructure lipid-based versatile carriers for drug delivery systems. Famciclovir is an antiviral agent employed for the treatment of Herpes zoster infections. Objective: The current research aims to develop a novel nanocochleate gel of Famciclovir for the treatment of herpes zoster infections with higher efficacy. Methods: The interaction studies using FTIR were carried out and indicated no such interactions between the drug and lipids. The nanocochleates were developed using hydrogel, trapping, liposome before cochleate dialysis, direct calcium dialysis and binary aqueous-aqueous emulsion methods, respectively. The 32 Box-Behnken design was applied by considering the concentration of lipids (phosphatidylcholine and cholesterol) and speed of rotation as independent factors, whereas particle size and entrapment efficiency as dependable factors. Results: The developed nanocochleates were estimated for the particle size (276.3 nm), zeta potential (-16.7 mV), polydispersity index (0.241), entrapment efficiency (73.87±0.19 %) and in-vitro diffusion release (>98.8 % in 10 h). The optimized batch was further converted into the topical gel using carbopol 940 as a gelling agent. The prepared gel was smooth, rapidly spreadable with a viscosity (5998.72 cp), drug content (95.3 %) and remained stable during stability studies. Conclusion: A novel nanocochleate gel of Famciclovir was successfully developed for the treatment of infections associated with Herpes Zoster with sustained release action.