Formulation Development and Evaluation of Ethosomal Gel of Acyclovir for the Treatment of Herpes Zoster

Abstract

The present study is to develop and evaluate an ethosomal gel formulation of acyclovir (ACV). It aims to provide a topical treatment for many viral infections that affect the skin. Administration of medications topically having the facility of delivering a high concentration of the drug to the skin than would be possible with systemic therapy. Topical administration of drugs is better for local action and the efficiency of the topically administered drug is increased with liposome, proliposomes and ethosomes. Recently, it was found that ethosomal carriers were phospholipid vesicular systems having relatively high concentrations of alcohol, enhances dermal and transdermal delivery of both lipophilic as well as hydrophilic molecules. ACV is the common antiviral agent that is used to treat infections caused by certain types of viruses. It treats cold sores around the mouth (caused by herpes simplex), shingles (caused by herpes zoster) and chickenpox. ACV 5% cream is used for the treatment of infection along with oral dosage forms like tablets. These formulations show poor therapeutic outcome due to the poor bioavailability (15-20%) of oral dosage forms. Ethosomes were formulated using phospholipid, ethanol, polyethylene glycol and purified water by cold method. Ethosomes were evaluated for vesicle size, shape, optical microscopy, entrapment efficiency and in-vitro release study. AEF5 have better drug entrapment efficiency than the other formulation. The best formulation (AEF5) was used to prepare gel by using carbopol 934 as a gelling agent. The ethosomes were entrapped in gel matrix of carbopol 980 in different concentration 0.5%, 1.00% and 1.5% w/w. FT-IR studies revealed no interaction between the drug and excipients. The formulated gel formulation was evaluated with parameter pH, viscosity, spreadability, in-vitro release test, washability, extrudability study and stability studies. The formulation AEG2 have better in-vitro drug release profile which contains carbopol 980 concentration 1%w/w. The present work also focuses on making the formulation more pharmaceutically acceptable.

Keywords: Acyclovir, Ethosomal gel, Viral infections, Phospholipid, % Entrapment efficiency, Vesicle size