Formulation and Evaluation of Topical Acyclovir Gel Using Different Polymers

Abstract

Background: Acyclovir is usually given as protracted therapy
and at greater dosing frequency for complete remittance of the
disease due to its low oral bioavailability, but this is associated
with side effects. Topical preparations of acyclovir are the
alternative route of administration to treat local dermatological
diseases caused by herpes simplex virus.
Objective: To prepare and evaluate the topical gel formulations
of acyclovir by using different polymers.
Materials and Methods: Acyclovir gels were formulated by
using three types of polymers, namely carboxymethylcellulose
sodium (CMC Na), hydroxypropyl methylcellulose (HPMC) and
carbopol-940 as gelling agents at different concentrations. They
were evaluated for several physicochemical characteristics
including physical appearance, grittiness, viscosity, spreadability,
pH, drug content uniformity and in vitro drug release studies. The
in vitro drug release of acyclovir from the selected gel
formulations was evaluated as per the procedure described in
United States Pharmacopoeia (USP), by using the standard 40mesh stainless steel dissolution basket (USP Apparatus 1)
containing cellulose acetate membrane with phosphate buffer pH
6.8 as the dissolution medium.
Results: Among all prepared gel formulations, formulation F8
containing 3% w/w of carboxymethylcellulose sodium was
selected as optimal gelling agent in acyclovir gel formulation due
to its desired physicochemical characteristics and it showed the
highest acyclovir in vitro release rate of 96.21 ± 0.92% over 5
hours.
Conclusion: The release of acyclovir from the gel formulations
was significantly affected by the type and concentration of
polymer (p-value < 0.05).