Development and evaluation of transdermal gel of acyclovir using Nerolidol as penetration enhancer

Abstract

The aim of this study was to investigate the effect of Nerolidol on the penetration of Acyclovir in the form of transdermal gel formulation. Different formulations were prepared containing different concentrations of Nerolidol (0-5%) using Aloe vera gel as a base. Formulations evaluated for pH, Viscosity, Percent drug content, Spreadability, Diffusion study and In-vitro permeation study. Rheological study showed that viscosity is inversely proportional to the rate of shear and thus the system shows pseudoplastic behaviour. pH of all the formulations was found to be around 6 which is skin compatible. The percent drug content was found to be within the range of 98 to 101% for all the formulations. Spreadability of formulations is found to be in the range of 11.25 to 12.66 gm.cm/sec. Stability studies showed that the formulation is stable at 40 o C at 75% RH for a period of one month. It was evident that the permeation of Acyclovir was enhanced, across freshly excised hairless rat abdominal skin, in presence of Nerolidol which can be attributed toincreased lipid disruption in the stratum corneum. Comparison of F5with marketed formulation (Acivir, Cipla) for permeation of Acyclovir across hairless rat abdominal skin, showed greater flux 12.89 mg/cm 2. as compared to flux 4.74 mg/cm 2. hr of marketed formulation. F0 (without Nerolidol) showed better flux of 6.59 mg/cm 2. hr than the marketed product, this can be attributed to the use of Aloe vera gel as an absorption base which consists of lignins, that intensify penetrative properties.