Valacyclovir

A simple, precise, economical and accurate difference spectroscopic method has been developed for the valacyclovir in bulk and in pharmaceutical dosage form. The proposed method is based on the principle that valacyclovir exhibits two different chemical forms that differs in the absorption spectra in acidic and basic solution. The absorptions were measured in acidic and basic solution separately against reagent blank. Valacyclovir has exhibited maximum absorbance at 252 and 262nm in acidic and basic solution respectively. Difference in absorbance between these two maxima was calculated to find out the amplitude. The amplitude plotted against concentration showed linear response in the concentration range of 0.5 – 2.5μg/mL with linear regression value 0.999. The proposed method was applied to pharmaceutical formulation and the common excipient present in the formulation does not interfere in the analysis of the drug. The method was validated as per ICH guidelines and statistical results of analysis were found to be satisfactory.

Gastro retentive drug delivery is an approach to prolong gastric residence time, thereby targeting site-specific drug release in the upper gastro intestinal tract (GIT) for local and systemic effect. The present study has been a satisfactory attempt to formulate floating drug delivery system of Valacyclovir, an orally administrated antiviral drug with a view of improving its oral bioavailability and giving sustained release of the drug. In present study design expert trial 8.0.6.1 software is used for designing of experiment. In central composite design based on response surface methodology yielded nine experimental runs. These nine formulations are evaluated for precompressional parameters like bulk density, tapped density, angle of repose and carr’s index. Formulations are also evaluated for postcompressional parameters like hardness, thickness, weight variation etc. all the formulations shows results in the acceptable range. All preliminary formulations are subjected to invitrobouyancy and dissolution study. The data obtained from the in vitro release study was fit to various kinetic models to explain the release profile of the drug. Kinetic models used were zero and first-order equations, Krosmeyersand peppas and Higuchi models. Based on results obtained from the prelimimary formulations five optimized formulations are selected and validated. Short-term stability study was done for optimized formulations.