Foscarnet, phosphonoformic acid, is an antiviral drug used to treat herpes viruses. It is used to treat in HIV rescue therapy. For this drug we developed a reverse-phase high performance liquid chromatographic technique and valid in keeping with the ICH pointers. For this purpose ODS C18 (4.6 x 150mm, 5mm) column was used. As a mobile part, a combination of Phosphate buffer, Acetonitrile and Water with a pH 4.0 were used which was adjusted with orthophosphoric acid to the quantitative relation of 40:60%v/v. ultraviolet detection was done at 225nm. Stress degradation conditions were established for Foscarnet by subjecting it to acid, base, oxidation, UV, water and thermal stress. The stress samples were assayed and the mass balance was compared against a qualified reference standard. The developed technique was valid as per ICH norms. The established technique was with success used for the regular analysis of commercially accessible indefinite quantity kind. The flow rate was 1.1 millilitre min-1 and therefore the retention time was 3.885 min. The activity curve was found to be linear upon the concentration ranges of 0.25-1.5ppm. The LOQ and LOD values were found to be 3.98 and 1.32. The proportion of recovery and low constant of variance confirms that the tactic is appropriate for the estimation of Foscarnet drug in pharmaceutical indefinite quantity kind.
