Liquid Chromatographic Assay for the Analysis of Atazanavir in Rat Plasma after Oral Administration: Application to a Pharmacokinetic Study

Abstract

A new reverse phase liquid chromatographic method for the investigation of atazanavir in rat plasma was developed after oral administration. The chromatographic separation was achieved on Phenomenex C 18 column (250 mm × 4.6 mm I.D., 5 μm), under isocratic conditions using UV detection at 249 nm. The optimized mobile phase consisted of a mixture of potassium dihydrogen phosphate (pH 3.5) and acetonitrile (58: 42, v/v) at a flow rate of 1ml/min. The system was found to produce sharp and well-resolved peak for atazanavir with retention time of 5.78 min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range 0.050-2.0 μg/ml, with determination coefficients, R 2 , exceeding 0.9989. The limits of detection (LOD) and quantitation (LOQ) were found to be 0.004 μg/ml and 0.012 μg/ml, respectively. The method was successfully applied for the pharmacokinetic in rats. Atazanavir concentration in plasma reached (C max ) was 0.087 μg/ml at 3 h after oral administration of 7.2 mg/kg/rat. The AUC 0-12 was 0.4812 μg/ml*h and the apparent plasma half-life (t 1/2 ) was 7.5 h. This method was found to be suitable for examining atazanavir concentration in rats, after oral administration of atazanavir in a single dose.