Liquid chromatographic assay for the protease inhibitor atazanavir in plasma

Atazanavir is the most recently introduced protease inhibitor for the suppression of the anti-human immunodefficiency virus. A sensitive and selective reversed-phase liquid chromatographic assay for this drug in human plasma has been developed and validated. Atazanavir was isolated from a 500 µL plasma sample using liquid–liquid extraction with dichloromethane. After evaporation and reconstitution of the extract the sample was analysed using liquid chromatography and ultraviolet detection at 280 nm. In the evaluated concentration range (44–4395 ng[sol ]mL atazanavir), intra-day precisions were ≤7% and inter-day precisions were ≤14%. Accuracies between 96 and 106% were found. The lower limit of quantification was 44 ng[sol ]mL with an intra-day precision of 7%, an inter-day precision of 14% and an accuracy of 87%. There was no interference from 32 tested potentially co-administrated drugs and metabolites. The usefulness of the assay was demonstrated for samples obtained from an HIV-infected patient treated with atazanavir. Copyright © 2005 John Wiley & Sons, Ltd.