Evaluation of an International Pharmacopoeia method for the analysis of indinavir sulfate by liquid chromatography

A gradient LC method for the determination of indinavir sulfate (IDV) and its impurities has been recently published in a consultation document of the International Pharmacopoeia, WHO Drug Information. The method uses a base-deactivated reversed-phase C18 column (25 cm × 4.6 mm i.d.), 5 μm kept at a temperature of 40 °C. The mobile phases consist of acetonitrile, phosphate buffer pH 7.5 and water. The flow rate is 1.0 ml/min. UV detection is performed at 220 nm. A system suitability test (SST) is described to govern the quality of the separation. The separation towards IDV components was investigated on 16 C18 columns and correlation was made with the column classification system developed in our laboratory. The method was evaluated using a Hypersil BDS C18 column (25 cm × 4.6 mm i.d.), 5 μm. A central composite design was applied to examine the robustness of the method. The method shows good precision, linearity, sensitivity and robustness. Six commercial samples were examined using this method.