A simple, precise, accurate method was developed for the estimation of Ritonavir by RP-HPLC technique. Chromatographic conditions used are stationary phase Ascentis C18 150mm x 4.6 mm, 2.7 , Mobile phase Acetonitrile: NaH 2 PO 4 in the ratio of 60:40. Then pH adjusted to 4 with orthophosphoric acidand flow rate was maintained at 1ml/min, detection wave length was 239 nm, column temperature was set to 30 ˚C and diluent was mobile phase. Conditions were finalized as optimized method. System

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... bility parameters were studied by injecting the standard six times and results were well under the acceptance criteria. Linearity study was carried out between 25% to150 % levels, R 2 value was found to be as 0.999. Precision was found to be 0.3 for repeatability and 0.7 for intermediate precision. LOD and LOQ are 0.54µg/ml and 1.65µg/ml respectively. By using above method assay of marketed formulation was carried out 99.49% was present. Degradation studies of Ritonavir were done, in all conditions purity threshold was more than purity angle and within the acceptable range.