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The paper describes HPLC, UV spectrophotometric and non aqueous titrimetric method for the estimation of poorly water soluble protease inhibitor. Ritonavir in raw material and tablet dosage form. HPLC analysis was carried out in a C18 column using acetonitrile, methanol, and buffer in the ratio 60: 20: 20 (v/v/v) at 240 nm. For the spectrophotometric determination, methanolic solution of Ritonavir was reacted with 3-methyl benzothiazolin-2-one hydrazone (MBTH). The oxidative coupled green coloured chromogen was analysed at 633 nm. Non aqueous titration was carried out using perchloric acid as titrant and the end point was determined using crystal violet as indicator. The three methods were validated and statistically evaluated to correlate the difference between the methods for estimation of Ritonavir in pharmaceutical dosage form.

Two chromatographic methods are developed and validated to estimate Atazanavir Sulfate and Ritonavir in new fixed dosage form, that is, tablet dosage form named Synthivan. The first method is based on HPLC separation of the two drugs on the reversed phase HiQSil C18 column (5 µm, 250 × 4.6 mm) at ambient temperature using an isocratic solvent system consisting of acetonitrile and water in the ratio 52:48 (v/v). Quantification is achieved with a PDA detector at 254 nm at a flow rate of 1.5 mL/min. Linearity of concentrations is found at 60–600 µg/mL and 20–200 µg/mL for Atazanavir sulfate and ritonavir, respectively. The second method is based on HPTLC separation of the two drugs on pre-coated silica gel 60F254 aluminum plates using toluene:methanol:glacial acetic acid:ethyl acetate (7:0.5:1.5:2, v/v/v/v) as solvent system followed by densitometric measurements of their spots at 254 nm. The linearity of the concentration is found to be 30–300 and 10–100 ng/spot for Atazanavir Sulfate and Ritonavir, respect...