A new stability indicating RP-HPLC method has been developed for simultaneous estimation of ombitasvir, paritaprevir and ritonavir in bulk and tablet dosage form. The method involves separation and analysis of the selected drugs on Inertsil ODS C18 (4.6 mm × 250 mm, 5 µm). The optimized mobile phase consists of orthophosphoric acid (40 %): acetonitrile (60 %) with a flow rate of 1 mL/min and detection at 252 nm. Retention time was 2.056 min for ombitasvir, 2.821 min for paritaprevir and 4.853 min for ritonavir. The developed method was validated as per the ICH guidelines. Linearity was observed in the range of 6.25-31.25 µg/mL for ombitasvir, 37.5-187.5 µg/mL for paritaprevir and 25-125 µg/mL for ritonavir with good correlation coefficient value (> 0.9990). The percentage recoveries of ombitasvir, paritaprevir and ritonavir were in the range of 99. 98-100.69 %, 99.16-100.75 % and 99.82-100.08 %, respectively. The percentage relative standard deviation was < 2 %. The method had the ability to quantify the drugs simultaneously from tablets dosage forms with no interference from the tablets excipients. Ombitasvir, paritaprevir and ritonavir were also subjected to acid, base, oxidation and thermal degradation studies. The proposed method effectively analyzed the studied drugs in the presence of their degradation products.

Objective: The objective of the study was to develop and validate a sensitive, precise, and accurate stability indicating reverse-phase (RP) highperformance liquid chromatography method for the quantification of saquinavir, ritonavir, and amprenavir simultaneously. Methods:The determination of saquinavir, ritonavir, and amprenavir in their mixtures was done using a mobile phase consisted of 0.1M phosphate buffer (pH 3.5) and methanol (70:30, v/v). The method is based on the simultaneous separation of studied drugs in a RP Inertsil ODS C18 (4.6 mm×100 mm, 5 µm) column at ambient temperature. Detection and quantitation were achieved with photodiode array detector set at 260 nm.Results: Saquinavir, ritonavir, and amprenavir showed linearity over a concentration range of 40-200 µg/ml (R 2 -0.9994), 20-100 µg/ml (R 2 -0.9992), and 30-150 µg/ml (R 2 -0.9990), respectively. The limit of quantification was 0.64 µg/ml, 0.57 µg/ml, and 0.53 µg/ml for saquinavir, ritonavir, and amprenavir, respectively. The accuracies for the three drugs were in the range of 99.40-100.53% (saquinavir), 99.45-100.47% (ritonavir), and 100.03-100.53% (amprenavir). The percentage relative standard deviations for the studied drugs were 0.785-0.848% (saquinavir), 0.338-0.499% (ritonavir), and 0.336-0.775% (amprenavir). No peaks were observed at the retention time of saquinavir, ritonavir, and amprenavir in placebo blank, mobile phase blank and stress degraded samples which suggested that the proposed was selective and specific. Conclusion:The method was found to be suitable for the regular analysis of saquinavir, ritonavir, and amprenavir simultaneously in the presence of their stress degradation products.

Inhibitor which is a novel ovarian cancer drug. For applicability to pharmacokinetic study, a LC-MS/MS based method for monitoring plasma levels of niraparib was developed. The analyte and Olaparib(IS) were chromatographed on YMC Pack ODS column C18 (50×4.6 mm i.d., 3µ) using MeOH:Ammonium Acetate (2 mM) as binary gradient mobile phase at flow rate 1mL/min with splitter (1:1) over 5 min RT. Detection of analytes were performed on LC-MS/MS system in SRM mode. The method was validated over concentration range of 4.38-1121.35 ng/mL and lower LOQ was 4.38 ng/mL for the analyte. Recoveries from spiked controls were >83% for the analyte and IS at all QC levels. Within batch and between batch accuracy for Niraparib was found within 94.2-105.8% and 98.9-102.0%. Within batch and between batch precision for niraparib was found <11.2% CV at all concentration levels. This method was successfully applied to monitor PK profile of niraparib on oral and IV administration to rats.