A sensitive and rugged method was developed and validated by using liquid chromatography coupled with triple quadrupole spectrometer (LC/MS/MS) technique for the determination of 2,3-dimethyl-2H-indazole-6-amine content in pazopanib hydrochloride. The separation was achieved by using Hypersil BDS C18 15 cm *4.6 mm length and 5.0 µm width column. Mobile phase-A was 0.1% formic acid in water and mobile phase-B was acetonitrile in the ratio of 45:55 v/v with 1.0 mL/min flow rate in isocratic mode. The limit of detection (LOD) and limit of quantification (LOQ) signal to noise ratio values were obtained as 3.7 and 10.9 respectively. The linearity range between 0.6 to 6.0 ng/mL and the correlation coefficient was found 0.999. The recovery found between 98.8 to 101.3% at four different levels.

A selective and sensitive method has been developed for the determination of ethyl-(3S,4R,5S)-4-acetamido-5-amino-2-azido-3-(pentan-3-yloxy)cyclohexanecarboxylate (OSPRC-A) by using liquid chromatography coupled with mass spectrometer with single mass analyzer (LC-MS).The method was developed by using column DEVELOSIL ODS-UG-5, (50×3.0 mm, 5.0 µm) with linearity range of 0.005% to 0.0151% which meets to quantification level of 150% range. The column oven temperature was maintained at 40ºC. The flow rate was set as 1.5 mL/min. Injection volume was 10 µL and the detection wavelength was 215 nm. The signal to noise ratio values obtained were found to be 4.79 at concentration level of 0.00015% for the limit of detection (LOD) and 13.46 at concentration level of 0.0005% for the limit of quantification (LOQ). The % recovery was found to be in between the range 80.0% to 101.32% at LOQ to 150% level. The result obtained in method precision and intermediate precision are found to be within the specification limit. The percentage RSD for the content of OSPRC-A of method precision was 4.26. The percentage RSD for the content of OSPRC-A for intermediate precision was 4.00. The sample prepared in analytical solution was found to be stable for 24 h. This method can be used for the identification of impurity, OSPRC-A in Oseltamivir phosphate drug substances in its manufacturing.