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A new, simple, and stereoselective RP-HPLC method was developed and validated for the simultaneous quantification of tadalafil, its one enantiomer, and two diastereomers in API and tablets. Using varied compositions of water, acetonitrile, and acetic acid as mobile phases in gradient mode at a 0.40 mL/min flow rate and detection at 285 nm, all this separation was achieved on the Lux Cellulose-3 (150 mm x 4.6 mm, 3 µm) column at a 30.0°C oven temperature. All isomers were eluted within 24 minutes, with a resolution of more than 2.3 between any two isomers. With 10.0 µL injection volume, the LOD and LOQ were determined to be 0.06 µg/mL and 0.10 µg/mL, respectively. The linearity of tadalafil (0.10-400 µg/mL), one enantiomer, and two diastereomers (0.10-4.0 µg/mL) was confirmed with a correlation coefficient of 0.999. The forced degradation study revealed the specificity for all the peaks as well as the conversion of tadalafil into diastereomers (6S, 12aR) in acidic conditions and into diastereomers (6R, 12aS) in alkaline conditions. At lower concentrations, the recoveries for all isomers ranged from 100.0 ± 15.0%, while the assay values for tadalafil were within 100.0 ± 2.0%. According to the validation outcome as per ICH guidelines, the proposed method is an accurate, precise, linear, and robust stereoselective method for simultaneous quantification.

This article explains the developed and validated rapid, timesaving, and cost-effective UHPLC method for simultaneous quantification of cinnarizine, its five specified impurities (Impurity-A to E), two degradation products (cinnamyl piperazine and benzhydrol), and two antioxidants (methylparaben and propylparaben). Furthermore, when coupled with a mass spectrometer, the proposed method provides additional advantages for confirmation of results and correct identification based on molecular weight. All analytes were eluted within 15 minutes on an ACQUITY, UPLC, BEH C18 (150 mm x 2.1 mm, 1.7 µm) column at 40.0°C by using two mobile phases containing different compositions of 10 mM ammonium acetate, acetonitrile, and acetic acid in gradient elution mode. The linearity curves of cinnarizine, its impurities, and degradation products showed good results in a correlation coefficient of 0.999 with a lower detection limit (0.1125 μg/ mL) and quantification limit (0.1875 μg/mL) at 230 nm. A forced degradation study on spiked and unspiked solutions proved their specificity with improvements and their significance. This proposed method involves a lower flow rate (0.35 mL/min.) with a shorter run time, which provides faster analysis, reduces wastage, reduces the cost, and specifies the greener advantages. The outcome of the validation as per ICH guidelines proved that the proposed UHPLC method is accurate, precise, and timesaving for simultaneous quantification of all analytes in active pharmaceutical ingredient, tablets, capsules, and oral suspension of cinnarizine.

This article explains the developed and validated rapid, timesaving, and cost-effective UHPLC method for simultaneous quantification of cinnarizine, its five specified impurities (Impurity-A to E), two degradation products (cinnamyl piperazine and benzhydrol), and two antioxidants (methylparaben and propylparaben). Furthermore, when coupled with a mass spectrometer, the proposed method provides additional advantages for confirmation of results and correct identification based on molecular weight. All analytes were eluted within 15 minutes on an ACQUITY, UPLC, BEH C18 (150 mm x 2.1 mm, 1.7 µm) column at 40.0°C by using two mobile phases containing different compositions of 10 mM ammonium acetate, acetonitrile, and acetic acid in gradient elution mode. The linearity curves of cinnarizine, its impurities, and degradation products showed good results in a correlation coefficient of 0.999 with a lower detection limit (0.1125 μg/ mL) and quantification limit (0.1875 μg/mL) at 230 nm. A forced degradation study on spiked and unspiked solutions proved their specificity with improvements and their significance. This proposed method involves a lower flow rate (0.35 mL/min.) with a shorter run time, which provides faster analysis, reduces wastage, reduces the cost, and specifies the greener advantages. The outcome of the validation as per ICH guidelines proved that the proposed UHPLC method is accurate, precise, and timesaving for simultaneous quantification of all analytes in active pharmaceutical ingredient, tablets, capsules, and oral suspension of cinnarizine.