A simple, effective LC–MS based method is developed and validated to determine N‐nitrosodimethylamine and N‐nitrosodiethylamine in pharmaceutical formulations of Sitagliptin and Metformin hydrochloride combination dosage forms. Atlantis T3 (100 × 3 mm, 3 μm) column, eluent‐A (0.1% formic acid in water), and eluent‐B (0.1% formic acid in methanol) were used to achieve chromatographic separation. A gradient program time (min)/%B: 0.01/3, 2/3, 4/55, 5/55, 5.5/90, 6.0/90, 6.5/3, and 7/3, and column flow rate: 0.75 mL/min was employed. The column oven and auto sample cooler temperatures were 40°C and 10°C, respectively. Atmospheric Pressure Ionisation positive mode with corona discharge potential as 4.0 V, drying gas (N2) flow as 110 mL/min, and nebulizer gas (N2) flow as 350 mL/min. Employing PerkinElmer triple quadrupole mass spectrometer, QSight 200 series, the source temperature was 450°C, and hot surface‐induced desolvation temperature was 250°C. Under optimized conditions, diluent‐1 and diluent‐2 offered better recovery and improved peak shapes. The required method sensitivity of nitrosodimethylamine (LOQ 0.74 ng/mL) and nitrosodiethylamine (LOQ 0.37 ng/mL) for the nitrosamine impurities were achieved using an optimized test concentration of Metformin hydrochloride at 45.7 mg/mL.

The current work describes the development and validation of a stability‐indicating UPLC method for the determination of olmesaratan medoxomil (OLM), amlodipine besylate (AMB), hydrochlorothiazide (HCT) and their degradation products in the triple‐combination tablet dosage form. The separation was achieved using a Zorbax Eclipse plus C8 RRHD (100 mm × 3.0 mm), 1.8 μm column with gradient elution of mobile phase A containing 0.02 m of sodium phosphate buffer (pH 3.35) and mobile phase B as acetonitrile and water (90:10, v/v). The detector signal was monitored at UV 250 nm. Analytical performance of the optimized UPLC method was validated as per International Conference on Harmonization guidelines. The linearity ranges for OLM, AMB and HCT were 0.59–240, 0.30–60 and 0.37–150 μg/ml, respectively, with correlation coefficients >0.999. The dosage form was subjected to forced‐degradation conditions of neutral, acidic and alkaline hydrolysis, oxidation and thermal and photodegradation. The method was proved to be stability indicating by demonstrating the specificity of the drugs from degradation products. The robustness of the method was evaluated through a two‐level, three‐factorial design with a multivariate approach. Statistical data analysis with best model fit P‐value < 0.05 from an ANOVA test indicated that the influence of individual factors is relatively higher than the interaction effects. The method is useful for the analysis of drug products.