Stability indicating assay of Dapagliflozin and Saxagliptin

The concentration of Saxagliptin(Sx) and Dapagliflozin(Dp) in the tablet was estimated simultaneously as per ICH guideline. For this purpose, a RP-HPLC method was newly established which is simple and robust showing Retention times were of 1.87 and 2.59 min for Sx and Dp respectively in the final developed condition. This method helped in separation of stable form of Saxagliptin and Dapagliflozin from their products. For the separation the conditions applied were, analytical column used was Phenomenex (Kinetex C₈, 150 × 4.6mm, 5µm), wavelength- 212nm, mobile phase in isocratic elution mode was 0.1% Perchloric acid: ACN (50:40) , rate of flow-1.2ml/min, Injection volume-10µl and run time-8mins. During the study for robustness, the % RSD was <1.5%. Different mediums such as 0.1N HCl (acidic), 0.1 N NaOH (basic) and 3% H₂O₂(oxidative) were used to study the forced degradation and the result showed 0.93%, 3.17% and 2.24% degradation for Saxagliptin and 1.18%, 28.20% and 1.67% for Dapagliflozin respectively. During chromatographic studies distinct peaks were observed for analyte and degradant. In case of Dapagliflozin, the LOD was obtained as 0.31µg/ml and LOQ as 0.93µg/ml. Similarly, in case of Saxagliptin, the LOD was obtained as 0.37µg/ml and LOQ as 1.1193µg/ml. This developed method(RP-HPLC) was proved to be fast, new, robust, highly sensitive and efficient for estimation of Sx and Dp present together. This developed method can help in quality control tests of many combined dosage forms in general and Saxagliptin and Dapagliflozin in particular.