Stability Indicating, pH and pK_a Dependent HPLC–DAD Method for the Simultaneous Determination of Weakly Ionizable Empagliflozin, Dapagliflozin and Canagliflozin in Pharmaceutical Formulations

Abstract

A simple, rapid, and accurate stability-indicating reverse phase HPLC–DAD method was developed and validated for the simultaneous determination of empagliflozin, dapagliflozin, and canagliflozin (Gliflozins). Optimum chromatographic separations among gliflozins in the presence of matrices and degradation products have been achieved within 7 min by using Hypercil™ C₁₈ column (25 × 4.6 mm, 5 μm) with acetonitrile and 0.1% formic acid buffer, pH 3.7 (60:40 v/v) as the mobile phase at a flow rate of 1 mL min⁻¹. The proposed method was performed at 230 nm for empagliflozin and dapagliflozin while detection of canagliflozin was carried out at 290 nm. Analytical performance of the method was thoroughly validated in accordance with the ICH guidelines with respect to system suitability, linearity, accuracy, precision, specificity, robustness, detection and quantification limits. Regression analysis showed good correlations with regard to R² ≥ 0.997 over the concentration range of 4–160 µg mL⁻¹ for gliflozins. The LOD was found to be 0.07 µg mL⁻¹, 0.12 µg mL⁻¹ and 0.29 µg mL⁻¹ for empagliflozin, dapagliflozin and canagliflozin, respectively. Method development was established keeping in view the structure of drugs, their pK_a values, ionizability of drugs, pH values of buffer system and buffer capacity. Peak purities of gliflozins in stress tests are less than 1.5, which further confirms no co-elution of degradation products. The proposed method is suitable for routine quality control analysis of gliflozins and to carry out stability studies.

Graphic Abstract