Stability-indicating RP-LC method for simultaneous estimation of dapagliflozin propanediol monohydrate and telmisartan based on QbD approach

Telmisartan and dapagliflozin propanediol monohydrate are simultaneously detected and estimated in bulk and pharmaceutical dose forms using the reverse phase liquid chromatography (RP-LC) method. A Symmetry^® C18 column (250 × 4.6 mm, 5 μm) was used as the stationary phase in the analysis, and a UV wavelength of 236 nm was used for detection. In order to explore the response surface during technique optimization and achieve effective separation with the fewest number of experimental trials, a Box–Behnken design (BBD) was used for experimental planning. The acetonitrile volume, the detection wavelength, and the mobile phase flow rate were the three independent variables considered. The tailing factors of both compounds, the peak resolution between the two medications, and the retention times of Telmisartan and Dapagliflozin propanediol monohydrate were among the measured responses that were utilized to create mathematical models. A mobile phase comprising acetonitrile, 0.01 M potassium dihydrogen phosphate, and methanol in a ratio of 70:20:10, v/v/v was given at a flow rate of 1.0 mL min⁻¹ and the pH was adjusted to 4 using 1% orthophosphoric acid, according to the optimal assay conditions indicated. In these circumstances, the technique was able to achieve baseline separation of both drugs with adequate resolution > 2. With correlation coefficients of r² = 0.9994 (n = 5) for dapagliflozin propanediol monohydrate and r² = 0.9995 (n = 5) for Telmisartan. Validation was carried out in concentration ranges of 0.04–40 µg mL⁻¹ for telmisartan and 0.01–10 µg mL⁻¹ for dapagliflozin propanediol monohydrate. In force degradation investigations, it was discovered that both the drugs were susceptible to all stress conditions, including acid and base hydrolysis, oxidative, dry heat, and photolytic conditions. The peak area of both drugs decreased but the degradant peak was not visible might be because chromophore group absent in liberated degradants.