QbD-Driven Analytical Method Development for HPTLC Quantification of Spironolactone and Hydrochlorothiazide in Pharmaceutical Dosage Form

The present study examines simultaneous multiple response optimization using Derringer's desirability function for the development of an HPTLC method to detect sprinolactone and hydrochlorothiazide in pharmaceutical dosage form. Central composite design (CCD) was used to optimize the chromatographic conditions for HPTLC. The independent variables used for the optimization were the acetone content in the mobile phase, the wavelength, and the distance travelled. HPTLC separation was performed on aluminium plates pre-coated with silica gel 60 F254 as the stationary phase using toluene: methyl acetate: acetone (5:3:2% v/v/v) as the mobile phase. Quantification was achieved based on a densitometric analysis of spironolactone and hydrochlorothiazide over the concentration range of 50–175 µg/ml for both analytes, at 229 nm. The method yielded compact and well-resolved bands at Rf of 0.71 ± 0.03 and 0.41 ± 0.02 for spironolactone and hydrochlorothiazide, respectively. The linear regression analysis for the calibration plots produced r2 = 0.9994 and r2 = 0.9991 for spironolactone and hydrochlorothiazide, respectively. The precision, accuracy, robustness, specificity, limit of detection, and limit of quantitation of the method were validated according to the ICH guidelines. The factors evaluated in the robustness test were determined to have an insignificant effect on the selected responses. The results indicate that the method is suitable for the routine quality control testing of marketed tablet formulations.