Implementation of QbD approach in RP-HPLC method optimization and validation for concurrent estimation of Deflazacort and Tamsulosin hydrochloride under ICH Q14 and Q2R2 framework

Background The simultaneous estimation of Tamsulosin Hydrochloride (TAM) and Deflazacort (DEF) in capsule dosage form requires a reliable analytical method. Reverse-phase high-performance liquid chromatography (RP-HPLC) was developed; optimised with a Box Bhenken Design (BBD) a QbD approach and validated with ICH Q2R2 guidelines and its applicability for routine quality control. Methods A systematic risk assessment and Design of Experiments (DoE) using a Box-Behnken Design (BBD) were employed to optimize critical method parameters (CMPs), including mobile phase pH, organic modifier concentration, and flow rate. Chromatographic separation was achieved on an Agilent C-18 column using a mobile phase of 0.1 % orthophosphoric acid (OPA, pH 6.8) and acetonitrile in a 50:50 v/v ratio at a flow rate of 1.0 ml/min, with detection at 283 nm. Results The optimized method yielded retention times of 3.3 min for TAM and 7.4 min for DEF. Validation, carried out as per ICH guidelines, confirmed the method’s linearity, accuracy, precision, specificity, LOD and LOQ for its reliability for simultaneous estimation of TAM and DEF. Conclusion The QbD-driven RP-HPLC method developed is simple, accurate, precise and robust. It is well-suited for routine quality control analysis of DEF and TAM in combined pharmaceutical dosage form (capsules), ensured the consistent method performance and its reproducibility.