Green analytical RP-HPLC method for daidzein in cubosomes: A QbD-based stability-indicating approach

The research outlines the formulation and rigorous validation of a reverse-phase high-performance liquid chromatography method for quantification of Daidzein (DAI) in cubosomal formulations, developed under a quality by design paradigm with a strong emphasis on environmental sustainability.Critical method parameters were identified through risk assessment and Taguchi screening, followed by response-surface optimisation using a central composite design.The optimised method comprising a methanol-water mobile phase (64.52:35.48,v/v), 1.08 ml/min flow rate, and detection at 249 nm yielded a markedly reduced run time of 4.6 minutes, representing an approximate 40%-55% reduction compared to conventional high-performance liquid chromatography methods reporting 6-10 minutes retention.The method demonstrated excellent performance, with a tailing factor of 1.16, theoretical plates of 4,772, and high desirability (0.997).Validation as per ICH Q2(R2) confirmed its sensitivity, precision, accuracy, and robustness, while forced-degradation studies established its stability-indicating capacity.Application to cubosomal formulations confirmed its suitability for routine quality assessment.Environmental evaluation via the efficient, valid green framework highlighted the method's enhanced greenness owing to reduced organic solvent use and shortened analytical time.By enabling accurate dose confirmation and stability monitoring, the method directly supports the therapeutic development of DAI-based nanocarriers for effective polycystic ovarian syndrome management.