Quality by design-steered development and validation of analytical and bioanalytical methods for raloxifene:...

A sensitive, rapid, reproducible, and economical HPLC method is reported for the quantification of raloxifene hydrochloride employing Quality by Design (QbD) principles. Factor screening studies, employing Taguchi design, indicated buffer volume percentage and isocratic flow rate as the critical method parameters (CMPs), which significantly influence the chosen critical analytical attributes, that is, tailing factor and theoretical plate number. Method conditions were subsequently optimized using face-centered cubic design with magnitude of variance inflation factor for assessing multicollinearity among CMPs. Method operable design region (MODR) was earmarked and liquid chromatographic separation optimized using 0.05 M citrate buffer, acetonitrile, and methanol (57:40:3 v/v/v) as ggmobile phase at 0.9 mL min^-1 flow rate, λ_max of 280 nm, and column temperature of 40°C. Validation of the developed analytical method was accomplished as per International Council on Harmonization (ICH) guidelines confirming high levels of linearity, precision, accuracy, robustness, and sensitivity. Application of Monte Carlo simulations enabled the attainment of best plausible chromatographic resolution and corroboration of the demarcated MODR. Establishment and validation of the bioanalytical method using rat plasma samples, along with forced degradation and stability studies, corroborated the aptness of developed HPLC methods for drug quantification in the biological fluids, as well as in bulk and marketed dosage forms.