Optimization and validation of RP-HPLC method for simultaneous estimation of palbociclib and letrozole

A simple, rapid, and robust RP-HPLC method have been developed and validated to measure palbociclib (PB) and letrozole (LT) at single wavelength (254 nm). A isocratic elution of samples performed on Intersil C₈ (4.6 mm × 250 mm particle size 5 μm) column with mobile phase consisting 0.02 M sodium dihydrogen phosphate buffer (pH 5.5): acetonitrile: methanol (80:10:10 v/v/v) delivered at flow rate 1.0 mL min^-1. A good linear response was achieved over the range of 5-50 μg mL^-1. The LODs for PB and LT were found to be 0.098 and 0.0821 µg mL^-1, while the LOQs for PB and LT were 0.381-0.315 µg mL^-1, respectively. The method was quantitatively evaluated in terms of system suitability test, linearity, precision, accuracy (recovery) and robustness as per standard guidelines. The method is simple, convenient and suitable for the analysis of PB and LT in bulk drug.