RP-HPLC Method Development and Validation for Palbociclib and Letrozole

Current aim is to develop a simple, rapid, accurate, economic, precise stability indicating assay method for the simultaneous estimation of Palbociclib and Letrozole in pure drug and dosage form. For these purpose choices of a common solvent was essential so various solvent ranges including methanol, ethanol, acetonitrile,and phosphate buffer and various concentrations ranges of various buffers were analyzed. Few methods have been reported on above drugs by using water as common solvent which is the cheapest; therefore finally the common solvent for the above drugs was chosen as sodium Dihydrogen phosphate pH 5.5 (0.05 mm) which is more cheaper than any organic solvent. Palbociclib and Letrozole show maximum absorbance at 220 and 240 nm respectively. Both drugs obey Beer Lambert's law in the concentration range of 2-10 mig/ml and 40-140 mig/ml for Palbociclib and Letrozole respectively.The RP-HPLC method was developed using Intersil ODS-C8, (4.6mm x 250mm; 5mim) column, at ambient temperature using mobile phase Methanol: Acetonitrile: 0.05mM sodium dihydrogen phosphate buffer (pH adjusted to 5.5 with NaOH) in10:10:80 v/v proportion found to give sharp, well defined peaks.