DEVELOPMENT OF LIQUID-LIQUID EXTRACTION PROCEDURE AND ITS APPLICATION FOR QUANTIFICATION OF ERLOTINIB IN SPIKED HUMAN PLASMA USING RP-HPLC WITH UV DETECTION

A simple, rapid and accurate RP-HPLC method was developed and validated for the quantification of Erlotinib in spiked human plasma using liquid-liquid extraction. Sufficient recovery was obtained when drug and internal standard (Nabumetone) were extracted using ethyl acetate and 1N NaOH. Chromatographic separation was performed on C18 Phenomenex Hyperclone column (250 × 4.6 mm, 5 μm) using mobile phase acetonitrile: 20 mM ammonium acetate buffer pH 4.6 (60:40%,V/V). Flow rate was kept constant at 1 mL/min and detection was carried out at 331 nm. Calibration curve was found to be linear in the range of 100-3200 ng/mL. During the calibration experiments, it was found that heteroscedasticity can be minimized using weighted regression calibration model with weighing factor of 1/x2.