Derivative Spectrophotometric Methods for Determination of Gefitinib in Bulk and in Formulation

A rapid, sensitive, cost effective and reproducible first-order derivative spectrophotometric method was developed for the estimation of gefitinib in bulk and in its marketed formulation. Preliminary spectrophotometric determination of the drug was carried out in acetate buffer pH 2.8 and in 0.1 N HCl with a total of 20 parametric variations. The selected method with three parametric variations employing peak–zero (P–0) and peak–peak (P–P) techniques was assessed for stability indicating potential in force degraded solutions. The developed method was validated with respect to linearity, accuracy, precision, and robustness. Linearity was observed in the concentration range of 5–50 μg/mL with an excellent correlation coefficient (r2) of 0.999. The limits of assay detection values were found for the range from 1.69–3.75 μg/mL, and quantitation limits ranged from 5.11–12.71 μg/mL for the proposed method. The proposed method was applicable for the determination of the drug in its marketed tablet formulation, and percentage recovery was found for the range from 97.42 to 98.58%.