Development and Validation of a Method for the Quantitative Determination of Gefitinib in a Liposomal Dosage Form

Epidermal growth factor receptor (EGFR) inhibitors are widely used in the treatment of lung cancer, one of the most common malignancies. Gefitinib, an EGFR tyrosine kinase inhibitor, has limited clinical efficacy due to slow absorption in the gastrointestinal tract and low and variable bioavailability after peroral administration. The purpose of this study was to develop a quantitative determination method for gefitinib in a liposomal dosage form intended to increase its bioavailability and therapeutic efficacy. Direct UV spectrometry was used for this. The developed methodology was validated in accordance with current recommendations. The liposomal bilayer components were shown not to affect the spectral characteristics of gefitinib and did not interfere with its quantitative determination, i.e., the technique was specific. Validation confirmed the linear dependence of the analytical signal on the gefitinib solution concentration. The method provided acceptable accuracy and precision in the analytical range from 70 to 130% of the nominal gefitinib content in a unit dosage form. The results were not burdened by systematic error. The limits of detection and quantitation calculated using the linearity parameters were 0.26 mg and 0.80 mg of gefitinib, respectively. The extended analytical range of the technique allowed it to be used to quantify and determine the dosing uniformity of gefitinib in the lyophilized liposomal dosage form.