Identification of Degradant Impurity in Gefitinib by Using Validated RRLC Method

Abstract

Degradation pathway for gefitinib is established as per ICH recommendations by validated and stability in-dicating reverse phase liquid chromatographic method. Gefitinib is subjected to stress conditions of acid, base, oxidation, thermal and photolysis. Significant degradation is observed in acid and base stress condi-tions. Two impurities are studied among which one impurity is found prominent degradant. The stress sam-ples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Effi-cient chromatographic separation is achieved on a Agilent make XDB-C18, 50 × 4.6 mm with 1.8 µm parti-cles stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 250 nm at a flow rate of 0.5 mL?min-1. In the developed RPLC method the resolution between ge-fitinib and the potential impurities is found to be greater than 5.0. Regression analysis shows an r value (cor-relation coefficient) of greater than 0.998 for gefitinib and the two potential impurities. This method is capa-ble to detect the impurities of gefitinib at a level of 0.01% with respect to test concentration of 0.5 mg?mL-1 for a 4-µL injection volume. The developed RRLC method is validated with respect to specificity, linearity & range, accuracy, precision and robustness for impurities determination and assay determination.