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

Idelalisib is a phosphatidylinositol 3-kinase delta inhibitor approved by the FDA and the EMA for the treatment of lympholytic lymphoma, B cell non-Hodgkin lymphoma, and lymphocytic lymphoma. The present report describes the validation of a simple, rapid, sensitive, and cost-effective zero-order and first-order derivative spectrophotometric method for the estimation of idelalisib in bulk and in its marketed formulation. Preliminary spectrophotometric analysis of the drug was carried out in methanol and a total of 12 parametric variations were considered. Three selected method variants employing peak-zero and peak-peak techniques were assessed for their stability indicating potential in stress degraded solutions of the drug. The developed method was validated with respect to linearity, accuracy, precision, and robustness. Excellent linearity was observed within the concentration range 1.0–60.0 μg/mL with a correlation coefficient of 0.9997. The limits of assay detection values were found for the range 0.42–3.11 μg/mL, and quantitation limits ranged from 1.29 to 9.42 μg/mL for the proposed method variants. The proposed method was used to quantify the drug in its marketed tablet formulation, and good recoveries ranging from 95.98 to 98.81% were obtained.