Validated Spectrofluorimetric Method for Estimation of Idelalisib in Bulk and in Formulation

Idelalisib is a phosphatidylinositol 3-kinase delta inhibitor approved by the USFDA and EMA for the treatment of lympholytic lymphoma, B-cell non-Hodgkin lymphoma and lymphocytic lymphoma. The present report describes the validation of simple, rapid, sensitive, and cost-effective spectrofluorimetric methods based on the native fluorescence of the drug in an acidic medium. Fluorescence characteristics of the drug were found to significantly differ in absolute ethanol (& lambda;ex = 330 and & lambda;em = 595 nm) and HCl (& lambda;ex = 270 and & lambda;em = 350 nm) and both methods were validated as per ICH guidelines. The two methods were extremely sensitive, precise and accurate demonstrating excellent linearity in concentration ranges from 0.1-2.0 & mu;g/mL (absolute ethanol) and 0.1-20 & mu;g/mL (HCl). The LOD and LOQ values were found to be 0.015 and 0.045 & mu;g/mL (ethanol) and 0.1615 and 0.4894 & mu;g/mL (HCl). The proposed methods were used to quantify the drug in its marketed tablet formulation with good recoveries, suggesting their applicability to routine analysis of the drug in bulk as well as in formulation.