Specific and highly sensitive spectrofluorimetric method for determination of febuxostat in its tablets and real human plasma. Application to stability studies

Abstract

A simple, rapid, specific and highly sensitive spectrofluorimetric method has been developed for determination of febuxostat (FEB) in its tablets and real human plasma. The proposed method is based on the investigation of the fluorescence spectral behavior of FEB in an aqueous acidic system. The fluorescence intensity was measured at 400 nm after excitation at 335 nm. The fluorescence–concentration plot was rectilinear over the range 0.5–20.0 ng ml⁻¹, with a limit of detection of 38.9 pg ml⁻¹ and limit of quantification of 117.3 pg ml⁻¹. The high sensitivity of the proposed method permits its application for the determination of FEB in real human plasma with good percentage recovery (81.73 ± 2.61). The application of the proposed method was further extended to stability studies of FEB after exposure to different forced degradation conditions, such as acidic, alkaline and oxidative conditions, according to ICH guidelines. A proposal for the degradation pathways was postulated.