Spectrofluorimetric Determination of Topiramate and Levetiracetam as Single Components in Tablet Formulations and in Human Plasma and Simultaneous Fourth Derivative Synchronous Fluorescence Determination of their Co-Adminstered Mixture in Human Plasma.

Two highly sensitive, rapid, simple, economic and validated spectrofluorimetric methods have been developed for determination of Topiramate and Levetiracetam in pharmaceutical tablets and in human plasma. Topiramate and Levetiracetam were determined separately by derivatization using 4-Chloro-7-nitrobenzofuran-2-oxo-1,3-diazole (NBD-Cl) and measured spectrofluorimetrically. The Relative fluorescence intensities were measured at λem/ex of 547/465 nm and 551/465 nm for Topiramate and Levetiracetam, respectively. While a binary mixture of Topiramate and Levetiracetam were determined by the fourth derivative synchronous fluorescence measurement after their reaction with NBD-Cl. In this method, the fourth derivative synchronous spectra were estimated as peak to peak measurement at 493-497 and 490.5-495 nm corresponding with zero-contribution of Levetiracetam and Topiramate, respectively. Linearity ranges for Topiramate and Levetiracetam in both methods were found to be 0.15-1.2 and 0.2-1.5 μg/mL, respectively. The different experimental parameters affecting the fluorescence of the two drugs were carefully studied and optimized. The proposed methods were validated in terms of linearity, accuracy, precision, limits of detection and quantification and other aspects of analytical validation. The proposed methods were successfully applied for the determination of the investigated drugs in human plasma samples obtained from healthy volunteers after single oral administration of the two drugs.