Liquid chromatography coupled with fluorimetric detection and third derivative synchronous fluorescence spectroscopy as two analytical methods for the simultaneous determination of rabeprazole sodium and domperidone after derivatization with 4-chloro-7-nitrobenzofurazan.

Two simple, sensitive, rapid, economic and validated methods, namely reversed phase liquid chromatography (method Ι) and third derivative synchronous fluorescence spectroscopy (method ΙΙ) have been developed for the simultaneous determination of rabeprazole sodium and domperidone in their laboratory prepared mixture after derivatization with 4-Chloro-7-nitrobenzofurazan. Reversed phase chromatography was conducted using a Zorbax® SB-Phenyl column (250.0 mm × 4.6 mm id) combined with a guard column at ambient temperature with fluorimetric detection at 540 nm after excitation at 483 nm. A mobile phase composed of a mixture of distilled water with methanol and acetonitrile in a ratio of 50:20:30 adjusted pH to 4 has been used at a flow rate of 1 mL/min. Sharp well resolved peaks were obtained for domperidone and rabeprazole sodium with retention times of 5.5 and 6.4 min respectively. While in method ΙΙ, the third-derivative spectra were estimated at 507 and 436 nm for rabeprazole sodium and domperidone respectively. Linearity ranges for rabeprazole sodium and domperidone respectively in both methods were found to be 0.15-2.0 and 0.1-1.5 μg/mL. The proposed methods were successfully applied for the analysis of the two compounds in their binary mixtures, and laboratory prepared tablets. The obtained results were favorably compared with those obtained by the comparison method. Furthermore, detailed validation procedure was also conducted.