Identification and characterization of stressed degradation products of rabeprazole using LC-ESI/MS/MS and 1H-NMR experiments: in vitro toxicity evaluation of major degradation products

摘要

Rabeprazole, an antiulcer drug in the class of proton pump inhibitors was subjected to force degradation studies as per ICH guidelines Q1A ( R2 ). The chromatographic separation of the drug and its degradation products were achieved on a Purospher STAR, C18 (250 × 4.6 mm, 5 μ) using 10 mM ammonium acetate (pH-7.0): acetonitrile as a mobile phase in gradient elution mode at a flow rate of 1.0 mL min ~(?1) . A total of 10 ( R1–R10 ) hitherto unknown degradation products were identified and characterised by LC-ESI-MS/MS experiments and accurate mass measurements. The most probable mechanisms for the formation of DPs have been proposed based on a comparison of the fragmentation of the [M + H] ~(+) ions of rabeprazole and its degradation products. Major degradation products ( R3 , R4 and R7 ) were isolated by semi preparative HPLC using Water's X-bridge Prep C18 (250 × 10 mm, 5 μ). In vitro toxicity evaluation of the isolated degradation products showed more than 50% cell inhibition at concentrations of less than 1 μM on HepG2 cell and PANC-1 cell lines. DNA binding studies using spectroscopic techniques indicate that the R3 , R4 and R7 ligand molecules bind to the surface of double stranded DNA and stabilize the DNA complex.