Simultaneous determination of rocuronium and its eight impurities in pharmaceutical preparation using high-performance liquid chromatography with amperometric detection.

A sensitive and selective HPLC method with amperometric detection (HPLC-ED) for the determination of rocuronium bromide and its eight impurities has been developed. The analysis was performed on Hypersil 100 Silica column 5 microm (250 mm x 4.6 mm; Thermo Electron). The mobile phase consisting of 4.53 g l(-1) solution of tetramethylammonium hydroxide adjusted to pH 7.4 with 85% phosphoric acid:acetonitrile (1:9), was found the best for the separation and determination of the studied compounds. The chromatograms were recorded over 10 min using the amperometric detection at a potential +0.9 V of the glassy carbon electrode versus the reference electrode Ag/AgCl. The limit of quantitation was 45 ng ml(-1) for rocuronium and from 25 to 750 ng ml(-1) for the examined impurities. The proposed HPLC-ED method was successfully applied to the analysis of rocuronium and its impurities in Esmeron solution for injection.