Simultaneous determination of the components in an anti-cold drug by gradient HPLC

A gradient high-performance liquid chromatographic method for the simultaneous determination of an anti-cold drug was reported. Nine components in the preparation, such as acetaminophen, anhydrous caffeine, riboflavin, dihydrocodeine phosphate, DL-methylephedrine hydrochloride, carbinoxamine maleate, noscapine, bisibuthiamine and bromhexine hydrochloride, could be completely separated by changing from water-acetonitrile (95 : 5) to water-acetonitrile (1 : 1) as the mobile phase containing 0.1 % of phosphoric acid and 0.08 w/v% of sodium heptansulfonate by a linear gradient program. The time required for the analysis was about 40 minutes, and the time for initializing was about 15 minutes. Under this method, the recoveries of these components were 99.900.4%, and showed good reproducibility for each component. The results of the determination were in good agreement with the conventional method.