Simultaneous determination of guaiphenesin and codeine phosphate in tablets by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method has been de veloped for the simultaneous determination of guaiphenesin and codeine phos phate in an antitussive tablet formulation. A 10-mu m C-18 column is used w ith a 1:1 methanol-water mixture (pH 3.0) as the mobile phase and spectroph otometric detection is carried out at 212 nm. The total elution time is sho rter than 4.4 min. The method showed good linearity, precision and reproduc tibility. The proposed method was successfully applied to the determination of guaiphenesin and codeine phosphate in tablets. (C) 1999 Elsevier Scienc e S.A. All rights reserved.