A sensitive, rapid and reproducible high performance liquid chromatographic (HPLC) determination of ephedrine and glycyrrhizin in human breast milk is described. Chromatography was performed on a C-18 bonded stationary phase with 2% acetic acidacetomtrile (2 : 1) as mobile phase, phenytoin as internal standard and ultraviolet detector. Solvent extraction of the drugs are not necessary ; however, one has only to precipitate the breast milk proteins. The peak-height ratio of ephedrine and glycyrrhizin to phenytoin is linearly related to amounts up to 30μg of ephedrine and 10μg of glycyrrhizin per injection. The proposed method was applied to the human breast milk of the patients receiving "Kakkonto extract granules"(Tsumura Jyuntendo Co., Ltd.).
