RESUMEN
AIM: To quantify magnesium isoglycyrrhizinate(MGL) and glycyrrhetic acid in the plasma of dog by develop a simple, rapid, sensitive high-performance liquid chromatography (HPLC-UV) method. METHODS: HPLC-UV methods with wavelength 252 nm were used for the quantitation of MGL and GA in plasma. The concentration of MGL and GA were assayed on a Kromasil ODS-1 C18 column with the column temperature 25 ℃. The mobile phase was a gradient system with 0.1 % diethylamine in water (pH 4.60 ) and acetonitrile at a flow rate of 1.0 ml?min~ -1 . RESULTS: There was a good linear response range of 0.2 -2.5 mg?L~ -1 and 2.5 -100 mg?L~ -1 , while the limit of quantification was 0.2 mg?ml~ -1 . The relative recovery rate of MGL was 94.3 %-101.9 %,GA 96.4 %-101.9 % (n=5);the absolute recovery rate was MGL 78.7 %-87.0 %, GA 77.5 %-87.7 % (n=5). The intra-day and inter-day variations were all less than 15% (n=5). The plasma samples preserved in refrigerator is stable at -20 ℃ for 14 days, freeze thawing 3 times and at room temperature for 10 h without degradation. CONCLUSION: This method is shown to be specific, sensitive, reliable and suitable for the quantitative determination of magnesium isoglycyrrhizinate following oral administration in biological sample.