A Spectrophotometric Method for the Determination of β-Glycyrrhetic Acid (Enoxolone) and its Esters in Biological Materials

Abstract

Abstract A method for the determination of β-glycyrrhetic acid (enoxolone) and its readily-hydrolysable esters in biological materials is described. The material containing the glycyrrhetic acid or its esters is hydrolysed with ethanolic sodium hydroxide, the glycyrrhetic acid is extracted from the acidified hydrolysate, submitted to two-dimensional, thin-layer chromatography on alumina, eluted with ethanol and estimated spectrophotometrically at 248 mμ. Mean recoveries of 100 μg. β-glycyrrhetic acid were 102 per cent (s.e.m. ± 4 per cent) from pure solution; 92 per cent (s.e.m. ± 4 per cent) from rat blood; 90 per cent (s.e.m. ± 4 per cent) from human urine; and recoveries of 20 μg. and 50 μg. from rat bile were 91 to 95 per cent. Mean recoveries of 100 μg. of ±-glycyrrhetic acid hydrogen succinate were 95 per cent (s.e.m. ± 5 per cent) from pure solution; 100 and 110 per cent from rat blood; and 92 and 109 per cent from human urine.