Determination of free concentration of sameridine in blood plasma by ultrafiltration and coupled-column liquid chromatography

Abstract

Sameridine is a new candidate drug with both local anaesthetic and analgesic properties. The free concentration of sameridine in blood plasma was determined by coupled-column liquid chromatography. Following adjustment of the pH and the temperature of the plasma samples, the free fraction was prepared by ultrafiltration. The coupled-column liquid chromatographic system consisted of a reversed-phase column, a cation-exchange extraction column and a cation-exchange analytical column. Sameridine was detected by UV determination at 205 nm and the system showed high selectivity. The limit of quantification was 1 nM and the within-day precision was 4.6% (R.S.D., n= 10).