AUTOMATED COLUMN LIQUID-CHROMATOGRAPHIC DETERMINATION OF A BASIC DRUGIN BLOOD-PLASMA USING THE SUPPORTED LIQUID MEMBRANE TECHNIQUE FOR SAMPLE PRETREATMENT

The determination of the basic drug Amperozide, one of its main metabo lites, and a third related compound in human blood plasma is described . All three compounds include an amine functionality. The process is g overned by a modified ASTED instrument (Gilson). The dialysis unit is exchanged for a supported liquid membrane (SLM), which gives a simulta neous cleanup and enrichment of the analytes. The ASTED is coupled to column liquid chromatographic equipment with UV detection. An efficien t cleanup is achieved, and there is no visible difference between the chromatograms after enrichment of a plasma blank and an aqueous blank. To increase the recovery, the same sample can be passed by the membra ne several times, while the receiving phase is kept stagnant. An enric hment with three passages takes 15-20 min. The limit of detection for Amperozide in blood plasma is then similar to 30 ng/mL. The use of the SLM technique for estimation of the degree of protein binding is disc ussed. Preliminary results agree reasonably with measurements with oth er techniques. The optimization of the enrichment with supported liqui d membranes is described and different membrane supports are compared.