AUTOMATED HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF (-)-2'-DEOXY-3'-THIACYTIDINE IN BIOLOGICAL-FLUIDS USING THE AUTOMATED SEQUENTIAL TRACE ENRICHMENT OF DIALYSATE SYSTEMS

A fully automated HPLC procedure was developed for the analysis of a s mall volume of perfusion solutions from an isolated perfused rat kidne y study. The method involved separation of (-)-2'-deoxy-3'-thiacytidin e (3TC) from the matrix by dialysis with 10 mM potassium phosphate buf fer pH 3.0. 3TC was subsequently separated from the dialysate as it fl owed through a SCX cation-exchange cartridge. The trapped 3TC was then eluted with a mobile phase of 50 mM ammonium acetate buffer (pH 5.5)- methanol (90.5:9.5, v/v) at a flow-rate of 1.0 ml/min for 2 min. The e luent was directed to the HPLC system and chromatographed with a BDS C -18 analytical column at a temperature of 45 degrees C. Detection of 3 TC was carried out by UV absorption at 274 nm. The procedure was valid ated from 25 to 10 000 ng/ml. Coefficients of variance (C.V.) of 3TC q uality control samples were less than 9%. C.V.s of the standard curve samples were also less than 10% except for the 25 ng/ml samples (11.5% ). The mean interpolated concentrations were within 8% of the nominal concentrations for all samples. No interference from concurrent drugs was observed. Preliminary results suggested that this procedure may al so be used for human serum and urine samples.