ANALYSIS OF CISAPRIDE IN NEONATAL PLASMA USING HIGHPERFORMANCE LIQUID-CHROMATOGRAPHY WITH A BASE-STABLE COLUMN AND FLUORESCENCE DETECTION

A simple, selective, sensitive and precise high-performance liquid chr omatographic plasma assay for the prokinetic drug cisapride is describ ed. Alkalinised samples of plasma (100 mu l) were extracted with 1.0 m l of 10% (v/v) isopropanol in chloroform, dried, redissolved in mobile phase and injected. Chromatography was performed at 20 degrees C by p umping a mobile phase of acetonitrile (370 ml) in pH 5.2, 0.02 M phosp hate buffer (630 mi) at 1.0 ml/min through a C-8 Symmetry column. Cisa pride and the internal standard were detected by fluorescence monitori ng at 295 nm (excitation) and 350 nm (emission), and were eluted 5 min and 8 min, respectively; after injection. Calibration plots in bovine serum albumin (3% w/v) were linear (r > 0.999) from 5 to 250 ng/ml. I ntra-day and inter-day precision (C.V.) was 9.5%, or less, and the acc uracy was within 5.5% of the nominal concentration over the range 8-20 0 ng/ml. Total assay recovery was above 82%. Endogenous plasma compone nts, the major cisapride metabolite (norcisapride), and other drugs us ed in neonatal pharmacotherapeutics did not interfere.