Rapid gas chromatographic method for the determination of nalidixic acid in plasma

Abstract

Nalidixic acid is mostly used for the treatment of urinary tract infections, but in some cases it is administered intravenously for the-treatment of general infections [I] . In those cases it is necessary to determine the plasma concentration of nalidixic acid, preferably by means of a rapid, simple method. In the literature, fluorimetric [2, 31 and liquid chromatographic [4,5] methods have been described_ The fluorimetric methods have the disadvantage of not being specific and the recently described high-performance liquid chromatographic (HPLC) method involves a time consuming derivatization step.In this paper we shall describe a gas chromatographic (GC) method that is specific and sensitive enough to determine therapeutic levels in a 1 ml plasma sample within 30 min of receipt of the sample. EXPERIMENTAL ApparatusA Packard-Becker i&lode1 419 gas chromatograph, equipped with flame ionisation detectors was used. The glass column (1.5 X 6 mm 0-D.) was packed with 20% OV-1'7 on Chromosorb W HP, 80-100 mesh (Chrompack, Middelburg, The Netherlands). The operating conditions were: injection port temperature, 290"; column temperature, 270"; detector temperature, 290"; carrier gas (nitrogen) flow-rate 20 ml/min; hydrogen flow-rate 30 ml/min; air flow-rate 300 ml/min.Quantitation was carried out both by means of peak height measurements and peak area measurements with the chromatography Data Analyser System IV (Spectra Physics, Santa Clara, Calif., U.S.A.).

Single-use phosphorimetric sensor for the determination of nalidixic acid in human urine and milk

“…There are several HPLC methods for the determination of nalidixic acid in human plasma and urine, 22,23 human blood, 24 or human urine, 25 and a GC method for the determination of nalidixic acid in human plasma. 26 The main inconvenience of the non-chromatographic methods is their lack of selectivity, which requires the carrying out of a previous extraction process of the analyte from the matrix using organic solvents; with the chromatographic methods, the main inconvenience is their laborious nature and extensive sample handling.…”