Jd. Davis et al., SIMULTANEOUS ASSAY OF FLUOROQUINOLONES AND THEOPHYLLINE IN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY, Journal of chromatography. Biomedical applications, 621(1), 1993, pp. 105-109
A sensitive and selective reversed-phase high-performance liquid chrom
atographic method for the determination of theophylline in plasma simu
ltaneously with either ciprofloxacin, enoxacin or norfloxacin has been
developed. It involves extraction of plasma with chloroform-isopropan
ol or dichloromethane-isopropanol prior to chromatography on a Spheris
orb ODS2 column. The mobile phase is 15% acetonitrile in a phosphate b
uffer (pH 3.0) containing tetrabutylammonium hydrogen sulphate (4.4 mM
) as an ion-pairing agent. Ultraviolet detection is carried out at 280
nm. Run time is less than 10 min for all three separations. The assay
s have been used to determine the effect of plasma concentrations of f
luoroquinolone on theophylline clearance.