HIGH-PRESSURE LIQUID-CHROMATOGRAPHY OF SULFISOXAZOLE AND N4-ACETYLSULFISOXAZOLE IN BODY-FLUIDS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 26  (1) , 51-54
Abstract
A simple, rapid chromatographic method for separating and quantitatively determining sulfisoxazole and its N4-acetyl metabolite in plasma and urine is described. A 100-.mu.l sample of plasma or urine is combined with 200 .mu.l of a solution containing 12 mg/l of the internal standard, N4-acetylsulfamethoxazole, in absolute methanol and centrifuged to obtain a clear supernatant solution. This solution is eluted through a 10-.mu.m microparticulate column with a mobile phase of 32/68 (by vol) methanol/sodium acetate buffer (0.01 mol/l, pH 4.7), at a flow rate of 1.2 ml/min. The eluted compounds are detected by their absorption at 254 nm. Concentration was calculated from the peak-height ratios of sulfisoxazole or N4-acetylsulfisoxazole to N4-acetylsulfamethoxazole. The peak-height ratio was linear with concentration in the range 0.05-200 mg/l for both drug and metabolite in plasma and urine. Because this assay can be completed within 30 min of obtaining a blood or urine sample, it should be a valuable tool in clinical drug monitoring and pharmacokinetic studies [in humans].