PHARMACOKINETICS OF NORFLOXACIN BY CONSTANT RATE INFUSION

After intravenous infusion of 400 mg of norfloxacin at constant rate for 1 h in 8healthy volunteers, the time course of the concentration in plasma had been determined. A biexponen-tial fit of the norfloxacin data in the post-infusion period was obtained. The pharmacokinetic perame-ters were α=3.31±1.43h~(-1), β=0.131±0.054h~(-1),t1/2α=0.245±0.093h, t1/2β=4.45±1.42h,k_(21)=0.62±0.32h~(-1),k_(12)=1.82±0.85h~(-1),k_(10)=0.907±0.272h~(-1),V_c=30.8±10.41,and AUC=15.11±5.13mg·h/l. The Cumulative excretion of unmetabolized norfloxacin in 0-1, 1-5, 5-9, 9-13hwere 85.6±15.8, 88.5±29.2mg, 31.5±3.1 and 12.3±9.5mg, respectively. The proportion ofthe uninary excretion of unmetabolized norfloxacin to the dose was 55.7±4.6% in the first 13h.The plasma concentrations of 6 patients had also been determined, there was no obvious difference ofthe mean peak concentrations between healthy volunteers and patients.