The comparative pharmacokinetics and tissue penetration of four quinolones including intravenously administered enoxacin

The pharmacokinetics and tissue penetration of four quinolones were studied. The compounds were norfloxacin (400 mg p.o.), enoxacin (600 mg p.o. and 400 mg i.v.), ciprofloxacin (100 mg i.v. and 500 mg p.o.) and ofloxacin (600 mg p.o.) given to healthy volunteers. Of the oral agents studied ofloxacin and ciprofloxacin were the most rapidly absorbed (Tmax 1.2 h) and enoxacin the least (Tmax 1.9 h). The serum levels attained were highest in the case of ofloxacin (after allowing for the higher dose administered). The serum half-lives were norfloxacin 3.75 h, ciprofloxacin 3.9 h (p.o.), 4.0 h (i.v.), ofloxacin 7.0 h and enoxacin 6.2 h (p.o.) and 5.1 h (i.v.). All agents penetrated the blister fluid readily. The 24 h urine recovery (as measured by a microbiological assay) was 62% for enoxacin (p.o.), 46.4% following i.v. enoxacin (plus 11.6% oxo-enoxacin, measured by HPLC) 27% for norfloxacin, 30.6% for oral ciprofloxacin, 75.7% for i.v. ciprofloxacin and 73% for ofloxacin