PHARMACOKINETICS OF THE NEW FLUOROQUINOLONE BALOFLOXACIN IN MICE, RATS AND DOGS

The pharmacokinetics of ylaminopiperidin-1-yl)-4-oxoquinoline-3-carbox ylic acid dihydrate (CAS 127294-70-6, balofloxacin, Q-35), a new fluor oquinolone, were studied in mice, rats and dogs by high performance li quid chromatography. The mean oral bioavailabilities of balofloxacin c alculated from the area under the curve after oral and intravenous adm inistration in mice, rats and dogs were 19.03, 87.50 and 87.73 %, resp ectively indicating that balofloxacin was almost completely absorbed i n vats and dogs but not in mice after single oral administration. The mean elimination half-lives in plasma after intravenous administration in mice, rats and dogs were 0.92, 1.33 and 6.38 h, respectively. Mean cumulative urinary excretion percentages of unchanged balofloxacin wi thin 24 h of oral administration of balofloxacin at the dose of 20 mg/ kg in mice, rats and clogs were 4.91, 21.77 and 22.49 % of the dose, r espectively A small portion of the metabolite was excreted into urine as balofloxacin glucuronide and N-desmethyl balofloxacin in these spec ies. After oral administration of balofloxacin at the dose of 100 mg/k g to rats, absorption was prolonged compared with that after administr ation at the doses of 5 and 20 mg/kg. Plasma concentration-time profil es and pharmacokinetic parameters of balofloxacin in male rats were si milar to those in female rats, indicating no sex-related differences. Once daily al-day multiple administrations had not affect on these pha rmacokinetic profiles of balofloxacin in rats.