Absorption of enrofloxacin and marbofloxacin after oral and subcutaneous administration in diseased koalas (Phascolarctos cinereus).
Koalas (n = 43) were treated daily for up to 8 weeks with enrofloxacin: 10 mg/kg subcutaneously (s.c.), 5 mg/kg s.c., or 20 mg/kg per os (p.o.); or marbofloxacin: 1.0-3.3 mg/kg p.o., 10 mg/kg p.o. or 5 mg/kg s.c. Serial plasma drug concentrations were determined on day 1 and again at approximately 2 weeks, by liquid chromatography. The median (range) plasma maximum concentrations (C(max) ) for enrofloxacin 5 mg/kg s.c. and 10 mg/kg s.c. were 0.83 (0.68-1.52) and 2.08 (1.34-2.96) μg/mL and the median (range) T(max) were 1.5 h (1-2) and 1 h (1-2) respectively. Plasma concentrations of orally dosed marbofloxacin were too low to be quantified. Oral administration of enrofloxacin suggested absorption rate limited disposition pharmacokinetics; the median (range) C(max) for enrofloxacin 20 mg/kg p.o. was 0.94 (0.76-1.0) μg/mL and the median (range) T(max) was 4 h (2-8). Oral absorption of both drugs was poor. Plasma protein binding for enrofloxacin was 55.4 ± 1.9% and marbofloxacin 49.5 ± 5.3%. Elevations in creatinine kinase activity were associated with drug injections. Enrofloxacin and marbofloxacin administered at these dosage and routes are unlikely to inhibit the growth of chlamydial pathogens in vivo.
Faculty of Veterinary Science, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia. joanna.griffith@sydney.edu.au
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Griffith
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Higgins
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Krockenberger
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Govendir
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000077422:Enrofloxacin; D005260:Female; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology*; D007279:Injections, Subcutaneous / Q000662:veterinary; D007408:Intestinal Absorption; D008297:Male; D048368:Phascolarctidae / Q000097:blood / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D000077422:Enrofloxacin; C080260:marbofloxacin