title: Chronopharmacokinetic study of gentamicin in dogs.
abstract: The purpose of this experiment was to determine whether the time of day of single intravenous doses of gentamicin affects the drug's pharmacokinetics in dogs maintained under a 12 h light (08:00 to 20:00 h), 12 h dark (20:00 to 08:00 h) cycle. Using a crossover design, 6 mixed-breed male dogs received a single dose of 2 mg/kg of gentamicin at 8:00 or 20:00 h. Serial blood samples were collected and pharmacokinetic parameters were calculated following each timed dose. The concentration of the antibiotic was lower following the 08:00 h compared to the 20:00 h administration. When gentamicin was administered at 20:00 h, the initial concentration, mean residence time, and area under the disposition curve were significantly higher (p < 0.05) and the apparent volume of distribution of the central compartment, apparent volume of distribution, apparent volume of distribution at steady-state, and total body clearance (1.73+/-0.55 at 20:00 h versus 3.31+/-0.67 L/min/kg at 08:00 h) were significantly lower than for the 08:00 h administration (p < 0.05). Our results show that the pharmacokinetics of gentamicin exhibits significant temporal variation when administered to dogs at different times of day.
authors.affiliation: Facultad de Ciencias Veterinarias, Universidad del Litoral, Argentina.
authors.forename: Nelsa
authors.initials: N
authors.lastname: Widerhon
authors.forename: Diego
authors.initials: D
authors.lastname: Díaz
authors.forename: Eduardo
authors.initials: E
authors.lastname: Picco
authors.forename: Marcela
authors.initials: M
authors.lastname: Rebuelto
authors.forename: Teresa
authors.initials: T
authors.lastname: Encinas
authors.forename: Juan
authors.initials: J
authors.lastname: Carlos Boggio
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019540:Area Under Curve; D018592:Cross-Over Studies; D004285:Dogs / Q000378:metabolism*; D004334:Drug Administration Schedule / Q000662:veterinary; D005839:Gentamicins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins