title: Pharmacokinetic study of an injectable long-acting parenteral formulation of doxycycline hyclate in calves.
abstract: Doxycycline hyclate (DOX-h) can be regarded as a time-dependant antibacterial. Hence, a parenteral long-acting formulation may be regarded as more pharmacologically sound. A poloxamer-based matrix was used to produce a long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its s.c. injection to calves. Serum concentrations profiles for such a prepartion were compared to the corresponding profiles obtained with an aqueous formulation of DOX-h injected either i.m. or i.v. in 10 calves in a crossover study at dose of 10mg/kg, with washout periods. DOX-h-LA showed the greatest values for bioavailability (602%); maximum serum concentration (C(max)) value was 1.99microg/mL with a time to reach C(max) (T(max)) of 25h and an elimination half-life of 40.81h. Considering minimum effective serum concentration of 0.5microg/mL a dose-interval of 80h can be achieved for DOX-h-LA, and only 9.7h and 17h after the i.v. or i.m. administration of DOX-h, respectively.
authors.affiliation: Departamento de Fisiología y Farmacología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Delegación Coyoacán, Ciudad de México C.P. 04510, Mexico.
authors.forename: D
authors.initials: D
authors.lastname: Vargas-Estrada
authors.forename: J
authors.initials: J
authors.lastname: Gracia-Mora
authors.forename: H
authors.initials: H
authors.lastname: Sumano
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D002417:Cattle; D003692:Delayed-Action Preparations; D004318:Doxycycline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D007700:Kinetics
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D004318:Doxycycline