title: Pharmacokinetics after administration of an injectable experimental long-acting parenteral formulation of doxycycline hyclate in goats.
abstract: OBJECTIVE
  To determine the pharmacokinetics after SC administration of an experimental, long-acting parenteral formulation of doxycycline hyclate in a poloxamer-based matrix and after IV and IM administration of an aqueous formulation of doxycycline hyclate in goats.
  
  
  METHODS
  30 clinically normal adult goats.
  
  
  METHODS
  Goats were allocated to 3 groups (10 goats/group). One group of goats received doxycycline hyclate (10 mg/kg) IM, a second group received the same dosage of doxycycline hyclate IV, and the third group received the long-acting parenteral formulation of doxycycline hyclate SC. Serum concentrations of doxycycline were determined before and at various intervals after administration.
  
  
  RESULTS
  The long-acting parenteral formulation of doxycycline hyclate had the greatest bioavailability (545%); mean +/- SD maximum serum concentration was 2.4 +/- 0.95 microg/mL, peak time to maximum concentration was 19.23 +/- 2.03 hours, and elimination half-life was 40.92 +/- 4.25 hours.
  
  
  CONCLUSIONS
  Results indicated that the long-acting parenteral formulation of doxycycline hyclate distributed quickly and widely throughout the body after a single dose administered SC, and there was a prolonged half-life. Bioavailability of the longacting parenteral formulation of doxycycline hyclate after SC administration was excellent, compared with bioavailability after IV and IM administration of an aqueous formulation of doxycycline hyclate. Although no local tissue irritation and adverse effects were detected, clinical assessment of drug-residues and toxicologic evaluations are warranted before this long-acting parenteral formulation of doxycycline hyclate can be considered for use in goats with bacterial infections.
authors.affiliation: Departamento de Fisiología y Farmacología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors.forename: Dinorah
authors.initials: D
authors.lastname: Vargas
authors.forename: Lilia
authors.initials: L
authors.lastname: Gutierrez
authors.forename: Ivan
authors.initials: I
authors.lastname: Juárez
authors.forename: Francisco
authors.initials: F
authors.lastname: Gonzalez
authors.forename: Héctor
authors.initials: H
authors.lastname: Sumano
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001424:Bacterial Infections / Q000188:drug therapy / Q000662:veterinary; D001682:Biological Availability; D004318:Doxycycline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D015511:Goat Diseases / Q000188:drug therapy; D006041:Goats; D006207:Half-Life; D007263:Infusions, Parenteral / Q000379:methods; D007267:Injections
chemical_list: D000900:Anti-Bacterial Agents; D004318:Doxycycline