Clinical pharmacokinetics of norfloxacin-glycine acetate after intravenous and intramuscular administration to horses

• Published in: Research in veterinary science Vol. 74; no. 1; pp. 79 - 83
• Main Authors: Park, S-C, Yun, H-I
• Format: Journal Article
• Language: English
• Published: England Elsevier India Pvt Ltd 01.02.2003; Elsevier Limited
• Subjects: Absorption; Animals; Anti-Infective Agents - administration & dosage; Anti-Infective Agents - blood; Anti-Infective Agents - pharmacokinetics; Area Under Curve; Bacteria; Bioavailability; Biological Availability; Cross-Over Studies; Drug dosages; Drug therapy; Fluoroquinolones; Glycine - administration & dosage; Glycine - analogs & derivatives; Glycine - blood; Glycine - pharmacokinetics; Gram-positive bacteria; Half-Life; Horses; Horses - metabolism; Injections, Intramuscular; Injections, Intravenous; Laboratory animals; Male; Norfloxacin - administration & dosage; Norfloxacin - analogs & derivatives; Norfloxacin - blood; Norfloxacin - pharmacokinetics; Salmonella; Standard deviation; Veterinary medicine
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/S0034-5288(02)00150-9

The pharmacokinetic properties of norfloxacin-glycine acetate (NFLXGA) were determined in six horses following a single intravenous (i.v.) and intramuscular (i.m.) dose of 4 mg kg −1 body weight. Following i.v. and i.m. administration, the plasma drug concentrations were best fitted by an open two-compartment model with a rapid distribution phase. After i.v. NFLXGA administration, the distribution ( t 1/2 α ) and elimination half-life ( t 1/2 β ) were 0.42 (0.05) and 5.44 (1.36) h. The volume of distribution of NFLXGA at steady state (Vd ss) was 2.19 (0.53) L kg −1 . After NFLXGA i.m. administration, the maximal absorption concentration ( C max) was 0.44 (0.04) μg ml −1 at 0.86 (0.15) h ( T max). The mean absorption ( t 1/2ka) and elimination half-life ( t 1/2 β ) of NFLXGA were 0.27 (0.07) and 9.47 (2.24) h, respectively. The mean systemic bioavailability ( F) following i.m. administration was 55 (12)%. The optimal dosage for each administration route was calculated from the pharmacokinetic data on the basis of the area under the inhibitory plasma concentration–time curve (AUIC) every 24 h and was found to be 13.36 and 7.35 mg kg −1 for i.m. and i.v. administration, respectively.