title: The disposition of gentamicin in equine plasma, synovial fluid and lymph.
abstract: Plasma (P), synovial fluid (SF) and lymph (L) concentrations of gentamicin were studied in two trials. A lymph vessel in the hindlimb was cannulated. The day after surgery (trial A), P and L samples were collected for 12 h after intravenous injection of gentamicin sulphate at 2.2 mg/kg dose rate. Approximately 48 h after surgery (trial B), the fetlock joint of the cannulated hindlimb was catheterized and P, SF and L samples collected for 12 h after a similar intravenous injection. The kinetic parameters were similar to those in other reports and did not differ between trials (P < 0.05). The P, L and SF disposition profiles were similar. The 95% confidence interval for P & L concentrations overlapped 2-3 h after injection. Thereafter, parallelism between L and P concentrations was observed, but L concentrations were on average 60% higher than P concentrations, and elimination from L was slower than from P. The mean L/SF and P/SF ratios were 1.54 +/- 0.2 and 1.25 +/- 0.2, 2-4 h after injection. Gentamicin elimination from SF appeared to be slower than from L and P. Lymph cannulation is a viable technique for antibiotic disposition studies. A sample of any of the fluids 3 h after injection was representative of the others. While SF concentrations were of limited value for predicting tissue fluid (L) concentrations 3-8 after injection, P concentrations were a useful index.
authors.affiliation: Department of Veterinary Clinical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: B H
authors.initials: BH
authors.lastname: Anderson
authors.forename: E C
authors.initials: EC
authors.lastname: Firth
authors.forename: T
authors.initials: T
authors.lastname: Whittem
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002404:Catheterization / Q000662:veterinary; D002452:Cell Count / Q000662:veterinary; D005260:Female; D005839:Gentamicins / Q000097:blood / Q000493:pharmacokinetics*; D006207:Half-Life; D006614:Hindlimb; D006736:Horses / Q000378:metabolism*; D007275:Injections, Intravenous / Q000662:veterinary; D008196:Lymph / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D013582:Synovial Fluid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001798:Blood Proteins; D005839:Gentamicins