title: Variable absorption of clavulanic acid after an oral dose of 25 mg/kg of Clavubactin and Synulox in healthy cats.
abstract: The aims of this investigation were to calculate the pharmacokinetic parameters and to identify parameters, based on individual plasma concentration-time curves of amoxicillin and clavulanic acid in cats, that may govern the observed differences in absorption of both drugs. The evaluation was based on the data from plasma concentration-time curves obtained following a single-dose, open, randomised, two-way crossover phase-I study, each involving 24 female cats treated with two Amoxi-Clav formulations (formulation A was Clavubactin and formulation was B Synulox; 80/20 mg, 24 animals, 48 drug administrations). Plasma amoxicillin and clavulanic acid concentrations were determined using validated bioassay methods. The half-life of elimination of amoxicillin is 1.2 h (t1/2 = 1.24 +/- 0.28 h, Cmax = 12.8 +/- 2.12 microg/ml), and that of clavulanic acid 0.6 h (t1/2 = 0.63 +/- 0.16 h, Cmax = 4.60 +/- 1.68 microg/ml). There is a ninefold variation in the AUCt of clavulanic acid for both formulations, while the AUCt of amoxicillin varies by a factor of two. The highest clavulanic acid AUCt values indicate the best absorption; all other data indicate less absorption. Taking into account that the amoxicillin-to-clavulanic acid dose ratio in the two products tested was 4:1, the blood concentration ratios may actually vary much more, apparently without compromising the products" high efficacy against susceptible microorganisms.
authors.affiliation: Institute for Anaesthesiology, University Medical Center Sint Radboud, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. T.Vree@anes.azn.nl
authors.forename: Tom B
authors.initials: TB
authors.lastname: Vree
authors.forename: Erik
authors.initials: E
authors.lastname: Dammers
authors.forename: Eri
authors.initials: E
authors.lastname: van Duuren
mesh_terms: D000284:Administration, Oral; D000658:Amoxicillin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D019818:Clavulanic Acid / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004341:Drug Evaluation / Q000662:veterinary; D004359:Drug Therapy, Combination / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D005215:Fasting; D005260:Female; D013607:Tablets / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D013607:Tablets; D019818:Clavulanic Acid; D019980:Amoxicillin-Potassium Clavulanate Combination; D000658:Amoxicillin