title: Tissue concentrations of clindamycin after multiple oral doses in normal cats.
abstract: Eighteen normal cats were randomly allocated into two blocks with three treatment groups and dosed orally with clindamycin aqueous solution for 10 days at a dosage rate of 5.5 mg/kg twice daily (Group 1), 11 mg/kg twice daily (Group 2), or 22 mg/kg once daily (Group 3). At the end of dosing, all cats were killed and tissues were taken for clindamycin concentration analysis. Clindamycin was extracted from tissues using solid-phase extraction columns followed by microbiological assay of clindamycin using a cylinder plate assay using M. luteus. Recovery from each tissue was determined by inoculating known concentrations of clindamycin into drug-naive tissues and comparing the observed concentration from the expected concentration. Confirmation that the bioassay detected clindamycin and not N-desmethylclindamycin, its active metabolite, was done using gas-chromatography-mass-spectrometry. Concentrations were highest in the lung, with tissue:serum ratios greater than 3 in all groups. Concentrations were higher in Group 3 than Group 1 (P less than 0.05). Only liver concentrations in Group 3 were statistically higher than in Group 2, although all tissues except bone marrow and CSF had numerically higher concentrations in Group 3 than Group 2. The tissue:serum ratio was greater than 1 in all tissues studied except bone, cerebrospinal fluid, brain, and skeletal muscle.
authors.affiliation: Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Texas A&M University, College Station 77843.
authors.forename: S A
authors.initials: SA
authors.lastname: Brown
authors.forename: M J
authors.initials: MJ
authors.lastname: Zaya
authors.forename: T M
authors.initials: TM
authors.lastname: Dieringer
authors.forename: R P
authors.initials: RP
authors.lastname: Hunter
authors.forename: J L
authors.initials: JL
authors.lastname: Nappier
authors.forename: G A
authors.initials: GA
authors.lastname: Hoffman
authors.forename: R E
authors.initials: RE
authors.lastname: Hornish
authors.forename: F S
authors.initials: FS
authors.lastname: Yein
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002415:Cats / Q000378:metabolism*; D002981:Clindamycin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D008297:Male; D011897:Random Allocation; D014018:Tissue Distribution
chemical_list: D002981:Clindamycin