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Comparative pharmacokinetic disposition of closantel in sheep and goats
Author(s) -
HENNESSY D. R.,
SANGSTER N. C.,
STEEL J. W.,
COLLINS G. H.
Publication year - 1993
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1993.tb00172.x
Subject(s) - pharmacokinetics , zoology , absorption rate , plasma concentration , absorption (acoustics) , disposition , veterinary medicine , chemistry , biology , pharmacology , medicine , chromatography , psychology , social psychology , physics , acoustics
The pharmacokinetic disposition of closantel was examined following intraruminal (i.r.) or intramuscular (i.m.) administration to adult Merino sheep and to adult and 3‐month‐old, suckling Angora goats. In adult goats the maximum concentration (C max ) and area under the plasma concentration with time curve ( AUC ) following 3.75, 7.5 and 15.0 mg closantel/kg given i.r. increased with dose however the time of C max (r max = 2.6d) in plasma was unaffected by dose rate. The elimination phase (K 10 ) of closantel was monoexponential with a half‐life ( t ½ ) of 4.7d again unaffected by dose rate. Apart from a more rapid absorption phase and earlier T max following 3.75 mg closantel/kg i.m., pharmacokinetic behaviour was similar to that following i.r. administration at 3.75 or 7.5 mg/kg. Although absorption rate was more rapid in kids after i.r. administration at 7.5 mg/kg, pharmacokinetic disposition of closantel was otherwise similar to that in adult goats. No closantel was detected in milk of treated does or in the plasma of their kids. I.R. closantel at 7.5 mg/kg was more slowly absorbed in goats than in sheep but C max was similar in both species. However, K 10 t ½ was significantly shorter in goats (4d) than in sheep (14d). Faster elimination resulted in an almost three‐fold lowering of AUC in goats and could dramatically reduce the sustained action of closantel in this species compared with sheep.