Abstract
Diflubenzuron is a potent inhibitor of chitin synthesis, with potential use against salmon lice infestations. The absorption, distribution and elimination of the substance in Atlantic salmon was examined after a single, oral dose of 75 mg/kg body weight. The kinetic properties were studied by whole-body autoradiography, liquid scintillation counting and thin layer chromatography, using a 14C-labelled isotope of the substance. The drug was poorly absorbed from the intestine, but reached a concentration of more than 4 µg/g in the mucus layer of the skin 2 days after administration. If maintained for several days, this concentration is probably sufficient to control all moulting stages of sea lice in Atlantic salmon. The main route of excretion was via the bile.
Keywords: salmon lice, kinetics, autoradiography, scintilation counting, metabolism
Sammendrag
Diflubenzuron er en potent hemmer av kitinsyntese med potensiell anvendelse mot lakselusinfestasjoner. Oppsuging, vevsfordeling og utskillelse av substansen ble undersøkt i atlantisk laks etter en enkelt, oral dose på 75 mg/kg kroppsvekt. De farmakokinetiske egenskaper ble undersøkt ved hjelp av helkroppsautoradiografì, væskescintillasjonstelling og tynnskiktkromatografi. En 14C-merket isotop av substansen ble benyttet i undersøkelsen. Oppsugingen fra tarmen var dårlig, men det ble oppnådd et nivå på mer enn 4 µg/g i hudens slimlag 2 dager etter dosering. Dersom denne konsentrasjonen opprettholdes over flere dager, er den sannsynligvis tilstrekkelig til å gi terapeutisk effekt på de av lakselusas utviklingsstadier som gjennomgår skallskifte. Utskillelsen var hovedsakelig via gallen.
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