Stability of ivermectin in rumen fluids

Andrew, N. W.; Halley, Bruce A.

doi:10.1111/j.1365-2885.1996.tb00052.x

Cited by 11 publications

(9 citation statements)

References 18 publications

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“…This explanation, however, is difficult to conciliate with our results, since the unabsorbed fraction of ingested ivermectin was fully recovered in the faeces of the lickers. Moreover, several studies argue for the stability of ivermectin in rumen fluids in cattle and sheep [3,6] and show that there is rather an extensive adsorption of ivermectin to the digesta particulates of the rumen [1]. Our model stipulates that the fraction of drug which is not absorbed in compartment GIT 1 will not be absorbed later in compartment GIT 2.…”

Section: Discussionmentioning

confidence: 99%

A pharmacokinetic model to document the actual disposition of topical ivermectin in cattle

et al. 2003

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-Ivermectin is a worldwide-used antiparasitic drug largely administered to cattle as a topical formulation (pour-on). The actual plasma and faecal disposition of pour-on ivermectin in cattle was documented using an original pharmacokinetic model, and taking into account the oral ingestion of the topical drug following physiological licking as a secondary route of exposure. Six pairs of monozygotic twin cattle received successively one i.v. and two pour-on administrations of ivermectin at a 3-5-month interval. For one pour-on administration, the twins were separated into an unrestrained group and a group where self-and allo-licking were prevented. Ivermectin concentrations in the plasma and faeces were determined by HPLC. Licking resulted in a high intraand inter-individual variability of systemic exposure after topical application. By the means of pharmacokinetic modelling, we showed that 58-87% of the pour-on dose was ingested, while only 10% was absorbed percutaneously. Approximately 72% of the ingested ivermectin transited directly into the faeces, resulting in a 7-fold higher faecal excretion of the parent drug than in the non-lickers. We conclude that topical administration does not guarantee a controlled drug delivery in cattle. More importantly, the simulations revealed that non-treated cattle could get easily contaminated by allo-licking, raising the public health problem of unexpected drug residues in edible tissues.ivermectin / pour-on / cattle / licking behaviour / pharmacokinetics

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Section: Discussionmentioning

confidence: 99%

A pharmacokinetic model to document the actual disposition of topical ivermectin in cattle

et al. 2003

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“…(1985) suggested the conversion of IVM in the ruminal fluid to a less potent anthelmintic molecules such as the monosaccaharide and/or aglycone derivatives. However, the in vitro stability of a radiolabeled IVM in ruminal fluid was suggested some time later (Andrew & Halley, 1996). As postulated by Ali and Hennessy (1996), the low IVM concentrations measured by Prichard et al.…”

Section: Discussionmentioning

confidence: 99%

“…The liver metabolism of both compounds has been characterized in different animal species (Chiu et al, 1987;Afzal et al, 1994;Zulalian et al, 1994). However, only limited information on IVM ruminal stability is available (Andrew & Halley, 1996) and the comparative gastrointestinal metabolism of MXD and IVM has not been investigated, in spite of the fact that the disposition of these ML compounds in the ruminant digestive tract is consider relevant to their overall kinetic behavior and pattern of efficacy. To gain some further insight on the subject, the goal of the current work was to investigate on a comparative basis the in vitro metabolism of MXD and IVM in sheep ruminal and abomasal contents.…”

Section: Introductionmentioning

confidence: 99%

Moxidectin and ivermectin metabolic stability in sheep ruminal and abomasal contents

Lifschitz

Virkel

Ballent

et al. 2005

Vet Pharm & Therapeutics

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The oral administration of macrocyclic lactones to sheep leads to poorer efficacy and shorter persistence of the antiparasitic activity compared to the subcutaneous treatment. Gastrointestinal biotransformation occurring after oral treatment to ruminant species has been considered as a possible cause of the differences observed between routes of administration. The current work was addressed to evaluate on a comparative basis the in vitro metabolism of moxidectin (MXD) and ivermectin (IVM) in sheep ruminal and abomasal contents. Both compounds were incubated under anaerobic conditions during 2, 6 and 24 h in ruminal and abomasal contents collected from untreated adult sheep. Drug concentrations were measured by high-performance liquid chromatography with fluorescence detection after sample clean up and solid phase extraction. Neither MXD nor IVM suffered metabolic conversion and/or chemical degradation after 24-h incubation in ruminal and abomasal contents collected from adult sheep. Unchanged MXD and IVM parent compounds represented between 95.5 and 100% of the total drug recovered in the ruminal and abomasal incubation mixtures compared with those measured in inactive control incubations. The partition of both molecules between the solid and fluid phases of both sheep digestive contents was assessed. MXD and IVM were extensively bound (>90%) to the solid material of both ruminal and abomasal contents collected from sheep fed on lucerne hay. The results reported here confirm the extensive degree of association to the solid digestive material and demonstrates a high chemical stability without evident metabolism and/or degradation for both MXD and IVM in ruminal and abomasal contents.

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“…This route of administration and elimination is potentially more disruptive to the pasture ecosystem than any other formulation because of their slow release and extended period activity [53]. Ivermectin is not metabolised in the rumen and a significant part of the drug may pass down the gastrointestinal tract into the faeces without absorption into the systemic circulation [5]. Oral formulations (oral paste or drench formulations) of ivermectin for sheep and horses have less bioavailability and persistence than the injectable formulation for cattle [50,65,76].…”

Section: Pharmacokinetics and Routes Of Eliminationmentioning

confidence: 99%

Use of anthelmintics in herbivores and evaluation of risks for the non target fauna of pastures

2002

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-The overall purpose of this paper was to review the major and most recent literature relating the effects of anthelmintics on dung breeding invertebrates and dung degradation. Faecal residues or metabolites of drugs belonging to the benzimidazole and levamisole/morantel groups are relatively harmless to dung fauna, on the contrary to other anthelmintics such as coumaphos, dichlorvos, phenothiazine, piperazine, synthetic pyrethroids, and most macrocyclic lactones which have been shown to be highly toxic for dung beetles (abamectin, ivermectin, eprinomectin, doramectin), among which moxidectin was the less toxic for dung beetles. To date, the detrimental impact upon non-target organisms has been considered acceptable in eradicating the parasites because of their economic importance to commercial livestock production. The consequences of routine treatments are discussed with consideration of the long-term consequences for cow pat fauna and sustainable pastureland ecology.anthelmintic / residue / dung beetle / Diptera / sustainable parasite control Résumé -Usage des anthelminthiques en élevage et évaluation des risques pour la faune non cible du pâturage. Cet article de synthèse passe en revue les travaux de la littérature les plus récents concernant les effets secondaires des principaux produits vétérinaires utilisés en routine sur la faune coprophage et sur la dégradation des excréments dans les pâturages. Les résidus (ou les métabolites) des groupes du benzimidazole et levamisole/morantel trouvés dans les excréments s'avèrent relativement peu toxiques pour la faune coprophage. Au contraire les anthelminthiques des groupes suivants s'avèrent hautement toxiques: coumaphos, dichlorvos, phénothiazine, pipérazine, pyréthroïdes de synthèse, et la plupart des lactones macrocycliques (abamectine, ivermectine, éprinomectine, doramectine), la moxidectine étant la moins toxique pour la faune coprophage. Jusqu'à présent, cet impact négatif a été considéré comme acceptable par les éleveurs et firmes pharmaceutiques en regard de l'importance économique du contrôle et/ou l'éradication des parasites. Les conséquences des traitements de routine sont discutées en considérant que l'absence de dégradation des bouses constatée 547

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Stability of ivermectin in rumen fluids

Cited by 11 publications

References 18 publications

A pharmacokinetic model to document the actual disposition of topical ivermectin in cattle

A pharmacokinetic model to document the actual disposition of topical ivermectin in cattle

Moxidectin and ivermectin metabolic stability in sheep ruminal and abomasal contents

Use of anthelmintics in herbivores and evaluation of risks for the non target fauna of pastures

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