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Phenotypic Profiling of Macrocyclic Lactones on Parasitic Schistosoma Flatworms. Antimicrob Agents Chemother 2023; 67:e0123022. [PMID: 36695583 PMCID: PMC9933704 DOI: 10.1128/aac.01230-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Macrocyclic lactones are front-line therapies for parasitic roundworm infections; however, there are no comprehensive studies on the activity of this drug class against parasitic flatworms. Ivermectin is well known to be inactive against flatworms. However, the structure-activity relationship of macrocyclic lactones may vary across phyla, and it is entirely possible other members of this drug class do in fact show antiparasitic activity on flatworms. For example, there are several reports hinting at the anti-schistosomal activity of doramectin and moxidectin. To explore this class further, we developed an automated imaging assay combined with measurement of lactate levels from worm media. This assay was applied to the screening of 21 macrocyclic lactones (avermectins, milbemycins, and others such as spinosyns) against adult schistosomes. These in vitro assays identified several macrocyclic lactones (emamectin, milbemycin oxime, and the moxidectin metabolite 23-ketonemadectin) that caused contractile paralysis and lack of lactate production. Several of these were also active against miracidia, which infect the snail intermediate host. Hits prioritized from these in vitro assays were administered to mice harboring patent schistosome infections. However, no reduction in worm burden was observed. Nevertheless, these data show the utility of a multiplexed in vitro screening platform to quantitatively assess drug action and exclude inactive compounds from a chemical series before proceeding to in vivo studies. While the prototypical macrocyclic lactone ivermectin displays minimal activity against adult Schistosoma mansoni, this family of compounds does contain schistocidal compounds which may serve as a starting point for development of new anti-flatworm chemotherapies.
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Heneberg P, Casero M. Recent large-scale philophthalmosis outbreak in Portugal: inefficacy of common antihelminthic agents. Parasit Vectors 2022; 15:167. [PMID: 35551666 PMCID: PMC9097061 DOI: 10.1186/s13071-022-05265-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Parasitic conjunctivitis caused by Philophthalmus spp. is a common ophthalmic disease in birds, with localized outbreaks occurring worldwide. There is no consensus on treating this disease; mechanical removal is considered a standard recommendation, but is associated with disease relapses within days or weeks. METHODS From 2015 to 2020, we examined 4295 Larus michahellis and Larus fuscus gulls in southern Portugal for the presence of Philophthalmus spp. Due to the need to treat dozens of infected gulls in the rescue station, we tested three treatment regimens aimed at targeting Philophthalmus lucipetus in the infected gulls: (I) the ophthalmic application of levamisole; (II) the oral application of milbemycin in combination with praziquantel; and (III) the subcutaneous application of ivermectin. RESULTS The outbreak of philophthalmosis in gulls in southern Portugal has been ongoing since the first cases were reported in 2015-2016. The prevalence of philophthalmosis has fluctuated annually, peaking a maximum of 10.3% in L. fuscus in 2017 and at 2.1% in L. michahellis in 2016. The infection intensity peaked at a median of 11.5 eye-flukes per host bird in L. fuscus in 2016 and a median of six eye-flukes per host bird in L. michahellis in 2017. Nine gulls were infected with >50 eye-flukes. None of the treatment options were effective at treating P. lucipetus infections: the numbers of eye-flukes in the infected birds did not decrease, and the clinical signs of the disease did not change. CONCLUSIONS An outbreak of philophthalmosis in southern Portugal has massively affected two species of gulls in the region. Two previously suggested philophthalmosis treatments (ocular levamisole and praziquantel given orally), as well as a third mode of treatment with a previously failed compound (ivermectin administered subcutaneously) were used. However, the treatments did not affect the numbers of P. lucipetus in the eyes of the treated gulls. Further research should address ophthalmic gel formulations or sub-conjunctival delivery mode for antihelminthic drugs that are effective against Philophthalmus spp. in vitro.
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Affiliation(s)
- Petr Heneberg
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - María Casero
- Wildlife Rehabilitation and Research Center of Ria Formosa (RIAS), Ria Formosa Natural Park, Olhão, Portugal
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Sharun K, Shyamkumar TS, Aneesha VA, Dhama K, Pawde AM, Pal A. Current therapeutic applications and pharmacokinetic modulations of ivermectin. Vet World 2019; 12:1204-1211. [PMID: 31641298 PMCID: PMC6755388 DOI: 10.14202/vetworld.2019.1204-1211] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 06/29/2019] [Indexed: 12/22/2022] Open
Abstract
Ivermectin is considered to be a wonder drug due to its broad-spectrum antiparasitic activity against both ectoparasites and endoparasites (under class of endectocide) and has multiple applications in both veterinary and human medicine. In particular, ivermectin is commonly used in the treatment of different kinds of infections and infestations. By altering the vehicles used in the formulations, the pharmacokinetic properties of different ivermectin preparations can be altered. Since its development, various vehicles have been evaluated to assess the efficacy, safety, and therapeutic systemic concentrations of ivermectin in different species. A subcutaneous route of administration is preferred over a topical or an oral route for ivermectin due to superior bioavailability. Different formulations of ivermectin have been developed over the years, such as stabilized aqueous formulations, osmotic pumps, controlled release capsules, silicone carriers, zein microspheres, biodegradable microparticulate drug delivery systems, lipid nanocapsules, solid lipid nanoparticles, sustained-release ivermectin varnish, sustained-release ivermectin-loaded solid dispersion suspension, and biodegradable subcutaneous implants. However, several reports of ivermectin resistance have been identified in different parts of the world over the past few years. Continuous use of suboptimal formulations or sub-therapeutic plasma concentrations may predispose an individual to resistance toward ivermectin. The current research trend is focused toward the need for developing ivermectin formulations that are stable, effective, and safe and that reduce the number of doses required for complete clinical cure in different parasitic diseases. Therefore, single-dose long-acting preparations of ivermectin that provide effective therapeutic drug concentrations need to be developed and commercialized, which may revolutionize drug therapy and prophylaxis against various parasitic diseases in the near future. The present review highlights the current advances in pharmacokinetic modulation of ivermectin formulations and their potent therapeutic applications, issues related to emergence of ivermectin resistance, and future trends of ivermectin usage.
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Affiliation(s)
- Khan Sharun
- Division of Surgery, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - T. S. Shyamkumar
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - V. A. Aneesha
- Division of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - Abhijit Motiram Pawde
- Division of Surgery, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - Amar Pal
- Division of Surgery, ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
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Comparative efficacy of ivermectin and Nigella sativa against helminths in Aseel chickens (Gallus gallus domesticus). J Helminthol 2018; 93:533-538. [PMID: 30149818 DOI: 10.1017/s0022149x18000718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, we evaluated the in vivo comparative efficacy of ivermectin and Nigella sativa extract against helminths in Aseel chickens, and the effects of helminths on blood parameters before and after treatment in Aseel chickens. Forty naturally infected adult Aseel chickens were randomly divided into four groups (n = 10 each): group A (ivermectin at 300 μg/kg); group B (N. sativa extract at 200 mg/kg); group C (ivermectin at 300 μg/kg + N. sativa extract at 200 mg/kg); group D was kept as a positive control to monitor time-related changes. On day 28 post treatment, the mean percentages of faecal egg-count reduction (FECR %) in groups A, B and C were recorded as 93.58, 88.09 and 100.00%, respectively. Further data analysis showed significantly higher efficacy in group C (100 ± 0.00%) than in groups A and B (P < 0.001). Highly significant (P < 0.001) improvements in mean percentage values of packed cell volume (PCV %) were recorded in groups A and C on days 14 and 28 post treatment. Meanwhile, the improvements in mean values of haemoglobin (Hb) concentration in groups A, B and C were highly significant (P < 0.001) when compared to that of group D on day 28 post treatment. The synergistic combination of ivermectin and N. sativa extract possessed greater efficacy than either ivermectin or N. sativa extract used alone. Furthermore, both PCV % and Hb concentration values gradually increased in the treated groups compared to the control group, in which PCV % and Hb concentration gradually decreased throughout the trial.
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Greenberg RM. Ion channels and drug transporters as targets for anthelmintics. CURRENT CLINICAL MICROBIOLOGY REPORTS 2014; 1:51-60. [PMID: 25554739 PMCID: PMC4278637 DOI: 10.1007/s40588-014-0007-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infections with parasitic helminths such as schistosomes and soil-transmitted nematodes are hugely prevalent and responsible for a major portion of the global health and economic burdens associated with neglected tropical diseases. In addition, many of these parasites infect livestock and plants used in agriculture, resulting in further impoverishment. Treatment and control of these pathogens rely on anthelmintic drugs, which are few in number, and against which drug resistance can develop rapidly. The neuromuscular system of the parasite, and in particular, the ion channels and associated receptors underlying excitation and signaling, have proven to be outstanding targets for anthelmintics. This review will survey the different ion channels found in helminths, focusing on their unique characteristics and pharmacological sensitivities. It will also briefly review the literature on helminth multidrug efflux that may modulate parasite susceptibility to anthelmintics and may prove useful targets for new or repurposed agents that can enhance parasite drug susceptibility and perhaps overcome drug resistance.
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Affiliation(s)
- Robert M Greenberg
- Department of Pathobiology School of Veterinary Medicine University of Pennsylvania 3800 Spruce Street Philadelphia PA 19104 Tel: 215-898-5678
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Lynagh T, Cromer BA, Dufour V, Laube B. Comparative pharmacology of flatworm and roundworm glutamate-gated chloride channels: Implications for potential anthelmintics. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:244-55. [PMID: 25516835 PMCID: PMC4266781 DOI: 10.1016/j.ijpddr.2014.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Flatworm and roundworm glutamate-gated chloride channels (GluCls) were compared. Several glutamate analogues activated both GluCls in the millimolar range. Quisqualate selectively activated the flatworm GluCl. Propofol and thymol inhibited both GluCls in the micromolar range.
Pharmacological targeting of glutamate-gated chloride channels (GluCls) is a potent anthelmintic strategy, evidenced by macrocyclic lactones that eliminate numerous roundworm infections by activating roundworm GluCls. Given the recent identification of flatworm GluCls and the urgent need for drugs against schistosomiasis, flatworm GluCls should be evaluated as potential anthelmintic targets. This study sought to identify agonists or modulators of one such GluCl, SmGluCl-2 from the parasitic flatworm Schistosoma mansoni. The effects of nine glutamate-like compounds and three monoterpenoid ion channel modulators were measured by electrophysiology at SmGluCl-2 recombinantly expressed in Xenopus laevis oocytes. For comparison with an established anthelmintic target, experiments were also performed on the AVR-14B GluCl from the parasitic roundworm Haemonchus contortus. l-Glutamate was the most potent agonist at both GluCls, but l-2-aminoadipate, d-glutamate and d-2-aminoadipate activated SmGluCl-2 (EC50 1.0 ± 0.1 mM, 2.4 ± 0.4 mM, 3.6 ± 0.7 mM, respectively) more potently than AVR-14B. Quisqualate activated only SmGluCl-2 whereas l-aspartate activated only AVR-14B GluCls. Regarding the monoterpenoids, both GluCls were inhibited by propofol, thymol and menthol, SmGluCl-2 most potently by thymol (IC50 484 ± 85 μM) and least potently by menthol (IC50 > 3 mM). Computational docking suggested that agonist and inhibitor potency is attributable to particular interactions with extracellular or membrane-spanning amino acid residues. These results reveal that flatworm GluCls are pharmacologically susceptible to numerous agonists and modulators and indicate that changes to the glutamate γ-carboxyl or to the propofol 6-isopropyl group can alter the differential pharmacology at flatworm and roundworm GluCls. This should inform the development of more potent compounds and in turn lead to novel anthelmintics.
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Key Words
- Anthelmintic
- Binding site
- ECD, extracellular domain
- GABA, γ-aminobutyric acid
- GABAAR, type A γ-aminobutyric acid receptor
- GluCl
- GluCl, glutamate-gated chloride channel
- GlyR, glycine receptor
- Propofol
- Schistosomiasis
- TMD, transmembrane domain
- Thymol
- cis-ACBD, cis-1-aminocyclobutane-1,3-dicarboxylate
- iGluR, (tetrameric) ionotropic glutamate receptor
- pLGIC, pentameric ligand-gated ion channel (or Cys-loop receptor)
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Affiliation(s)
- Timothy Lynagh
- Neurophysiology and Neurosensory Systems, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Brett A Cromer
- Health Innovations Research Institute and School of Medical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
| | - Vanessa Dufour
- Centre for Host-Parasite Interactions, Institute of Parasitology, McGill University - MacDonald Campus, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Bodo Laube
- Neurophysiology and Neurosensory Systems, Technical University of Darmstadt, 64287 Darmstadt, Germany
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Molecular cloning and characterization of novel glutamate-gated chloride channel subunits from Schistosoma mansoni. PLoS Pathog 2013; 9:e1003586. [PMID: 24009509 PMCID: PMC3757052 DOI: 10.1371/journal.ppat.1003586] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/15/2013] [Indexed: 12/28/2022] Open
Abstract
Cys-loop ligand-gated ion channels (LGICs) mediate fast ionotropic neurotransmission. They are proven drug targets in nematodes and arthropods, but are poorly characterized in flatworms. In this study, we characterized the anion-selective, non-acetylcholine-gated Cys-loop LGICs from Schistosoma mansoni. Full-length cDNAs were obtained for SmGluCl-1 (Smp_096480), SmGluCl-2 (Smp_015630) and SmGluCl-3 (Smp_104890). A partial cDNA was retrieved for SmGluCl-4 (Smp_099500/Smp_176730). Phylogenetic analyses suggest that SmGluCl-1, SmGluCl-2, SmGluCl-3 and SmGluCl-4 belong to a novel clade of flatworm glutamate-gated chloride channels (GluCl) that includes putative genes from trematodes and cestodes. The flatworm GluCl clade was distinct from the nematode-arthropod and mollusc GluCl clades, and from all GABA receptors. We found no evidence of GABA receptors in S. mansoni. SmGluCl-1, SmGluCl-2 and SmGluCl-3 subunits were characterized by two-electrode voltage clamp (TEVC) in Xenopus oocytes, and shown to encode Cl−-permeable channels gated by glutamate. SmGluCl-2 and SmGluCl-3 produced functional homomers, while SmGluCl-1 formed heteromers with SmGluCl-2. Concentration-response relationships revealed that the sensitivity of SmGluCl receptors to L-glutamate is among the highest reported for GluCl receptors, with EC50 values of 7–26 µM. Chloride selectivity was confirmed by current-voltage (I/V) relationships. SmGluCl receptors are insensitive to 1 µM ivermectin (IVM), indicating that they do not belong to the highly IVM-sensitive GluClα subtype group. SmGluCl receptors are also insensitive to 10 µM meclonazepam, a schistosomicidal benzodiazepine. These results provide the first molecular evidence showing the contribution of GluCl receptors to L-glutamate signaling in S. mansoni, an unprecedented finding in parasitic flatworms. Further work is needed to elucidate the roles of GluCl receptors in schistosomes and to explore their potential as drug targets. Schistosomiasis is a debilitating disease caused by blood flukes in the genus Schistosoma that afflicts over 200 million people worldwide. Treatment relies almost exclusively on a single drug, praziquantel. Reports of sub-optimal efficacy of praziquantel raise concerns about the prospect of drug resistance and highlight the need to develop new schistosomicidal drugs. Neuroactive receptors are recognized targets of insecticides and anthelmintics. Likewise, neuronal receptors of schistosomes are attractive targets for drug development. Lacking a coelom and a proper circulatory system, schistosomes are thought to lack the capacity for endocrine signaling, and therefore depend entirely on neuronal modulation to control functions vital to their survival and reproduction. We characterized a novel family of glutamate-gated chloride channel (GluCl) receptors from S. mansoni that are pharmacologically and evolutionarily distinct from GluCls in nematodes, insects and snails. Our phylogenetic analyses suggest that these receptors are also widely distributed in other flukes and tapeworms. This study provides the first molecular evidence for the contribution of an inhibitory component to glutamatergic signaling in S. mansoni. Our findings add to a growing body of evidence suggesting that glutamatergic signaling in schistosomes may be physiologically important, and could be targeted for chemotherapeutic intervention.
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Lynagh T, Lynch JW. Ivermectin binding sites in human and invertebrate Cys-loop receptors. Trends Pharmacol Sci 2012; 33:432-41. [PMID: 22677714 DOI: 10.1016/j.tips.2012.05.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 04/27/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
Abstract
Ivermectin is a gold standard antiparasitic drug that has been used successfully to treat billions of humans, livestock and pets. Until recently, the binding site on its Cys-loop receptor target had been a mystery. Recent protein crystal structures, site-directed mutagenesis data and molecular modelling now explain how ivermectin binds to these receptors and reveal why it is selective for invertebrate members of the Cys-loop receptor family. Combining this with emerging genomic information, we are now in a position to predict species sensitivity to ivermectin and better understand the molecular basis of ivermectin resistance. An understanding of the molecular structure of the ivermectin binding site, which is formed at the interface of two adjacent subunits in the transmembrane domain of the receptor, should also aid the development of new lead compounds both as anthelmintics and as therapies for a wide variety of human neurological disorders.
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Affiliation(s)
- Timothy Lynagh
- Neurosensory Systems Group, Technical University of Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
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Fasciola gigantica: Parasitological and scanning electron microscopy study of the in vitro effects of ivermectin and/or artemether. Exp Parasitol 2010; 124:279-84. [DOI: 10.1016/j.exppara.2009.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 10/12/2009] [Accepted: 10/21/2009] [Indexed: 01/09/2023]
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Abstract
AbstractTriclabendazole (TCBZ) remains the drug of choice for treating infections of the liver fluke,Fasciola hepaticain livestock and has become the main drug used to treat human cases of the disease as well. Cases of resistance in livestock continue to be reported, suggesting that the problem is increasing. In order to address the problem, there is a need for better understanding of drug action. A ‘state-of-play’ review on different aspects of TCBZ activity was published by the present author in 2005. The main purpose of the current review is to assess what progress has been made in the past four years towards understanding the main aspects of drug activity, including drug pharmacokinetics and pharmacodynamics and an understanding of the mechanism(s) of resistance. Also, what advances have been made in identifying alternative compounds and using drug combinations to enhance TCBZ activity. Stemming from a number ofin vivostudies, it has become evident that fluke isolates of differing sensitivity to TCBZ differ in some of their biological parameters, and information on this interesting phenomenon will be presented. An update on the use of TCBZ for human fascioliasis is also given. The review will indicate what progress has been made, but will also highlight areas that remain inadequately understood and require greater research focus.
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Gokbulut C, Bilgili A, Hanedan B, Aksit D, Aksoy AM, Turgut C. Breed-related plasma disposition of ivermectin following subcutaneous administration in Kilis and Damascus goats. Res Vet Sci 2009; 87:445-8. [PMID: 19410269 DOI: 10.1016/j.rvsc.2009.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Revised: 04/02/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
Abstract
Many factors related with drug and animals affect the plasma disposition of endectocides including ivermectin (IVM). The aim of the present study was to investigate the breed differences in pharmacokinetics of IVM in goats following subcutaneous administration. Two different goat breeds (Kilis and Damascus goats) were allocated into two treatment groups with respect to breed. The injectable formulation of IVM was administered subcutaneously at a dose rate of 0.2 mg/kg bodyweight. Blood samples were collected before treatment and at various times between 1h and 40 days after treatment and the plasma samples were analysed by high performance liquid chromatography (HPLC) using fluorescence detection. The results indicated that the plasma disposition of IVM was substantially affected by breed differences following subcutaneous administration in goats. The last detectable plasma concentration (t(last)) of IVM was significantly later in Kilis goats (38.33 days) compared with Damascus goats (22.50 days). Although, there were no significant differences on C(max) (10.83 ng/ml vs. 10.15 ng/ml) and t(max) (2.75 days vs. 2.33 days) values; the area under the concentration-time curve-AUC (110.26 ng.d/ml vs. 73.38 ng.d/ml) the terminal half-life-t(1/2lambdaz) (5.65 days vs. 3.81 days) and the mean plasma residence time-MRT (9.31 days vs. 6.35 days) were significantly different in Kilis goats compared with Damascus goats, respectively. The breed-related difference observed on the plasma disposition of IVM between Kilis and Damascus goats could be attributable to different excretion pattern or specific anatomical and/or physiological characteristics such as body fat composition of each breed.
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Affiliation(s)
- Cengiz Gokbulut
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Adnan Menderes, Isikli Koyu, 09100 Aydin, Turkey.
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Gokbulut C, Karademir U, Boyacioglu M, McKellar QA. Comparative plasma dispositions of ivermectin and doramectin following subcutaneous and oral administration in dogs. Vet Parasitol 2005; 135:347-54. [PMID: 16280198 DOI: 10.1016/j.vetpar.2005.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 09/30/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
This study evaluates the comparative plasma dispositions of ivermectin (IVM) and doramectin (DRM) following oral and subcutaneous administration (200 microg/kg) over a 40-day period in dogs. Twenty bitches were allocated by weight in to four groups (Groups I-IV) of five animals each. Animals in the first two groups (Groups I and II) received orally the injectable solutions of IVM and DRM, respectively, at the dose of 200 microg/kg bodyweight. The other two groups (Groups III and IV) received subcutaneously injectable solutions at the same dose rate. Blood samples were collected between 1h and 40 days after treatment and the plasma samples were analysed by high performance liquid chromatography (HPLC) using fluorescence detection. The results indicated that IVM produced a significantly higher maximum plasma concentration (C(max): 116.80+/-10.79 ng/ml) with slower absorption (t(max): 0.23+/-0.09 day) and larger area under the concentration versus time curve (AUC: 236.79+/-41.45 ng day/ml) as compared with DRM (C(max): 86.47+/-19.80 ng/ml, t(max): 0.12+/-0.05 day, AUC: 183.48+/-13.17 ng day/ml) following oral administration of both drugs; whereas no significant differences were observed on the pharmacokinetic parameters between IVM and DRM after subcutaneous administrations. In addition, subcutaneously given IVM and DRM presented a significantly lower maximum plasma concentration (C(max): 66.80+/-9.67 ng/ml and 54.78+/-11.99 ng/ml, respectively) with slower absorption (t(max): 1.40+/-1.00 day and 1.70+/-0.76 day, respectively) and larger area under the concentration versus time curve (AUC: 349.18+/-47.79 ng day/ml and 292.10+/-78.76 ng day/ml, respectively) as compared with the oral administration of IVM and DRM, respectively. No difference was observed for the terminal half-lives ((t(1/2lambda(z)) and mean residence times (MRT) of both molecules. Considering the pharmacokinetic parameters, IVM and DRM could be used by the oral or subcutaneous route for the control of parasitic infection in dogs.
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Affiliation(s)
- Cengiz Gokbulut
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Adnan Menderes, Isikli Koyu, Aydin, Turkey.
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Gokbulut C, Nolan AM, McKellar QA. Plasma pharmacokinetics and faecal excretion of ivermectin, doramectin and moxidectin following oral administration in horses. Equine Vet J 2001; 33:494-8. [PMID: 11558745 DOI: 10.2746/042516401776254835] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The present study was carried out to investigate whether the pharmacokinetics of avermectins or a milbemycin could explain their known or predicted efficacy in the horse. The avermectins, ivermectin (IVM) and doramectin (DRM), and the milbemycin, moxidectin (MXD), were each administered orally to horses at 200 microg/kg bwt. Blood and faecal samples were collected at predetermined times over 80 days (197 days for MXD) and 30 days, respectively, and plasma pharmacokinetics and faecal excretion determined. Maximum plasma concentrations (Cmax) (IVM: 21.4 ng/ml; DRM: 21.3 ng/ml; MXD: 30.1 ng/ml) were obtained at (tmax) 7.9 h (IVM), 8 h (DRM) and 7.9 h (MXD). The area under the concentration time curve (AUC) of MXD (92.8 ng x day/ml) was significantly larger than that of IVM (46.1 ng x day/ml) but not of DRM (53.3 ng x day/ml) and mean residence time of MXD (17.5 days) was significantly longer than that of either avermectin, while that of DRM (3 days) was significantly longer than that of IVM (2:3 days). The highest (dry weight) faecal concentrations (IVM: 19.5 microg/g; DRM: 20.5 microg/g; MXD: 16.6 microg/g) were detected at 24 h for all molecules and each compound was detected (> or = 0.05 microg/g) in faeces between 8 h and 8 days following administration. The avermectins and milbemycin with longer residence times may have extended prophylactic activity in horses and may be more effective against emerging and maturing cyathostomes during therapy. This will be dependent upon the relative potency of the drugs and should be confirmed in efficacy studies.
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Affiliation(s)
- C Gokbulut
- Division of Veterinary Pharmacology, University of Glasgow, UK
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Sibille P, Calléja C, Carreras F, Bigot K, Galtier P, Boulard C. Fasciola hepatica: influence of gender and liver biotransformations on flukicide treatment efficacy of rats infested and cured with either clorsulon/ivermectin or triclabendazole. Exp Parasitol 2000; 94:227-37. [PMID: 10831390 DOI: 10.1006/expr.2000.4501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two fasciolicide preparations have been compared in 130 rats experimentally infected with Fasciola hepatica. Parasitological, immunological, and biochemical parameters have been followed to monitor the efficacy of the treatments. While Fascinex (triclabendazole) efficiently cured both male and female rats when administered as soon as 4 weeks postinfection, treatment with Ivomec-D (clorsulon + ivermectin) displayed a low efficacy on either male or female rats at this time point (54 and 0%, respectively). Moreover, when administered 8 weeks postinfection, the Ivomec-D treatment proved highly efficient on male rats while it displayed little effect on the female population (100 and 53%, respectively). This unexpected result has been related to an overexpression of a P4503A isoform that is observed only in females that have been treated with Ivomec-D. The influence of this P4503A cytochrome on drug metabolism and the need for the incorporation of both genders in clinical trials are discussed.
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Affiliation(s)
- P Sibille
- Station de Pathologie Aviaire et Parasitologie, INRA, Nouzilly, 37380, France
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Rehbein S, Visser M. Efficacy of an injectable ivermectin/clorsulon combination against Fasciola hepatica in sheep. Vet Rec 1999; 145:468. [PMID: 10576286 DOI: 10.1136/vr.145.16.468] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- S Rehbein
- Kathrinenhof Research Center, Rohrdorf, Germany
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Affiliation(s)
- Q A McKellar
- Department of Veterinary Pharmacology, University of Glasgow Veterinary School, UK
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