Closantel sodium |
![]() Last updated: 16/09/2025 |
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(Not known by any other names) |
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A salicylanilide anthelmintic and antiparasitic veterinary drug | |
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Used for the treatment and control of adult and immature flukes, nematodes and larval stages of some arthropods | |
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Sheep; Cattle |
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Approved - usually supplied as a prescription only medicine to be authorised by suitably qualified person (POM-VPS) | |
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Approved |
Chemical structure |
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Closantel sodium exhibits chiral isomerism, meaning its molecular structure includes a chiral centre that allows for the existence of stereoisomers. This chirality arises from the spatial arrangement of atoms around specific carbon centres in its complex aromatic framework. Although closantel sodium is typically used as a single active form in veterinary medicine, the presence of chiral centres implies that different isomers could theoretically exist. | |
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C₂₂H₁₃Cl₂I₂N₂NaO₂ | |
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CC1=CC(=C(C=C1NC(=O)C2=C(C(=CC(=C2)I)I)[O-])Cl)C(C#N)C3=CC=C(C=C3)Cl.[Na+] | |
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LREGMDNUOGTSIK-UHFFFAOYSA-M | |
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InChI=1S/C22H14Cl2I2N2O2.Na/c1-11-6-15(17(10-27)12-2-4-13(23)5-3-12)18(24)9-20(11)28-22(30)16-7-14(25)8-19(26)21(16)29;/h2-9,17,29H,1H3,(H,28,30);/q;+1/p-1 | |
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Yes |
General status |
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Anthelmintic, Antiparasitic, Insecticide, Acaricide | |
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Salicylanilide | |
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Synthetic | |
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Acts by uncoupling oxidative phosphorylation. | |
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[Fumarate reductase, Inhibitor] | |
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61438-64-0 | |
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262-794-7 | |
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23683671 | |
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Antiparasitic products, insecticides & repellents: Anthelmintics | |
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QP54AA51 | |
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No | |
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Allowed substance (Table 1: Bovine, Ovine) | |
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685.1 | |
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sodium;2-[[5-chloro-4-[(4-chlorophenyl)-cyanomethyl]-2-methylphenyl]carbamoyl]-4,6-diiodophenolate | |
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White to yellowish-brown crystalline powder | |
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Commercial |
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Current | |||
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1970s, first synthesised; 1980s, initial vet use | |||
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Available in a variety of formulations including solutions for injection and oral suspension | |||
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The production of closantel sodium typically involves a multi-step synthetic process starting from halogenated aromatic precursors. One common route begins with the reaction of 4-chlorobenzyl cyanide with sodium methylate in methanol under sealed conditions at around 50 DegC. This is followed by treatment with hydrazine hydrate and sodium hydroxide in diethylene glycol at elevated temperatures, which helps form the intermediate structure. The final step involves refluxing in toluene, which facilitates the formation of the closantel backbone and its conversion into the sodium salt form. An alternative method uses catalytic hydrogenation of a nitroso-containing intermediate in the presence of hydrogen gas and a suitable catalyst, offering higher purity and reduced environmental impact compared to older iron-based reduction techniques. | |||
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Published GHG data is not available for most pharmaceuticals. However, according to industry, global averages suggest producing 1 kg of a typical active pharmaceutical ingredient can range from 10 to 100 kg CO₂e for small molecule drugs and potentially up to 1000 kg CO₂e for complex biologicals such as vaccines, depending on the drug type, its formulation, complexity of synthesis, solvent recovery, and energy sources used. |
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215 | V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source |
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220 | V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source |
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1.29 X 1008 | Calculated | - | |||||||
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8.11 | V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) 3 = Unverified data of known source |
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As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below. | ||||||||||
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Fate indices |
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Known metabolites |
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Terrestrial ecotoxicology |
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262 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat5 = Verified data used for regulatory purposes |
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Aquatic ecotoxicology |
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2.5 | F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) Anguilla anguilla3 = Unverified data of known source |
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General |
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High (class III) | - | - | ||||||||
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262 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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Intramuscular LD₅₀ = 28.4 mg kg⁻¹ | V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) Rat3 = Unverified data of known source |
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Subcutaneous LD₅₀ = 67.0 mg kg⁻¹ | V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID ) Mouse3 = Unverified data of known source |
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Around 80% excreted in the faeces | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes |
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Health issues |
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Possible lung and kidney toxicant |
Handling issues |
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No information available | |||
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Not listed (Not listed) | |||
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closantel sodium | ||
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Record last updated: | 16/09/2025 |
Contact: | aeru@herts.ac.uk |
Please cite as: | Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242 |