Niclosamide (Ref: ENT 25823 )

Niclosamide (Ref: ENT 25823 )	Last updated: 19/05/2024
(Also known as: clonitralide)

GENERAL INFORMATION

Description

A largely obsolete antiparasitic control agent for humans and animals

Availability status

Introduction & key dates

Examples of veterinary uses

Used for treating tape worm infections. Also used to control aquatic pests (Aquatic snails; Sea lamprey)

Examples of species treated

Horses; Ruminants; Cats; Dogs; Sheep; Poultry; Aquatic situations

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₁₃H₈Cl₂N₂O₄

Canonical SMILES

C1=CC(=C(C=C1[N+](=O)[O-])Cl)NC(=O)C2=C(C=CC(=C2)Cl)O

Isomeric SMILES

International Chemical Identifier key (InChIKey)

RJMUSRYZPJIFPJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H8Cl2N2O4/c14-7-1-4-12(18)9(5-7)13(19)16-11-3-2-8(17(20)21)6-10(11)15/h1-6,18H,(H,16,19)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
niclosamide	-

General status

Veterinary substance type

Anthelmintic, Antiparasitic, Nematicide

Substance groups

Chloronitrophenol molluscidie

Minimum active substance purity

>96%

Known relevant impurities

Substance origin

Synthetic

Mode of action

Respiratory & stomach action. Acts by uncoupling oxidative phosphorylation in the tapeworm

Molecular targets

[DNA, Antagonist], [Oxidative phosphorylation, Uncoupler], [Glucose uptake, Inhibitor]

CAS RN

50-65-7

EC number

200-056-8

CIPAC number

599

US EPA chemical code

PubChem CID

4477

CLP index number

No data found

Therapeutic Class

Antiparasitic products, insecticides & repellents: Anthelmintics

ATCvet Code

QP52AG03

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

327.12

PIN (Preferred Identification Name)

5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide

IUPAC name

2'5-dichloro-4'-nitrosalicylanilide

CAS name

5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide

Other status information

Relevant Environmental Water Quality Standards

Physical state

Yellow-grey coloured crystalline solid

Related substances & organisms

niclosamide-olamine

niclosamide-sodium

Formulations

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Example products (past and present) using this active

Formulation and application details

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

5.0

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Melting point (°C)

224

Boiling point (°C)

Degradation point (°C)

208

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

3.63 X 10⁰⁴

Calculated

Log P

4.56

Other data: 1.0 at pH 9.6

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

5.6

Vapour pressure at 20 °C (mPa)

8.0 X 10^-08

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Refractive Index

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Air degradation

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.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

106

Slightly mobile

K_oc (mL g⁻¹)

3112

Notes and range

Literature values for sediments: K_d range 52.2-186.5 mL g⁻¹, K_oc range 1742-4980 mL g⁻¹, soils=5

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Yes

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

250

Threshold for concern

CT₅₀ (days)

Not available

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

2,5-dichloro-4-aminosalicylanilide

Rat (Urine)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.34

Oncorhynchus mykiss

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

0.2

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.02

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

> 0.11

Danio rerio

Moderate

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

1.6

Chironomus riparius 48 hr

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

5.0

Scenedesmus subspicatus

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀ development (mg l⁻¹)

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 250 mg kg⁻¹

Rat

Intravenous LD₅₀ = 7.5 mg kg⁻¹

Mouse

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

May be absorbed through the skin or mucous membranes

Mammalian dose elimination route and rate

Some metabolism, metabolites and unchanged parent lost mainly via the faeces

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

May cause gastrointestinal problems, anorexia, irritability & alopecia
Salts may cause occular irritation
Harmful if swallowed

Handling issues

Property

Value and interpretation

General

Avoid formation of dust
IMDG Transport Hazard Class 9

CLP classification 2013

Health: H319
Environment: H400, H410

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

niclosamide

French

niclosamide

German

clonitralid

Danish

Italian

Spanish

niclosamida

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	19/05/2024
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