Fenbendazole (Ref: Hoe 881v)

Fenbendazole (Ref: Hoe 881v)	Last updated: 14/04/2021
(Also known as: phenbendasol)

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate	Ecotoxicity	Human health
Environmental fate High alert: Drainflow: Mobile Warning: Significant data are missing	Ecotoxicity High alert: Fish acute ecotoxicity: High; Daphnia acute ecotoxicity: High	Human health Moderate alert: Possible Reproduction/development effects Warning: Significant data are missing

GENERAL INFORMATION

Description

A broad spectrum anthelmintic used against gastrointestinal parasites in livestocks and domestic pets

Availability status

Introduction & key dates

Examples of species treated

Cattle, Sheep, Horses, Domestic pets, Hedgehogs, Bears, Elephants, Pigeons, Exotic birds, Ferrets, Fish

Chemical structure

Isomerism

Chemical formula

C₁₅H₁₃N₃O₂S

Canonical SMILES

COC(=O)NC1=NC2=C(N1)C=C(C=C2)SC3=CC=CC=C3

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

HDDSHPAODJUKPD-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H13N3O2S/c1-20-15(19)18-14-16-12-8-7-11(9-13(12)17-14)21-10-5-3-2-4-6-10/h2-9H,1H3,(H2,16,17,18,19)

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Anthelmintic, Antiparasitic, Nematicide

Substance groups

Benzimidazole

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Binds to tubulin, a protein required for functions including nutrient uptake, thus disrupting parasite energy metabolism

Molecular targets

[Tubulin alpha-3 chain, antagonist]

CAS RN

43210-67-9

EC number

256-145-7

CIPAC number

US EPA chemical code

PubChem CID

ATCvet Code

QP52AC13

Therapeutic Class

Antiparasitic products, insecticides & repellents: Anthelmintics

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Ruminants, Porcine, Equidae)

Molecular mass

299.35

PIN (Preferred Identification Name)

IUPAC name

methyl N-(6-phenylsulfanyl-1H-benzoimidazol-2-yl)carbamate

CAS name

2-(methoxycarbonylamino)-5-(phenylthio)benzimidazole

Other status information

Relevant Environmental Water Quality Standards

Physical state

White to dirty white coloured crystalline powder

Formulations

Property

Product

Manufacturer

Authorisation Route

UK Legal Class

Example products using this active

Beaphar Worming Granules for Cats & Kittens

Sinclair Animal & Household Care Ltd

UK National authorisation (IC)

Authorised veterinary medicine for general sale (AVM - GSL)

Fenzol 5% Oral Suspension

Norbrook Labs

UK National authorisation

Prescription only medicine to be authorised by suitably qualified person (POM-VPS)

Panacur 1.5% pellets

Intervet Ltd

UK National authorisation

Prescription only medicine to be authorised by suitably qualified person (POM-VPS)

Wormazole 880mg Granules for Dogs

Norbrook Labs

UK National authorisation

For non-food animal use and may be supplied without a prescription by a suitable qualified person (NFA-VPS)

Formulation and application details

Various preparations are available for oral administration

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.01

Low

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

Melting point (°C)

233

Boiling point (°C)

Decomposes on melting

Degradation point (°C)

Flashpoint (°C)

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

7.08 X 10⁰³

Calculated

Log P

3.85

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.40

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

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

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

Max absorption at 296nm

Surface tension (mN m⁻¹)

Refractive Index

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

0.53

Fast

Note

Slight variation with pH: 0.71 days at pH5 & 0.47 days at pH9

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

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Mobile

K_oc

Notes and range

General literature states K_oc range 35-57 mL g⁻¹

Freundlich

K_f

K_foc

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

oxfendazole (Ref: HOE 8105)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 10000

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)

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

1068

Eisenia foetida

Low

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 pollinators (1)

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

Mode of exposure

Other pollinators (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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.04

Oncorhynchus mykiss

High

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

0.0165

Daphnia magna

High

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

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

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

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)

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

Mesocosm study data

NOEAEC 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)

> 10000

Rat

Low

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ > 1250 mg kg⁻¹

Rat

Subcutaneous LD₅₀ > 2000 mg kg⁻¹

Rat

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

Mammalian dose elimination route and rate

Slow adsorption, excreted mainly unchanged in 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

No further information available

Handling issues

Property

Value and interpretation

General

Light sensitive

CLP classification 2013

WHO Classification

None - not a ppp

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

fenbendazole

French

fenbendazole

German

Danish

Italian

Spanish

fenbendazol

Greek

Polish

Swedish

Hungarian

Dutch

Record last updated:	14/04/2021
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