D-phenothrin (Ref: OMS 1809)

D-phenothrin (Ref: OMS 1809)	Last updated: 15/09/2025
(Also known as: ENT 27972; phenoxythrin; cyfenothrin; phenothrine; R-phenothrin)

GENERAL INFORMATION

Description

A synthetic pyrethroid insecticide for parasite control

Examples of veterinary uses

Used to eradicate adult ticks, lice, mites and fleas

Examples of species treated

Dogs; Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Phenothrin is a molecule with two chiral centres. The technical material known as phenothrin is an isomeric mixture of four isomers (1R- cis, 1R- trans, 1S- cis, 1S- trans). The specific isomer, d-phenothrin is a refined mixture that contains ≥95% of the 1R isomers, specifically a 1:4 ratio of 1R-cis to 1R-trans.

Chemical formula

C₂₃H₂₆O₃

Canonical SMILES

CC(=CC1C(C1(C)C)C(=O)OCC2=CC(=CC=C2)OC3=CC=CC=C3)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

SBNFWQZLDJGRLK-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C23H26O3/c1-16(2)13-20-21(23(20,3)4)22(24)25-15-17-9-8-12-19(14-17)26-18-10-6-5-7-11-18/h5-14,20-21H,15H2,1-4H3

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Ectoparasiticide

Substance groups

Pyrethroid insecticide; Pyrethroid ester insecticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Non-systemic with rapid contact and stomach action. Sodium channel modulator. Blocks nerve impulse transmission.

Molecular targets

[Voltage-dependent sodium channel, Blocker]

CAS RN

26002-80-2

Alternative/old CAS RN

188023-86-1

EC number

247-404-5

CIPAC number

356

US EPA chemical code

069005

PubChem CID

4767

CLP index number

No data found

Therapeutic Class

Antiparasitic products, insecticides & repellents: Pyrethrins & pyrethroids

ATCvet Code

QP53AC03

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

350.46

PIN (Preferred Identification Name)

(3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate

IUPAC name

(3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropane-1-carboxylate

CAS name

(3-phenoxyphenyl)methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate

Forever chemical

Other status information

Marine Pollutant

Relevant Environmental Water Quality Standards

Physical state

Yellow to brown coloured liquid with a faint characteristic odour

Related substances & organisms

sumithrin

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1976, registered Japan

Example manufacturers & suppliers of products using this active now or historically

Killgerm
Henan Tianfu Chemical Co. Ltd. China
TargetMol Chemicals Inc. USA

Example products using this active

Forte

Formulation and application details

Usually formulated as emulsifiable concentrates, macro-emulsions, and micro-emulsions

Commercial production

Phenothrin is synthesised through a multi-step process that combines a cyclopropane carboxylic acid derivative with 3-phenoxybenzyl alcohol via esterification. The cyclopropane acid component is typically derived from chrysanthemic acid, which can be sourced from natural pyrethrins or synthesised chemically. The alcohol moiety is prepared through etherification of phenol with benzyl halides. These two components are then reacted under controlled conditions, often in the presence of a base catalyst and an organic solvent, to form the ester bond that defines phenothrin’s structure. The process requires careful temperature regulation and purification steps such as distillation or crystallization to isolate the desired isomeric forms.

Impact on climate of production and use

Data for the amount of life cycle GHGs produced by phenothrin are not available in the public domain. However, whilst estimates vary, more general data suggests that between 14 and 19 kilograms of CO₂e is emitted per kilogram of insecticide produced.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.0097

at 25 °C

Low

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

5000

Xylene

5000

Acetone

4960

Hexane

Melting point (°C)

Boiling point (°C)

290

Degradation point (°C)

Flashpoint (°C)

107

(closed cup)

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

1.02 X 10⁰⁶

Calculated

Log P

6.01

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.06

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.021

at 25°C

Low volatility

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

6.75 X 10^-01

Moderately volatile

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

1.548

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Moderately persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Best available literature data gives soil half life between 14 and 60 days

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)

Sediment 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)

Non-mobile

K_oc (mL g⁻¹)

180000

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-1.94

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

730

Cyprinidae

Threshold for concern

CT₅₀ (days)

Not available

Known metabolites

None

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)

> 2500

Colinus virginianus

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 dw soil)

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

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

0.13

Apis mellifera

High

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

0.16

Apis mellifera

High

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

Chronic

Notes

[The residual time to 25% mortality (RT25) value for honeybees is 3 hrs - USEPA data]

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)

> 0.0027

Oncorhynchus mykiss

High

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)

> 0.0043

Daphnia magna

High

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

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

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

> 0.00002

Americamysis bahia

High

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 (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

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)

2.1

Rat

Other Mammal toxicity endpoints

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

0.07

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

Excreted mainly as metabolites in urine but a proportion is excreted unchanged in faeces

Health issues

Specific human health issues (hazard-based)

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

The substance can be absorbed into the body by inhalation of its aerosol and by ingestion
May cause dizziness, headaches, fatigue and diarrhoea
Endocrine issues - Increase of estrogen-sensitive cells proliferation
Possible liver toxicant
One reported study suggests links with breast cancer

Handling issues

Property

Value and interpretation

General

Prevent generation of mists
Non-corrosive
Will generate acrid smoke and gases if heated to decomposition
Combustable
IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H302, H312, H332
Environment: H400, H410

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3352

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

d-phenothrin

French

phenothrine

German

Phenothrin

Danish

phenothrin

Italian

fenotrin

Spanish

fenotrina

Greek

Polish

fenotryna

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	15/09/2025
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