Top Environmental Fate Ecotoxicology Human Health Translations
Home
A to Z
Search
Support
Edit history
Purchasing and licensing
NEW
- User survey
Prallethrin (Ref: OMS 3033)
Last updated: 22/10/2025
(Also known as: S-4068SF; d-prallethrin)
GENERAL INFORMATION
Description
A synthetic pyrethroid with fast knock-down activity against various insect pests
Examples of veterinary uses
Use to control insect pests on domestic pets and pet bedding
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
Prallethrin is a complex chiral molecule. The technical material is an isomeric mixture of 8 stereoisomers but consists mainly of [1R,trans; S] and [1R,cis; S] isomers in a ratio of approximately 4:1..
Chemical formula
C₁₉H₂₄O₃
Canonical SMILES
CC1=C(C(=O)CC1OC(=O)C2C(C2(C)C)C=C(C)C)CC#C
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
SMKRKQBMYOFFMU-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C19H24O3/c1-7-8-13-12(4)16(10-15(13)20)22-18(21)17-14(9-11(2)3)19(17,5)6/h1,9,14,16-17H,8,10H2,2-6H3/t14-,16?,17+/m0/s1
2D structure diagram/image available?
Yes
General status
Veterinary substance type
Insecticide
Substance groups
Pyrethroid insecticide; Pyrethroid ester insecticide
Minimum active substance purity
>900 g/Kg
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact, with rapid knock down effect, acts on the insects nervous system. Sodium channel modulator.
Molecular targets
[Sodium channel, Modulator]
CAS RN
23031-36-9
EC number
245-387-9
CIPAC number
743
US EPA chemical code
128722
PubChem CID
9839306
CLP index number
607-431-00-9
Therapeutic Class
-
ATCvet Code
None allocated
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
300.40
PIN (Preferred Identification Name)
(1E)-2-methyl-4-oxo-3-(prop-2-yn-1-yl)cyclopent-2-en-1-yl (1E,3E)-2,2-dimethyl-3-(2-methylprop-1-en-1-yl)cyclopropane-1-carboxylate
IUPAC name
(RS)-2-methyl-4-oxo-3-prop-2-ynylcyclopent-2-enyl (1RS,3RS;1RS,3SR)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
CAS name
2-methyl-4-oxo-3-(2-propynyl)-2-cyclopenten-1-yl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate
Global Governance status: Listed (✓) under
UK Poisons List Order 1972 Rotterdam Convention Montreal Protocol
XNo
The Poisons List Order 1972
XNo
Rotterdam Convention
XNo
Montreal Protocol
Stockholm Convention OSPAR EU Water Framework Directive
XNo
Stockholm Convention
XNo
OSPAR
XNo
EU Water Framework Directive
Relevant Environmental Water Quality Standards
-
Forever chemical
-
Other status information
-
Physical state
Yellowish-brown oily liquid
Commercial
Property
Value
Availability status
Current
Introduction & key dates
1988, introduced Japan
Example manufacturers & suppliers of products using this active now or historically
  • MGK
  • Sumitomo Chemical Co.
Example products using this active
  • Etoc
  • MGK Concentrate
  • Alto Cirrus Fogging Concentrate
Formulation and application details
Various formulations are available including oils, foams, fogging concentrates and plug in vapourisers
Commercial production
Prallethrin is synthesised through a multi-step chemical process rooted in pyrethroid chemistry, specifically involving the esterification of chrysanthemic acid derivatives with alcohols. The key intermediate is a cyclopropane carboxylic acid, which is reacted with a substituted cyclopentenol, often containing a propargyl group, to form the final ester compound. This reaction is carefully controlled to yield the desired cis-trans isomeric mixture, which is crucial for prallethrin’s insecticidal potency. The process emphasises high purity and precise stereochemistry, as impurities can affect both efficacy and safety.
Impact on climate of production and use
Published GHG data is not available and estimating the emissions from pharmaceutical production is challenging. However, according to industry averages, the carbon footprint of producing 1 kg of a typical active pharmaceutical ingredient can range from 50 to 500 kg CO₂e, depending on the complexity of synthesis, solvent recovery, and energy sources used.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C at pH 7 (mg l⁻¹)
8.03
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
 Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
500000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Hexane		 -
500000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol		 -
500000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Xylene		 -
Melting point (°C)
-25
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 -
Boiling point (°C)
313.5
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 -
Degradation point (°C)
- - -
Flashpoint (°C)
139
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
(Pensky-Martens closed test)		 -
Octanol-water partition coefficient at pH 7, 20 °C
P
3.09 X 1004 Calculated -
Log P
4.49
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.03
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 -
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.64
R4 R = Peer reviewed scientific publications
4 = Verified data
25°C		 Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
0.010
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 Non-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
- - -
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)
- - -
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
Kd (mL g⁻¹)
- - -
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (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
- - -
Bio-concentration factor
BCF (l kg⁻¹)
- - -
CT₅₀ (days)
- -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
460
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Rat		 Moderate
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 2000
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Anas platyrhynchos		 Low
Birds - Short term dietary LC₅₀ (mg kg⁻¹ bw d⁻¹)
- - -
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)
0.026
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Apis mellifera		 High
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
- - -
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)
- - -
Beneficial insects (Butterflies)
Contact
- - -
Notes
-
Oral
- - -
Notes
-
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.012
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Oncorhynchus mykiss		 High
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
> 0.003
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Oncorhynchus mykiss 61 day		 High
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.0062
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Daphnia magna		 High
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
> 0.00065
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Daphnia magna		 High
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (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 (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
- - -
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)
Intermediate (class II) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
460
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Rat		 Moderate
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
> 5000
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Rat		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.29
B4 B = UK CRD and ACP Evaluation Documents / and other DEFRA (UK) documents; Also Chemicals Regulation Division, Health and Safety Executive (HSE), UK (click here )
4 = Verified data
Rat 4 hr		 -
Other Mammal toxicity endpoints
- - -
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
Rapidly metabolised, followed by renal excretion
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
Health issues
Specific human health issues (hazard-based)
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
XNo, known not to cause a problem
XNo, known not to cause a problem
 No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
XNo, known not to cause a problem
 No data found
Eye irritant Phototoxicant  
XNo, known not to cause a problem
 No data found  
General human health issues
Toxic if ingested or inhaled
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 6.1
CLP classification 2013
Health: H302, H331
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
UN2811
Waste disposal & packaging
Packaging Group I (great danger)
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
prallethrin
French
-
German
-
Danish
-
Italian
-
Spanish
praletrin
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
Record last updated: 22/10/2025
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

© Copyright University of Hertfordshire, 2006-2026. All Rights Reserved

Your use of this website and its various databases is subject to the terms detailed in the University of Hertfordshire’s copyright and IPR statement that can be found at https://www.herts.ac.uk/about-us/legal. In addition, your use of this website and its various databases is subject to the terms of this additional Copyright Statement and the database Conditions of use document. Unless explicitly stated otherwise, the content of this website and databases are owned and controlled by the University of Hertfordshire. Site content, including its selection and arrangement, is owned by the University of Hertfordshire and is protected by copyright and other laws. Except as otherwise expressly permitted under copyright law or within the database Conditions of Use document, the content of this site may not be copied, reproduced, republished, downloaded, posted, broadcast or transmitted in any way without first obtaining the University of Hertfordshire’s written permission. By using our databases the user is deemed to have agreed to comply with all of the terms and conditions as described above and within all relevant documentation.