Cyromazine (Ref: OMS 2014)

Cyromazine (Ref: OMS 2014)	Last updated: 15/03/2024
(Also known as: CGA 72662; cyclopropylmelamine ; cyromazinum; AI3-52713)

SUMMARY

Cyromazine is a contact insecticide and insect growth regulator. It is highly soluble in water and considered relatively volatile. Its persistence in soil and water systems is highly dependent on local conditions. Cyromazine has a low mammalian toxicity but may cause adverse effects on reproduction and development if ingested and is also a skin irritant. It is moderately toxic to birds, fish, aquatic invertebrates and earthworms but less so to honeybees.

GENERAL INFORMATION

Description

A triazine insect growth regulator with veterinary applications

Availability status

Current

Introduction & key dates

1980, first reported

Examples of veterinary uses

Used for the control of flies - particularly to reduce the incidence of blowfly strike on sheep

Examples of species treated

Rabbits; Sheep

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved

EU Regulatory approval status

Approved

Chemical structure

Isomerism

None

Chemical formula

C₆H₁₀N₆

Canonical SMILES

C1CC1NC2=NC(=NC(=N2)N)N

Isomeric SMILES

International Chemical Identifier key (InChIKey)

LVQDKIWDGQRHTE-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C6H10N6/c7-4-10-5(8)12-6(11-4)9-3-1-2-3/h3H,1-2H2,(H5,7,8,9,10,11,12)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
cyromazine	-

General status

Veterinary substance type

Insecticide, Antiparasitic, Ectoparasiticide

Substance groups

Triazine insecticide; Triazine acaricide

Minimum active substance purity

950 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Contact action, interfering with moulting and pupation.

Molecular targets

CAS RN

66215-27-8

EC number

266-257-8

CIPAC number

420

US EPA chemical code

121301

PubChem CID

47866

CLP index number

No data found

Therapeutic Class

Antiparasitic products, insecticides & repellents: Ecoparasiticides, insecticides & repellents

ATCvet Code

QP53AX

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Ovine)

Molecular mass

166.18

PIN (Preferred Identification Name)

N1-cyclopropyl-1,3,5-triazine-2,4,6-triamine

IUPAC name

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

CAS name

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Other status information

Relevant Environmental Water Quality Standards

Physical state

White powder

Formulations

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Example products (past and present) using this active

Rearguard 6% Cutaneous Solution

Elanco Europe Ltd

UK National authorisation

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

Vetrazin 6% Pour-on Solution

Novartis Animal Health UK Ltd

Not licensed

Banish liquid

Norbrook Labs, New Zealand

Not licensed

Formulation and application details

Often supplied as a cutaneous spray or pour-on formulation

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

13000

High

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

1400

Acetone

210

Dichloromethane

100

Hexane

17000

Methanol

Melting point (°C)

223.2

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

223.2

Flashpoint (°C)

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

1.17 X 10⁰⁰

Calculated

Log P

0.069

Low

Fat solubility of residues

Solubility

Not relevant

Data type

Regulatory studies - negligible residues seen in animal studies

Density (g ml⁻¹)

1.35

Dissociation constant pKa) at 25 °C

5.22

Weak base

Vapour pressure at 20 °C (mPa)

4.48 X 10^-04

Low volatility

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

5.80 X 10^-09

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

Negligible

From soil surface

Negligible

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

Neutral solution: 208nm = 39070
Acidic solution: 215.5nm = 29540, 241.3nm = 17340
Basic solution: 230nm = 11540

Surface tension (mN m⁻¹)

59.0

at 20°C

Refractive Index

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)

31.8

Moderately persistent

DT₅₀ (field)

9.7

Non-persistent

DT₉₀ (lab at 20 °C)

101

Persistent

DT₉₀ (field)

Note

EU dossier lab studies DT₅₀ range: 1.8-56 days, DT₉₀ range 9.6-186 days, field studies DT₅₀ range 2.3 (Switzerland) - 17 (France) days; Other sources: 150 days (DW4)

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

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

Value

Stable

Note

Stable pH 5 to pH 9 at temperatures between 30 and 70 °C

Water-sediment DT₅₀ (days)

228

Slow

Water phase only DT₅₀ (days)

Slow

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

7.62

Moderately mobile

K_foc (mL g⁻¹)

409

¹/_n

0.81

Notes and range

EU dossier K_f range 0.52-50.38 mL g⁻¹, K_foc range 40.2-1784 mL g⁻¹, ¹/_n range 0.714-0.92, Soils=11

pH sensitivity

Yes

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.37

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

melamine (Ref: CGA 235129)

Major fraction

0.745

carboxylic acid of cyromazine (Ref: NOA 435343)

Major fraction

0.107

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

1-methyl-cyromazine

Rat; Plant

hydroxy-cyromazine

Animal

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

3387

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

High

(ppm diet)

300

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 1785

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1370 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

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

> 1000

Eisenia foetida

Low

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

333

Eisenia foetida 56 day

Low

Soil micro-organisms

[Microbial soil respiration and nitrification: NOEC=100 mg kg⁻¹]

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)

> 200

Apis mellifera

Low

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

186

Apis mellifera

Low

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

Chronic

Notes

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)

> 1.3

Bombus terrestris 77 day LC₅₀

Moderate

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) as Mortality LR₅₀ g ha⁻¹

> 900

Coccinella septempunctata

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps) as Reproduction EC₅₀ g ha⁻¹

> 891

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

Typhlodromus pyri

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

> 900

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

> 100

Oncorhynchus mykiss

Low

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

> 1

Oncorhynchus mykiss

Moderate

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

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

> 100

Daphnia magna

Low

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

4.6

Daphnia magna

Moderate

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)

> 120

Chironomus riparius

Low

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

0.025

Chironomus riparius whole system

Moderate

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)

124

Scenedesmus subspicatus

Low

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

> 100

Unknown species

Low

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)

3387

Rat

Low

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

3100

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 3.6

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.06

Dog SF=100

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

0.1

Rabbit SF=100

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

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

0.06

Dog SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Negligible risk to bystanders

Occupational

No unacceptable risks to operators or other workers identified

Mammalian dose elimination route and rate

In rats circa 10-15% absorbed 10hrs after application, urinary and faecal excretion

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Hgh dose can cause nausea, vomiting, abdominal distress and diarrhoea

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H315, H319, H373, H335
Environment: H411

WHO Classification

III (Slightly hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cyromazine

French

cyromazine

German

Cyromazin

Danish

cyromazin

Italian

ciromazina

Spanish

ciromazina

Greek

Polish

cyromazyna

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	15/03/2024
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