Cymiazol (Ref: CGA 50439)

Cymiazol (Ref: CGA 50439)	Last updated: 14/10/2025
(Also known as: cymiazole; cimiazol; xymiazole)

SUMMARY

Cymiazol is an acaricide. It is moderately soluble in water and volatile. It does not tend to be persistent in soil systems but may be in some water systems. It is not susceptible to hydrolysis. It is moderately toxic to mammals and may bioaccumulate. It is an eye and skin irritant. It shows a moderate level of toxicity to birds, fish and honeybees.

GENERAL INFORMATION

Description

A veterinary drug used as an ectoparasiticide

Examples of veterinary uses

Used for the control of mites and ticks especially those resistant to organochlorines, organophosphates and carbamates

Examples of species treated

Cattle; Sheep; Honeybees

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₁₂H₁₄N₂S

Canonical SMILES

CC1=CC(=C(C=C1)N=C2N(C=CS2)C)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

YUAUPYJCVKNAEC-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C12H14N2S/c1-9-4-5-11(10(2)8-9)13-12-14(3)6-7-15-12/h4-8H,1-3H3/b13-12-

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Acaricide, Ecoparasiticide

Substance groups

Benzenamine insecticide; Benzenamine acaricide; Amidine compound

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Contact action. Acts on nervous system. Octopamine receptor agonist.

Molecular targets

[Octopamine receptor, Agonist]

CAS RN

61676-87-7

EC number

262-890-9

CIPAC number

None allocated

US EPA chemical code

PubChem CID

43714

CLP index number

No data found

Therapeutic Class

Antiparasitic products, insecticides & repellents: Sulphur containing products

ATCvet Code

QP53AA02

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

218.3

PIN (Preferred Identification Name)

2,4-dimethyl-N-[(2E)-3-methyl-1,3-thiazol-2(3H)-ylidene]aniline

IUPAC name

2,4-dimethyl-N-(3-methyl-2(3H)-thiazolylidene)benzenamine

CAS name

N-(3-Methyl-3H-thiazol-2-ylidene)-2,5-xylidine

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

Liquid

Related substances & organisms

cymiazol hydrochloride

Commercial

Property

Value

Availability status

Introduction & key dates

Circa 1978, introduced

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

Novartis AG

Example products using this active

Ektoban
Tickotan

Formulation and application details

For Varroa mite control, it is supplied as granules, which are dissolved in water. The solution is applied either topically or orally, mixed into the winter feed of honeybee colonies. May also be available as wettable granules for other applications.

Commercial production

The production of cymiazol involves the synthesis of its core structure: an iminophenyl thiazolidine derivative. The process typically starts with the preparation of a 2,4-dimethylphenyl precursor, which is then reacted with a thiazole ring system through a condensation reaction to form the imine linkage. The final compound, N-(2,4-dimethylphenyl)-3-methyl-1,3-thiazol-2(3H)-imine, is purified and often converted into its hydrochloride salt to enhance solubility and stability for veterinary formulations.

Impact on climate of production and use

Data for the amount of life cycle GHGs produced by cymiazol are not available in the public domain. However, as a rough estimate, comparing with other similar speciality chemicals its GHG emissions are likely to be in the range of 5–20 kg CO₂e per kg of product.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C at pH 7 (mg l⁻¹)

150

Moderate

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

800000

Benzene

800000

Methanol

110000

Hexane

800000

Dichloromethane

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

3.98 X 10⁰⁰

Calculated

Log P

0.6

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

5.2

Weak acid

Vapour pressure at 20 °C (mPa)

2.4

Low volatility. If applied directly to plants or soil, drift is a concern & mitigation is advisable

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

3.49 X 10^-03

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)

Non-persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Data for aerobic soils

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Stable

Note

Not pH or temperature sensitive, stable to 70 °C

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)

K_oc (mL g⁻¹)

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

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

725

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)

> 1212

Coturnix japonica

Moderate

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)

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)

> 50

Moderate

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)

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)

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)

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)

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)

725

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)

> 3100

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

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

Cymiazol is primarily eliminated from the body through hepatic metabolism, followed by renal excretion

Health issues

Specific human health issues (hazard-based)

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

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

No information available

CLP classification 2013

Health: H302, H319

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cymiazol

French

German

Danish

Italian

Spanish

Greek

Polish

cymiazol

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	14/10/2025
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

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