Sarolaner

Sarolaner	Last updated: 12/09/2025
(Not known by any other names)

GENERAL INFORMATION

Description

An orally administered isoxazoline systemic insecticide and acacide

Examples of veterinary uses

Used for the treatment of fleas, ticks and other parasites. It is also used as part of a treatment strategy for the control of Flea Allergy Dermatitis

Examples of species treated

Dogs; Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved - usually available as a prescription only medicine to be authorised by a veterinarian (POM-V)

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Sarolaner exhibits stereoisomerism, specifically enantiomerism, due to the presence of a chiral centre in its isoxazoline ring system. Two forms exist: the R-enantiomer and the S-enantiomer. Commercial sarolaner is formulated as the pure S-enantiomer, which has been shown to possess greater binding affinity and functional potency against insect pests.

Chemical formula

C₂₃H₁₈Cl₂F₄N₂O₅S

Canonical SMILES

CS(=O)(=O)CC(=O)N1CC2(C1)C3=C(CO2)C=C(C=C3)C4=NOC(C4)(C5=CC(=C(C(=C5)Cl)F)Cl)C(F)(F)F

Isomeric SMILES

CS(=O)(=O)CC(=O)N1CC2(C1)C3=C(CO2)C=C(C=C3)C4=NO[C@@](C4)(C5=CC(=C(C(=C5)Cl)F)Cl)C(F)(F)F

International Chemical Identifier key (InChIKey)

FLEFKKUZMDEUIP-QFIPXVFZSA-N

International Chemical Identifier (InChI)

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Insecticide, Acaracide

Substance groups

Isoxazoline

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Inhibitor of GABA-elicited currents at both susceptible (CfRDL-A285) and resistant (CfRDL-S285) flea GABACls with similar potency

Molecular targets

[GABA-gated chloride, Blocker], [Glutamate-gated chloride, blocker]

CAS RN

1398609-39-6

EC number

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Ectoparasiticide for systemic use

ATCvet Code

QP53BE03

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

581.36

PIN (Preferred Identification Name)

1-(6-((5S)-5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl)spiro(1H-2-benzofuran-3,3'-azetidine)-1'-yl)-2-methylsulfonylethanone

IUPAC name

1-(6-((5S)-5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl)spiro(1H-2-benzofuran-3,3'-azetidine)-1'-yl)-2-methylsulfonylethanone

CAS name

Forever chemical

Other status information

Potential marine pollutant

Relevant Environmental Water Quality Standards

Physical state

White to off-white crystals or powder

Commercial

Property

Value

Availability status

Current

Introduction & key dates

Circa 2014, introduced

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

Zoetis UK Ltd

Example products using this active

Simparica
Felisecto Spot-on Solution
Mipet Chewable Tablets

Formulation and application details

Formulated in a variety of ways including spot-on treatments and chewable tablets

Commercial production

Sarolaner is synthesised through a multi-step organic process that constructs its complex isoxazoline-based structure and ensures high enantiomeric purity. The synthesis begins with key intermediates such as methanesulfonylacetic acid and a fluorinated aromatic precursor, which undergo condensation and cyclisation reactions in solvents like ethyl acetate, often in the presence of triethylamine as a base. The formation of the isoxazoline ring is a critical step, followed by spirocyclization to build the unique azetidine-isobenzofuran framework. After the reaction, the mixture is cooled, filtered and purified to isolates the pharmacologically active S-enantiomer

Impact on climate of production and use

Published GHG data is not available for most pharmaceuticals. However, according to industry, global averages suggest producing 1 kg of a typical active pharmaceutical ingredient can range from 10 to 100 kg CO₂e for small molecule drugs and potentially up to 1000 kg CO₂e for complex biologicals such as vaccines, depending on the drug type, its formulation, 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 (mg l⁻¹)

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

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

1.78 X 10⁰³

Calculated

Log P

3.25

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

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

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

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)

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 550

Rat

Moderate

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)

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

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)

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)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

> 0.54

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)

> 0.27

Daphnis magna

Moderate

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) (EC₅₀)

0.27

Raphidocelis subcapitata

Moderate

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)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 550

Rat

Moderate

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

2000

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

Pattern of use is unlikely to result in toxicological relevant exposure

Occupational

Pattern of use is unlikely to result in toxicological relevant exposure

Mammalian dose elimination route and rate

Biliary excretion with elimination via 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

May induce a mild neurotoxic effect

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 9

CLP classification 2013

Health: H302
Environment: H400, H410

WHO Classification

Not listed (Not listed)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

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English

sarolaner

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Record last updated:	12/09/2025
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