Sulphachlorpyridazine

Sulphachlorpyridazine	Last updated: 15/09/2025
(Also known as: sulfachlorpyridazine; BA-10370)

GENERAL INFORMATION

Description

An antibacterial / antibiotic veterinary medicine used to control a range of infections

Examples of veterinary uses

Used to treat urinary tract and other bacterial infections

Examples of species treated

Pigs; Poultry; Calves

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₁₀H₉ClN₄O₂S

Canonical SMILES

C1=CC(=CC=C1N)S(=O)(=O)NC2=NN=C(C=C2)Cl

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

XOXHILFPRYWFOD-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H9ClN4O2S/c11-9-5-6-10(14-13-9)15-18(16,17)8-3-1-7(12)2-4-8/h1-6H,12H2,(H,14,15)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
sulphachlorpyridazine	-

General status

Veterinary substance type

Antibiotic, Microbiocide, Antimicrobial, Antibacterial

Substance groups

Sulfonamide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Inhibits folic acid synthesis in prokaryotes

Molecular targets

[Dihydropteroate synthase, Inhibitor]

CAS RN

80-32-0

EC number

201-269-9

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Antiinfectants for systemic use: Antibacterials for systemic use

ATCvet Code

QJ01EW12

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: All food producing species)

Molecular mass

284.72

PIN (Preferred Identification Name)

IUPAC name

4-amino-N-(6-chloropyridazin-3-yl)benzenesulfonamide

CAS name

4-amino-N-(6-chloro-3-pyridazinyl)benzenesulfonamide

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

Related substances & organisms

trimethoprim

Commercial

Property

Value

Availability status

Current

Introduction & key dates

Mid 20th century, first approvals; Early 2000s, most EU approvals revoked

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

Novartis Animal Health

Example products using this active

Cosumix Plus 750
Nefrosul
Cluricol
Durasulf
Vetisulid

Formulation and application details

Commonly formulated as a soluble powder for mixing into drinking water or feed.

Commercial production

The production of sulphachlorpyridazine involves a multi-step chemical synthesis starting with sulfanilamide, which serves as the sulfonamide backbone. This compound undergoes a nucleophilic substitution reaction with 6-chloro-3-pyridazine sulfonyl chloride, forming the key bond between the sulfanilamide and the pyridazine ring. The reaction typically takes place in an organic solvent under controlled temperature and pH conditions to ensure high yield and purity. After the coupling step, the crude product is subjected to filtration, washing, and recrystallisation to remove impurities and isolate the active pharmaceutical ingredient.

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 at pH 7 (mg l⁻¹)

7000

High

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

Melting point (°C)

187

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

2.04 X 10⁰⁰

Calculated

Log P

0.31

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

1.40

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

Substance may enter the environment via the faeces of treated animals or by leaching from spilt medicated feed.

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

General literature states DT₅₀ range 3.5-21 days

Manure DT₅₀ (days)

<8.0

Slightly persistent; Other data 127 days for slurry

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)

Mobile

K_oc (mL g⁻¹)

Notes and range

General literature states K_oc range 3.3-82 mL g⁻¹

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

2.91

Calculated

High leachability

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)

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)

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)

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)

535.7

Oryzias latipes

Low

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)

0.375

Daphnia 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)

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)

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)

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

Elimination may occur in the urine, bile, feces, sweat, tears, or milk

Health issues

Specific human health issues (hazard-based)

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

Ingestion of sulfonamide can cause nausea, vomiting & diarrhoea
Possible kidney, gastrointestinal & liver toxicant

Handling issues

Property

Value and interpretation

General

Light sensitive

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

sulphachlorpyridazine

French

sulfachlorpyridazine

German

Sulfachlorpyridazine

Danish

Italian

Spanish

sulfacloropiridazina

Greek

Polish

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

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