Sulphadoxine

Sulphadoxine	Last updated: 06/09/2025
(Also known as: sulfadoxine; sulphormethoxine; sulforthomidine)

GENERAL INFORMATION

Description

A sulfonamide antibacterial drug to treat or prevent various infections in livestock

Examples of veterinary uses

Used to treat respiratory tract infections such as bovine pneumonia pasteurellosis

Examples of species treated

Cattle; Horses; Pigs; 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

Sulphadoxine does not exhibit classical isomerism such as enantiomerism or geometric isomerism. Its molecular structure lacks chiral centres. However, it can exist in different tautomeric forms, particularly involving the amino and sulfonamide groups, which may shift hydrogen atoms within the molecule under certain conditions. Despite this, sulphadoxine is typically used and studied as a single, well-defined compound without significant isomeric variation in clinical practice.

Chemical formula

C₁₂H₁₄N₄O₄S

Canonical SMILES

COC1=C(N=CN=C1OC)NS(=O)(=O)C2=CC=C(C=C2)N

Isomeric SMILES

International Chemical Identifier key (InChIKey)

PJSFRIWCGOHTNF-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C12H14N4O4S/c1-19-10-11(14-7-15-12(10)20-2)16-21(17,18)9-5-3-8(13)4-6-9/h3-7H,13H2,1-2H3,(H,14,15,16)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
sulphadoxine	-

General status

Veterinary substance type

Medicinal drug, Antibacterial, Antiparasitic

Substance groups

Sulfonamide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Helps inhibit the enzyme dihydropteroate synthetase which restricts folic acid production

Molecular targets

[Dihydropteroate synthetase], [Bifunctional dihydrofolate reductase-thymidylate synthase, Inhibitor]

CAS RN

2447-57-6

EC number

219-504-9

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Antiinfectants for systemic use: Antibacterials for systemic use

ATCvet Code

QJ01EQ13

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: All food producing species)

Molecular mass

310.33

PIN (Preferred Identification Name)

IUPAC name

4-amino-N-(5,6-dimethoxy-4-pyrimidinyl)benzenesulfonamide

CAS name

4-sulfanilamido-5,6-dimethoxypyrimidine

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

White or off-white crystalline powder

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1981, first approved for medical use USA

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

Bimeda Animal Health Ltd

Example products using this active

Bimotrim Co Injection Solution for Injection

Formulation and application details

Usually supplied as solution for injection

Commercial production

The production of sulphadoxine involves a multi-step synthetic process that begins with the preparation of 4-amino-5,6-dimethoxypyrimidine, a key heterocyclic intermediate. This compound is synthesised through a series of reactions starting from methoxyacetic acid, which undergoes condensation, heterocyclisation, and chlorination to yield the desired pyrimidine derivative. In the final step, this intermediate is reacted with 4-acetylaminobenzenesulfonyl chloride in the presence of a base such as sodium carbonate and a solvent like dimethylformamide at elevated temperatures. After the condensation reaction, the acetyl group is hydrolysed to produce the active sulfonamide moiety.

Impact on climate of production and use

Sulphadoxine’s synthesis involves chlorination, condensation, and hydrolysis steps, which likely place it in the mid-to-high range of emissions for pharmaceuticals. Assuming a moderate estimate of 250 kg CO₂e per kg of sulphadoxine, this would account for raw material extraction, reaction energy, solvent use, and waste treatment.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

2700

High

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

Melting point (°C)

192

Boiling point (°C)

523

Degradation point (°C)

Flashpoint (°C)

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

5.01 X 10⁰⁰

Calculated

Log P

0.7

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

6.16

Vapour pressure at 20 °C (mPa)

2.11 X 10^-04

Low volatility

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)

> 5200

Mouse

Low

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)

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)

> 5200

Mouse

Low

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Subcutaneous LD₅₀ = 2900 mg kg⁻¹

Mouse

Intraperitoneal LD₅₀ = 2900 mg kg⁻¹

Mouse

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

Eliminated partly by metabolism and partly by excretion of the unchanged compounds in urine or 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 contribute towards hepatitis &/or pneumonitis
Side effects may include nausea, vomiting, convulsions, excitation & anorexia

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

sulphadoxine

French

German

Danish

Italian

Spanish

sulfadoxina

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	06/09/2025
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