Sulphadimidine

Sulphadimidine	Last updated: 06/09/2025
(Also known as: sulfadimidine; sulfamethazine)

GENERAL INFORMATION

Description

A Ssulfonamide drug used in veterinary medicine often in combination with chlortetracycline and penicillin

Examples of veterinary uses

Multiple uses including for the treatment of bovine respiratory disease, calf diphtheria, bacterial pneumonia and procine colibacillosis as wel as coccidiosis, fowl cholera and pullorum disease.

Examples of species treated

Pigs; Fowl; Cattle; Sheep

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Sulphadimidine exhibits tautomeric isomerism, a form of structural isomerism where the molecule can exist in equilibrium between two or more isomeric forms due to the migration of a proton and a shift in bonding. Specifically, the sulfonamide group (-SO₂NH-) and the pyrimidine ring allow for tautomeric shifts between amino and imino forms, particularly under varying pH conditions.

Chemical formula

C₁₂H₁₄N₄O₂S

Canonical SMILES

CC1=CC(=NC(=N1)NS(=O)(=O)C2=CC=C(C=C2)N)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

ASWVTGNCAZCNNR-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C12H14N4O2S/c1-8-7-9(2)15-12(14-8)16-19(17,18)11-5-3-10(13)4-6-11/h3-7H,13H2,1-2H3,(H,14,15,16)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
sulphadimidine	-

General status

Veterinary substance type

Antibacterial, Anti-infective, Antibiotic, Antimicrobial, Medicinal drug

Substance groups

Sulfonamide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

A competitive inhibitor of dihydropteroate synthase

Molecular targets

[Dihydropteroate synthetase, Antagonist]

CAS RN

57-68-1

EC number

200-346-4

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Antiparasitic products, insecticides & repellents: Antiprotozoals; Antiinfectants for systemic use: Antibacterials for systemic use

ATCvet Code

QP51AG01; QJ01EQ

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: All food producing species)

Molecular mass

278.33

PIN (Preferred Identification Name)

IUPAC name

4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide

CAS name

4,6-dimethyl-2-sulfanilamidopyrimidine

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Possible groundwater contaminant

Physical state

White crystalline powder

Commercial

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Availability status

Current

Introduction & key dates

1941, first reported

Example products (past and present) using this active

Intradine 30.89% w/v Solution for Injection

Norbrook Laboratories Ltd

Not licensed

Formulation and application details

Often supplied as a solution for injection or a solution for oral administration

Commercial production

The synthesis of sulphadimidine typically begins with the formation of the p-aminobenzenesulfonamide core, which is then coupled with a 2-amino-4,6-dimethylpyrimidine derivative. The process involves a nucleophilic substitution reaction, where the sulfonamide nitrogen attacks the electrophilic carbon on the pyrimidine ring, forming the key N–C bond that links the two moieties. This reaction is usually carried out under controlled temperature and pH conditions to ensure selectivity and yield. The crude product is then purified through recrystallisation or chromatographic techniques.

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)

1500

at 29 °C

High

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

Melting point (°C)

198.5

Boiling point (°C)

452

Degradation point (°C)

Flashpoint (°C)

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

1.55 X 10⁰⁰

Calculated

Log P

0.19

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

7.59

Vapour pressure at 20 °C (mPa)

9.09 X 10^-04

Low volatility

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

3.09 X 10^-11

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Acidic: max at 241nm and 297nm
Neutral: max at 241nm
Basic: max at 243nm and 257nm

Surface tension (mN m⁻¹)

Refractive Index

15044

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

18.6

Non-persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

General literature suggests biodegradation may be slow in some soils.

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Note

Hydolysis not expected

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)

Moderately mobile

K_oc (mL g⁻¹)

115.3

Notes and range

General literature K_d range 0.9-3.5 mL g⁻¹, K_oc values range 61-170 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

2.46

Calculated

Transition state

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

N4-acetylated sulfonamide

Human (Liver)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

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)

> 100

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)

31.4

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) (IC50)

8.7

Raphidocelis subcapitata

Moderate

Algae - Chronic (growth rate, fresh; mg l⁻¹) (72 hr ErC10)

1.0

Raphidocelis subcapitata

Moderate

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)

> 2000

Mouse

Low

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Subcutaneous LD₅₀ > 2000 mg kg⁻¹

Rat

Intravenous LD₅₀ = 2450 mg kg⁻¹

Rabbit

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

Partly metabolibised and eliminated predominately in urine with lesser amounts in faeces, bile and milk.

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

Eye irritant

Phototoxicant

No data found

General human health issues

Harmful if inhaled
may cause gastric irritation and vomiting
Possible liver and kidney toxicant
Some published studies suggest substance is carcinogenic

Handling issues

Property

Value and interpretation

General

Light sensitive
Not explosive or oxidising

CLP classification 2013

Health: H315, H319

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

sulphadimidine

French

German

Danish

Italian

sulfametazina

Spanish

sulfadimidina

Greek

Polish

sulfametazina

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