Carbadox

Carbadox	Last updated: 10/10/2025
(Not known by any other names)

GENERAL INFORMATION

Description

A drug used to treat gram-negative bacterial infections

Examples of veterinary uses

Used for improved productivity - increased rate of weight gain and improved feed efficiency. Also has therapeutic applications, for example, to control swine dysentery and bacterial swine enteritis.

Examples of species treated

Pigs; Cattle

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Carbadox exhibits tautomeric isomerism, a form of isomerism where the molecule can exist in multiple structural forms due to the migration of a proton and a shift in bonding electrons. Specifically, the molecule contains functional groups, such as hydrazone and quinoxaline 1,4-dioxide, that allow for tautomeric shifts, potentially resulting in more than one tautomer coexisting within its crystalline structure. Recent crystallographic studies have revealed that carbadox can adopt two distinct molecular configurations in the solid state: five molecules in a lower-energy configuration and three in a slightly higher-energy (~10%) form.

Chemical formula

C₁₁H₁₀N₄O₄

Canonical SMILES

COC(=O)NN=CC1=[N+](C2=CC=CC=C2[N+](=C1)[O-])[O-]

Isomeric SMILES

COC(=O)N/N=C/C1=[N+](C2=CC=CC=C2[N+](=C1)[O-])[O-]

International Chemical Identifier key (InChIKey)

OVGGLBAWFMIPPY-WUXMJOGZSA-N

International Chemical Identifier (InChI)

InChI=1S/C11H10N4O4/c1-19-11(16)13-12-6-8-7-14(17)9-4-2-3-5-10(9)15(8)18/h2-7H,1H3,(H,13,16)/b12-6+

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Antibacterial, Antimicrobial, Medicinal drug, Growth promotor, Feed additive

Substance groups

Quinoxaline

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

It is believed to act as a bacterial DNA-damaging agent, likely through the generation of reactive intermediates that interact with nucleic acids.

Molecular targets

[Unclear but interferes with DNA replication and transcription]

CAS RN

6804-07-5

EC number

229-879-0

CIPAC number

US EPA chemical code

PubChem CID

135511839

CLP index number

613-050-00-9

Therapeutic Class

Antiinfectants for systemic use: Antibacterials for system use

ATCvet Code

QJ01MQ

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

262.22

PIN (Preferred Identification Name)

IUPAC name

methyl N-[(E)-(1,4-dioxidoquinoxaline-1,4-diium-2-yl)methylideneamino]carbamate

CAS name

2-(methoxycarbonylhydrazonomethyl)quinoxaline 1,4-dioxide

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

Banned in many countries as a growth promotor; Not approved as feed additive in EU; Evidence of use in third world countries;

Physical state

Yellow crystalline solid

Commercial

Property

Value

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

1970s, introduced

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

Pfizer Animal Health.
Zoetis UK Ltd

Example products using this active

Mecadox
Fortigro
Nutriton
Getroxel

Formulation and application details

As a growth promotor it was formulated as a premix or feed additive

Commercial production

The production of carbadox involves a multi-step chemical synthesis based around the construction of its quinoxaline 1,4-dioxide core, a structure known for its antimicrobial properties. The process typically begins with the condensation of o-phenylenediamine with a suitable dicarbonyl compound to form the quinoxaline ring. This intermediate is then subjected to oxidation, often using hydrogen peroxide or peracids, to introduce the 1,4-dioxide functionality. Additional steps include the attachment of side chains, such as the methylcarbamoyl and hydrazone groups, which are critical for its biological activity.

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)

15000

High

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

Melting point (°C)

239

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

4.27 X 10^-02

Calculated

Log P

-1.37

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.44

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

8.6 X 10^-05

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

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)

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)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

carbadoxaldehyde

Swine (plasma)

0.130

quinoxaline-2-carboxylic acid

Swine (plasma)

0.190

hydrazine

Swine (plasma, urine)

desoxycarbadox

Swine (plasma)

0.190

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 50

Rat

High

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)

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)

> 50

Rat

High

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

Rapidly absorbed through the skin

Mammalian dose elimination route and rate

Metabolises and then eliminated in the urine

Health issues

Specific human health issues (hazard-based)

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

General human health issues

Possile adrenal & liver toxicant
May cause photosensitisation
Publish studies suggest substance is carcinogenic; CLP data - known carcinogen

Handling issues

Property

Value and interpretation

General

Flammable

CLP classification 2013

Handling: H228
Health: H392, H350

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

carbadox

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	10/10/2025
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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