Oxytetracycline

Oxytetracycline	Last updated: 26/08/2025
(Also known as: terramycin; oxytracyl; oxytetrin; terramitsin; oxitetracycline; crop antibiotic; liquamycin)

GENERAL INFORMATION

Description

A highly active broad spectrum antibiotic used to control infection animals diseses and bacterial pathogens. Usually used as the hydrochloride salt.

Examples of veterinary uses

Used to control gastrointestinal and respiratory diseases as well as some skin conditions including Rickettsial infections, Lupus

Examples of species treated

Calves; Non-lactating dairy cattle; Beef; Pigs; Fish; Poultry; Cats; Dogs

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Oxytetracycline exhibits complex stereoisomerism, with six chiral centres in its molecular structure, allowing for multiple stereoisomers. These chiral centres are located at carbon atoms 4, 4a, 5, 5a, 6, and 12a, and their configuration significantly influences the compound’s biological activity and chemical behaviour. Additionally, oxytetracycline can undergo tautomerization and epimerization, especially under varying pH conditions, leading to the formation of inactive derivatives such as anhydrotetracyclines and isotetracyclines. These transformations affect its stability and efficacy, making isomerism a critical factor in its environmental fate.

Chemical formula

C₂₂H₂₄N₂O₉

Canonical SMILES

CC1(C2C(C3C(C(=O)C(=C(C3(C(=O)C2=C(C4=C1C=CC=C4O)O)O)O)C(=O)N)N(C)C)O)O

Isomeric SMILES

C[C@@]1([C@H]2[C@@H]([C@H]3[C@@H](C(=O)C(=C([C@]3(C(=O)C2=C(C4=C1C=CC=C4O)O)O)O)C(=O)N)N(C)C)O)O

International Chemical Identifier key (InChIKey)

IWVCMVBTMGNXQD-PXOLEDIWSA-N

International Chemical Identifier (InChI)

InChI=1S/C22H24N2O9/c1-21(32)7-5-4-6-8(25)9(7)15(26)10-12(21)17(28)13-14(24(2)3)16(27)11(20(23)31)19(30)22(13,33)18(10)29/h4-6,12-14,17,25,27-29,32-33H,1-3H3,(H2,23,31)/t12-,13-,14+,17+,21-,22+/m1/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
oxytetracycline	-

General status

Veterinary substance type

Bactericide, Antimicrobial, Antiseptic, Medicated feed additive

Other bioactivity & uses

Antimicrobial

Substance groups

Micro-organism derived substance

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Broad-spectrum, protein synthesis inhibitor and binds to the 30S and 50S bacterial ribosomal subunits

Molecular targets

[30S ribosomal protein S9, Antagonist], [30S ribosomal protein S4, Antagonist], [16S rRNA, Antagonist]

CAS RN

79-57-2

Alternative/old CAS RN

2058-46-0; 6153-64-6 (dihydrate)

EC number

201-212-8

CIPAC number

316

US EPA chemical code

006308

PubChem CID

Therapeutic Class

Dermatologicals: Antibiotics and chemotherapeutics for dermatological use; Antiinfectants for systemic use: Antibacterials for systemic use

ATCvet Code

QD06AA03 for topical use; QJ01AA06 for systemic use; Others available

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: All food producing species)

Molecular mass

460.44

PIN (Preferred Identification Name)

IUPAC name

(4S,4aR,5S,5aR,6S,12aS)-4-dimethylamino-1,4,4a,5,5a,6,11,12a-octahydro-3,5,6,10,12,12a-hexahydroxy-6-methyl-1,11-dioxonaphthacene-2-carboxamide

CAS name

(4S,4aR,5S,5aR,6S,12aS)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,5,6,10,12,12a-hexahydroxy-6-methyl-1,11-dioxo-2-naphthacenecarboxamide

Forever chemical

Other status information

Possible groundwater contaminant

Relevant Environmental Water Quality Standards

Physical state

Pale yellow to tan coloured crystalline powder

Related substances & organisms

copper sulphate

Commercial

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Availability status

Current

Introduction & key dates

1974, first registered USA

Example products (past and present) using this active

Alamycin Solution for Injection

Norbrook Laboratories Ltd

UK National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Engemycin DD Solution for Injection

MSD Animal Health UK Ltd

UK National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Hypersol Powder for Drinking Water

Huvepharma SA

GB National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Cyclosol LA 200mg/ml Solution for Injection

Eurovet Animal Health B.V.

GB National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Formulation and application details

Currently available formulations include solutions for injection, cutaneous sprays, powders for adding to drinking water and medicated premix feeds

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

600

Moderate

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

Melting point (°C)

Decomposes on melting

Boiling point (°C)

Degradation point (°C)

179

Flashpoint (°C)

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

Log P

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

Substance may enter the environment via the faeces of treated animals or by leaching from spilt medicated feed. Monitoring studies have identified this substance in livestock manures.

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)

43.8

Aerobic sediment slurry; Other data DT₅₀ (1) 79 days slurry; (2) 12,0-15.4 day 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)

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)

0.6

Mollusca

Low potential

CT₅₀ (days)

Not available

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

7200

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)

> 5620

Anas platyrhynchos as HCl variant

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

1954

as HCl variant

Low

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)

100

as HCl variant

Moderate

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)

116

Oncorhynchus mykiss as HCl variant

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)

102

Daphnia magna as HCl variant

Low

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

46.2

Daphnia magna as HCl variant

Low

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)

0.372

Raphidocelis subcapitata as HCl variant

Moderate

Algae - Chronic (growth rate, fresh; mg l⁻¹) (NOEC)

0.183

Raphidocelis subcapitata as HCl variant

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)

7200

Mouse

Low

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

Systemically available oxytetracycline was primarily excreted in the urine and bile

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

May cause hypersensitivity reactions
May cause tooth discoloration

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H302, H312, H317, H332, H360d
Environment: H400, H410

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

oxytetracycline

French

oxytetracycline

German

Oxytetracyclin

Danish

oxytetracyclin

Italian

oxytetracicline

Spanish

oxitetraciclina

Greek

Polish

oksytetracyklina

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	26/08/2025
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