Oxytocin

Oxytocin	Last updated: 15/09/2025
(Also known as: endopituitrina; pitocin)

GENERAL INFORMATION

Description

A naturally occurring hormone used to manages key aspects of the reproductive system

Examples of veterinary uses

Obstetric

Examples of species treated

Horses, Cattle, Pigs, Sheep, Goats, Dogs, Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved - usually supplied as a prescription only medicine to be authorised by a veterinarian (POM-V)

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Oxytocin exhibits optical isomerism due to the presence of multiple chiral centres in its peptide structure. As a cyclic nonapeptide (nine amino acids), oxytocin contains several L-amino acids, each with a chiral alpha-carbon, contributing to its overall three-dimensional conformation. Studies have shown that oxytocin and its analogs can exhibit cis–trans isomerism around the Cys–Pro peptide bond, which influences the molecule’s folding and receptor affinity.

Chemical formula

C₄₃H₆₆N₁₂O₁₂S₂

Canonical SMILES

CCC(C)C1C(=O)NC(C(=O)NC(C(=O)NC(CSSCC(C(=O)NC(C(=O)N1)CC2=CC=C(C=C2)O)N)C(=O)N3CCCC3C(=O)NC(CC(C)C)C(=O)NCC(=O)N)CC(=O)N)CCC(=O)N

Isomeric SMILES

CC[C@H](C)[C@H]1C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@@H](CSSC[C@@H](C(=O)N[C@H](C(=O)N1)CC2=CC=C(C=C2)O)N)C(=O)N3CCC[C@H]3C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N)CC(=O)N)CCC(=O)N

International Chemical Identifier key (InChIKey)

XNOPRXBHLZRZKH-DSZYJQQASA-N

International Chemical Identifier (InChI)

InChI=1S/C43H66N12O12S2/c1-5-22(4)35-42(66)49-26(12-13-32(45)57)38(62)51-29(17-33(46)58)39(63)53-30(20-69-68-19-25(44)36(60)50-28(40(64)54-35)16-23-8-10-24(56)11-9-23)43(67)55-14-6-7-31(55)41(65)52-27(15-21(2)3)37(61)48-18-34(47)59/h8-11,21-22,25-31,35,56H,5-7,12-20,44H2,1-4H3,(H2,45,57)(H2,46,58)(H2,47,59)(H,48,61)(H,49,66)(H,50,60)(H,51,62)(H,52,65)(H,53,63)(H,54,64)/t22-,25-,26-,27-,28-,29-,30-,31-,35-/m0/s1

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Vasodilator agent

Substance groups

Cyclic nonapeptide hormone

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Substance has a central role in the regulation of parturition and lactation

Molecular targets

[Oxytoxin, Agonist], [Vasopressin receptor, Agonist]

CAS RN

50-56-6

EC number

200-048-4

CIPAC number

US EPA chemical code

PubChem CID

439302

Therapeutic Class

Systemic hormonal preparations; Posterior pituitary lobe hormones

ATCvet Code

QH01BB02

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

1007.2

PIN (Preferred Identification Name)

IUPAC name

(2S)-1-[(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-[(4-hydroxyphenyl)methyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl]-N-[(2S)-1-[(2-amino-2-oxoethyl)amino]-4-methyl-1-oxopentan-2-yl]pyrrolidine-2-carboxamide

CAS name

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

Current

Physical state

Commercial

Property

Value

Availability status

Not applicable

Introduction & key dates

1906, first identified

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

Bela-Pharm GmbH & Co KG
Agilis International Ltd, Australia
MSD Animal health UK Ltd

Example products using this active

Oxytobel Solution for Injection

Formulation and application details

Usually formulated as a solution for injection

Commercial production

The commercial production of oxytocin involves a tightly controlled solid-phase peptide synthesis process that begins by sequentially assembling the nine amino acid sequence of oxytocin using protected L-amino acids anchored to a resin. After chain elongation, a disulfide bridge is formed between two cysteine residues to create the hormone’s characteristic cyclic structure. The crude peptide is then cleaved from the resin and purified using reverse-phase high-performance liquid chromatography to remove impurities and ensure correct folding. To enhance stability and solubility, the final product is often formulated as an acetate salt.

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)

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

Melting point (°C)

192

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

93.3

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

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)

> 10000

Rat

Low

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)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 10000

Rat

Low

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

Rapidly eliminated through enzymatic degradation and renal excretion

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

No data found

General human health issues

No further information

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Not regulated

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

Shelf-life of the veterinary medicinal product as packaged for sale is approximately18 months, when stored 2-8 DegC. Stable at normal temperatures and pressures.

TRANSLATIONS

Language

Name

English

oxytocin

French

German

Danish

Italian

Spanish

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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