Avoparcin

Avoparcin	Last updated: 15/09/2025
(Also known as: avotan; CL 81588 ; compound 254)

GENERAL INFORMATION

Description

A gram-positive glycopeptide antibiotic used in livestock feed for growth promotion

Examples of veterinary uses

Mainly used in livestock feed for growth promotion. Was also used as an aid in the prevention of necrotic enteritis in poultry

Examples of species treated

Pigs; Meat poultry, Cattle

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Avoparcin exhibits isomerism in the form of alpha- and beta-isomers, which differ in their chemical substituents and stereochemistry. Specifically, the alpha-avoparcin variant has a hydrogen atom at a key position, while beta-avoparcin features a chlorine atom in that same location. These structural differences arise from variations in the biosynthetic pathway of the glycopeptide antibiotic and influence the compound’s physicochemical properties and potentially its biological activity. Both isomers are typically present as a mixture in commercial formulations, and the compound is known for its complex stereochemistry, with multiple chiral centres contributing to its three-dimensional configuration.

Chemical formula

C₈₃H₉₂ClN₉O₃₁

Canonical SMILES

CC1C(C(CC(O1)OC2C(C(C(OC2OC3=C4C=C5C=C3OC6=C(C=C(C=C6)C(C7C(=O)NC(C8=CC(=CC(=C8C9=C(C=CC(=C9)C(C(=O)N7)NC(=O)C5NC(=O)C(NC(=O)C(C(C1=CC=C(O4)C=C1)O)NC(=O)C(C1=CC=C(C=C1)OC1C(C(C(C(O1)C)O)O)O)NC)C1=CC=C(C=C1)O)O)O)O)C(=O)O)OC1CC(C(C(O1)C)O)N)Cl)CO)O)O)N)O

Isomeric SMILES

C[C@H]1[C@@H]([C@@H](C[C@@H](O1)O[C@H]2[C@H]3C(=O)N[C@@H](C4=CC(=CC(=C4C5=C(C=CC(=C5)[C@H](C(=O)N3)NC(=O)[C@H]6C7=CC(=C(C(=C7)OC8=C(C=C2C=C8)Cl)O[C@H]9C([C@H]([C@@H]([C@H](O9)CO)O)O)O[C@H]1C[C@H]([C@H]([C@@H](O1)C)O)N)OC1=CC=C(C=C1)[C@H]([C@H](C(=O)N[C@H](C(=O)N6)C1=CC=C(C=C1)O)NC(=O)[C@@H](C1=CC=C(C=C1)O[C@H]1[C@@H]([C@@H]([C@H]([C@@H](O1)C)O)O)O)NC)O)O)O)O)C(=O)O)N)O

International Chemical Identifier key (InChIKey)

OTKPPUXRIADSGD-PPRNARJGSA-N

International Chemical Identifier (InChI)

InChI=1S/C83H92ClN9O31/c1-30-64(99)46(85)27-54(115-30)122-72-37-12-20-50(45(84)22-37)120-52-24-38-23-51(73(52)124-83-74(70(105)68(103)53(29-94)121-83)123-55-28-47(86)65(100)31(2)116-55)118-41-17-9-35(10-18-41)67(102)62(92-75(107)57(87-4)33-7-15-42(16-8-33)119-82-71(106)69(104)66(101)32(3)117-82)79(111)88-58(34-5-13-39(95)14-6-34)76(108)90-60(38)78(110)89-59-36-11-19-48(97)43(21-36)56-44(25-40(96)26-49(56)98)61(81(113)114)91-80(112)63(72)93-77(59)109/h5-26,30-32,46-47,53-55,57-72,74,82-83,87,94-106H,27-29,85-86H2,1-4H3,(H,88,111)(H,89,110)(H,90,108)(H,91,112)(H,92,107)(H,93,109)(H,113,114)/t30-,31-,32-,46+,47+,53+,54-,55-,57+,58-,59+,60+,61-,62+,63-,64-,65-,66-,67+,68+,69+,70-,71+,72+,74?,82-,83-/m0/s1

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Antibiotic, Antibacterial, Growth promotor, Feed additive

Substance groups

Glycopeptide

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Inhibition of bacterial cell wall synthesis

Molecular targets

[Bacterial cell wall synthesis, Inhibitor]

CAS RN

37332-99-3

EC number

253-466-4

CIPAC number

US EPA chemical code

PubChem CID

16132294

Therapeutic Class

Antiinfectives for systemic use: Antibacterials for systemic use

ATCvet Code

QJ01XA

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

1741.12

PIN (Preferred Identification Name)

IUPAC name

(1S,2R,18R,19R,22S,25R,28R,40S)-2-[(2R,4R,5R,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-48-[(2S,4S,5S,6R)-3-[(2R,4R,5R,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-5-chloro-18,32,35,37-tetrahydroxy-22-(4-hydroxyphenyl)-19-[[(2R)-2-(methylamino)-2-[4-[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxyphenyl]acetyl]amino]-20,23,26,42,44-pentaoxo-7,13-dioxa-21,24,27,41,43-pentazaoctacyclopentaconta-

CAS name

Forever chemical

Other status information

Banned as a growth promotor in EU since 1997; Not approved as feed additive in EU

Relevant Environmental Water Quality Standards

Physical state

White, amorphous solid

Related substances & organisms

virginiamycin

Commercial

Property

Value

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

1988, first use in animals; 1997, banned in EU

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

Rhone-Poulenc
Aventis

Example products using this active

Avotan
Klorotavin

Formulation and application details

Supplied as a feed additive

Commercial production

Avoparcin is produced through a microbial fermentation process using the actinomycete strain Amycolatopsis coloradensis ATCC 53629, a soil-dwelling bacterium known for synthesising glycopeptide antibiotics. The production begins with cultivating this strain in a nutrient-rich fermentation medium, optimized to enhance the yield of the avoparcin complex, which includes both alpha- and beta-avoparcin isomers. During fermentation, the organism biosynthesises the antibiotic through a series of enzymatic steps encoded in its genome, assembling the complex glycopeptide structure from amino acid precursors and sugar moieties. After fermentation, the broth undergoes filtration, extraction, and purification, typically involving solvent precipitation and chromatographic techniques to isolate the active compounds.

Impact on climate of production and use

As microbial-based products tend to use fermentation-based production processes rather than chemical synthesis, they typically have a lower fossil fuel input in formulation and active ingredient creation, and also have reduced downstream emissions due to biodegradability and minimal soil disruption, their life-cycle GHG emissions are expected to be low. Whilst hard and precise data is not available, broad estimates suggest that typically emissions are likely to be below 5 kg CO₂e/kg.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

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

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

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.

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)

Beef cattle manure

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 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)

> 10000

Rat

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

Mainly eliminated via the 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

Linked to the emergence of Vancomycin Resistant Enterococci WRE

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

avoparcin

French

avoparcine

German

Danish

Italian

Spanish

avoparcina

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