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Ethinyl estradiol
Last updated: 02/02/2024
(Also known as: ethinyl estradiol; EE; aethinyloestradiolum; etinilestradiol; 17alpha-ethinyloestradiol)

GENERAL INFORMATION
Description
A prescription drug that is a synthetic oral estrogen
Availability status
-
Introduction & key dates
1943, introduced USA
Examples of veterinary uses
Used to start the heat cycle in horses and to prevent pregnancy in cats and dogs
Examples of species treated
Dogs; Cats; Horses
Approval status
VMR 2013/2033 approval status (GB/UK)
Not approved
EU Regulatory approval status
Not approved
Chemical structure
Isomerism
-
Chemical formula
C₂₀H₂₄O₂
Canonical SMILES
CC12CCC3C(C1CCC2(C#C)O)CCC4=C3C=CC(=C4)O
Isomeric SMILES
C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@]2(C#C)O)CCC4=C3C=CC(=C4)O
International Chemical Identifier key (InChIKey)
BFPYWIDHMRZLRN-SLHNCBLASA-N
International Chemical Identifier (InChI)
InChI=1S/C20H24O2/c1-3-20(22)11-9-18-17-6-4-13-12-14(21)5-7-15(13)16(17)8-10-19(18,20)2/h1,5,7,12,16-18,21-22H,4,6,8-11H2,2H3/t16-,17-,18+,19+,20+/m1/s1
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
ethinyl estradiol hemihydrate Variant
General status
Veterinary substance type
Contraceptive, Hormone therapy, Medicinal drug
Substance groups
Oestrogen
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Semi-synthetic
Mode of action
Diffuses into the target cells and interacts with a protein receptor
Molecular targets
[Estrogen receptor, Agonist], [Orphan nuclear receptor PXR, Agonist]
CAS RN
57-63-6
EC number
200-342-2
CIPAC number
-
US EPA chemical code
-
PubChem CID
-
Therapeutic Class
Genito urinary system & sex hormones: Sex hormones & modulators of the genital system
ATCvet Code
QG03CA03
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
296.40
PIN (Preferred Identification Name)
-
IUPAC name
19-nor-17α-pregna-1,3,5(10)-trien-20-yne-3,17-diol
CAS name
(17-α)-19-norpregna-1,3,5(10)-trien-20-yne-3,17,diol
Other status information
Found in water bodies
Relevant Environmental Water Quality Standards
-
Physical state
Creamy coloured solid
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
- - - -
Formulation and application details
-
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
4.8
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
166
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Ethanol
-
250
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Ether
-
200
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Acetone
-
50
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Chloroform
-
Melting point (°C)
183
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Boiling point (°C)
Decomposes before boiling
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.41 X 1004 Calculated -
Log P
4.15
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
- - -
Dissociation constant pKa) at 25 °C
10.21
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
-
-
Vapour pressure at 20 °C (mPa)
- - -
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
Surface tension (mN m⁻¹)
- - -
Refractive Index
87.37
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
-
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)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
- - -
Koc
-
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
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 soil and groundwater metabolites

None

Other known metabolites
Metabolite name and reference
Aliases
Formation medium / Rate
Estimated maximum occurrence fraction
Metabolising enzymes
2-methoxyethinylestradiol - Rat (Liver) - -
2-hydroxyethinylestradiol-3-methy1 ether - Rat (Liver) - -
2-hydroxyethinylestradiol
Note: Main metabolic product in liver
- Rats (liver); Human (Liver) - Cytochrome P450 3A4
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
1737
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
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
- - -
- - -
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
- - -
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)
1.61
R4 R = Peer reviewed scientific publications
4 = Verified data
Pimephales promelas
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.0001
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Danio rerio
High
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
6.4
R4 R = Peer reviewed scientific publications
4 = Verified data
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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
0.84
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Unknown species
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
Intermediate (class II) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
1737
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
- - -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
Subcutaneous LD₅₀ > 2000 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat
-
Intraperitoneal LD₅₀ = 471 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
rat
-
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
Metabolised in the liver and excreted in the faeces, urine and, in small amounts, in milk
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
Yes, known to cause a problem
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E2 E = Unspecified genotoxicity type (miscellaneous data source)
2 = Mixed/ambiguous results
?Possibly, status not identified
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
Yes, known to cause a problem
No data found
?Possibly, status not identified
Respiratory tract irritant Skin irritant Skin sensitiser
?Possibly, status not identified
?Possibly, status not identified
No data found
Eye irritant Phototoxicant  
?Possibly, status not identified
No data found  
General human health issues
May cause gastointestinal problems
May cause jaundice, hypertension, nasal congestion, headache, dizziness and fluid retention
Published studies have demonstrated that enthinyl estradiol can cause cancer at higher dose levels; CLP data - known human carcinogen; US NTP - known carcinogen
Handling issues
Property
Value and interpretation
General
May react vigorously with strong oxidizing and reducing agents
CLP classification 2013
Health: H302, H350, H360, H372
Environment: H410, H411
WHO Classification
Not listed (Not listed)
UN Number
Not regulated
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
ethinyl estradiol
French
-
German
Aethinyoestradiol
Danish
-
Italian
-
Spanish
etinilestradiol
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-

Record last updated: 02/02/2024
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