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Clenbuterol hydrochloride
Last updated: 09/02/2024
(Also known as: clenbuterol HCl)
GENERAL INFORMATION
Description
A non-steroidal medication veterinary drug which possesses some properties similar to those of anabolic steroids.
Availability status
Current
Introduction & key dates
late 1970s, developed in Germany
Examples of veterinary uses
Substance is used as a decongestant and bronchodilator to treat breathing disorders and as a smooth muscle relaxant. It is also used for increasing muscle mass.
Examples of species treated
Horses; Cattle
Approval status
VMR 2013/2033 approval status (GB/UK)
Approved
EU Regulatory approval status
Approved
Chemical structure
Isomerism
Clenbuterol is isomeric existing in both the S- and R-forms
Chemical formula
C₁₂H₁₉Cl₃N₂O
Canonical SMILES
CC(C)(C)NCC(C1=CC(=C(C(=C1)Cl)N)Cl)O.Cl
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
OPXKTCUYRHXSBK-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C12H18Cl2N2O.ClH/c1-12(2,3)16-6-10(17)7-4-8(13)11(15)9(14)5-7;/h4-5,10,16-17H,6,15H2,1-3H3;1H
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
clenbuterol Parent
General status
Veterinary substance type
Muscle relaxant, Bronchodilator agent, Thermogenic drug, Medicinal drug
Substance groups
Amine
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Steroid like action, induces activation of adenylate cyclase through the action of G proteins. A beta-2 selective adrenergic agonist
Molecular targets
[Beta-2 adrenergic receptor, Agonist], [Beta-1 adrenergic receptor, Agonist], [Beta-3 adrenergic receptor, Agonist], [Beta-nerve growth factor, stimulator], [Tumor necrosis factor]
CAS RN
21898-19-1
EC number
244-643-7
CIPAC number
-
US EPA chemical code
-
PubChem CID
5702273
Therapeutic Class
Genito urinary system & sex hormones: Other gynecologicals; Respiratory system: Drugs for obstructive airway diseases
ATCvet Code
QG02CA91; QR03CC13
Controlled Drug?
UK: Class C, Schedule 4 Pt2
Regulation 37/2010 MRL Classification
Allowed substance (Table 1: Bovine, Equidae)
Molecular mass
313.6
PIN (Preferred Identification Name)
1-(4-amino-3,5-dichlorophenyl)-2-(tert-butylamino)ethanol;hydrochloride
IUPAC name
1-(4-amino-3,5-dichlorophenyl)-2-(tert-butylamino)ethanol;hydrochloride
CAS name
-
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
White to pale yellow crystalline powder
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
Dilaterol Syrup for Horses Le Vet Beheer B.V. GB National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Equipulim Syrup for Horses CP Pharma Handelsgesellschaft mbH GB National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Ventipulmin Solution for Injection 30mg/l Boehringer Ingelheim Ltd UK National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Formulation and application details
Available in a variety of formulations including syrups, granules and solutions for injection
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
112
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 Moderate
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
P
8.71 X 1002 Calculated -
Log P
2.94
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 Moderate
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
- - -
Dissociation constant pKa) at 25 °C
17.84
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
-
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
73.38
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
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
Kd (mL g⁻¹)
- - -
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (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)
159
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
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
- - -
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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
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)
159
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
Rat		 Moderate
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
May be absorbed through the skin
Mammalian dose elimination route and rate
Major fraction of the drug is excreted into the urine
F3 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 )
3 = Unverified data of known source
 -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not 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
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
✓Yes, known to cause a problem
 No data found
✓Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
✓Yes, known to cause a problem
 No data found
Eye irritant Phototoxicant  
✓Yes, known to cause a problem
 No data found  
General human health issues
Very toxic
Possible liver and cardiovascular toxicant
May cause muscle tremor, headache, dizziness and gastric irritation
May cause hypotension
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 9
CLP classification 2013
-
WHO Classification
Not listed (Not listed)
UN Number
UN2811
Waste disposal & packaging
Packaging Group II (moderate danger)
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
clenbuterol hydrochloride
French
-
German
-
Danish
-
Italian
-
Spanish
-
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
Record last updated: 09/02/2024
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