Betamethasone

Betamethasone	Last updated: 07/09/2025
(Also known as: betadexamethasone; betafluorene)

GENERAL INFORMATION

Description

A glucocorticoid drug which exhibits anti-inflammatory and immunosuppressant properties

Examples of veterinary uses

Mainly used to treat a variety of conditions including skin irritations and infections, allergic reactions, arthritis, breathing disorders

Examples of species treated

Dogs

Approval status

VMR 2013/2033 approval status (GB/UK)

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

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Betamethasone exhibits stereoisomerism, specifically diastereomerism, due to multiple chiral centres in its steroid backbone. It is an isomer of dexamethasone, differing in the configuration at the 16th carbon, betamethasone has a 16beta-methyl group, while dexamethasone has it in the 16alpha position. During its synthesis, additional isomers may also form, such as 8alpha-fluoro and 14beta-fluoro derivatives.

Chemical formula

C₂₂H₂₉FO₅

Canonical SMILES

CC1CC2C3CCC4=CC(=O)C=CC4(C3(C(CC2(C1(C(=O)CO)O)C)O)F)C

Isomeric SMILES

C[C@H]1C[C@H]2[C@@H]3CCC4=CC(=O)C=C[C@@]4([C@]3([C@H](C[C@@]2([C@]1(C(=O)CO)O)C)O)F)C

International Chemical Identifier key (InChIKey)

UREBDLICKHMUKA-DVTGEIKXSA-N

International Chemical Identifier (InChI)

InChI=1S/C22H29FO5/c1-12-8-16-15-5-4-13-9-14(25)6-7-19(13,2)21(15,23)17(26)10-20(16,3)22(12,28)18(27)11-24/h6-7,9,12,15-17,24,26,28H,4-5,8,10-11H2,1-3H3/t12-,15-,16-,17-,19-,20-,21-,22-/m0/s1

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Anti-inflammatory, Immunosuppressant

Substance groups

Corticosteroid

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Modifies the levels and array of proteins synthesised by the various target tissues

Molecular targets

[Glucocorticoid receptor, Agonist]

CAS RN

378-44-9

EC number

206-825-4

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Dermatologicals: Corticosteriods, dermatological preparations; Systemic hormone preparations excluding sex hormones & insulin: Corticosteroids for systemic use; Sensory organs: Otologicals

ATCvet Code

QD07CC01; QH02AB01; QS02CA90

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Bovine, Porcine)

Molecular mass

392.46

PIN (Preferred Identification Name)

IUPAC name

(8S,9R,10S,11S,13S,14S,16S,17R)-9-fluoro- 11,17-dihydroxy-17-(2-hydroxyacetyl)-10,13,16-trimethyl- 6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro- 3H-cyclopenta[a]phenanthren-3-one

CAS name

1-dehydro-9-fluoro-17-hydroxy-16β-methyl-corticosterone

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

Cream coloured crystalline powder

Related substances & organisms

betamethasone acetate

Commercial

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Availability status

Current

Introduction & key dates

1985, patented; 1961 first medical approvals

Example products (past and present) using this active

Betafuse gel

Norbrook Laboratories Ltd

GB National authorisation

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

Fuselieve Gel

Norbrook Laboratories Ltd

GB National authorisation

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

Otomax Ear Drops Suspension

MSD Animal Health UK Ltd

GB National authorisation

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

Formulation and application details

Often formulated as gels for topical use or as a solution with dropper for ear conditions

Commercial production

The production of betamethasone typically begins with the steroidal precursor 3alpha-acetoxy-16-pregnen-11,20-dione, which undergoes a series of chemical transformations to build the desired corticosteroid framework. The process starts with a reaction involving diazomethane, introducing a methyl group, followed by hydrogenation using a palladium-on-carbon catalyst to refine the molecular structure and enhance stereoselectivity. In some advanced methods, biological oxidation using microorganisms like Arthrobacter is employed to selectively dehydrogenate intermediates, improving yield and purity. Subsequent purification steps include filtration, solvent extraction (typically with chloroform/methanol), and drying, ultimately yielding pharmaceutical-grade betamethasone.

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 (mg l⁻¹)

65.5

Moderate

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

160000

Methanol

Melting point (°C)

235.6

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

232

Flashpoint (°C)

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

1.02 X 10⁰²

Calculated

Log P

2.01

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

13.48

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

Methanol: 238nm = 15200

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)

> 4500

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)

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)

> 20

Daphnia magna

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)

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)

> 4500

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

Metabolised end excreted in the urine

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

May cause perioral or allergic contact dermatitis

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H360, H373

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

betamethasone

French

German

Danish

Italian

Spanish

betametasona

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	07/09/2025
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