Dexamethasone isonicotinate

Dexamethasone isonicotinate	Last updated: 16/09/2025
(Also known as: dexamethasone-21-isonicotinate)

GENERAL INFORMATION

Description

An anti-inflammatory corticosteroid veterinary drug

Examples of veterinary uses

Used, for example, for the control of CNS inflammation in dogs and cats and for the treatment of primary bovine ketosis.

Examples of species treated

Cattle; Horses; Lamas; Elephants; Pigs; 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

Dexamethasone isonicotinate exhibits chiral isomerism, due to multiple asymmetric carbon atoms in its steroid backbone. As a synthetic glucocorticoid ester, it retains the stereochemistry of dexamethasone, which includes defined configurations at positions such as 11beta, 16alpha, and 17alpha. The isonicotinate esterification at the 21-hydroxyl group does not alter the core stereochemistry but adds a functional group that can influence pharmacokinetics. The marketed form is a single stereoisomer (11beta,16alpha).

Chemical formula

C₂₈H₃₂FNO₆

Canonical SMILES

CC1CC2C3CCC4=CC(=O)C=CC4(C3(C(CC2(C1(C(=O)COC(=O)C5=CC=NC=C5)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)COC(=O)C5=CC=NC=C5)O)C)O)F)C

International Chemical Identifier key (InChIKey)

BQTXJHAJMDGOFI-NJLPOHDGSA-N

International Chemical Identifier (InChI)

InChI=1S/C28H32FNO6/c1-16-12-21-20-5-4-18-13-19(31)6-9-25(18,2)27(20,29)22(32)14-26(21,3)28(16,35)23(33)15-36-24(34)17-7-10-30-11-8-17/h6-11,13,16,20-22,32,35H,4-5,12,14-15H2,1-3H3/t16-,20+,21+,22+,25+,26+,27+,28+/m1/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
dexamethasone	Parent

General status

Veterinary substance type

Anti-inflammatory

Substance groups

Corticosteroid

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Unbound dexamethasone crosses cell membranes and binds to specific cytoplasmic receptors leading to a reduction in inflammation

Molecular targets

[Glucocorticoid receptor, Agonist], [Nuclear receptor 0B1, stimulator], [Annexin A1, stimulator], [Nitric oxide synthase, inducible, Negative modulator]

CAS RN

2265-64-7

Alternative/old CAS RN

68402-70-0

EC number

218-866-5

CIPAC number

US EPA chemical code

PubChem CID

16752

Therapeutic Class

Alimentary tract & metabolism; Cardiovascular system; Dematologicals; Systemic hormone preparations excluding sex hormones & insulins; Respiratory system; Sensory organs

ATCvet Code

QA01AC02; QC05AA09; QD07AB19; QH02AB02; QR01AD03; QS01BA01; QS02BA06; QS03BA01

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1 Bovine, Caprine, Porcine, Equidae)

Molecular mass

497.6

PIN (Preferred Identification Name)

IUPAC name

[2-[(8S,9R,10S,11S,13S,14S,16R,17R)-9-fluoro-11,17-dihydroxy-10,13,16-trimethyl-3-oxo-6,7,8,11,12,14,15,16-octahydrocyclopenta[a]phenanthren-17-yl]-2-oxoethyl] pyridine-4-carboxylate

CAS name

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

Related substances & organisms

dexamethasone

dexamethasone acetate

dexamethasone phenylpropionate

dexamethasone sodium phosphate

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1957, first synthesised; 1970s, veterinary adoption

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

Emdoka bvba

Example products using this active

Trovex Suspension for Injection

Formulation and application details

Available in a variety of formulations including solutions for injection, chewable tables and dropper suspension solutions as ear drops

Commercial production

The production of dexamethasone isonicotinate involves the esterification of dexamethasone at its 21-hydroxyl group with isonicotinic acid. This process typically begins with the activation of isonicotinic acid using a coupling agent such as dicyclohexylcarbodiimide or oxalyl chloride, forming a reactive intermediate. Dexamethasone is then introduced under controlled conditions, often in an anhydrous solvent like dichloromethane or pyridine, to facilitate the ester bond formation. The reaction mixture is stirred at room temperature or slightly elevated temperatures until completion, after which the product is purified by recrystallization or chromatography to isolate the desired ester.

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)

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

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)

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 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)

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)

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

Metablised and around 30% excreted in the urine within 4 days. Also excreted in human breast milk.

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

Eye irritant

Phototoxicant

No data found

General human health issues

May cause hypertension
May cause retinal toxicity, glaucoma & subcapsular cataract
May cause delayed wound healing, atrophy & skin fragility

Handling issues

Property

Value and interpretation

General

Emits toxic fumes of hydrogen fluoride when heated to decomposition

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

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Name

English

dexamethasone isonicotinate

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Polish

Swedish

Hungarian

Dutch

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Record last updated:	16/09/2025
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