Prednisolone

Prednisolone	Last updated: 07/09/2025
(Also known as: D1-dehydrohydrocortisone; hydroretrocortine; meticortelone)

GENERAL INFORMATION

Description

A veterinary corticosteroid drug

Examples of veterinary uses

Used for the control of inflammatory and allergic conditions such as asthma, rheumatoid arthritis and colitis

Examples of species treated

Dogs; Dogs; Cattle; Bears; Horses

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

Prednisolone exhibits stereoisomerism, specifically diastereomerism, due to the presence of multiple chiral centres in its steroid backbone. As a synthetic glucocorticoid derived from cortisol, prednisolone contains several asymmetric carbon atoms, which allow for different spatial arrangements of its substituent groups giving diastereomers. For example, 11beta-hydroxy configuration in prednisolone is crucial for its anti-inflammatory activity, whereas its 11alpha-epimer (known as 11-epi-prednisolone) shows significantly reduced potency.

Chemical formula

C₂₁H₂₈O₅

Canonical SMILES

CC12CC(C3C(C1CCC2(C(=O)CO)O)CCC4=CC(=O)C=CC34C)O

Isomeric SMILES

C[C@]12C[C@@H]([C@H]3[C@H]([C@@H]1CC[C@@]2(C(=O)CO)O)CCC4=CC(=O)C=C[C@]34C)O

International Chemical Identifier key (InChIKey)

OIGNJSKKLXVSLS-VWUMJDOOSA-N

International Chemical Identifier (InChI)

InChI=1S/C21H28O5/c1-19-7-5-13(23)9-12(19)3-4-14-15-6-8-21(26,17(25)11-22)20(15,2)10-16(24)18(14)19/h5,7,9,14-16,18,22,24,26H,3-4,6,8,10-11H2,1-2H3/t14-,15-,16-,18+,19-,20-,21-/m0/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
prednisolone	-

General status

Veterinary substance type

Immunosuppressant, Anti-inflammatory, Medicinal drug

Substance groups

Synthetic glucocorticoid

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Irreversibly binds with glucocorticoid receptors (GR) alpha and beta

Molecular targets

[Glucocorticoid receptor, Agonist]

CAS RN

50-24-8

EC number

200-021-7

CIPAC number

US EPA chemical code

PubChem CID

Therapeutic Class

Sensory organs: Otologicals; Antiinfectants for systemic use: Antibacterials for intramammary use

ATCvet Code

QS02CA01; QJ51RV01

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Bovine)

Molecular mass

360.44

PIN (Preferred Identification Name)

IUPAC name

(11β)-11,17,21-trihydroxypregna-1,4-diene-3,20-dione

CAS name

11,17-dihydroxy-17- (2-hydroxyacetyl)- 10,13-dimethyl-6,7,8,9,10,11,12,13,14,15,16,17- dodecahydrocyclopenta [a]phenanthren-3-one

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

White solid

Related substances & organisms

prednisolone acetate

methylprednisolone

methylprednisolone acetate

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1950s, first synthesised;1960s, commonly used in vet medicine

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

Dechra Veterinary Products A/S
Veva Animal Health Ltd
Norbrook Laboratories Ltd
Ecuphar NV

Example products using this active

Canaural Ear Drops Suspension
Dermipred 10 Tablets
Noroclav Intramammary Suspension
Prednicare Tablets

Formulation and application details

Available in a wide range of formulations including solutions for injection, cutaneous sprays, oral tablets, powders and gels

Commercial production

Prednisolone is synthesised through a multi-step chemical process, often starting from prednisone acetate. The production involves a sequence of reactions: first, the 3,20-keto groups are protected, followed by reduction of the 11-keto group to form the active 11beta-hydroxyl configuration. Next, the 21-hydroxyl group is esterified, and then the protected keto groups are deprotected. Finally, the 21-acetate ester is hydrolysed to yield prednisolone.

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)

223

Moderate

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

33000

Ethanol

5500

Chloroform

20000

Acetone

Melting point (°C)

235

with decomposition

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

240

Flashpoint (°C)

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

4.17 X 10⁰¹

Calculated

Log P

1.62

Low

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

In methanol: 242nm = 15000

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

Stable

Note

Not expected to hydrolyse

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)

Moderately mobile

K_oc (mL g⁻¹)

180

Notes and range

Estimated

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 soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

prednisolone gluconoride

Animal (Liver)

prednisolone sulphate

Animal (Liver)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1680

Mouse

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 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)

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) (NOEC)

160

Raphidocelis subcapitata

Low

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)

1680

Mouse

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Subcutaneous LD₅₀ = 147 mg kg⁻¹

Rat

Intraperitoneal LD₅₀ > 2000 mg kg⁻¹

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

In dairy cows prednisolone is mainly excreted via milk during milking. In other animals it is metabolised in the liver and excreted in the urine as both metabolites and the unchanged substance

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

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

IARC Group 3 carcinogen - not classifiable
May cause fluid retention, acne, constipation, and mood swings
Toxic to lungs and mucous membranes
Osteoporosis is a possible side effect of long term treatment

Handling issues

Property

Value and interpretation

General

Risk of explosion if present during electrical/static discharge

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

prednisolone

French

German

Danish

Italian

Spanish

prednisolona

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