Cefazolin

Cefazolin	Last updated: 16/09/2025
(Also known as: cefazoline; cephazolin; HSDB 3213; cefazolin acid)

GENERAL INFORMATION

Description

A drug used to treat gram-positive and some gram-negative bacterial infections

Examples of veterinary uses

Broad spectrum uses including those of the skin and involving the lung, bone, joint, stomach, blood, heart valve, and urinary tract.

Examples of species treated

Horses

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Cefazolin exhibits isomerism primarily through its degradation products rather than its active form. During storage or under certain conditions, cefazolin can undergo hydrolytic ring-opening reactions that produce structural isomers known as cefazoloic acid derivatives. These include the open-ring delta-2, delta-3, and delta-4 isomers, which differ in the position of the double bond within the opened beta-lactam ring.

Chemical formula

C₁₄H₁₄N₈O₄S₃

Canonical SMILES

CC1=NN=C(S1)SCC2=C(N3C(C(C3=O)NC(=O)CN4C=NN=N4)SC2)C(=O)O

Isomeric SMILES

CC1=NN=C(S1)SCC2=C(N3[C@@H]([C@@H](C3=O)NC(=O)CN4C=NN=N4)SC2)C(=O)O

International Chemical Identifier key (InChIKey)

MLYYVTUWGNIJIB-BXKDBHETSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H14N8O4S3/c1-6-17-18-14(29-6)28-4-7-3-27-12-9(11(24)22(12)10(7)13(25)26)16-8(23)2-21-5-15-19-20-21/h5,9,12H,2-4H2,1H3,(H,16,23)(H,25,26)/t9-,12-/m1/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
Cefazolin sodium pentahydrate	Variant

General status

Veterinary substance type

Antibiotic, Antibacterial, Medicinal drug

Substance groups

Cephalosporin

Minimum active substance purity

Known relevant impurities

Structural isomers may be present as impurities

Substance origin

Semi-synthetic

Mode of action

Interferes with the later stages of bacterial cell wall synthesis

Molecular targets

[Penicillin-binding protein 1A, Antagonist], [Penicillin-binding protein 1B, Antagonist], [Penicillin-binding protein 1C, Antagonist], [Penicillin-binding protein 2, Antagonist], [Peptidoglycan synthetase ftsI, Antagonist], [Serum paraoxonase/arylesterase 1, Antagonist]

CAS RN

25953-19-9

EC number

247-362-8

CIPAC number

US EPA chemical code

PubChem CID

33255

Therapeutic Class

Antiinfectants for systemic use: Antibacterials for intramammary use

ATCvet Code

QJ51DA04

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed susbstance (Table 1: Bovine, Ovine, Caprine)

Molecular mass

454.51

Chemical name

PIN (Preferred Identification Name)

IUPAC name

(6R,7R)-3-{[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl}-8-oxo-7-[(1H-tetrazol-1-ylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

CAS name

Global Governance status: Listed (✓) under

UK Poisons List Order 1972	Rotterdam Convention	Montreal Protocol
XNo The Poisons List Order 1972	XNo Rotterdam Convention	XNo Montreal Protocol
Stockholm Convention	OSPAR	EU Water Framework Directive
XNo Stockholm Convention	XNo OSPAR	XNo EU Water Framework Directive

Relevant Environmental Water Quality Standards

Forever chemical

Other status information

Physical state

White to yellowish-white, odorless crystalline powder

Commercial

Property

Value

Availability status

Introduction & key dates

Early 1970s, first synthesis; 1973, first approvals USA

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

Dopharma Research B.V.

Example products using this active

Cefovet TS
Kefzol
Ancef
Zolicef

Formulation and application details

Usually administrated by either intramuscular or intravenous infusion. Human products were often used, off-label, for animal treatment.

Commercial production

The production of cefazolin typically begins with 7-aminocephalosporanic acid, a core cephalosporin nucleus derived from Cephalosporin C, which is isolated from the fungus Acremonium. This intermediate undergoes chemical derivatisation, where a specific side chain, usually a tetrazolylacetyl group, is introduced to form the active cefazolin molecule. Traditionally, this is done via batch manufacturing, a stepwise process involving precise control of reaction conditions, purification, and crystallisation. However, newer methods like continuous-flow synthesis have emerged, offering faster, more flexible, and less wasteful production. In this approach, reagents are mixed and reacted in a flow reactor without isolating intermediates, followed by acid-base extraction and precipitation to purify the final product.

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 at pH 7 (mg l⁻¹)

210

at 25 °C

Moderate

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

Melting point (°C)

198

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

2.63 X 10^-01

Calculated

Log P

-0.58

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

3.6

Vapour pressure at 20 °C (mPa)

2.0 X 10^-13

Low volatility

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

Max = 272nm with a possible shoulder above 290nm)

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)

Very mobile

K_oc (mL g⁻¹)

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)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 11000

Mouse

Low

Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)

Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary LC₅₀ (mg kg⁻¹ bw d⁻¹)

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)

Beneficial insects (Butterflies)

Contact

Notes

Oral

Notes

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) (EC₅₀)

> 1000

Raphidocelis subcapitata

Low

Algae - Chronic (growth rate, fresh; mg l⁻¹) (NOEC)

> 1000

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)

> 11000

Mouse

Low

Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)

Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intramuscular LD₅₀ > 4000 mg kg⁻¹

Mouse

Intravenous LD₅₀ > 3000 mg kg⁻¹

Mouse

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

Excreted virtually unchanged in the urine

Health issues

Specific human health issues (hazard-based)

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

May cause gastrointestinal problems
May cause hypoprothrombinemia or hypersensitivity
Possible liver toxicant

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cefazolin

French

cefazoline

German

Danish

Italian

Spanish

cefazolina

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

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

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