Cefpodoxime

Cefpodoxime	Last updated: 16/09/2025
(Also known as: Simplcef)

GENERAL INFORMATION

Description

Cefpodoxime is an oral, third-generation cephalosporin antibiotic active against most gram-positive and gram-negative organisms.

Examples of veterinary uses

Used to treat infections of the respiratory and urinary tracts

Examples of species treated

Dogs; Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Cefpodoxime exhibits stereoisomerism, primarily due to the presence of multiple chiral centres in its beta-lactam and dihydrothiazine rings. The active form of cefpodoxime has the configuration (6R,7R), which is essential for its antibacterial activity, as only this stereoisomer effectively inhibits bacterial cell wall synthesis. In addition, cefpodoxime proxetil, the oral prodrug form, exists as a diastereomeric mixture due to the chiral centre in its ester side chain. During synthesis, a known side reaction called delta2-isomerisation can occur under basic conditions, shifting the double bond from the 3-position to the 2-position of the dihydrothiazine ring, creating further isomeric forms that may impact drug stability and efficacy.

Chemical formula

C₁₅H₁₇N₅O₆S₂

Canonical SMILES

COCC1=C(N2C(C(C2=O)NC(=O)C(=NOC)C3=CSC(=N3)N)SC1)C(=O)O

Isomeric SMILES

COCC1=C(N2[C@@H]([C@@H](C2=O)NC(=O)/C(=N\OC)/C3=CSC(=N3)N)SC1)C(=O)O

International Chemical Identifier key (InChIKey)

WYUSVOMTXWRGEK-HBWVYFAYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H17N5O6S2/c1-25-3-6-4-27-13-9(12(22)20(13)10(6)14(23)24)18-11(21)8(19-26-2)7-5-28-15(16)17-7/h5,9,13H,3-4H2,1-2H3,(H2,16,17)(H,18,21)(H,23,24)/b19-8-/t9-,13-/m1/s1

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Medicinal prodrug: antibiotic

Substance groups

Cephalosporin

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Acts by interfering with the formation of the bacteria's cell wall so that the wall ruptures, resulting in bacterial death

Molecular targets

[Peptidoglycan synthase FtsI, Inhibitor]

CAS RN

82619-04-3

EC number

CIPAC number

US EPA chemical code

PubChem CID

6335986

Therapeutic Class

Other Beta-Lactam antibacterials: Third-generation cephalosporins

ATCvet Code

QJ01DD13

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

427.46

PIN (Preferred Identification Name)

(6R,7R)-7-(((2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl)amino)-3-(methoxymethyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

IUPAC name

(6R,7R)-7-(((2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl)amino)-3-(methoxymethyl)-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid

CAS name

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Physical state

Orange to red coloured solid

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1980s, first synthesised; 2000s, vet use introduced; 2103, not approved UK

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

Pfizer Animal Health

Example products using this active

Proxetil
Vantil

Formulation and application details

Usually supplied in tablet form

Commercial production

Cefpodoxime is synthesised through a multi-step process beginning with 7-aminocephalosporanic acid (7-ACA), the core structure of cephalosporins. The first key step involves acylation of 7-ACA with a side chain such as S-benzothiazol-2-yl(2-amino-4-thiazolyl)(methoxyimino)thioacetate, forming the active nucleus with enhanced beta-lactamase resistance. This intermediate is then chloroacetylated using chloroacetyl chloride to introduce a protective group. Next, the carboxylic acid function is esterified with 1-iodoethyl isopropyl carbonate, producing cefpodoxime proxetil, the orally bioavailable prodrug. Finally, the chloroacetamide group is cleaved using thiourea in a polar aprotic solvent like N,N-dimethylacetamide, yielding 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 (mg l⁻¹)

0.4

Low

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 soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

cefpodoxime
Note: Active metabolite

Humans; Animals

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 8000

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)

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)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 8000

Mouse

Low

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 2535 mg kg⁻¹

Mouse

Subcutaneous LD₅₀ > 10000 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

Absorbed from the gastrointestinal tract and de-esterified to its active metabolite, cefpodoxime. Excreted rapidly in the urine (approx. 12 hrs)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

May cause mild gastro-intestinal problems including diarrhoea, nausia and vomiting
May cause sensitisation via contact or inhalation

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H317, H334

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cefpodoxime

French

German

Danish

Italian

Spanish

cefpodoxima

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