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Cephalexin
Last updated: 25/02/2022
(Also known as: cefalexin; ceporexin-E; cephanasten; cophalexin; CEX)

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate Ecotoxicity Human health
   
Human health
High alert:
Reproduction/development effects
Warning:
Significant data are missing
GENERAL INFORMATION
Description
A broad spectrum antibiotic used to treat bacterial infections of the skin, urinary tract, respiratory tract, bones and joints.
Availability status
-
Introduction & key dates
1967
Examples of species treated
Dogs, Cats, Cattle, Pigs, Sheep
Chemical structure
Isomerism
-
Chemical formula
C₁₆H₁₇N₃O₄S
Canonical SMILES
CC1=C(N2C(C(C2=O)NC(=O)C(C3=CC=CC=C3)N)SC1)C(=O)O
Isomeric SMILES
CC1=C(N2[C@@H]([C@@H](C2=O)NC(=O)[C@@H](C3=CC=CC=C3)N)SC1)C(=O)O
International Chemical Identifier key (InChIKey)
ZAIPMKNFIOOWCQ-UEKVPHQBSA-N
International Chemical Identifier (InChI)
InChI=1S/C16H17N3O4S/c1-8-7-24-15-11(14(21)19(15)12(8)16(22)23)18-13(20)10(17)9-5-3-2-4-6-9/h2-6,10-11,15H,7,17H2,1H3,(H,18,20)(H,22,23)/t10-,11-,15-/m1/s1
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
Cephalexin hydrate -
General status
Veterinary substance type
Antibiotic, Medicinal drug, Antibacterial, Antimicrobial
Substance groups
Cephalosporin
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Semi-synthetic
Mode of action
Interferes with the bacteria's cell wall formation, causing it to rupture, and killing the bacteria.
Molecular targets
[Penicillin-binding protein 3, antagonist], [Penicillin-binding protein 2a, antagonist], [Penicillin-binding protein 1b, antagonist], [Penicillin-binding protein 2B, antagonist], [Penicillin-binding protein 1A, antagonist]
CAS RN
15686-71-2
EC number
239-773-6
CIPAC number
-
US EPA chemical code
-
PubChem CID
-
ATCvet Code
QJ51DA01
Therapeutic Class
Antiinfectants for systemic use: Antibacterials for intramammary use
Controlled Drug?
No
Regulation 37/2010 MRL Classification
Allowed substance (Table 1: Bovine)
Molecular mass
347.39
PIN (Preferred Identification Name)
-
IUPAC name
(6R,7R)-7-{[(2R)-2-amino-2-phenylacetyl]amino}- 3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene- 2-carboxylic acid
CAS name
7-(D-2-amino-2-phenylacetamido)-3-methyl-delta(sup 3)-cephem-4-carboxylic acid
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
White crystalline powder
Formulations
Property
Product
Manufacturer
Authorisation Route
UK Legal Class
Example products using this active
Cefaseptin 120 mg film-coated tablets Vetoquinol UK Ltd UK National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Cephacare flavour 50 mg tablets for cats and dogs Animalcare Ltd EU Mutually recognised procedure Prescription only medicine to be authorised by a veterinarian (POM-V)
Cephorum Film Coated Tablets 500 mg Forum Products Ltd UK National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Ceporex Vet Oral Drops, Granules for Oral Suspension 1000mg for cats and dogs Schering-Plough Ltd UK National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Formulation and application details
Available as tablets, capsules and powder for oral suspension
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
1790
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
197
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
-
Boiling point (°C)
727
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
394
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
4.47 X 1000 Calculated -
Log P
0.65
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Low
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
- - -
Dissociation constant pKa) at 25 °C
5.2
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
pKa(2) = 7.3
Vapour pressure at 20 °C (mPa)
4.31 X 10-10
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
Max: 260nm = 7750
CA3 CA = Medical and toxicological databases and information systems e.g. TOXNET (click here )
3 = Unverified data of known source
-
Surface tension (mN m⁻¹)
- - -
Refractive Index
- - -
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)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
- - -
Koc
-
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
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)
> 20000
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Rat
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
- - -
- - -
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
- - -
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 pollinators (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other pollinators (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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
Aquatic invertebrates - Chronic 21 day NOEC (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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
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)
> 20000
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Rat
Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
- - -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
Intraperitoneal LD₅₀ = 4000 mg kg⁻¹
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Rat
-
Subcutaneous LD₅₀ > 6100 mg kg⁻¹
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
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
Majority (~80-90%) is excreted unchanged in urine within 6 hours of administration, remainder lost in bile and faeces
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
No data found
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
Yes, known to cause a problem
No data found No data found
Respiratory tract irritant Skin irritant Skin sensitiser
Yes, known to cause a problem
Yes, known to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
May cause diarrhoea, dizziness, headache, indigestion, joint pain, stomach pain and tiredness
Handling issues
Property
Value and interpretation
General
Hazardous combustion or decomposition products are produced in a fire
CLP classification 2013
-
WHO Classification
None - not a ppp
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
cephalexin
French
cefalexine
German
-
Danish
-
Italian
-
Spanish
cefalexina
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 25/02/2022
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