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Chlorhexidine
Last updated: 08/04/2021
(Also known as: chlorohexidine)

GENERAL INFORMATION
Description
Used mainly as a used topical disinfectant cleanser for skin wounds and as an antibactericide for ear and gum infections killing both gram-positive and gram-negative microbes.
Availability status
-
Introduction & key dates
1953, UK
Examples of species treated
Cattle, Cats, Dogs
Chemical structure
Isomerism
Isomeric
Chemical formula
C₂₂H₃₀Cl₂N₁₀
Canonical SMILES
C1=CC(=CC=C1NC(=NC(=NCCCCCCN=C(N)N=C(N)NC2=CC=C(C=C2)Cl)N)N)Cl
Isomeric SMILES
C1=CC(=CC=C1N/C(=N/C(=NCCCCCCN=C(/N=C(/NC2=CC=C(C=C2)Cl)\N)N)N)/N)Cl
International Chemical Identifier key (InChIKey)
GHXZTYHSJHQHIJ-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C22H30Cl2N10/c23-15-5-9-17(10-6-15)31-21(27)33-19(25)29-13-3-1-2-4-14-30-20(26)34-22(28)32-18-11-7-16(24)8-12-18/h5-12H,1-4,13-14H2,(H5,25,27,29,31,33)(H5,26,28,30,32,34)
2D structure diagram/image available?
Yes
General status
Veterinary substance type
Antiseptic, Bactericide, Antimicrobial
Substance groups
Unclassified
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Disrupts the integrity of the cell membrane and causes the leakage of intracellular components of the organisms.
Molecular targets
[Bacterial cell wall]
CAS RN
55-56-1
EC number
200-238-7
CIPAC number
-
US EPA chemical code
-
PubChem CID
-
ATCvet Code
QD08AC52
Therapeutic Class
Dermatogiocals: Antiseptics and disinfectants
Controlled Drug?
No
Regulation 37/2010 MRL Classification
Allowable substance (Table 1: All food producing species)
Molecular mass
505.45
PIN (Preferred Identification Name)
-
IUPAC name
N',N'''''-hexane-1,6-diylbis(N-(4-chlorophenyl)(imidodicarbonimidic diamide))
CAS name
1,6-bis(5-(p-chlorophenyl)biguanidino)hexane
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
Colourless to pale yellow crystalline solid
Formulations
Property
Product
Manufacturer
Authorisation Route
UK Legal Class
Example products using this active
Action Actodine Kilco Chemicals Ltd UK National authorisation (IC) Authorised veterinary medicine for general sale (AVM - GSL)
Deosan SummerTeatcare Plus ( 0.425%w/w ) Teat dip and Teat Spray Emulsion JohnsonDiversey Ltd UK National authorisation Authorised veterinary medicine for general sale (AVM - GSL)
Propisderm 0.5 % w/w Teat dip solution Hypred S.A. UK National authorisation Authorised veterinary medicine for general sale (AVM - GSL)
Sebolyse shampoo for dogs and cats Dechra Veterinary Products A/S UK National authorisation Prescription only medicine to be authorised by a veterinarian (POM-V)
Formulation and application details
Available as solutions for topical application
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
800
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
134
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.20 X 1000 Calculated -
Log P
0.08
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)
1.07
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
-
Dissociation constant pKa) at 25 °C
10.78
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
at 25 °C
-
-
Vapour pressure at 20 °C (mPa)
2.64 X 10-09
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
as acetate
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
1.25e-25
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
as acetate
Non-volatile
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
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
-
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Non-mobile
Koc
31600
Notes and range
Literature estimate
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)
- -
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 1800
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Mouse as the digluconate
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)
- - -
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)
> 1.4
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Danio rerio
Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 0.06
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Daphnia magna as acetate
High
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)
> 1800
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Mouse as the digluconate
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
500
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
> 2.03
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
Subcutaneous LD₅₀ = 1000 mg kg⁻¹
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Rat
-
Intraperitoneal LD₅₀ = 60 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
Excretion is primarily through the faeces (~ 90%). Also found in breast milk.
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
?Possibly, status not identified
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
Yes, known to cause a problem
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
No further information available
Handling issues
Property
Value and interpretation
General
May decompose on heating emiting dangerous gaseous substances - halogenated compounds, oxides of nitrogen
CLP classification 2013
-
WHO Classification
NL (Not listed)
UN Number
3077
Waste disposal & packaging
Packaging Group III (minor danger)
TRANSLATIONS
Language
Name
English
chlorhexidine
French
-
German
-
Danish
-
Italian
-
Spanish
clorhexidina
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 08/04/2021
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