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Sulfasalazine
Last updated: 12/01/2024
(Also known as: salicylazosulfapyridine; sulphasalazine)

GENERAL INFORMATION
Description
A widely used human and veterinary sulfonamide antibacterial and immunosuppressive medication
Availability status
Current
Introduction & key dates
1930s, developed; 1950s, first approved USA
Examples of veterinary uses
Used to treat rheumatoid arthritis, inflammatory bowl disease, colitis & Crohn's disease
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
-
Chemical formula
C₁₈H₁₄N₄O₅S
Canonical SMILES
C1=CC=NC(=C1)NS(=O)(=O)C2=CC=C(C=C2)NN=C3C=CC(=O)C(=C3)C(=O)O
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
OQANPHBRHBJGNZ-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C18H14N4O5S/c23-16-9-6-13(11-15(16)18(24)25)21-20-12-4-7-14(8-5-12)28(26,27)22-17-3-1-2-10-19-17/h1-11,20H,(H,19,22)(H,24,25)
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
sulfasalazine -
General status
Veterinary substance type
Medicinal drug: anti-bacterial; anti-inflammatory
Substance groups
Aminosalicylate
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Works by reducing the production of chemicals that mediate inflammation such as inflammatory cytokines and eicosanoids.
Molecular targets
[Arachidonate 5-lipoxygenase, Inhibitor], [Prostaglandin G/H synthase 2, Inhibitor], [Prostaglandin G/H synthase 1, Inhibitor], [Peroxisome proliferator-activated receptor gamma, Agonist], [Inhibitor of nuclear factor kappa-B kinase subunit alpha, Inhibitor], [Inhibitor of nuclear factor kappa-B kinase subunit beta, Inhibitor], [Cystine/glutamate transporter, Inhibitor]
CAS RN
599-79-1
EC number
209-974-3
CIPAC number
-
US EPA chemical code
-
PubChem CID
-
Therapeutic Class
Intestinal antiinflammatory agents: Aminosalicylic acid and similar agents
ATCvet Code
QA07EC01
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
398.39
PIN (Preferred Identification Name)
2-hydroxy-5-((E)-2-(4-((pyridin-2-yl)sulfamoyl)phenyl)diazen-1-yl)benzoic acid
IUPAC name
2-hydroxy-5-((E)-2-(4-((pyridin-2-yl)sulfamoyl)phenyl)diazen-1-yl)benzoic acid
CAS name
5-((para-(2-pyridylsulfamoyl)phenyl)azo)-salicylic acid
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
Brown to orange coloured powder
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
Salazopyrin Pharmacia Not licensed Not licensed
Formulation and application details
-
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
- - -
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
Decomposes on melting
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
-
Boiling point (°C)
- - -
Degradation point (°C)
220
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
-
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
3.16 X 1002 Calculated -
Log P
2.5
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
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
- - -
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)
- - -
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.
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 soil and groundwater metabolites

None

Other known metabolites
Metabolite name and reference
Aliases
Formation medium / Rate
Estimated maximum occurrence fraction
Metabolising enzymes
5-aminosalicylic acid
Note: Active substance
- Colonic - -
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
15600
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
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 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 - 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)
- - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
15600
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
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
Intravenous LD₅₀ = 1096 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Mouse
-
Subcutaneous LD₅₀ = 3000 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
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
Mainly eliminated in the urine either as free metabolites or as glucuronide conjugates
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
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
;
E2 E = Unspecified genotoxicity type (miscellaneous data source)
2 = Mixed/ambiguous results
No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found No data found No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
May cause vomiting, loss of appetite and jaundice
May cause dry eyes
Studies suggest substance may act as a co-carcinogen
Handling issues
Property
Value and interpretation
General
Will emit toxic gases when heated to decomposition
CLP classification 2013
-
WHO Classification
Not listed (Not listed)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
sulfasalazine
French
sulfasalazine
German
Sulfasalazin
Danish
-
Italian
-
Spanish
sulfasalazina
Greek
-
Polish
-
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-

Record last updated: 12/01/2024
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