5-AMINOSALICYLIC ACID

5-Aminosalicylic acid, also known as mesalamine or 5-aminosalicylic acid (5-ASA), is a medication used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease.
5-Aminosalicylic acid is generally used for mildly to moderately severe disease.
5-Aminosalicylic acid is taken by mouth or rectally.

CAS:    89-57-6
MF:    C7H7NO3
MW:    153.14
EINECS:    201-919-1

Synonyms
5-Aminosalicylic acid, 98.5%, IKK inhibitor;2-HYDROXY-5-AMINOBENZOIC ACID;3-Carboxy-4-hydroxyaniline;5-AMINO-2-HYDROXYBENZOIC ACID;5-AMINOSALICYLIC ACID;5-ASA;5-AS;rowasa

The formulations which are taken by mouth appear to be similarly effective.
Common side effects include headache, nausea, abdominal pain, and fever.
Serious side effects may include pericarditis, liver problems, and kidney problems. 
Use in pregnancy and breastfeeding appears safe.
In people with a sulfa allergy certain formulations may result in problems.
5-Aminosalicylic acid is an aminosalicylate and anti-inflammatory.
5-Aminosalicylic acid works by direct contact with the intestines.
5-Aminosalicylic acid was approved for medical use in the United States in 1987.
5-Aminosalicylic acid is on the World Health Organization's List of Essential Medicines.
5-Aminosalicylic acid is available as a generic medication.
In 2023, 5-Aminosalicylic acid was the 202nd most commonly prescribed medication in the United States, with more than 2 million prescriptions.
5-Aminosalicylic acid is used for the treatment of active ulcerative proctitis.

5-Aminosalicylic acid, also known as mesalazine or mesalamine, is a metabolite and potential pharmacologically active component of sulphasalazine, a drug used in the treatment of Crohn’s disease and ulcerative colitis. 
However, the mechanism by which this drug works has not been established. 
In whole blood assays, 5-Aminosalicylic acid proves to be a weak, non-selective inhibitor of both COX-1 and COX-2 with IC50 values of 410 and 61 μM, respectively. 
In ionophore-stimulated colonic mucosal cells, 1 mM 5-ASA does not inhibit prostaglandin E2 (PGE2) production, but does reduce leukotriene B4 (LTB4) synthesis approx. 50%. 
In ionophore-stimulated human leukocytes, 400 μM 5-ASA reduces LTB4 production approximately 20%. 
5-Aminosalicylic acid does not inhibit 15-hydroxy PGDH at concentrations up to 50 μM.
5-Aminosalicylic acid is a monohydroxybenzoic acid that is salicylic acid substituted by an amino group at the 5-position. 
5-Aminosalicylic acid has a role as a non-steroidal anti-inflammatory drug. 
5-Aminosalicylic acid is an aromatic amine, an amino acid, a member of phenols, a monocarboxylic acid and a monohydroxybenzoic acid. 
5-Aminosalicylic acid is functionally related to a salicylic acid. 
5-Aminosalicylic acid is a conjugate acid of a mesalaminate(1-).
Preparation by reduction of m-nitrobenzoic acid with Zn dust and HCl.

5-Aminosalicylic acid, with the CAS number 89-57-6, is an organic compound that belongs to the class of salicylates. 
5-Aminosalicylic acid is characterized by the presence of both an amino group (-NH2) and a carboxylic acid group (-COOH) attached to a benzene ring, specifically at the 5 and 2 positions, respectively. 
5-Aminosalicylic acid is a white to off-white crystalline powder that is soluble in water and exhibits weak acidity. 
5-Aminosalicylic acid is primarily known for its role as a therapeutic agent in the treatment of inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, due to its anti-inflammatory properties. 
5-Aminosalicylic acid functions by inhibiting the production of inflammatory mediators and promoting mucosal healing. 
Additionally, 5-Aminosalicylic acid can undergo various chemical reactions, including acetylation and esterification, which can modify its pharmacological properties. 
5-Aminosalicylic acid's safety profile is generally favorable, although side effects may occur in some patients. 
Overall, 5-Aminosalicylic acid is a significant compound in both medicinal chemistry and therapeutic applications.

5-Aminosalicylic acid Chemical Properties
Melting point: 275-280 °C (dec.) (lit.)
Boiling point: 276.03°C (rough estimate)
density: 1.3585 (rough estimate)
bulk density: 300kg/m3
vapor pressure: 0Pa at 25℃
refractive index: 1.5500 (estimate)
Fp: 279-281°C
storage temp.: 2-8°C
solubility: Soluble in dimethyl sulfoxide.
pka: 2.74, 5.84(at 25℃)
form: tablets
color: off-white to gray
PH: 4.0-4.1 (0.8g/l, H2O, 20℃)
PH Range: Non-B uorescence (3.1) to light green B uorescence (4.4)
Water Solubility: <0.1 g/100 mL at 21 ºC
Decomposition: 279-281 ºC
Merck: 14,5904
BRN: 2090421
BCS Class: 4
Stability: Stable. Incompatible with acids, acid anhydrides, acid chlorides, chloroformates, strong oxidizing agents.
Major Application: Detergent, hair dyes, prevention of colorectal cancer, treating inflammatory bowel disease, autoimmune disorders, gastrointestinal inflammation, chemokine-mediated diseases, mucosal tissue disorder, sleep disorders, rectoanal tenesmus, ulcerative colitis
InChI: 1S/C7H7NO3/c8-4-1-2-6(9)5(3-4)7(10)11/h1-3,9H,8H2,(H,10,11)
InChIKey: KBOPZPXVLCULAV-UHFFFAOYSA-N
LogP: 0.98 at 25℃
CAS DataBase Reference: 89-57-6(CAS DataBase Reference)
NIST Chemistry Reference: 5-Aminosalicylic acid(89-57-6)
EPA Substance Registry System: Benzoic acid, 5-amino-2-hydroxy- (89-57-6)

Off-White to pink crystals, melting point about 280 ℃ (decomposition). 
Soluble in hydrochloric acid, slightly soluble in hot water, and slightly bath in cold water or ethanol. 
In the manufacture of light-sensitive paper, azo and sulfur dyes.

Uses    
5-Aminosalicylic acid is used in the preparation of gastrointestinal anti-inflammatory agents. 
5-Aminosalicylic acid is a metabolite of sulfasalazine. 
5-Aminosalicylic acid acts as a drug involved in the treatment of Crohn's disease and ulcerative colitis. 
Further, 5-Aminosalicylic acid is used to make dyes and light-sensitive papers.
5-Aminosalicylic acid has been used to synthesize 5-formyl-aminosalicylate-inulin to quantify its release during in vitro digestion and fermentation and compare the in vitro fermentation properties of the conjugated inulin to native inulin. 
5-Aminosalicylic acid is also used in cell adhesion assay to study its effects on E-cadherin glycosylation and membranous turnover. 
5-Aminosalicylic acid is used to evaluate its effects on the neutrophilic inflammation index (NII) phenotype to study the effectiveness of the high cholesterol diet-gut inflammation (HCD-GI) platform. 
5-Aminosalicylic acid is a peroxidase substrate suitable for use in ELISA procedures. 
This substrate produces a soluble end product that is brown in color and can be read spectrophotometrically at 450 nm. 
The reaction may be stopped with 3 N NaOH and read at 550 nm.

Medical uses
5-Aminosalicylic acid is used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease (effective only in colonic diseases).
In 2022 Germany introduced guidance to use mesalamine to treat acute uncomplicated diverticulitis.

Clinical Use    
Induction and maintenance of remission in ulcerative colitis

Side effects
Most often reported side effects are headache, nausea, diarrhea, and abdominal pain.
Very rarely, use of 5-Aminosalicylic acid has been associated with an exacerbation of the symptoms of colitis, Stevens–Johnson syndrome, and erythema multiforme.

Pregnancy
There is no data on use in pregnant women, but the drug does cross the placenta and is excreted in breast milk. 
The drug should not be used in children under two years of age, people with kidney disease, or people who are allergic to aspirin.

Mechanism of action
The exact mechanism of mesalazine is unknown, but 5-Aminosalicylic acid is speculated that mesalazine decreases synthesis of prostaglandin and leukotriene, modulating the inflammatory response derived from the cyclooxygenase and lipooxygenase pathways.
5-Aminosalicylic acid appears to act locally on colonic mucosa.
In 2025, 5-Aminosalicylic acid was reported to bind tubulin and stabilize microtubules.

Chemistry
5-Aminosalicylic acid is an active metabolite of sulfasalazine, which is metabolized to sulfapyridine and mesalazine.
5-Aminosalicylic acid is also the active metabolite of the prodrugs balsalazide (accompanied by the inert carrier molecule 4-aminobenzoyl-β-alanine) and olsalazine (which is metabolized to two equivalents of mesalazine). 
5-Aminosalicylic acid is in the category of disease-modifying antirheumatic drugs (DMARDs) family of medications.
5-Aminosalicylic acid is unclear exactly how it works.
5-Aminosalicylic acid is claimed to be a PPAR-γ agonist.

Manufacturing Process    
Procedure A: To 5-nitrosalicylic acid potassium salt (55 g, 246 mmol) dissolved in water (200 mL) was added potassium hydroxide pellets to reach pH 11.5. 
To this solution 2 g of Raney nickel were added. 
The mixture was heated-up to reflux and hydrazine hydrate (40 mL, 80% in water, 64 mmol) was added dropwise during 3-4 hrs. 
The reflux was maintened until HPLC showed the disappearance of the starting material and the complete reduction of 5-nitrosalicylic acid (3-4 hrs). 
The hot mixture was filtered under nitrogen and the solution was collected. 
The solution was cooled to 40°C and the pH was adjusted to 2.3 by addition of 35% HCl aqueous solution. 
The precipitation of 5-aminosalicylic acid occurred. 
The solution was cooled at 0°C, and after standing at this temperature for 2 hr, the precipitate was filtered, washed with water, and dried at 60-70°C. 
5-Aminosalicylic acid was obtained in 89% yield.

Procedure B: To 5-nitrosalicylic acid potassium salt (55 g, 246 mmol) dissolved in water (200 mL) was added potassium hydroxide pellets to reach pH 11.5. 
The solution was charged in a stainless steel autoclave and 2 g of Raney nickel are added. 
Hydrogen was introduced into the autoclave reaching a pressure of 8 atm. 
The mixture was heated-up to 100°C. 
The temperature was maintained until HPLC-test 5-aminosalicylic acid showed the disappearance of the starting material and the complete reduction of 5- aminosalicylic acid (6-8 hrs). 
Hydrogen was purged and replaced by nitrogen. 
The hot mixture was filtered under nitrogen, the filtrate was cooled to 40°C, and the pH was adjusted to 2.3 by addition of 35% HCl aqueous solution. 
The precipitation of the 5-aminosalicylic acid occurred. 
The solution was cooled at 0°C, and after standing at this temperature for 2 hr, the precipitate was filtered, washed with ion depleted water, and dried at 60-70°C.

Biochem/physiol Actions    
5-Aminosalicylic acid is a first-line medicine, used to treat inflammatory bowel diseases like ulcerative colitis (UC). 
5-Aminosalicylic acid has a high-efficiency rate in maintenance and induction of remission. 
5-Aminosalicylic acid is an active component of sulfasalazine and also consists of the carbohydrate polymer, inulin. 
5-Aminosalicylic acid might exhibit anti-oxidant activity to lessen tissue injury. 
5-Aminosalicylic acid is vital for the prevention of T cell activation and proliferation. 
5-Aminosalicylic acid negatively regulates cyclooxygenase and lipoxygenase pathways and lowers the formation of prostaglandins and leukotrienes. 
5-Aminosalicylic acid stimulates the membranous expression of E-cadherin and boosts intercellular adhesion.

Side effects    
5-Aminosalicylic acid is widely used to treat ulcerative colitis and is better tolerated than sulfadiazine. 
Common side effects of 5-Aminosalicylic acid include nausea, vomiting, abdominal pain, headache, and rash. 
5-Aminosalicylic acid is a rare side effect with only a few case reports. 
5-Aminosalicylic acid usually occurs within 2-4 weeks of medication and causes chest pain and dyspnea. 
In addition, 5-Aminosalicylic acid can aggravate bloody diarrhea in patients with Crohn's disease, which may be accompanied by decreased appetite or hair loss, and is generally uncommon.