5-Aminosalicylic acid
[CAS# 89-57-6]

Identification

• Classification: API >> Digestive system medication >> Acid and gastric mucosal protective drugs
• Name: 5-Aminosalicylic acid
• Synonyms: 2-Hydroxy-5-aminobenzoic acid; 3-Carboxy-4-hydroxyaniline; 5-ASA; Mesalamine; Mesalazine; Rowasa; 5-Amino-2-hydroxybenzoic acid
• Molecular Formula: C₇H₇NO₃
• Molecular Weight: 153.14
• CAS Registry Number: 89-57-6
• EC Number: 201-919-1
• SMILES: C1=CC(=C(C=C1N)C(=O)O)O

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*
• Melting point: 275 - 280 °C (Decomposes) (Expl.)
• Boiling point: 403.9±40.0 °C 760 mmHg (Calc.)^*
• Flash point: 198.1±27.3 °C (Calc.)^*
• Solubility: DMSO 30 mg/mL, Water $lessThan$1 mg/mL (Expl.)
• Index of refraction: 1.691 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H317-H319-H335-H412
• Safety Statements: P261-P264-P264+P265-P271-P272-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P333+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin sensitization	Skin Sens.	1A	H317
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H302

Discovery and Applications

5-Aminosalicylic acid is an aromatic compound characterized by a benzene ring substituted with an amino group (–NH₂) at the 5-position and a hydroxyl group (–OH) and a carboxylic acid group (–COOH) at the 2-position, making it a derivative of salicylic acid. Its molecular formula is C₇H₇NO₃. The compound is also commonly known as mesalazine or mesalamine.

5-Aminosalicylic acid was first identified and synthesized as part of research into salicylic acid derivatives. It gained prominence due to its therapeutic properties, particularly in the treatment of inflammatory bowel diseases. Its structure, combining amino, hydroxyl, and carboxyl groups on an aromatic ring, contributes to its biological activity.

The primary application of 5-aminosalicylic acid is in the pharmaceutical field as an anti-inflammatory agent used to treat conditions such as ulcerative colitis and Crohn’s disease. It acts locally in the colon to reduce inflammation, although its exact mechanism of action is not fully elucidated, it is believed to involve inhibition of cyclooxygenase and lipoxygenase pathways, reducing the production of inflammatory mediators like prostaglandins and leukotrienes.

The compound is administered orally or rectally in various formulations, including tablets, enemas, and suppositories, designed to deliver the drug directly to the site of inflammation in the intestinal tract. Controlled-release and delayed-release formulations improve its efficacy by ensuring targeted delivery and minimizing systemic absorption.

In addition to its anti-inflammatory effects, 5-aminosalicylic acid exhibits antioxidant properties by scavenging free radicals, which may contribute to mucosal healing in the gastrointestinal tract. Its safety profile is generally favorable, but side effects can include headache, nausea, and hypersensitivity reactions in some patients.

Analytical characterization of 5-aminosalicylic acid employs techniques such as nuclear magnetic resonance (NMR) spectroscopy to verify its chemical structure and purity. Infrared (IR) spectroscopy detects characteristic absorption bands for amino, hydroxyl, and carboxyl groups. High-performance liquid chromatography (HPLC) is widely used for quantitative analysis and quality control in pharmaceutical preparations.

From a chemical standpoint, 5-aminosalicylic acid’s reactivity includes typical aromatic substitution reactions, with its amino and hydroxyl groups influencing the electron density of the ring. The compound can be derivatized to form prodrugs, such as sulfasalazine, which release 5-aminosalicylic acid upon metabolism in the colon.

Safety considerations for handling the compound in laboratory or manufacturing settings involve standard precautions to avoid inhalation or skin contact, including the use of personal protective equipment and adequate ventilation.

In summary, 5-aminosalicylic acid is an established anti-inflammatory agent used primarily in treating inflammatory bowel diseases. Its chemical structure and properties have been thoroughly studied, enabling diverse pharmaceutical formulations that maximize therapeutic efficacy. Analytical methods and safety protocols ensure its quality and safe use in medical and industrial contexts.

References

1994. Disposition of 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid in fetal and maternal body fluids during treatment with different 5-aminosalicylic acid preparations. Acta Obstetricia et Gynecologica Scandinavica, 73(4).
DOI: 10.3109/00016349409006251

1994. Amino acid derivatives of 5-ASA as novel prodrugs for intestinal drug delivery. Digestive Diseases and Sciences, 39(12).
DOI: 10.1007/bf02087696

1990. Inhibition of cell mediated cytotoxicity by sulphasalazine: effect of in vivo treatment with 5-aminosalicylic acid and sulphasalazine on in vitro natural killer cell activity. Gut, 31(9).
DOI: 10.1136/gut.31.9.1030