Drug Groups

approved; investigational

Description

Balsalazide is an anti-inflammatory drug used in the treatment of Inflammatory Bowel Disease. It is sold under the name "Colazal" in the US and "Colazide" in the UK.

The chemical name is (E)-5-[[-4-(2-carboxyethyl) aminocarbonyl] phenyl]azo] -2-hydroxybenzoic acid. It is usually administered as the disodium salt.

Balsalazide releases mesalazine, also known as 5-aminosalicylic acid, or 5-ASA, in the large intestine. Its advantage over that drug in the treatment of Ulcerative colitis is believed to be the delivery of the active agent past the small intestine to the large intestine, the active site of ulcerative colitis.

Indication

For the treatment of mildly to moderately active ulcerative colitis.

Pharmacology

Balsalazide is a prodrug that has little or no pharmacologic activity until it is enzymatically cleaved in the colon to produce mesalamine (5-aminosalicylic acid), an anti inflammatory drug indicated for the treatment of mildly to moderately active ulcerative colitis. Balsalazide disodium is delivered intact to the colon where it is cleaved by bacterial azoreduction to release equimolar quantities of mesalamine, which is the therapeutically active portion of the molecule, and the intert 4-aminobenzoyl-(beta)-alanine. As a result, the spectrum of pharmacologic activity of balsalazide is similar to that of mesalamine.

Toxicity

A single oral dose of balsalazide disodium at 5 grams/kg or 4-aminobenzoyl-(beta)-alanine, a metabolite of balsalazide disodium, at 1 gram/kg was non-lethal in mice and rats. No symptoms of acute toxicity were seen at these doses.

Affected Organisms

Biotransformation

Cleaved in the colon via bacterial azoreduction to 5–aminosalicylic acid (5–ASA) and 4–aminobenzoyl-beta-alanine, the inactive carrier moiety.

Absorption

Low and variable, intact balsalazide is poorly absorbed systemically.

Half Life

Half-life could not be determined.

Protein Binding

≥99%

Elimination

The products of the azoreduction of this compound, 5-ASA and 4-aminobenzoyl-?-alanine, and their N-acetylated metabolites have been identified in plasma, urine and feces. Following single-dose administration of 2.25 g COLAZAL (three 750 mg capsules) under fasting conditions in healthy subjects, mean urinary recovery of balsalazide, 5-ASA, and N-Ac-5-ASA was 0.20%, 0.22% and 10.2%, respectively.

References

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