CAS: 1242567-09-4

Impurity Balsalazide USP Impurity 2 Applications An isomeric impurity of the anti-inflammatory drug Balsalazide (B116310). Balsalazide USP Impurity 2.

Balsalazide 3-isomer (BZ3) is a diacid that is used as an anti-hypertensive drug. BZ3 has been shown to be a prodrug of balsalazide, which is converted in vivo to the active form by hydrolysis of the ester linkage. The prodrug approach was designed to provide an orally available agent for use in patients with colitis and ulcerative colitis. The synthetic process begins with the reaction of salicylic acid and bisoprolol to form the ester product, which then undergoes a second reaction with acetyl chloride to form the acyl chloride intermediate. This intermediate reacts with balsalazide and yields BZ3 when heated to high temperatures. BZ3 contains no impurities because it is synthesized from pure starting materials, whereas commercially available balsalazide may contain impurities such as salicylic acid or colitis.