Spectrophotometric Determination of Mesalazine

Mesalazine (MESA) is determined by a simple and rapid visible spectrophotometric method. This method is depend on oxidative coupling reaction of mesalazine with histidine (HIS) in alkaline media using N-bromosuccinimide (NBS) as oxidizing agent to form a water soluble and stable product, that it has a maximum absorption at 459 nm. Beer's law is followed in a concentration range of 50 to 750 g /20ml (2.5-37.5 g /ml) with a molar absorptivity of 3.3682103 l.mol-1. cm-1. The recommended method has been successfully applied to the assay of MESA in pharmaceutical preparations.