Spectrophotometric determination of Sulfasalazine drug in pure and Pharmaceutical preparation using sodium 1, 2-naphthoquinone-4-sulfonate (NQS) reagent

A simple spectrophotometric method was developed to determine the sulfasalazine drug. The method based on the reaction between sodium 1, 2-naphthoquinone-4-sulfonate (NQS) regent with the amino group in the sulfasalazine drug. Maximum absorption of the product was recorded at 456 nm. Beer’s law was obeyed within the concentration range (1-25) ×10⁻⁵ M. The molar absorptivity was 1.438 ×10⁴ L. mole⁻¹. cm⁻¹. Molar ratio and Job’s methods revealed that the ratio between the sulfasalazine drug and NQS reagent is 1:1. Average recovery, relative standard deviation (RSD), limit of quantitation (LOQ) and limit of detection (LOD) were 103.6011%, 0.6072%, 0.0273 and 0.0911 M, respectively. The suggested method was also applied to the sulfasalazine tablets (pharmaceutical preparation).