P‐Dimethyl Amino Benzaldehyde as a New Chromogenic Reagent for the Determination of Nonsteroidal Anti‐Inflammatory Drug by First‐Order Derivative Spectrophotometry

Abstract

Mefenamic acid reacts with P‐dimethylamino benzaldehyde to give a bluish‐green complex in acidic media after heating for 90 s at 90°C, having maximum absorbance at 597.5 nm. The reaction is selective for mefenamic acid with 0.02 mg/10 mL as visual limit of quantitation and provides a basis for a new spectrophotometric determination. The reaction obeys Beer's Law from 0.02 mg to 2.5 mg/10 mL of mefenamic acid and the relative standard deviation is 0.50%. The quantitative assessment of tolerable amounts of other drugs not interfering has also been studied. First‐order derivative spectrophotometric procedure was applied for the determination of mefenamic acid in pharmaceutical preparations.

Keywords:

• Mefenamic acid
• P‐dimethyl amino benzaldehyde
• first order spectrophotometry