Spectrophotometric determination of paracetamol in drug formulations with 2-iodylbenzoate

Abstract

Paracetamol (N-acetyl-4-aminophenol) undergoes oxidation with 2-iodylbenzoate in acid medium, producing an orange-yellow colour that attains maximum intensity within 1 min and absorbs maximally at 444 nm. Determination is made either by adding an excess of the reagent to paracetamol and measuring the colour spectrophotometrically or by titrating the test solution photometrically with standardised 2-iodylbenzoate. The Sandell sensitivity is 0.232 µg cm^–2 of paracetamol and the method is suitable for routine analysis and unaffected by the presence of salicylamide, oxyphenbutazone, analgin and a number of other excipients.