Colorimetric Determination of Paracetamol Using 9-Chloroacridine Reagent: Application to Pharmaceutical Formulations

This paper aims to develop a simple, sensitive and accurate spectrophotometric method for quantitative determination of paracetamol in aqueous medium. The method is based on the reaction between the hydrolyzed paracetamol and 9-chloroacridine reagent (9-CA). The spectra of the product show maximum absorption at 436 nm. Beer’s law is obeyed in the concentration range of 0.25-11 mg/mL with molar absorptivity value 5.3×10 L/mol/cm. The average recovery percentage (Rec%) is 99.27% and relative standard deviation (RSD) is £ 2.82%. In addition, the stability constant has been determined and the reaction mechanism is proposed. The method has been applied successfully for the assay of paracetamol in pharmaceutical formulations. It is found that the method does not require extraction process and it agree well with British pharmacopeia.