Simultaneous Spectrophotometric Determination of Paracetamol and p-Aminophenol in Pharmaceutical Products with Tiron Using Dissolved Oxygen as Oxidant

Abstract

A simple, rapid, and specific method was developed for the determination of paracetamol and p-aminophenol. The method is based on the hydrolysis of paracetamol to p-aminophenol, which, using dissolved oxygen as an oxidant in the alkaline region, was further transformed into benzoquinoneimine, capable of reacting with tiron to produce a green indophenol dye. The stabilization of indophenol dye was achieved by the addition of copper(II) solution. The absorbance was measured at 601 nm in alkaline medium, and the molar absorptivity was found to be 1.1 × 10 4 L/(mol cm). Paracetamol (PCT) and p-aminophenol (PAP) were determined in pharmaceutical products in the 1.5-15 mg/L PAP concentration range with a detection limit of 1.2 × 10 -6 M or 0.13 µ g/mL PAP. The developed method can be applied to the determination of p-aminophenol in the presence of paracetamol without prior separation. The proposed method is successfully employed for determination of paracetamol and p-aminophenol in various synthetic mixtures and pharmaceutical preparations. The obtained results were statistically compared with those given by the official method and the procedures evaluated as regards to both figures of merit and ease of applicability.

Spectrophotometric determination of paracetamol in drug formulations with 1 – naphthol

“…The recovery ranged from 98.28 % to 101.6 % while the relative standard deviation of all the five samples ranged from 0 % to 0.76 %. These values are also in agreement with similar work available in literature (Cekic et al 2005). …”

Determination of paracetamol: Historical evolution

“…Besides, the main advantage is the reduction of reagent consumption; the developed method is based on the microwave assisted alkaline hydrolysis of PCT to p-aminophenol (PAP) and its subsequent oxidation in alkaline medium by periodate to benzoquinoneimine, which reacts at room temperature with PBHQ to produce a blue indophenol dye. Also, a simple, rapid and specific method was developed for the determination of PCT and PAP [88]; it is based on the hydrolysis of PCT to PAP, which, using dissolved oxygen as an oxidant in the alkaline region, was further transformed into benzoquinoneimine, capable of reacting with tiron to produce a green indophenol dye. The stabilisation of indophenol dye was achieved by the addition of Cu(II) solution.…”

Enhanced aminophenols monitoring using in-channel amperometric detection with dual-channel microchip capillary electrophoresis

“…However, because of p-aminophenol's wide application in industry as a raw chemical material and as an important intermediate, the amount of wastewater from its production has been increasing (Cekic et al 2005;Song and Chen 2001;Xu et al 2005;Hamm 2000;Vandaveer et al 2002). Moreover, as p-aminophenol is a metabolite of aniline, nitrobenzene and paracetamol, it is used as a biological marker for human aniline exposure and other applications in occupational medicine and toxicology (Xu et al 2005;Van Bocxlaer et al 1997).…”