Simultaneous Spectrophotometric determination of phenacetin and paracetamol in human plasma for the quantitative assessment of liver function reserve

Abstract

A simple, economical and reliable spectrophotometric method was developed for the simultaneous determination of phenacetin and paracetamol in human plasma. We purified the plasma samples by solid phase extraction procedure. The analytes reacted with chromogenic sodium 1,2-naphthoquinone-4-sulfonate and cetyltrimethyl ammonium bromide, and the products conformed to Beer’s law over the range 2 to 24 μg/ml for phenacetin and 1 to 16 μg/ml for paracetamol. The method was validated according to the Food and Drug Administration (FDA) guideline. There was no statistical difference between the proposed method and the modified high performance liquid chromatography (HPLC) method with regard to accuracy and precision. The proposed method is suitable for the quantitative assessment of liver function reserve in patients with liver cirrhosis. Key words: Spectrophotometric method, phenacetin, paracetamol, liver function reserve.