SPECTROPHOTOMETRIC DETERMINATION OF PARACETAMOL USING ZIRCONIUM (IV) OXIDE AND AMMONIUM TRIOXOVANADATE (V)

Abstract

The aims of this work were to develop and validate rapid, simple and sensitive spectrophotometric method for the determination of paracetamol and to use the developed method to quantitatively assay paracetamol in   pharmaceutical preparations. The method was based on the oxidation Paracetamol by zirconium (IV) and vanadium (V) in alkaline and acidic media respectively. The stoichiometric studies indicated a mole-ratio of 1:1 for the reactions of paracetamol with both oxides. Effects of pH, temperature and time on the reaction processes were investigated and results showed that the optimum conditions for the oxidation of paracetamol by Zr (IV) were pH of 9.0, temperature of 50˚C and at reaction time of 20 min yielding red- brown complex which absorbed at a λmax of 420 nm. Similarly, optimum conditions for the oxidation of paracetamol by V (V) were pH of 1.0, temperature of 70˚C at 8 min giving a bluish-violet complex which absorbed at a λmax of 600 nm. The Beer-Lambert’s law was obeyed at a concentration range of 5.0-40.0 μg/cm3 for paracetamol with both Zr (IV) and V(V) with correlation coefficients of 0.997 and 0.999 respectively. The mean % recovery of paracetamol in dosage form with Zr (IV) was 99.06%, while V (V) gave 100.17%. Hence, the recovery studies had proved the method to be accurate, simple and precise. The procedures were successfully applied to the determination of this compound in pharmaceutical tablets. This novel method provides potentially easy, reliable and cheap means of analysis of paracetamol in bulk and pharmaceutical preparations. Keywords: spectrophotometric, novel, stoichiometric, zirconium, vanadium, paracetamol