ELECTROOXIDATION AND DETERMINATION OF THE ANTIINFLAMMATORY DRUGS PIROXICAM AND TENOXICAM AT THE CARBON PASTE ELECTRODE

An investigation of the oxidation behaviour of the anti-inflammatory drug Piroxicam and a new one which is similar in structure and activity (Tenoxicam) at the carbon paste electrode (CPE) is presented. These compounds show a relatively similar voltammetric behaviour and degree of accumulation at the CPE surface. However, modification of the CPE with lauric acid improves sensitivity and also its selectivity, especially in complex media such as urine etc. To eliminate potent interfering compounds such as uric acid and ascorbic acid, the medium exchange method was also applied. A somewhat stronger adsorption of Tenoxicam than of Piroxicam was observed and therefore a lower concentration limit of linearity is obtained for Tenoxicam. After 60 s preconcentration, a detection limit of nearly 1 × 10-9 M for both Piroxicam and Tenoxicam could be determined. This method seems to be suitable for determinations in biological fluids. © 1990.