KINETIC AND CHEMICAL ASSESSMENT OF THE UV/H2O2 TREATMENT OF ANTIEPILEPTIC DRUG CARBAMAZEPINE

The UV/H2O2-induced degrdn. of carbamazepine, a worldwide used antiepileptic drug, recently found as contaminant in many municipal sewage treatment plant (STP) effluents and other aquatic environments, is studied. The oxidn. treatment caused an effective removal of the drug. At complete abatement of the substrate after 4 min treatment, a 35% value of removed total org. C (TOC) was obtained. A kinetic const. of (2.05±0.14) ´ 109 L/mol-s was detd. for OH radical attack to carbamazepine in the UV/H2O2 process. Preparative TLC of the reaction mixt. led to the isolation of acridine-9-carboxaldehyde as a reaction intermediate. HPLC and GC/MS anal. indicated formation of small amts. of acridine, salicylic acid, catechol and anthranilic acid among the reaction products. Under the same reaction conditions, synthetically prepd. 10,11-epoxycarbamazepine was easily degraded to acridine as main product, suggesting that this epoxide is a likely intermediate in the oxidative conversion of carbamazepine to acridine. Under sunlight irradn., carbamazepine in water underwent slow degrdn. to afford likewise acridine as main product. In view of the mutagenic properties of acridine, these results would raise important issues concerning the possible environmental impact of carbamazepine release through domestic wastewaters and support the importance of prolonged oxidn. treatments to ensure complete degrdn. of arom. intermediates.