Degradação da citarabina, creatinina e ureia pelo processo sonoeletroquímico foto-assistido em meio à urina artificial

Abstract

The increase in the number of patients diagnosed with cancer is a reality experienced in many health units worldwide. In this context, the residues resulting from cancer treatment are worrisome as one of their characteristics is their potential toxicity and environmental impact. In this aspect, the present study sought to evaluate the combination of three techniques: electrochemistry, photochemistry and sonochemistry, called photo-assisted sono-electrochemistry, for the degradation of the chemotherapeutic drug cytarabine, creatinine and urea. The tests were carried out using a continuous-flow electrochemical bench-scale reactor. A Ti mesh cathode and a Ti/Ru0.3Ti0.7O2 anode were used. The working electrode was irradiated by an ultraviolet light source inserted directly into the cell and the spacing between the electrodes was maintained at 4.36 mm. The experimental design was applied in terms of percentage of total organic carbon removal (TOC) to analyze the mineralization of the organic compounds in solution. Thus, the most significant variables were obtained and the optimum conditions for the degradation assays were determined. From the experimental design, the most significant variable was the flow-rate with a negative influence, followed by the electric current and the time, both of which had a positive influence on the response. From UPLC-MS (Ultra Performance Liquid Chromatography coupled with Mass Spectrometry) analysis it is inferred that the process resulted in the removal of ancitabine (cytarabine precursor) and suggests that a longer degradation time will be required for cytarabine degradation. Thus, the UPLCMS evaluation corroborates with the data obtained by the experimental planning and, therefore, the central composite design was carried out to explore the optimum degradation condition, obtaining a flow rate of 1.73 mL min-1, current 1.4 A and reaction time of 198 min. The results indicated that the use of urine as a supporting electrolyte increases the TOC content in the medium and interferes in the electrochemical process due to the reduction of the electrode sites of the electrode, causing the degradation to have lower removal values than in aqueous medium containing only NaCl as supporting electrolyte. However, significant removal of the organic compounds present in the effluent is observed even in a more complex degradation matrices.