Degradation of Vancomycin Hydrochloride by Electrooxidation

Many pharmaceuticals are considered recalcitrant pollutants and represent a problem for human and animal health due to continuous contribution in the aquatic environment and the bacteria resistance development to antibiotics. Vancomycin is one of the most antibiotics administered in medicine, nevertheless, there is not much knowledge about the presence, fate and the effects of Vancomycin in the environment. The advanced oxidation techniques (AOTs) are shown as alternatives for the treatment of water and wastewater in order to degrade pollutants and contaminants. Therefore, this work is aimed to evaluate the Vancomycin degradation in an aqueous medium using electrooxidation (EO) technique and to optimize the reaction conditions. The experiments were conducted in a homemade electrochemical cell in acrylic with a working volume of 500 cm3; DSA electrodes – Dimensionally Stable Anodes (70TiO2-30RuO2) were used (effective area of work - 41.25 cm2); NaCl P.A. was used as supporting electrolyte; 130 mg L-1 of Vancomycin was used in aqueous solution. The optimization was done using central composite design (CCD) totaling 18 experiments. The evaluated factors were: interelectrodes distance (ID), applied current and supporting electrolyte concentration. All experiments were conducted for 20 minutes with sampling at 0, 1, 2, 3, 4, 5, 10 and 20 minutes. Vancomycin concentrations were determined by High Performance Liquid Cromatography with Diode-Array Detection (HPLC-DAD) (Mobile phase: phosphate buffer 0.05 mol L-1, pH 4.7: MeOH: ACN [80:15:5, v/v], Injection volume: 40 L; C18 with flow rate of 1.0 mL min-1, λ: 210 nm. The results show that the electrooxidation is effective in Vancomycin degradation, showing as an alternative to degradation of this drug. The method used obtained 100% of degradation in 2 minutes of treatment in optimum conditions: 400 mA, 3 cm interelectrodes distance and 1,100 mg L-1 NaCl.