Supported Ionic Liquids (SILs) as functional materials for the removal of hazardous pharmaceuticals

Abstract

Environmental contamination by highly toxic pharmaceuticals is a matter of great concern. Cytostatic drugs, used to treat cancer, are amongst the most toxic pharmaceutical released into the aquatic environment. To mitigate this serious environmental and public health problem, several technologies have emerged for their removal envisioning their implementation in wastewater treatment plants [1-2]. Nevertheless, they are not completely efficient in the removal of pharmaceuticals, including cytostatics. Since urine only represents 1% of the volume of the total domestic wastewater [3], one of the best ways to avoid contamination with cytostatics is by removing them at the entrance point, i.e. from the urine. This could be achieved using silica particles functionalized with ionic liquids (IL), to be applied as a device in urinary settings. Materials functionalized with ionic liquids, namely supported Ionic Liquids (SILs), can be envisaged as suitable tools for the removal of pharmaceuticals, since they join the advantages of solid supports and the tunable char acteristics of ILs [4]. In this work, several SILs based on quaternary ammonium were synthetized using silica as the support material and changing the alkyl chain length of the quaternary ammonium. After characteriza tion, the adsorption behavior of these SILs for distinct cytostatic drugs, viz. cyclophosphamide, mycophenolate acid and its pro-drug mycophenolate mofetil, 5-fluorouracil and its pro-drug, was evaluated by determining ad sorption kinetics and isotherms. Studies of adsorption of each drug in continuous mode and in mimicked urine samples were conducted demonstrating the potential of SILs to be incorporated in a urinary device