Photocatalytic Degradation of Oseltamivir Phosphate and Residual Toxicity Evaluation of its Metabolites as a Sustainable Solution for Antiviral Drug Pollution

Abstract The global consumption of antiviral drugs (AVD) during the ongoing pandemic has overwhelmed wastewater treatment plants, which struggle to effectively remove these compounds due to their hydrophilic nature. Current methods fall short of fully degrading AVDs, leaving behind potentially harmful residues. In this study, we aim to investigate the photocatalytic degradation of oseltamivir phosphate under UV light, with and without the presence of catalysts. To address this challenge, we explored the use of titanium dioxide (TiO 2 ) as a cost-effective and highly stable photocatalyst. In combination with carbon nanotubes and UV-A radiation (365 nm), TiO 2 demonstrated exceptional efficiency in degrading oseltamivir phosphate, a common antiviral drug. Under optimized conditions, initial concentration (C0) of 1 mg/L, TiO 2 and carbon nanotube catalyst concentration (Ccat) of 0.1 g/L, and pH of 6.0, the system achieved complete degradation (100%). The degradation process followed pseudo-first-order kinetics with a strong correlation coefficient (r 2 = 0.8593). To confirm the degradation, we monitored changes in pH, Raman shifts, and FTIR spectra before and after treatment. Analytical methods, including UV–visible spectrophotometry and High-Performance Liquid Chromatography (HPLC), were used to quantify the degradation efficiency. Moreover, toxicity studies on wheat seeds indicated that the metabolites produced during oseltamivir phosphate degradation were non-toxic, suggesting the process is environmentally safe. This approach offers a promising solution for addressing AVD pollution in wastewater while minimizing ecological risks.