The chlorination behaviour and environmental fate of the antiretroviral drug nevirapine in South African surface water

The wastewater treatment process, besides discharging pharmaceuticals into the environment, has been found to result in the formation of a variety of undescribed compounds. Here we investigate the laboratory scale chlorination of the commonly used anti-HIV drug Nevirapine, characterise its disinfection transformation products (DTPs), and using liquid chromatography with high resolution mass spectrometry, screen environmental surface water for these DTPs. Chlorination of Nevirapine was scaled up, fractioned by preparative chromatography and the fractions were tested in vitro for toxicity and anti-HIV activity. Nevirapine was found to be resistant to degradation at relevant chlorination levels, which may partially explain its ubiquitous presence in South African surface water. During simulated chlorination, a variety of DTPs with varying properties were formed, some of which were detected in the environment, close to wastewater treatment plants. Interestingly, some of these compounds, although not as toxic as Nevirapine, retained antiviral activity. Further purification and synthesis is required to fully characterise these novel molecules. [Display omitted] •Nevirapine is resistant to chlorination; may explain its environmental prevalence.•Nevirapine forms a variety of chlorination disinfection transformation products in vitro.•These compounds were detected in the environment by UHPLC-QTOF.•The disinfection transformation products were non-toxic in vitro, with slight antiviral activity.•Potentially biologically active modified pharmaceuticals are released into the environment.