Ireland has a successful pharmaceutical industry with over 100 pharmaceutical manufacturing sites across the island. Although this success has many benefits, the irreversible effects emissions from pharmaceutical manufacturing can have on the environment are a major drawback. Although known pollutants are regularly monitored with limits set out by the Environmental Protection Agency, one significant pollutant has been overlooked: pharmaceutical pollution. Detecting these pollutants and ensuring they are at a safe concentration for the environment is of utmost importance. In recent years, capillary electrophoresis is being recognised as a suitable alternative to high‐performance liquid chromatography due to its many benefits such as faster analysis, water‐based buffers and smaller sample volumes. In this paper, a capillary zone electrophoresis (CZE) method with a preconcentration step of solid‐phase extraction was developed for an anti‐parasitic active pharmaceutical ingredient (API) called ZB23. The API was successfully detected in a wastewater sample in less than 10 min using the CZE parameters of 25 mM borate buffer with a pH of 10.5, 15% MeOH, 10 kV voltage, 25 mbar for 5 s injection size, an Lt of 40 cm, an Ld of 31.5 cm and a detection wavelength of 214 nm.