Although the issue of pharmaceuticals in the environment has been known for many years in some quarters, it has recently come to the attention of the general public in a much more substantive way. This has led to a growing body of research on environmental risk assessment and the environmental classification of drugs, as well as on the stewardship of drugs post-manufacturing (Kümmerer 2007). As with any chemical-containing article it is important that we understand, control, avoid or minimise the impact of the drugs entering the environment, and the deliberately high biological activity of active pharmaceutical ingredients (APIs) makes this especially important. There are many authoritative publications on the impact of pharmaceuticals on the environment post consumer use, and so these issues will not be addressed in any significant way in this chapter, but very little work has been carried out on determining the environmental impact of pharmaceuticals prior to administration to the patient.