June 1, 2010 by David Taylor
This chapter has now been published in the text book Green and Sustainable Pharmacy (Edit: Kümmerer & Hemple, Pub: Springer) and describes the environmental activities being pursued by the research pharmaceutical companies to produce a more sustainable business.
The chapter includes sections on the whole life cycle of pharmaceuticals: Stakeholders, Greener Drug Design, Sustainability issues in R&D, manufacturing, sales & distribution and finally product use and disposal. The chapter concludes with a summary of the current position and the immediate research needs.
In the last 20 years since Richardson and Bowron (1985) produced their seminal publication, we have learnt a great deal about the potential impact of pharmaceutical residues in the environment. We recognise that many pharmaceuticals can be found at ng l-1 concentrations in the environment, (with some at concentrations in the low µg l-1) primarily as a direct consequence of therapeutic use by patients leading to constant input from multiple sources. The impact on human health appears to be insignificant, as does the acute impact on ecosystems. At present long term impacts on ecosystems caused by some pharmaceuticals cannot be ruled out, although increasingly the evidence from chronic studies does not indicate that these are widespread (Boxall et al. 2008).
Nevertheless the research pharmaceutical companies take their stewardship responsibilities seriously and are continuing to pursue research to reduce the uncertainties further. There are a number of areas where further investigations would be helpful, as described below.
A very large amount of information on pharmacokinetics and mammalian toxicology is produced during the development of any new medicine. Initial studies (Owen et al. 2007) have shown that such information could be valuable in developing intelligent ecological testing strategies but much more work is needed to investigate and validate this approach.
It is known that some pharmaceuticals are removed from wastewater by biological treatment plants; some are partially removed whilst others pass straight through. However, it is not known whether the pharmaceuticals are degraded or simply adsorbed onto the sewage sludge and, if the latter is the dominant mechanism, whether the adsorbed material can be desorbed. It has also been observed that removal efficiencies can vary dramatically, even with the same plant configuration, which raises the question as to whether all existing biological treatment plants could be tuned for maximum removal efficiency.
Most pharmaceutical compounds are not ‘readily degradable’ but few of them could be classified as completely persistent. Most of them appear to degrade slowly in the environment via a variety of biotic and abiotic mechanisms. Further studies in this area, especially if the mechanism could be linked to structure, would enable improved prediction of actual environmental concentrations to be undertaken and could potentially provide valuable information during the lead identification and optimisation stages in drug design.