Pharmaceuticals in the Environment
When pharmaceuticals are administered to patients, some of the active ingredient may not be completely metabolised (biochemically altered and inactivated). These unmetabolised portions are generally excreted and find their way into sewage effluents where they are transported to wastewater treatment systems that remove most of the pharmaceutical residues. However, extremely low concentrations may pass through the wastewater treatment plant and be discharged to the environment. Historically, the presence and amount of pharmaceuticals in different parts of the environment have been estimated. Recently, as a result of advances in analytical techniques, extremely low concentrations of pharmaceuticals are being measured in wastewater, surface water (rivers and streams) and drinking water.
Pharmaceuticals in the environment have been regulated in the USA by the US Food and Drug Administration (FDA) since 1977 under the auspices of the National Environmental Policy act of 1969. Regulation occurs through the environmental review process for New Drug Applications submitted to the FDA. In the late 1980s, additional information was required from pharmaceutical companies by the FDA and more extensive information was provided in environmental risk assessments that accompanied New Drug Applications. However, an evaluation of the data submitted from the late 1980s through the mid-1990s led the FDA to revise the regulations in 1997 to minimise environmental risk assessment data required in New Drug Applications.
In Europe, pharmaceuticals in the environment have received regulatory attention through the submission of Environmental Risk Assessments (ERAs) that accompany Marketing Authorisation Approval. Revised draft guidelines for European ERAs were recently reviewed by various stakeholders and the final guidelines are expected to be available in mid-2004. In Canada, a requirement for environmental assessment is in place and the ERA process is under consideration.
Since the late 1980s GlaxoSmithKline has been actively working with various regulatory agencies to ensure that potential environmental impacts of pharmaceuticals are understood and minimised. Recently, there have been significant industry efforts to develop improved environmental risk assessment models in the United States and Europe. These models are being used to identify potential risks of GlaxoSmithKline pharmaceutical products entering the environment through patient use.
GSK is playing a major role in the development of one such model,
working with the research-based pharmaceutical industry, through
its trade association PhRMA (Pharmaceutical Research and
Manufactures of America). The industry task force developed a state-of-the-art
spatially explicit model to facilitate a deeper understanding of
potential environmental distribution of pharmaceuticals at a local
or regional level. The PhATE™ (Pharmaceutical Assessment
and Transport Evaluation) model is a watershed-based approach and
was developed as a tool to more realistically estimate concentrations
of active pharmaceutical ingredients (APIs) discharged to U.S. surface
waters through consumption of medicines.
PhATE uses a mass balance approach to model predicted
environmental concentrations (PECs) in eleven watersheds that are
felt to be representative of most hydrologic regions of the United
States. Upon dividing the associated rivers into discrete segments,
the model estimates the mass of API that enters a segment from upstream
or from publicly owned treatment works (POTWs) and the mass that
is subsequently lost from the segment via in-stream loss mechanisms
or flow diversions (i.e., man-made withdrawals). POTW discharge loads
are estimated based on the population served, API use per capita,
and the mass of the API removed in the POTW.
Environmental concentration data reported by the U.S. Geological Survey (USGS) provided the means by which the model could be corroborated (Kolpin
et al., 2002; Tabor and Barber, 1993). Details of the model development were reported in February, 2004 (Anderson
et al., 2004).
Although the model is still under active development, it currently allows potential concentration profiles to be evaluated across diverse geographic localities. For most pharmaceutical compounds, measured concentrations are generally low (ng/l-ug/L range), and the potential for adverse acute environmental impacts is anticipated to be low as well. Work continues within and among the pharmaceutical industry, academia, government labs and other scientific institutions, to further our understanding of these issues.
Risk assessments using these models, combined with currently available human and environmental fate and effects data, indicate that GlaxoSmithKline pharmaceuticals in the environment do not present a risk to humans or the environment. As part of its product stewardship activities, GlaxoSmithKline continues to monitor the latest scientific studies and findings to continually improve risk assessments in this area.
Anderson, P.D., V.J. D'Aco, P. Shanahan, S.C.
Chapra, M.E. Buzby, V.L. Cunningham, B.M. DuPlessie, E.P. Hayes,
F. Mastrocco, N.J.
Parke, J.C. Rader, J.H. Samuelian, and B.W. Schwab, in review.
Screening analysis of human pharmaceutical compounds in U.S.
surface waters, Environmental Science and Technology,
38: 838-849.
Kolpin, D.W., E.T. Furlong, M.T. Meyer, E.M.
Thurman, S.D. Zaugg, L.B. Barber, and H.T. Buxton. 2002. Pharmaceuticals,
hormones,
and other organic wastewater contaminants in U.S. streams, 1999-2000:
a national reconnaissance. Environmental Science and Technology,
36: 1202-1211.
Tabor, C.F., and L.B. Barber. 1996. Fate of
linear alkylbenzene sulfonate in the Mississippi River: Environmental
Science and Technology,
30: 161-171.
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