Project

iPiE - Intelligence-led Assessment of Pharmaceuticals in the Environment

Goal: The overall aim of the IPiE project is to develop predictive frameworks that utilise information from existing datasets on environmental fate and effects of APIs, toxicological studies, pharmacological mode of action and in silico models to support more intelligent environmental testing of pharmaceuticals in development and to prioritise legacy pharmaceuticals for full environmental risk assessment and/or environmental (bio) monitoring.

Methods: Database Development, Expert Systems, Environmental Monitoring, ecotoxicity testing, chemical prioritisation, QSARs, environmental fate testing, QSPRs, exposure modelling

Date: 1 January 2015 - 31 December 2018

Updates
0 new
0
Recommendations
0 new
0
Followers
0 new
65
Reads
0 new
1024

Project log

Rik Oldenkamp
added a research item
An environmental risk assessment (ERA) is presented for Mycophenolic acid (MPA), an immunosuppressive pharmaceutical used for prevention of organ rejection, and its prodrug Mycophenolate mofetil (MPM). MPA will not significantly adsorb to activated sludge. 14C‐MPA attained >80% degradation in activated sludge, supporting an older environmental fate test with 14C‐MPM. Based on the logDOW of 2.28, 0.48 and ≤–1.54 at pH 5, 7 and 9, respectively, MPA is not expected to bioaccumulate. Sales amounts of MPA+MPM in Europe were used to derive predicted environmental concentrations (PECs) in surface waters; PECs were refined by including expected biodegradation in sewage treatment, average drinking water use and average dilution of the effluents in the receiving waters per country. Further, the ePiE (exposure to Pharmaceuticals in the Environment) model was run for four European catchments. PECs were complemented with 110 measured environmental concentrations (MECs), ranging from below limit of quantitation (<0.001 µg/L) to 0.656 µg/L. Predicted no‐effect concentrations (PNECs) were derived from chronic tests with cyanobacteria, green algae, daphnids and fish. The comparison of PECs and MECs with the PNECs resulted in a differentiated ERA, where in the majority (mostly >90%) of cases the risk ratio of PEC/PNEC or MEC/PNEC is <1, meaning no significant risk, but in generally <10% of instances there is potential risk to aquatic organisms. As this ERA is not risk or no risk, but shows partial risk, the questions must be asked, 'how much risk is acceptable?' and 'through which measures can this risk be reduced?', which questions are all the more important in view of limited alternatives for, and the serious consequences of not using, MPM or MPA. This article is protected by copyright. All rights reserved.
Stewart F Owen
added a research item
Background: The presence of pharmaceuticals in the environment is a growing global concern and although environmental risk assessment is required for approval of new drugs in Europe and the USA, the adequacy of the current triggers and the effects-based assessments has been questioned. Objective: To provide a comprehensive analysis of all regulatory compliant aquatic ecotoxicity data and evaluate the current triggers and effects-based environmental assessments to facilitate the development of more efficient approaches for pharmaceuticals toxicity testing. Methods: Publicly-available regulatory compliant ecotoxicity data for drugs targeting human proteins was compiled together with pharmacological information including drug targets, Cmax and lipophilicity. Possible links between these factors and the ecotoxicity data for effects on, growth, mortality and/or reproduction, were evaluated. The environmental risks were then assessed based on a combined analysis of drug toxicity and predicted environmental concentrations based on European patient consumption data. Results: For most (88%) of the of 975 approved small molecule drugs targeting human proteins a complete set of regulatory compliant ecotoxicity data in the public domain was lacking, highlighting the need for both intelligent approaches to prioritize legacy human drugs for a tailored environmental risk assessment and a transparent database that captures environmental data. We show that presence/absence of drug-target orthologues are predictive of susceptible species for the more potent drugs. Drugs that target the endocrine system represent the highest potency and greatest risk. However, for most drugs (>80%) with a full set of ecotoxicity data, risk quotients assuming worst-case exposure assessments were below one in all European countries indicating low environmental risks for the endpoints assessed. Conclusion: We believe that the presented analysis can guide improvements to current testing procedures, and provide valuable approaches for prioritising legacy drugs (i.e. those registered before 2006) for further ecotoxicity testing. For drugs where effects of possible concern (e.g. behaviour) are not captured in regulatory tests, additional mechanistic testing may be required to provide the highest confidence for avoiding environmental impacts.
Rik Oldenkamp
added a research item
Environmental risk assessment of pharmaceuticals requires the determination of their environmental exposure concentrations. Existing exposure modelling approaches are often computationally demanding, require extensive data collection and processing efforts, have a limited spatial resolution, and have undergone limited evaluation against monitoring data. Here, we present ePiE (exposure to Pharmaceuticals in the Environment), a spatially explicit model calculating concentrations of active pharmaceutical ingredients (APIs) in surface waters across Europe at ~1 km resolution. ePiE strikes a balance between generating data on exposure at high spatial resolution while having limited computational and data requirements. Comparison of model predictions with measured concentrations of a diverse set of 35 APIs in the river Ouse (UK) and Rhine basins (North West Europe), showed around 95% were within an order of magnitude. Improved predictions were obtained for the river Ouse basin (95% within a factor of 6; 55% within a factor of 2), where reliable consumption data were available and the monitoring study design was coherent with the model outputs. Application of ePiE in a prioritisation exercise for the Ouse basin identified metformin, gabapentin, and acetaminophen as priority when based on predicted exposure concentrations. After incorporation of toxic potency, this changed to desvenlafaxine, loratadine and hydrocodone.
Stewart F Owen
added 2 research items
The primary culture of fish gill cells can provide functional, cell diverse, model in vitro platforms able to tolerate an aqueous exposure analogous to in vivo tissues. The utility of such models could be extended to a variety of longer term exposure scenarios if a method could be established to extend culture viability when exposed to water for longer periods. Here we report findings of a series of experiments to establish increased longevity, as monitored by culture transepithelial electrical resistance (TEER) and concurrent histological developments. Experimental cultures improved TEER during apical freshwater exposure for a mean of twelve days, compared to previous viabilities of up to 3 days. Cultures with larger surface areas and the use of trout serum rather than foetal bovine serum (FBS) contributed to the improvement, while perfusion of the intact gill prior to cell harvest resulted in a significantly faster preparation. Detailed scanning electron microscopy analysis of cultures revealed diverse surface structures that changed with culture age. Cultures grown on membranes with an increased porosity, collagen coating or 3D structure were of no benefit compared to standard membranes. Increased culture longevity, achieved in this study and reported for the first time, is a significant breakthrough and opens up a variety of future experimentation that has previously not been possible. The extended viability facilitates exploration of in vitro chronic or pulse-exposure test paradigms, longer term physiological and environmental monitoring studies and the potential for interactive co-culture with other organoid micro-tissues.
Pharmaceuticals are designed to interact with specific molecular targets in humans and these targets generally have orthologs in other species. This provides opportunities for the drug discovery community to use alternative model species for drug development. It also means, however, there is potential for mode of action related effects in non-target wildlife species as many pharmaceuticals reach the environment through patient use and manufacturing wastes. Acquiring insight in drug target ortholog predictions across species and taxonomic groups has proven difficult because of the lack of an optimal strategy and because necessary information is spread across multiple and diverse sources and platforms. We introduce a new research platform tool, ECOdrug, that reliably connects drugs to their protein targets across divergent species. It harmonizes ortholog predictions from multiple sources via a simple user interface underpinning critical applications for a wide range of studies in pharmacology, ecotoxicology and comparative evolutionary biology. ECOdrug can be used to identify species with drug targets and identify drugs that interact with those targets. As such, it can be applied to support intelligent targeted drug safety testing by ensuring appropriate and relevant species are selected in ecological risk assessments. ECOdrug is freely accessible and available at: http://www.ecodrug.org.
Stewart F Owen
added a research item
There is an acknowledged need for in vitro fish intestinal model to help understand dietary exposure to chemicals in the aquatic environment. The presence and use of such models is however largely restrictive due to technical difficulties in the culturing of enterocytes in general and the availability of appropriate established cell lines in particular. In this study, the rainbow trout (Oncorhynchus mykiss) intestinal derived cell line (RTgutGC) was used as a surrogate for the “gut sac” method. To facilitate comparison, RTgutGC cells were grown as monolayers (double-seeded) on permeable Transwell supports leading to a two-compartment intestinal model consisting of polarised epithelium. This two-compartment model divides the system into an upper apical (lumen) and a lower basolateral (portal blood) compartment. In our studies, these cells stained weakly for mucosubstances, expressed the tight junction protein ZO-1 in addition to E-cadherin and revealed the presence of polarised epithelium in addition to microvilli protrusions. The cells also revealed a comparable transepithelial electrical resistance (TEER) to the in vivo situation. Importantly, the cell line tolerated apical saline (1:1 ratio) thus mimicking the intact organ to allow assessment of uptake of compounds across the intestine. Following an exposure over 72 h, our study demonstrated that the RTgutGC cell line under sub-lethal concentrations of copper sulphate (Cu) and modified saline solutions demonstrated uptake of the metal with saturation levels comparable to short term ex situ gut sac preparations. Gene expression analysis revealed no significant influence of pH or time on mRNA expression levels of key stress related genes (i.e. CYP3A, GST, mtA, Pgp and SOD) in the Transwell model. However, significant positive correlations were found between all genes investigated suggesting a co-operative relationship amongst the genes studied. When the outlined characteristics of the cell line are combined with the division of compartments, the RTgutGC double seeded model represents a potential animal replacement model for ecotoxicological studies. Overall, this model could be used to study the effects and predict aquatic gastrointestinal permeability of metals and other environmentally relevant contaminants in a cost effective and high throughput manner.
Stewart F Owen
added a research item
At high internal doses, pharmaceuticals have the potential for inducing biological/pharmaco-logical effects in fish. One particular concern for the environment is their potential to bioaccu-mulate and reach pharmacological levels; the study of these implications for environmental risk assessment has therefore gained increasing attention. To avoid unnecessary testing on animals, in vitro methods for assessment of xenobiotic metabolism could aid in the ecotoxi-cological evaluation. Here we report the use of a 3-D in vitro liver organoid culture system (spheroids) derived from rainbow trout to measure the metabolism of seven pharmaceuticals using a substrate depletion assay. Of the pharmaceuticals tested, propranolol, diclofe-nac and phenylbutazone were metabolised by trout liver spheroids; atenolol, metoprolol, diazepam and carbamazepine were not. Substrate depletion kinetics data was used to estimate intrinsic hepatic clearance by this spheroid model, which was similar for diclofenac and approximately 5 fold higher for propranolol when compared to trout liver microsomal fraction (S9) data. These results suggest that liver spheroids could be used as a relevant and metabolically competent in vitro model with which to measure the biotransformation of pharmaceuticals in fish; and propranolol acts as a reproducible positive control.
Alistair Boxall
added a project goal
The overall aim of the IPiE project is to develop predictive frameworks that utilise information from existing datasets on environmental fate and effects of APIs, toxicological studies, pharmacological mode of action and in silico models to support more intelligent environmental testing of pharmaceuticals in development and to prioritise legacy pharmaceuticals for full environmental risk assessment and/or environmental (bio) monitoring.