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Evaluating the Effects of Pharmaceutical Evaluating the Effects of Pharmaceutical Products on Aquatic OrganismsProducts on Aquatic Organisms
Roger D. Roger D. MeyerhoffMeyerhoff & Alison N. Perkins& Alison N. Perkins
Health, Safety and EnvironmentalLilly Research Laboratories
Division of Eli Lilly and Company
Human Pharmaceuticals Found in SurfaceHuman Pharmaceuticals Found in Surface WatersWaters
Acetominophen – analgesic Albuterol – asthma, bronchitis
Caffeine ‐ stimulant Carbamazepine ‐ anticonvulsant
Cimetidine ‐ anti‐ulcer Ciprofloxacin ‐ antibiotic
Codiene ‐ analgesic Diltiazem (Cardizem) ‐ Ca blocker
Enalaprilat ‐ ACE inhib. 17a‐Ethinylestradiol ‐ birth control
Fluoxetine ‐ SSRI Gemfibrozil ‐ cholesterol lowering
Ibuprofen ‐ analgesic Metformin ‐ anti‐diabetic
Norfloxacin ‐ antibiotic Oxytetracycline ‐ antibiotic
Progesterone ‐ hormone rep Ranitidine ‐ anti‐ulcer
Roxithromycin ‐ antibiotic Sulfamethoxazole – antibiotic
Tetracycline – antibiotic Trimethoprim ‐ antibiotic
Regulatory GuidelinesRegulatory Guidelines
US FDAUS FDA Regulations for Environmental Assessments (final rule in 21 CFR Part
25, 1997) for requirements of NEPA (1969). Triggered at ≥ 1 μg/L in the effluents of sewage treatment facilities, or expected annual use of ≥ 44,000 kg, or extraordinary circumstances.
European UnionEuropean Union Council Directive 2001/83/EC requires an environmental
risk assessment for human drugs. Triggered at ≥ 0.01 μg/L in surface waters, or expected individual use ≥ 2mg/day, or potential for reproductive effects at levels < 0.01 μg/L.
CanadaThe New Substances Notification Regulations of the Canadian Environmental
Protection Act, 1999, requires environmental assessments. Use in amounts > 1000 kg/yr or accumulated use > 50,000 kg require environmental data under current New Substance Notification Guidelines.
Risk Assessment OverviewRisk Assessment Overview
Biological EffectsEnvironmentalExposure Levels
Environmental RiskAssessment
Distribution and FateDistribution and Fate
Environmental Fate Chemistry StudiesEnvironmental Fate Chemistry Studies
Solubility in water (OECD 105)Melting temperature (OECD 102)Dissociation constant (OECD 112)Hydrolysis (OECD 111)Octanol/water partition coefficient (OECD 107or 117)Ultraviolet/visible light absorption (OECD 101)Adsorption and biodegradation in sediments (OECD 308) Sorption to sludge solids (OECD 106 or 121)
Biodegradation in sludge (OECD 302a)Soil adsorption study (OECD 106 or 121)Soil degradation study (OECD 307)
Possible Water ConcentrationsPossible Water Concentrations‐ Surface water concentrations can be estimated by probability
modeling of representative surface waters in a given country
Low Flow
Mean Flow
Purpose of Ecological Risk AssessmentPurpose of Ecological Risk AssessmentProtection of Populations and Communities
Ecosystem ResponsesEcosystem ResponsesEcosystem ResponsesEcosystem Responses
Ecosystem ResponsesCommunity Responses
Population ResponsesOrganism Responses
Biochemical Responses
Cellular ResponsesOrgan Responses
Surrogate species tested to protect populations and communities
Biomarkers sometimes assessed
Pathology or physiology canbe evaluated
TrophicTrophic SystemSystemEnergy and Material Transfer
Decomposer Microorganisms
Algae/Plants
Herbivores
Carnivores
TopCarnivores
Field Evaluation of Aquatic CommunitiesField Evaluation of Aquatic Communities
Testing Representative SpeciesTesting Representative Species
Special Laboratory FacilitiesSpecial Laboratory Facilities
Hazard EvaluationsHazard Evaluations
Representative Species Testing
Aquatic Environment*‐ Activated sludge respiratory inhibition (OECD 209)‐Algal growth inhibition test (OECD 201)‐Daphnia magna acute immobilization test (OECD 202)‐ Fish acute toxicity test (OECD 203)‐Daphnia magna life‐cycle study (OECD 211)‐ Fish early life stage study (OECD 210)
* Exposure concentrations verified by analytical chemistry throughout each study
Sludge Respiration Inhibition
0
10
20
30
40
50
60
70
80
90
100
0 62.5 125 250 500 1000 3000 10000 30000 100000Concentration (ppb)
Inhi
bitio
n (%
)
Treatment
PositiveControl
No Significantinhibition at or above limit ofsolubility (388 ppb at pH 7)
Sludge Respiration Inhibition StudySludge Respiration Inhibition StudyRuboxistaurin mesylate,
a protein kinase C β inhibitorN N
N OOH
ONMe2·MeSO3H·H2O
Algal Growth Inhibition StudyAlgal Growth Inhibition Study
Algal Cell Density
0
50000
100000
150000
200000
250000
300000
350000
0 1 2 3Time (Days)
Cel
l Den
sity
(cel
ls/m
l)
0.0
20.046.0
110.0
280.0
660.01500.0
Conc. (ppb)
*
*
*
**
* Growth Rate SignificantlyDifferent than Control
Algal EC50 = 450 ppbAlgal NOEC = 20 ppb
Results from Acute StudiesResults from Acute Studies
Trout LC 50 > 1700 ppb
Daphnid EC50 = 350 ppb
Fish Early Life Stage & Fish Early Life Stage & DaphnidDaphnid Reproduction StudiesReproduction StudiesDaphnia Fecundity
0.002.004.006.008.00
10.0012.0014.00
0 3.8 8.3 22 46 111
Concentration (ppb)Yo
ung
(No.
/Rep
ro. D
ay)
Fish ELS
0102030405060708090
0 33 71 130 250 480Concentration (ppb)
Dry
Wei
ght (
mg)
Daphnid Repro. NOEC from two studies: 6.6 to 22 ppb
***
* *
Fish ELS NOEC = 71 ppb
Hazard EvaluationsHazard EvaluationsSpecial Studies for the Aquatic Environment‐ Spiked sediment study with Benthic Invertebrates (OECD 218)
to evaluate the toxicity of a chemical to aquatic invertebrates that are associated with sediment
‐ Fish bioconcentration study (OECD 305) for evaluation of bioaccumulation of a chemical in fish when octanol/water partition coefficient is high (Log Kow >3)
‐ Fathead minnow full life cycle study (no guideline)for evaluation of chemical effects on reproduction in fish
Hazard EvaluationHazard Evaluation
Special Studies for the Aquatic Environment
Physiological biomarkers‐ Vitellogenin production in male fish exposed to 17‐alpha ethinylestradiol (EE2)
Pharmacological biomarkers‐ Pharmaceutical receptors known to exist in fish thatproduce pharmacology similar to that in mammals
Pathological evaluations‐ Gross or microscopic evaluation of fish tissues
Risk Assessment CalculationsRisk Assessment CalculationsSewage Treatment Micro‐organismsPredicted no‐effect concentration (PNEC) should be greater than the
concentration calculated to enter sewage treatment facility
Aquatic EnvironmentThe predicted concentration of the chemical in surface water must be below the predicted no‐effect concentration for all aquatic organisms.
The lowest PNEC for all aquatic organisms is usually determined by dividing the most sensitive of the 3 chronic no‐effect concentrations by 10
PEC/PNEC Ratios for Ruboxistaurin MesylateSewage treatment: 0.45/100 = 0.0045Aquatic Organisms: 0.045/0.66 = 0.068
Any ratio less than 1 is considered to be an insignificant risk
Risk Assessment CalculationsRisk Assessment CalculationsFish Risk Assessment Based on Mammalian Data
• When the mode of pharmacological action and target tissues in mammals and fish are similar, plasma levels from mammalian studies can be used to evaluate potential risk to fish (Huggett et al., 2005).
• Measure or estimate plasma conc. in fish from log P and PEClog Pb:w = 0.73 x log P – 0.88 (Fitzsimmons et al., 2001)Plasma conc. = PEC x Pb:w
• Assume pharmacological action and target tissues are functionally the same (eg. 1/1), or measure differences.
• If plasma exposure ratio (mammal:fish)/(FER mammal:fish) is 10 or less, then further investigation is needed.
• The plasma exposure ratios for ruboxistaurin and its metabolites are over 35
SummarySummaryEvaluating the potential impact of a pharmaceutical on
aquatic organisms is influenced by:• Predicted concentrations in the aquatic environment• Knowledge of target mechanism and metabolism• Results from standard laboratory tests with sludge
microorganisms, algae, invertebrates and fish• Results from special studies used to determine effects
on sediment organisms, fish reproduction, or biomarkers
• An understanding of how expected effects can carry through levels of biological organization and impactorganisms at different trophic levels
Risk assessments are conducted before pharmaceuticals are registered for use by patients