A novel two-dimensional liquid chromatographic system for the online toxicity prediction of pharmaceuticals and related substances

In this study, a novel two-dimensional liquid chromatographic (2D-LC) system was developed for simultaneous separation and toxicity prediction of pharmaceutical and its related substances. A conventional ODS column was used on the 1st-D to separate the sample; while, bio-partitioning micellar chromatography served as the 2nd-D to predict toxicity of the components. The established system was tested for the toxicity of ibuprofen and its impurities with known toxicity. With only one injection, ibuprofen and its impurities were separated on the 1st-D; and LC50 values of individual impurity were obtained based on the quantitative retention-activity relationships, which agreed well with the reported data. Furthermore, LC50 values of photolysis transformation products (TPs) of carprofen, ketoprofen and diclofenac acid (as unknown compounds) were screened in this 2D-LC system, which could be an indicator of the toxicity of these TPs and was meaningful for the environmental monitoring and drinking water treatment. The established 2D-LC system was cost-effective, time-saving and reliable, and was promising for fast online screening of toxicity of known and unknown analytes in the complex sample in a single step. It may find applications in environment, pharmaceutical and food, etc.

Parecoxib Increases Blood Pressure Through Inhibition of Cyclooxygenase-2 Messenger RNA in an Experimental Model

BACKGROUND

Cyclooxygenase-2 selective inhibitors have been developed to alleviate pain and inflammation; however, the use of a selective cyclooxygenase-2 inhibitor is associated with mild edema, hypertension, and cardiovascular risk.

AIM

To evaluate, in an experimental model in normotensive rats, the effect of treatment with parecoxib in comparison with diclofenac and aspirin and L-NAME, a non-selective nitric oxide synthetase, on mean arterial blood pressure, and cyclooxygenase-1 and -2 messenger RNA and protein expression in aortic tissue.

METHODS

Rats were treated for seven days with parecoxib (10 mg/kg/day), diclofenac (3.2 mg/kg/day), aspirin (10 mg/kg/day), or L-NAME (10 mg/kg/day). Mean arterial blood pressure was evaluated in rat tail; cyclooxygenase-1 and -2 were evaluated by reverse transcription-polymerase chain reaction and Western blot analysis in aortic tissue.

RESULTS

Parecoxib and L-NAME, but not aspirin and diclofenac, increased mean arterial blood pressure by about 50% (p < 0.05) without changes in cardiac frequency. Messenger RNA cyclooxygenase-1 expression in aortic tissue was not modified with any drug (p < 0.05). L-NAME and parecoxib treatment decreased messenger RNA cyclooxygenase-2 and cyclooxygenase-2 (p < 0.05). While cyclooxygenase-1 protein decreased with the three drugs tested but not with L-NAME (p < 0.05), the cyclooxygenase-2 protein decreased only with aspirin and parecoxib (p < 0.05).

CONCLUSION

Parecoxib increases the blood pressure of normotensive rats by the suppression of COX-2 gene expression, which apparently induced cardiovascular control.

Effects of trophic exposure to dexamethasone and diclofenac in freshwater fish

Steroidal and non-steroidalanti-inflammatories are pharmaceutical prescribed in human medicine and have the potential to contaminate water and sediments via inputs from sewage treatment plants. Their impacts on humans and ecosystems are emerging issues in environmental health. The aim of the present work was to evaluate the effects of diclofenac and dexamethasone in male fish Hoplias malabaricus after trophic exposure. Fish were fed twice every week with Astyanax sp. submitted to intraperitoneal inoculation with diclofenac (0; 0.2; 2.0 or 20.0 μg/kg) or dexamethasone (0; 0.03; 0.3 or 3.0 μg/kg). After 12 doses, blood was collected for testosterone dosage. The gonad and liver were collected to calculate gonadosomatic (GSI) and hepatosomatic index (HSI). Antioxidants enzymes activity and biotransformation were also evaluated in liver and gonads. In liver, diclofenac caused oxidative stress with increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and lipoperoxidation (LPO). The GST activity was reduced by diclofenac in liver. Trophic exposure of H. malabaricus to dexamethasone caused an increase in antioxidant system (GPx, CAT, GST, and GSH) and LPO in liver. However, it reduced antioxidant system (GPX and GST activities and GSH) in gonads. Both diclofenac and dexamethasone reduced the levels of testosterone, causing impairment to reproduction. Diclofenac reduced HSI at the 0.2 μg/kg, but not GSI. Our results suggest that the anti-inflammatory drugs diclofenac and dexamethasone caused oxidative stress and reduced testosterone levels that can have a negative impact in aquatic organisms.

Toxicity screening of diclofenac, propranolol, sertraline and simvastatin using Danio rerio and Paracentrotus lividus embryo bioassays

Early life-stage bioassays have been used as an alternative to short-term adult toxicity tests since they are cost-effective. A single couple can produce hundreds or thousands of embryos and hence can be used as a simple high-throughput approach in toxicity studies. In the present study, zebrafish and sea urchin embryo bioassays were used to test the toxicity of four pharmaceuticals belonging to different therapeutic classes: diclofenac, propranolol, simvastatin and sertraline. Simvastatin was the most toxic tested compound for zebrafish embryo, followed by diclofenac. Sertraline was the most toxic drug to sea urchin embryos, inducing development abnormalities at the ng/L range. Overall, our results highlight the potential of sea urchin embryo bioassay as a promising and sensitive approach for the high-throughput methods to test the toxicity of new chemicals, including pharmaceuticals, and identify several drugs that should go through more detailed toxicity assays.

Ecotoxicogenomic assessment of diclofenac toxicity in soil

Diclofenac is widely used as nonsteroidal anti-inflammatory drug leaving residues in the environment. To investigate effects on terrestrial ecosystems, we measured dissipation rate in soil and investigated ecotoxicological and transcriptome-wide responses in Folsomia candida. Exposure for 4 weeks to diclofenac reduced both survival and reproduction of F. candida in a dose-dependent manner. At concentrations ≥ 200 mg/kg soil diclofenac remained stable in the soil during a 21-day incubation period. Microarrays examined transcriptional changes at low and high diclofenac exposure concentrations. The results indicated that development and growth were severely hampered and immunity-related genes, mainly directed against bacteria and fungi, were significantly up-regulated. Furthermore, neural metabolic processes were significantly affected only at the high concentration. We conclude that diclofenac is toxic to non-target soil invertebrates, although its mode of action is different from the mammalian toxicity. The genetic markers proposed in this study may be promising early markers for diclofenac ecotoxicity.

Short and long-term exposure to diclofenac alter oxidative stress status in common carp Cyprinus carpio

Diclofenac (DCF) has been detected in significant amounts in municipal treated wastewater effluent. Diverse studies report that trace concentrations of DCF may induce toxic effects on different aquatic organisms as well as developmental, reproductive and renal damage. This study aimed to determine whether short and long-term exposure to DCF alter the oxidative stress (OS) status in blood, muscle, gills, brain and liver of common carp Cyprinus carpio. The median lethal concentration of DCF at 96 h (96-h LC50) and subsequently the lowest observed adverse effect level were determined. Carp were exposed (short and long-term) to the latter value for different exposure times (4 and 24 days) and the following biomarkers were evaluated in gill, brain, liver and blood: hydroperoxides content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC) and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Also, the DCF was determined by LC-MS/MS. Significant increases in HPC, LPX and PCC were observed respect to control (P < 0.05) particularly in blood, muscle, gill, brain and liver. SOD, CAT and GPx activity also increased in these organs, with respect to controls (P < 0.05). DCF concentrations decreased and increased in water system and carp, respectively. Cyprinus carpio exposed to DCF was affected in OS status during the initial days of the study (at 4 days), exhibiting an increased response at 24 days in blood and liver. In contrast, a decrease was observed in muscle, gills and brain at 24 days with respect to 4 days. In conclusion, DCF induces OS on blood, muscle, gills, brain and liver in the carp C. carpio in short and long-term exposure. The biomarkers employed in this study are useful in the assessment of the environmental impact of this agent on aquatic species.

Oxidation of diclofenac by potassium ferrate (VI): reaction kinetics and toxicity evaluation

The reaction kinetics and toxicity of diclofenac (DCF) oxidation by ferrate (VI) under simulated water disinfection conditions were investigated. Experimental results indicated that the reaction between DCF and Fe(VI) followed first-order kinetics with respect to each reactant. Furthermore, the effects of pH and temperature on DCF oxidation by Fe(VI) were elucidated using a systematic examination. The apparent second-order rate constants (kapp) increased significantly from 2.54 to 11.6M(-1)s(-1), as the pH of the solution decreased from 11.0 to 7.0, and the acid-base equilibriums of Fe(VI) and DCF were proposed to explain the pH dependence of kapp. The acute toxicity of DCF solution during Fe(VI) oxidation was evaluated using a Microtox bioassay. Overall, the DCF degradation process resulted in a rapid increase of the inhibition rate of luminescent bacteria. These toxicity tests suggest that the formation of enhanced toxic intermediates during the Fe(VI) disinfection process may pose potential health risk to consumers.

Ecotoxicity of ketoprofen, diclofenac, atenolol and their photolysis byproducts in zebrafish (Danio rerio)

The occurrence of pharmaceutical compounds in wastewater treatment plants and surface waters has been detected worldwide, constituting a potential risk for aquatic ecosystems. Adult zebrafish, of both sexes, were exposed to three common pharmaceutical compounds (atenolol, ketoprofen and diclofenac) and their UV photolysis by-products over seven days. The results show that diclofenac was removed to concentrations<LOD after 5 min of UV irradiation. The oxidative stress response of zebrafish to pharmaceuticals and their photolysis by-products was evaluated through oxidative stress enzymes (glutathione-S-transferase, catalase, superoxide dismutase) and lipid peroxidation. Results suggest that the photolysis by-products of diclofenac were more toxic than those from the other compounds tested, showing an increase in GST and CAT levels, which are also supported by higher MDA levels. Overall, the toxicity of waters containing atenolol and ketoprofen was reduced after the parent compounds were transformed by photolysis, whereas the toxicity increased significantly from the by-products generated through diclofenac photolysis. Therefore, diclofenac photolysis would possibly necessitate higher irradiation time to ensure that the associated by-products are completely degraded to harmless form(s).

Evaluation of developmental toxicity and teratogenicity of diclofenac using Xenopus embryos

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) with analgesic and anti-pyretic properties. This compound is therefore used to treat pain, inflammatory disorders, and dysmenorrhea. Due to its multimodal mechanism of action and ability to penetrate placenta, diclofenac is known to have undesirable side effects including teratogenicity. However, limited data exist on its teratogenicity, and a detailed investigation regarding harmful effects of this drug during embryogenesis is warranted. Here, we analyzed the developmental toxic effects of diclofenac using Xenopus embryos according to the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) protocol. Diclofenac treatment exerted a teratogenic effect on Xenopus embryos with a teratogenic index (TI) value of 2.64 TI; if this value is higher than 1.2, the cut-off value indicative of toxicity. In particular, mortality of embryos treated with diclofenac increased in a concentration-dependent manner and a broad spectrum of malformations such as shortening and kinking of the axis, abdominal bulging, and prominent blister formation, was observed. The shape and length of internal organs also differed compared to the control group embryos and show developmental retardation on histological label. However, the expression of major tissue-specific markers did not change when analyzed by reverse transcription-polymerase chain reaction (RT-PCR). In conclusion, diclofenac treatment can promote teratogenicity that results in morphological anomalies, but not disrupt the developmental tissue arrangement during Xenopus embryogenesis.

Synthesis, hydrolysis kinetics and pharmacological evaluation of aceclofenac prodrugs

The mutual prodrugs of aceclofenac with various naturally available antioxidants; menthol, thymol, eugenol, guiacol and vanillin have been synthesized by the DCC coupling method, purified and characterized by spectral data, as well as, partition coefficient, solubility and hydrolytic studies. The title compounds have more lipophilic character as compared to the parent moieties and good stability in acidic environment, which is prerequisite for the oral absorption of the drug. Under gastric as well as intestinal pH conditions these prodrugs showed variable susceptibility towards hydrolysis. The synthesized derivatives were evaluated for antiinflammatory, analgesic activities and ulcerogenic potential. Prodrug showed improved solubility in organic solvents, which implies lipophilic character of ester prodrugs and were also found to be chemically stable in acidic environment. The aceclofenac mutual prodrugs showed improved analgesic and anti-inflammatory activities with reduced ulcerogenicity.

Acute and chronic responses of denitrifying culture to diclofenac

Acute and chronic effect as well as biodegradation potential at different sludge retention times (SRTs) of a priority pollutant, diclofenac on denitrification process was assessed. The continuous amendment of the culture for 6months with 1μg/L diclofenac resulted in 30% decrease in gas production. The average diclofenac removal observed in the diclofenac-acclimated culture was less than 15%. Batch tests showed that nitrate was removed in diclofenac free-control reactor at a higher rate compared to diclofenac amended reactor. Although, SRT did not have any progressive effect on diclofenac degradation, the system operated at low SRT was more sensitive to diclofenac and resulted in an increase in N2O emission. Wastewater treatment plants (WWTPs) operated at higher SRTs may tolerate and recover from the adverse effects of such micropollutants. The study can lead to other researchers to understand the fate and effect of other emerging pollutants in the anoxic unit of WWTPs.

Hypoxia and the pharmaceutical diclofenac influence the circadian responses of three-spined stickleback

Pollution with low concentrations of pharmaceuticals, especially when combined with low-oxygen conditions (hypoxia), is a threat to aquatic ecosystems worldwide. The non-steroidal anti-inflammatory drug diclofenac is commonly detected in wastewater effluents, and has potential to accumulate in the bile of fish. Diclofenac has been shown to activate aryl hydrocarbon receptor (AHR), which induces transcription in the metabolic enzyme cytochrome P450 1a (cyp1a). Previously, crosstalk has been shown to occur between AHR and hypoxia inducible factor 1 (HIF-1). In addition, both of these transcription factors interact with the proteins regulating circadian (24-h) rhythms in vertebrates. Yet little is known about the significance of these interactions during simultaneous exposure to chemicals and hypoxia in fish in vivo. We exposed wild-caught three-spined sticklebacks (Gasterosteus aculeatus) to diclofenac (1 μg/L, 14 days), hypoxia (2.0 mg/L, up to 24h) and the combination of both. We then analyzed markers of chemical biotransformation (EROD activity, cyp1a and ahr mRNA levels), glycolysis (lactate dehydrogenase (LDH) enzyme activity, ldh and enolase 1a mRNA levels), and the transcription of core circadian clock genes clock and period 1 in liver tissue. Samples were taken at three time points during the light period in order to address disturbances in the circadian variation of metabolic processes. The results show that mRNA levels and LDH activity tended to be lowest before the dark period, but this pattern was disturbed by hypoxia and diclofenac. Diclofenac and hypoxia co-exposure induced EROD activity more strongly than diclofenac exposure alone, while cyp1a mRNA level was increased also by hypoxia and diclofenac alone. LDH activity and mRNA expression showed a clear time-dependent response during hypoxia, which is consistent with the previously suggested decreased accumulation of HIF-1 during the dark period. Furthermore, LDH activity and transcription was disturbed by diclofenac, indicating important effects of environmental pollutants in disturbing natural acclimation. This study demonstrates the need for more studies to understand the potential disturbances in endogenous rhythms caused by environmental pollution in natural populations.

Effects of the pharmaceuticals diclofenac and metoprolol on gene expression levels of enzymes of biotransformation, excretion pathways and estrogenicity in primary hepatocytes of Nile tilapia (Oreochromis niloticus)

The expression levels of key enzymes of the xenobiotic metabolism and excretion pathways concerning biotransformation phases I (cytochrome P4501A), II (glutathione S-transferase) and III (multidrug resistance protein) and of the estrogenic biomarker vitellogenin (vtg) were investigated in primary hepatocytes isolated from male Nile tilapia (Oreochromis niloticus) after exposure to diclofenac and metoprolol, two pharmaceuticals prevalent in the aquatic environment worldwide. The lowest test concentration (4×10(-9) M) was chosen to reflect an environmentally relevant exposure situation. Furthermore concentration dependent effects were investigated. Therefore a series of concentrations higher than the environmentally relevant range were used (10- and 100-fold). Diclofenac significantly induced all chosen biomarkers already at the environmentally relevant concentration indicating that biotransformation and elimination occur via the pathways under investigation. Estrogenic potential of this substance was demonstrated by VTG up-regulation as well. Metoprolol was either less effective than diclofenac or metabolized using different pathways. Key enzymes of the xenobiotic metabolism were less (CYP1A, GST) or not (MDRP) induced and a mild increase in vtg mRNA was detected only for 4×10(-8) M. No concentration-dependency for metoprolol was found.

Binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and these pharmaceuticals in isolated form induce oxidative stress on Hyalella azteca

Toxicity in natural ecosystems is usually not due to exposure to a single substance, but is rather the result of exposure to mixtures of toxic substances. Knowing the effects of contaminants as a mixture compared to their effects in isolated form is therefore important. This study aimed to evaluate the oxidative stress induced by binary mixtures of diclofenac with paracetamol, ibuprofen, naproxen, and acetylsalicylic acid and by these nonsteroidal anti-inflammatory drugs (NSAIDs) in isolated form, using Hyalella azteca as a bioindicator. The median lethal concentration (LC50) and the lowest observed adverse effect level (LOAEL) of each NSAID were obtained. Amphipods were exposed for 72 h to the latter value in isolated form and as binary mixtures. The following biomarkers were evaluated: lipid peroxidation (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Significant increases in LPX and PCC with respect to the control group (p ≤ 0.05) were induced by NSAIDs both in isolated form and as binary mixtures. Changes in SOD, CAT, and GPx activity likewise occurred with NSAIDs in isolated form and as binary mixtures. In conclusion, NSAIDs used in this study induce oxidative stress on H. azteca both in isolated form and as binary mixtures, and the interactions occurring between these pharmaceuticals are probably antagonistic in type.

Toxicological effects of clofibric acid and diclofenac on plasma thyroid hormones of an Indian major carp, Cirrhinus mrigala during short and long-term exposures

In the present investigation, the toxicity of most commonly detected pharmaceuticals in the aquatic environment namely clofibric acid (CA) and diclofenac (DCF) was investigated in an Indian major carp Cirrhinus mrigala. Fingerlings of C. mrigala were exposed to different concentrations (1, 10 and 100μgL(-1)) of CA and DCF for a period of 96h (short term) and 35 days (long term). The toxic effects of CA and DCF on thyroid hormones (THs) such as thyroid stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) levels were evaluated. During the short and long-term exposure period TSH level was found to be decreased at all concentrations of CA (except at the end of 14(th) day in 1 and 10μgL(-l) and 21(st) day in 1μgL(-l)) whereas in DCF exposed fish TSH level was found to be increased when compared to control groups. T4 level was found to be decreased at 1 and 100μgL(-l) of CA exposure at the end of 96h. However, T4 level was decreased at all concentrations of CA and DCF during long-term (35 days) exposure period. Fish exposed to all concentrations of CA and DCF had lower level of T3 in both the treatments. These results suggest that both CA and DCF drugs induced significant changes (P<0.01 and P<0.05) on thyroid hormonal levels of C. mrigala. The alterations of these hormonal levels can be used as potential biomarkers in monitoring of pharmaceutical drugs in aquatic organisms.

Pollution-induced community tolerance to non-steroidal anti-inflammatory drugs (NSAIDs) in fluvial biofilm communities affected by WWTP effluents

We assessed the tolerance acquired by stream biofilms to two non-steroidal anti-inflammatory-drugs (NSAIDs), ibuprofen and diclofenac. Biofilms came from a stream system receiving the effluent of a wastewater treatment plant (WWTP). The response of biofilms from a non-polluted site (upstream the WWTP) was compared to that of others downstream with relevant and decreasing levels of NSAIDs. Experiments performed in the laboratory following the pollution-induced community tolerance (PICT) approach determined that both algae and microbial communities from biofilms of the sites exposed at the highest concentrations of ibuprofen and diclofenac acquired tolerance to the mixture of these NSAIDs occurring at the sites. It was also observed that the chronic pollution by the WWTP effluent affected the microbial metabolic profile, as well as the structure of the algal community. The low (at ng L(-1) level) but chronic inputs of pharmaceuticals to the river ecosystem result in tolerant communities of lower diversity and altered microbial metabolism.

Effects of active pharmaceutical ingredients mixtures in mussel Mytilus galloprovincialis

Active pharmaceutical ingredients (APIs) are emergent environmental contaminants widely detected in surface waters as result of incomplete waste water treatment plant (WWTP) removal processes and improper disposal. The assessment of potential effects of APIs on non-target organisms is still scarce since besides presenting multiple chemical structures, properties and modes of action, these compounds occur as complex mixtures. This study comprises a 15-day exposure of mussels Mytilus galloprovincialis to mixtures (at environmentally relevant nominal concentrations) of non-steroidal inflammatory drugs ibuprofen (IBU) and diclofenac (DCF) (250 ng L(-1) each) and selective serotonin reuptake inhibitor (SSRI) fluoxetine (FLX) (75 ng L(-1)) (MIX 1) along with the addition of classical pro-oxidant copper (Cu) (5 μg L(-1)) (MIX 2). The goals included the assessment of oxidative stress, neurotoxic and endocrine effects on this sentinel species applying both a multibiomarker and gene expression (here and later gene expression is taken as synonym to gene transcription, although it is acknowledged that it is also affected by, e.g. translation, and mRNA and protein stability) analysis approaches. The results revealed a swifter antioxidant response in digestive glands than in gills induced by MIX 1, nevertheless the presence of Cu in MIX 2 promoted a higher lipid peroxidation (LPO) induction. Neither mixture altered acetylcholinesterase (AChE) activity, while both triggered the formation of vitellogenin-like proteins in females confirming the xenoestrogenic effect of mixtures. All these results varied with respect to those obtained in previous single exposure essays. Moreover, RT-PCR analysis revealed a catalase (CAT) and CYP4Y1 gene expression down- and upregulation, respectively, with no significant changes in mRNA levels of genes encoding superoxide dismutase (SOD) and glutathione-S-transferase (GST). Finally, this study highlights variable tissue and time-specific biomarker responses and gene expression alterations, which along with several interactions between each mixture component on each biomarker confirm the susceptibility of mussels to API mixtures.

Effects of non-steroidal anti-inflammatory drug (NSAID) diclofenac exposure in mussel Mytilus galloprovincialis

In recent years, research studies have increasingly focused on assessing the occurrence of active pharmaceutical ingredients (APIs) in ecosystems. However, much remains unknown concerning the potential effects on APIs on non-target organisms due to the complexity of the mode of action, reactivity and bioconcentration potential for each specific drug. The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is one of the most frequently detected APIs in surface waters worldwide and has recently been included in the list of priority substances under the European Commission. In this study, mussels (Mytilus galloprovincialis) were exposed to an environmentally relevant nominal concentration of DCF (250 ng L(-1)) over 15 days. The responses of several biomarkers were assessed in the mussel tissues: condition index (CI); superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and phase II glutathione-S-transferase (GST) activities, lipid peroxidation levels (LPO) associated with oxidative stress, acetylcholinesterase (AChE) activity related to neurotoxic effects and vitellogenin-like proteins linked to endocrine disruption. This study demonstrated significant induction of SOD and GR activities in the gills in addition to high CAT activity and LPO levels in the digestive gland. Phase II GST remained unaltered in both tissues, while the up-regulation of the AChE activity was directly related to the vitellogenin-like protein levels in exposed females, indicating an alteration in the estrogenic activity, rather than a breakdown in cholinergic neurotransmission function. This study confirmed that DCF at a concentration often observed in surface water induces tissue-specific biomarker responses. Finally, this study also revealed the importance of a multi-biomarker approach when assessing the potentially deleterious effects in a species that may be vulnerable to the continuously discharge of APIs into the ecosystems; this approach provides crucial new information regarding the unknown effects of DCF.

Vacuum ultraviolet photolysis of diclofenac and the effects of its treated aqueous solutions on the proliferation and migratory responses of Tetrahymena pyriformis

The effects of dissolved O2, phosphate buffer and the initial concentration of diclofenac on the vacuum ultraviolet photolysis of this contaminant molecule were studied. Besides kinetic measurements, the irradiated, multicomponent samples were characterized via the proliferation and migratory responses (in sublethal concentrations) of the bioindicator eukaryotic ciliate Tetrahymena pyriformis. The results suggest that hydroxyl radicals, hydrogen atoms and hydroperoxyl radicals may all contribute to the degradation of diclofenac. The aromatic by-products of diclofenac were presumed to include a hydroxylated derivative, 1-(8-chlorocarbazolyl)acetic acid and 1-(8-hydroxycarbazolyl)acetic acid. The biological activity of photoexposed samples reflected the chemical transformation of diclofenac and was also dependent on the level of dissolved O2. The increase in toxicity of samples taken after different irradiation times did not exceed a factor of two. Our results suggest that the combination of vacuum ultraviolet photolysis with toxicity and chemotactic measurements can be a valuable method for the investigation of the elimination of micropollutants.

Effect of paracetamol and diclofenac on population growth of Plationus patulus and Moina macrocopa

Two non-steroidal anti-inflammatory commonly used in Mexico are paracetamol and diclofenac. These drugs reach natural waterbodies transport through the hydrological areas of agriculture and effluent treatment plants and can affect plankton. In this study, we quantified the chronic effects of paracetamol and sodium diclofenac on the population dynamics of the rotifer Plationus patulus and the cladoceran Moina macrocopa under laboratory conditions. Both these species of zooplankton are common in freshwaters and are sensitive to chemicals in the medium. Our results showed that densities of both P. patulus and M. macrocopa decreased with increasing levels of both the analgesic drugs. Both zooplankton species did not survive beyond when paracetamol was applied at 32 mg I(-1) in the medium. Diclofenac in general had more adverse effect than paracetamol for either zooplankton species. P. patulus was more sensitive than M. macrocopa to both analgesic drugs. When diclofenac was present in the medium at > or = 12.5 mg I(-1), rotifer reproduction was inhibited, while the tested cladocerans continued to grow but to lower densities compared to control. The rate of population increase (r) per day of P. patulus and M. macrocopa was significantly and inversely related to the concentration of paracetamol and diclofenac in the medium. However, the relationship between r and drug concentration differed depending on the zooplankton species and drug. In controls, the r of P. patulus was 0.18 d(-1), for M. macrocopa under similar conditions, it was slightly lower (0.16 d(-1)). The rvalues of both zooplankton populations became negative (-0.10 to -0.15 d(-1)) when exposed to paracetamol at 32 mg l(-1) or diclofenac at 25 mg I(-1).

Pathology working group review of histopathologic specimens from three laboratory studies of diclofenac in trout

While the pathology peer review/pathology working group (PWG) model has long been used in mammalian toxicologic pathology to ensure the accuracy, consistency, and objectivity of histopathology data, application of this paradigm to ecotoxicological studies has thus far been limited. In the current project, the PWG approach was used to evaluate histopathologic sections of gills, liver, kidney, and/or intestines from three previously published studies of diclofenac in trout, among which there was substantial variation in the reported histopathologic findings. The main objectives of this review process were to investigate and potentially reconcile these interstudy differences, and based on the results, to establish an appropriate no observed effect concentration (NOEC). Following a complete examination of all histologic sections and original diagnoses by a single experienced fish pathologist (pathology peer review), a two-day PWG session was conducted to allow members of a four-person expert panel to determine the extent of treatment-related findings in each of the three trout studies. The PWG was performed according to the United States Environmental Protection Agency (US EPA) Pesticide Regulation (PR) 94-5 (EPA Pesticide Regulation, 1994). In accordance with standard procedures, the PWG review was conducted by the non-voting chairperson in a manner intended to minimize bias, and thus during the evaluation, the four voting panelists were unaware of the treatment group status of individual fish and the original diagnoses associated with the histologic sections. Based on the results of this review, findings related to diclofenac exposure included minimal to slightly increased thickening of the gill filament tips in fish exposed to the highest concentration tested (1,000 μg/L), plus a previously undiagnosed finding, decreased hepatic glycogen, which also occurred at the 1,000 μg/L dose level. The panel found little evidence to support other reported effects of diclofenac in trout, and thus the overall NOEC was determined to be >320 μg/L. By consensus, the PWG panel was able to identify diagnostic inconsistencies among and within the three prior studies; therefore this exercise demonstrated the value of the pathology peer review/PWG approach for assessing the reliability of histopathology results that may be used by regulatory agencies for risk assessment.

Is Atyaephyra desmarestii a useful candidate for lethal and sub-lethal toxicity tests on pharmaceutical compounds?

Single and mixture toxicity tests on three pharmaceutical compounds, Diclofenac (DF), Ibuprofen (IB) and Carbamazepine (CBZ), were carried out with the freshwater shrimp Atyaephyra desmarestii. Lethal and sublethal responses were analyzed for single compounds. Lethal concentrations (LC50) obtained for each individual compound, after 96 h of exposure, were 6.3 mg L(-1) for DF, 13.3 mg L(-1) for IB and 94.3 mg L(-1) for CBZ. The selected sublethal endpoints of food ingestion, osmoregulatory capacity and respiration rates were not affected by the exposures to environmentally-relevant concentrations. Based on mortality data obtained, the predictive no effect concentration (PNEC) was calculated for each of the compounds, and compared with predicted environmental concentrations (PEC) reported in surface waters. The environmental risk of each compound was estimated as the ratio between PEC/PNEC, and indicated that IB could represent a medium risk in freshwater environments. Additionally, binary and ternary mixture toxicity assays of the selected compounds were carried out. The data obtained was applied to two predictive toxicity models: Concentration Addition (CA) and Independent Action (IA). Finally, risk assessment was estimated using risk quotients (RQ) for the compound mixtures based on EC50 and LC50 values.

A multiple stressor approach to study the toxicity and sub-lethal effects of pharmaceutical compounds on the larval development of a marine invertebrate

We studied the effects of three common pharmaceutical compounds on growth, development and body mass of larval stages of the marine shrimp Palaemon serratus at different temperatures and salinities. The pharmaceuticals compounds tested were the anti-inflammatory and analgesic diclofenac sodium, the lipid regulator clofibric acid and the fungicide clotrimazole. Neither diclofenac nor clofibric acid had any effect on growth, development or survival, although the maximum concentrations tested were 40 times higher than those observed in European coastal waters. Clotrimazole had significant effects at the higher concentration (2.78 μg L(-1)) when larvae were reared in full salinity sea water (32 PSU) and at the lower concentration (0.14 μg L(-1)) when larvae were reared at 20PSU. Changes in body mass at larval stage resulted from effects of these compounds on growth and developmental rates, specifically the changes in intermoult duration and in the number of larval instars required to reach the juvenile stage. The results demonstrate that the effects of emergent compounds on growth and development may be stronger when organisms are under some additional stress.

Alteration in certain enzymological parameters of an Indian major carp, Cirrhinus mrigala exposed to short- and long-term exposure of clofibric acid and diclofenac

The extensive use of pharmaceuticals in human and veterinary medicine may enter the aquatic environment and pose a serious threat to non-target aquatic organisms like fish. In this study, Indian major carp Cirrhinus mrigala was exposed to different concentrations (1, 10 and 100 μg L⁻¹) of most commonly used pharmaceutical drugs clofibric acid (CA) and diclofenac (DCF) to evaluate its impacts on certain enzymological parameters during short- and long-term exposures. During short-term (96 h) exposure period, plasma glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and gill Na⁺/K⁺-ATPase activity were significantly altered at all concentrations of both the CA- and DCF-treated fish. In long-term exposure (35 days), gill Na⁺/K⁺-ATPase activity was found to be significantly increased at all concentration of CA and DCF exposures throughout the study period (except at the end of 7th day in 10 and 100 µg L⁻¹) . However, a biphasic trend was observed in plasma GOT and GPT activity when compared to the control groups. In both short- and long-term exposure, a significant (P < 0.01 and P < 0.05) changes were observed in all enzymological parameters of fish C. mrigala exposed to different concentrations of CA and DCF. The alterations of these enzymological parameters can be effectively used as potential biomarkers in monitoring of pharmaceutical toxicity in aquatic environment and organisms.

Short and long-term effects of clofibric acid and diclofenac on certain biochemical and ionoregulatory responses in an Indian major carp, Cirrhinus mrigala

Extensive use of pharmaceuticals in human and veterinary medicine and aquaculture practices pose a serious threat to aquatic organisms. In the present investigation, Cirrhinus mrigala an Indian major carp was exposed to different concentrations of clofibric acid (CA) and diclofenac (DCF) and certain biochemical and ionoregulatory responses were assessed under short and long term exposures. During short-term (96h) exposure period, plasma glucose and sodium (Na(+)) levels were increased at all concentrations (1, 10 and 100μgL(-1)) of CA and DCF treated fish. Plasma protein and chloride (Cl(-)) levels were found to be decreased at all concentrations of CA and DCF exposed fish comparatively to control groups. Meanwhile an increase in plasma potassium (K(+)) level was noted in fish exposed to CA treatments alone and in DCF treatments it was decreased. In long-term exposure (35d), plasma Na(+) and Cl(-) levels were found to be significantly increased at all concentration of CA and DCF. However, a biphasic trend was observed in plasma glucose, protein and K(+) levels. In both the treatments, a significant (P<0.01 and P<0.05) changes were observed in all parameters measured in fish exposed to different concentrations of CA and DCF. The results of the present investigation indicate that both the drugs caused significant changes in biochemical and ionoregulatory responses of fish at all concentrations. The alterations of these parameters can be useful in monitoring of pharmaceutical residues present in aquatic environment.

Diclofenac-induced oxidative stress in brain, liver, gill and blood of common carp (Cyprinus carpio)

Due to its analgesic properties, diclofenac (DCF) is one of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs). While residue from this pharmaceutical agent has been found in diverse water bodies in various countries, there is not enough information of its potential toxicity on aquatic organisms, particularly in species which are economically valuable due to their high consumption by humans, such as the common carp Cyprinus carpio. This study aimed to evaluate potential DCF-induced oxidative stress in brain, liver, gill and blood of C. carpio. The median lethal concentration of DCF at 96h (96-h LC50) was determined and used to establish the concentration equivalent to the lowest observed adverse effect level (LOAEL). Carp specimens were exposed to this concentration for different exposure times (12, 24, 48, 72 and 96h) and the following biomarkers were evaluated: lipid peroxidation (LPX) and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Also, the DCF and 4-hydroxy DCF was determined by LC-MS/MS. Results show a statistically significant LPX increase (P<0.05) in liver and gill mainly as well as significant changes in the activity of the antioxidant enzymes evaluated in these organs, with respect to controls (P<0.05). The DCF concentrations decreased in water system and increased in the carp. The DCF biotransformation to 4-hydroxy DCF was observed to 12h. The pharmaceutical agent DCF is concluded to induce oxidative stress on the common carp C. carpio, with the highest incidence of oxidative damage occurring in liver and gill. Furthermore, the biomarkers employed in this study are useful in the assessment of the environmental impact of this agent on aquatic species.

The effects of diclofenac on early life stages of common carp (Cyprinus carpio)

Diclofenac residues have been found in surface water, and thus could present a potential risk to aquatic species. The aim of this study was to assess the impact of diclofenac on the mortality, growth, and development of fish, as well as the impact of the drug on histological changes and selected parameters of oxidative stress in the fish. Subchronic toxic effects of diclofenac at concentrations of 0.015, 0.03, 1, and 3mg/L on embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30-day toxicity test under experimental conditions. Exposure to diclofenac at 3mg/L was associated with increased mortality, increased activity of glutathione S-transferase, and decreased activity of glutathione reductase. Decreases in the levels of thiobarbituric-acid-reactive substances were associated with concentrations ≥ 0.03 mg/L. Based on these results a no observed effect concentration (NOEC)=0.015 mg/L and lowest observed effect concentration (LOEC)=0.03 mg/L were generated.

Degradation of diclofenac by advanced oxidation and reduction processes: kinetic studies, degradation pathways and toxicity assessments

Many pharmaceutical compounds and metabolites are found in surface and ground waters suggesting their ineffective removal by conventional wastewater treatment technologies. Advanced oxidation/reduction processes (AO/RPs), which utilize free radical reactions to directly degrade chemical contaminants, are alternatives to traditional water treatment. This study reports the absolute rate constants for reaction of diclofenac sodium and model compound (2, 6-dichloraniline) with the two major AO/RP radicals: the hydroxyl radical (•OH) and hydrated electron (e(aq)(-)). The bimolecular reaction rate constants (M(-1) s(-1)) for diclofenac for •OH was (9.29 ± 0.11) × 10(9), and for e(-)(aq) was (1.53 ± 0.03) ×10(9). To provide a better understanding of the decomposition of the intermediate radicals produced by hydroxyl radical reactions, transient absorption spectra are observed from 1 - 250 μs. In addition, preliminary degradation mechanisms and major products were elucidated using (60)Co γ-irradiation and LC-MS. The toxicity of products was evaluated using luminescent bacteria. These data are required for both evaluating the potential use of AO/RPs for the destruction of these compounds and for studies of their fate and transport in surface waters where radical chemistry may be important in assessing their lifetime.

Diclofenac: New data on chronic toxicity and bioconcentration in fish

Diclofenac (DCF) is a widely used nonsteroidal anti-inflammatory drug that is regularly detected in surface waters. To support a robust aquatic risk assessment, two early life stage (ELS) tests, compliant with the Organisation for Economic Co-operation and Development (OECD) test guideline 210, were conducted in rainbow trout and in zebrafish. Population relevant endpoints, such as hatching, growth, and survival, and in the trout study, histopathological effects in potential target organs, were examined. The bioconcentration of DCF in rainbow trout was measured in a separate study according to OECD test guideline 305. The bioconcentration factor (BCF) in rainbow trout remained below 10, demonstrating no relevant bioconcentration of DCF in fish. In the rainbow trout ELS test, the no observed effect concentration (NOEC) including histopathology was 320 µg/L. The effect of DCF on zebrafish growth was less clear, and the NOEC can be interpreted as 10 µg/L. However, for a number of reasons, the authors consider the moderately reduced growth of zebrafish exposed to concentrations of up to 320 µg/L not a repeatable, treatment-related effect of DCF. This leads us to a conclusion that DCF has, with high probability, no adverse effect on both fish species up to 320 µg/L. This NOEC indicates a sufficient safety margin for fish populations, because concentrations of DCF in European rivers are in the range of ng/L to low µg/L.

Comparing the effects of salts of diclofenac and alminoprofen with aspirin on serum electrolytes, creatinine and urea levels in rabbits

The effects of diclofenac sodium, diclofenac potassium, alminoprofen and aspirin on serum electrolytes (serum Na(+) and K(+)), urea and creatinine were compared in rabbits in acute and chronic phases of treatment. The data suggested that all the four drugs markedly increased the serum electrolytes, urea and creatinine levels in both post-treatment phases. In conclusion, present study does not present any advantage of diclofenac sodium over diclofenac potassium at electrolyte levels on short and long term treatment. Nevertheless, current data support the evidence of renal function impairment by all the four drug therapies used in the present study, which is generally caused by NSAIDS.

Does ketoprofen or diclofenac pose the lowest risk to fish?

Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 μg/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 μg/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6 ‰ of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar.

Enzymatic and microbial transformation assays for the evaluation of the environmental fate of diclofenac and its metabolites

Diclofenac has been of environmental concern due to the potential harmful effects on non-target organisms at environmentally relevant concentrations. In this study, we evaluated the transformation kinetics of diclofenac and its two major metabolites in two laboratory-scale experiments: the transformation of diclofenac in the presence of rat liver S9 fraction with co-factors, and the transformation of diclofenac, 4'-hydroxy-diclofenac and diclofenac β-O-acyl glucuronide in the inoculum used for the OECD 301C ready-biodegradability test. 4'-Hydroxy-diclofenac was identified as the major phase I metabolite and diclofenac β-O-acyl glucuronide was identified as the major phase II metabolite in the S9 assay. Transformation of diclofenac in the microbial degradation test did not occur significantly for 28 d, whereas 4'-hydroxy-diclofenac degraded slowly, indicating that the biological removal of diclofenac is not likely to occur in conventional STPs unless sorptive removal is significant. However, diclofenac β-O-acyl glucuronide deconjugated to form equimolar diclofenac within 7 d, in the microbial degradation test. The mixture of diclofenac and its two metabolites, formed after incubating diclofenac in S9 medium for 2 h, was spiked in the inoculum to link both assays. The concentrations of diclofenac and its metabolites, measured over time, agreed well with predicted values, using rate parameters obtained from independent experiments. The results show that phase II metabolites generated in mammals may deconjugate easily in conventional STPs to form a parent compound and that these processes should be considered during the environmental monitoring and risk assessment of diclofenac.

Inhibition of glycogen synthase kinase-3β prevents NSAID-induced acute kidney injury

Clinical use of nonsteroidal anti-inflammatory drugs (NSAIDs) like diclofenac (DCLF) is limited by multiple adverse effects, including renal toxicity leading to acute kidney injury. In mice with DCLF-induced nephrotoxicity, TDZD-8, a selective glycogen synthase kinase (GSK)3β inhibitor, improved acute kidney dysfunction and ameliorated tubular necrosis and apoptosis associated with induced cortical expression of cyclooxygenase-2 (COX-2) and prostaglandin E2. This renoprotective effect was blunted but still largely preserved in COX-2-null mice, suggesting that other GSK3β targets beyond COX-2 functioned in renal protection. Indeed, TDZD-8 diminished the mitochondrial permeability transition in DCLF-injured kidneys. In vitro, GSK3β inhibition reinstated viability and suppressed necrosis and apoptosis in DCLF-stimulated tubular epithelial cells. DCLF elicited oxidative stress, enhanced the activity of the redox-sensitive GSK3β, and promoted a mitochondrial permeability transition by interacting with cyclophilin D, a key component of the mitochondrial permeability transition pore. TDZD-8 blocked GSK3β activity and prevented GSK3β-mediated cyclophilin D phosphorylation and the ensuing mitochondrial permeability transition, concomitant with normalization of intracellular ATP. Conversely, ectopic expression of a constitutively active GSK3β abolished the effects of TDZD-8. Hence, inhibition of GSK3β ameliorates NSAID-induced acute kidney injury by induction of renal cortical COX-2 and direct inhibition of the mitochondrial permeability transition.

Molecular and microscopic assessment of the effects of caffeine, acetaminophen, diclofenac, and their mixtures on river biofilm communities

The authors examined effects of three common contaminants, caffeine (CF), acetaminophen (AC), and diclofenac (DF), as well as their mixtures on the development, functioning, and biodiversity of river biofilm communities. Biofilms were cultivated in rotating annular reactors. Treatments included AC, CF, DF, AC + CF, AC + DF, CF + DF, AC + CF + DF at 5 µg/L, and their molar equivalent as carbon and nutrients. Incubations using ¹⁴C-labeled AC, DF, and CF indicated that 90% of the CF, 80% of the AC, and less than 2% of the DF were converted to CO₂. Digital imaging revealed a variety of effects on algal, cyanobacterial, and bacterial biomass. Algal biomass was unaffected by AC or CF in combination with DF but significantly reduced by all other treatments. Cyanobacterial biomass was influenced only by the AC + DF application. All treatments other than AC resulted in a significant decrease in bacterial biomass. Diclofenac or DF + CF and DF + AC resulted in increases in micrometazoan grazing. The denaturing gradient gel electrophoresis of Eubacterial community DNA, evaluated by principal component analysis and analysis of similarity, indicated that relative to the control, all treatments had effects on microbial community structure (r = 0.47, p < 0.001). However, the AC + CF + DF treatment was not significantly different from its molar equivalent carbon and nutrient additions. The Archaeal community differed significantly in its response to these exposures based on community analyses, confirming a need to integrate these organisms into ecotoxicological studies.

Sub-lethal effects induced by a mixture of three non-steroidal anti-inflammatory drugs (NSAIDs) on the freshwater bivalve Dreissena polymorpha

Non-steroidal anti-inflammatory drugs (NSAIDs) are the sixth top-selling drugs worldwide and are commonly found in freshwater ecosystems in the high ng/l to low μg/l range. Recent studies have investigated both the acute and the chronic toxicity of single NSAIDs on different biological models, but these studies have completely neglected the fact that, in the environment, non-target organisms are exposed to mixtures of drugs that have unforeseeable toxicological behavior. This work investigated the sub-lethal effects induced by a mixture of three common NSAIDs, namely, diclofenac, ibuprofen and paracetamol, on the freshwater bivalve, the zebra mussel (Dreissena polymorpha). The mussels were exposed to three different environmental concentrations of the mixture (Low, Mid and High). A multi-biomarker approach was used to highlight cyto-genotoxic effects and the imbalance of the oxidative status of the treated specimens. The Neutral Red Retention Assay (NRRA) was used as a biomarker of cytotoxicity, whereas the activities of catalase, superoxide dismutase, glutathione peroxidase and glutathione S-transferase were measured to assess the role played by the oxidative stress enzymes. In addition, the single cell gel electrophoresis assay, the DNA Diffusion assay and the micronucleus test were used to investigate possible genotoxic effects. According to our NRRA results, each treatment was able to induce a significant cellular stress in bivalves, probably due to the raise of oxidative stress, as indicated by the alteration of enzyme activities measured in treated specimens. Moreover, the mixture induced significant enhancements of DNA fragmentation, which preluded fixed genetic damage, as highlighted by the increase of both apoptotic and micronucleated cells.

Risk of single and combined exposure of birds to non-steroidal anti-inflammatory drugs and lead

OBJECTIVES

Pharmaceuticals and heavy metals such as diclofenac and lead, respectively, have been identified as environmental contaminants toxic to birds and posing serious threats to declining populations of raptors worldwide. The aim of the present study was to test the hypothesis that a sublethal combination of non-steroidal anti-inflammatory drugs and lead induces more pronounced effects than single exposures in birds.

METHODS

A total of 40 Japanese quails (Coturnix coturnix japonica) at the age of 2 months and average weight of 180g were on a random basis divided into four experimental groups of 10 specimens (i.e., control, diclofenac, lead, and lead+diclofenac exposures). Six lead shots in the total weight of 1.5 grams were inserted into the crop on day 0 of the experiment, while a total of 5 mg/kg of diclofenac administered intramuscularly were divided into treatments on days 0 and 5. Group responses were compared using haematology and biochemistry after 10 days.

RESULTS

There was no mortality in control and both single and combined diclofenac and lead exposure groups, nor did the birds show any clinical signs of intoxication. Univariate analyses of blood parameters yielded a decrease in haematocrit in birds exposed to both substances when compared with the control, a lower haemoglobin level of the lead-exposed group, increased activity of aspartate aminotransferase in the NSAIDs-exposed group, increased activity of alkaline phosphatase in birds exposed to a combination of diclofenac and lead, and a higher phosphorus level in the lead-exposed group. The principal component analysis revealed no multivariate pattern of responses of blood parameters and did not allow separation of exposure groups from controls when the variables and samples were projected onto a two dimensional space.

CONCLUSIONS

Results of the present study can enhance understanding of combination toxicity of veterinary drugs and heavy metals in birds, i.e. a scenario that has become environmentally relevant in recent decades. Fortunately, individual blood parameter effects prevailed and no joint mortal effects were recognised in Japanese quails exposed to a combination of sublethal doses of diclofenac and lead.

Biomarker assessment of toxicity with miniaturised bioassays: diclofenac as a case study

The development of suitable biomarker-based microbioassays with model species with ecological relevance would help increase the cost-efficiency of routine environmental monitoring and chemical toxicity testing. The anti-inflammatory drug diclofenac has been widely reported in the environment but ecotoxicological data are scarce. The aim of this work is to assess the acute and chronic sublethal toxicity of diclofenac in relevant taxa of aquatic and riparian ecosystems (the fish Danio rerio and the fern Polystichum setiferum). Reliable biomarkers of cell viability (mitochondrial activity), plant physiology (chlorophyll), growth (DNA content) or oxidative damage (lipid peroxidation) were assessed as sensitive endpoints of toxicity. DNA quantification shows that diclofenac induces acute lethal phytotoxicity at 24 and 48 h (LOECs 30 and 0.3 μg l(-1), respectively). Hormetic effects in mitochondrial activity in spores of Polystichum setiferum mask lethality, and adverse effects are only observed at 48 h (LOEC 0.3 μg l(-1)). In chronic exposure (1 week) LOEC for DNA is 0.03 μg l(-1). Mitochondrial activity shows a strong hormetic stimulation of the surviving spore population (LOEC 0.3 μg l(-1)). Little changes are observed in chlorophyll autofluorescence (LOEC 0.3 μg l(-1)). A very short exposure (90 min) of zebrafish embryos induces a reduction of lipid peroxidation at 0.03 μg l(-1). Environmental concentrations of diclofenac can be deleterious for the development of significant populations of sensitive individuals in aquatic and riparian ecosystems.

Ecotoxicological impacts of clofibric acid and diclofenac in common carp (Cyprinus carpio) fingerlings: hematological, biochemical, ionoregulatory and enzymological responses

Investigation on the toxic effects of pharmaceutical drugs namely clofibric acid (CA) and diclofenac (DCF) were studied in a common carp Cyprinus carpio at different concentrations such as 1, 10 and 100 μg L(-1) for a short-term period of 96 h under static bioassay method. At all concentrations, red blood cell (RBC), plasma sodium (Na(+)), potassium (K(+)), and glutamate oxaloacetate transaminase (GOT) levels were decreased in fish treated with CA and DCF. Contrastingly, white blood cell (WBC), plasma glucose, protein, lactate dehydrogenase (LDH) and gill Na(+)/K(+)-ATPase level were increased. However, a mixed trend was observed in hemoglobin (Hb), hematocrit (Hct), plasma chloride (Cl(-)), mean cellular volume (MCV), mean cellular hemoglobin (MCH), mean cellular hemoglobin concentration (MCHC) and glutamate pyruvate transaminase (GPT) levels. There was a significant (P<0.01 and P<0.05) change in all parameters measured in fish exposed to different concentrations of CA and DCF. In summary, the alterations in hematological, biochemical, ionoregulatory and enzymological parameters can be used as biomarkers in monitoring the toxicity of CA and DCF in aquatic environment. However, more detailed studies on using of specific biomarkers to monitor the human pharmaceuticals are needed.

Can pharmaceuticals interfere with the synthesis of active androgens in male fish? An in vitro study

The in vitro interference of fibrate (gemfibrozil, clofibrate, clofibric acid), anti-inflammatory (ibuprofen, diclofenac), and anti-depressive (fluoxetine, fluvoxamine) drugs with key enzymatic activities-C17,20-lyase and CYP11β-involved in the synthesis of active androgens in gonads of male carp have been investigated. Among the tested compounds, fluvoxamine and fluoxetine were the strongest inhibitors of C17,20-lyase and CYP11β enzymes, with IC50s in the range of 321-335 μM and 244-550 μM, respectively. To our knowledge this is the first report on the interaction of pharmaceutical compounds with enzymatic systems involved in the synthesis of oxy-androgens. As oxy-androgens are known to influence spermatogenesis and stimulate reproductive behavior and secondary sexual characteristics in male fish, this work highlights the need for further investigating these endpoints when designing specific in vivo studies to assess the endocrine disruptive effect of pharmaceuticals in fish.

Diclofenac in fish: blood plasma levels similar to human therapeutic levels affect global hepatic gene expression

Diclofenac is a nonsteroidal anti-inflammatory drug frequently found in the aquatic environment. Previous studies have reported histological changes in the liver, kidney, and gills of fish at concentrations similar to those measured in treated sewage effluents (approximately 1 µg/L). Analyses or predictions of blood plasma levels in fish allow a direct comparison with human therapeutic plasma levels and may therefore be used to indicate a risk for pharmacological effects in fish. To relate internal exposure to a pharmacological interaction, we investigated global hepatic gene expression together with bioconcentration in blood plasma and liver of rainbow trout (Oncorhynchus mykiss) exposed to waterborne diclofenac. At the highest exposure concentration (81.5 µg/L), the fish plasma concentration reached approximately 88% of the human therapeutic levels (C(max) ) after two weeks. Using an oligonucleotide microarray followed by quantitative PCR, we found extensive effects on hepatic gene expression at this concentration, and some genes were found to be regulated down to the lowest exposure concentration tested (1.6 µg/L), corresponding to a plasma concentration approximately 1.5% of the human C(max) . Thus, at concentrations detected in European surface waters, diclofenac can affect the expression of multiple genes in exposed fish. Functional analysis of differentially expressed genes revealed effects on biological processes such as inflammation and the immune response, in agreement with the mode of action of diclofenac in mammals. In contrast to some previously reported results, the bioconcentration factor was found to be stable (4.02 ± 0.75 for blood plasma and 2.54 ± 0.36 for liver) regardless of the water concentration.

Chronic exposure to diclofenac on two freshwater cladocerans and Japanese medaka

Consequences of long-term exposure to diclofenac up to 3 months were evaluated using freshwater crustaceans (Daphnia magna and Moina macrocopa) and a fish (Oryzias latipes). Marked decrease of reproduction was observed at 25 mg/L for D. magna, and at 50 mg/L for M. macrocopa. Three-month exposure of fish to 0.001-10 mg/L of diclofenac resulted in significant decreasing trend in hatching success and delay in hatch. The hatching of the eggs produced from the fish exposed to 10 mg/L was completely interfered, while fertility of the parent generation was not affected. Gonadosomatic index (GSI) of female fish was also affected at 10 mg/L. Predicted no effect concentration of diclofenac was estimated at 0.1 mg/L, which is a few orders of magnitude greater than those observed in ambient water. Therefore direct impact of diclofenac exposure is not expected. However its bioaccumulation potential through food web should warrant further evaluation.

Effects of the pharmaceuticals gemfibrozil and diclofenac on the marine mussel (Mytilus spp.) and their comparison with standardized toxicity tests

Human pharmaceuticals, like the lipid lowering agent gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac are causing environmental concern. In this study, the marine mussel (Mytilus spp.) was exposed by injection to environmentally relevant and elevated (1 μg/L and 1000 μg/L) concentrations of both compounds and biomarker expression was observed. Gemfibrozil exposure induced biomarkers of stress (glutathione S-transferase and metallothionein) at both concentrations 24h and 96 h after exposure, respectively. Biomarkers of damage (lipid peroxidation (LPO) and DNA damage) were significantly affected, as well as the biomarker for reproduction, alkali-labile phosphate assay, indicating the potential oxidative stress and endocrine disrupting effect of gemfibrozil. Diclofenac significantly induced LPO after 96 h indicating tissue damage. Additionally standard toxicity tests using the marine species Vibrio fischeri, Skeletonema costatum and Tisbe battagliai showed differences in sensitivity to both drugs in the mg/L range. Results indicate a suite of tests should be used to give accurate information for regulation.

Effects of the pharmaceuticals gemfibrozil and diclofenac on biomarker expression in the zebra mussel (Dreissena polymorpha) and their comparison with standardised toxicity tests

Pharmaceuticals, including the lipid regulator gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac have been identified in waste water treatment plant effluents and receiving waters throughout the western world. The acute and chronic toxicity of these compounds was assessed for three freshwater species (Daphnia magna, Pseudokirchneriella subcapitata, Lemna minor) using standardised toxicity tests with toxicity found in the non-environmentally relevant mid mg L(-1) concentration range. For the acute endpoints (IC(50) and EC(50)) gemfibrozil showed higher toxicity ranging from 29 to 59 mg L(-1) (diclofenac 47-67 mg L(-1)), while diclofenac was more toxic for the chronic D. magna 21 d endpoints ranging from 10 to 56 mg L(-1) (gemfibrozil 32-100 mg L(-1)). These results were compared with the expression of several biomarkers in the zebra mussel (Dreissena polymorpha) 24 and 96 h after exposure by injection to concentrations of 21 and 21,000 μg L(-1) corresponding to nominal concentrations of 1 and 1000 μg L(-1). Exposure to gemfibrozil and diclofenac at both concentrations significantly increased the level of lipid peroxidation, a biomarker of damage. At the elevated nominal concentration of 1000 μg L(-1) the biomarkers of defence glutathione transferase and metallothionein were significantly elevated for gemfibrozil and diclofenac respectively, as was DNA damage after 96 h exposure to gemfibrozil. No evidence of endocrine disruption was observed using the alkali-labile phosphate technique. Results from this suite of biomarkers indicate these compounds can cause significant stress at environmentally relevant concentrations acting primarily through oxidation pathways with significant destabilization of the lysosomal membrane and that biomarker expression is a more sensitive endpoint than standardised toxicity tests.

Cytotoxicity assessment of four pharmaceutical compounds on the zebra mussel (Dreissena polymorpha) haemocytes, gill and digestive gland primary cell cultures

Pharmaceutical compounds are considered the new environmental pollutants but at present few studies have evaluated their ecotoxicity on aquatic invertebrates. This study was aimed to investigate the in vitro cytotoxicity of four common drugs, namely atenolol (ATL), carbamazepine (CBZ), diclofenac (DCF) and gemfibrozil (GEM), on three different cell typologies from the zebra mussel (Dreissena polymorpha): haemocytes, gill and digestive gland cells. Results obtained by the Trypan blue exclusion test revealed that exposure to increasing concentrations (0.001; 0.01; 0.1; 1 and 10 mg L(-1)) of CBZ, DCF and GEM were able to significantly decrease the viability of each cell type, while the MTT (3(4,5-dimethyl-2thiazholyl)-2,5-diphenyl-2H-tetrazolium bromide) reduction assay highlighted only a slight reduction of mitochondrial activity of gill and digestive gland cells. Overall, DCF was the most cytotoxic drug for zebra mussel cells, followed by GEM, CBZ, while ATL has not a noteworthy toxic potential. Our preliminary results lay the groundwork for further in vitro evaluations, which will allow a better definition of the potential toxicity of these drugs.

Sub-chronic diclofenac sodium induced alterations of alkaline phosphatase activity in serum and skeletal muscle of mice

The present study has been carried on changes in activity of alkaline phosphatase in serum and gastrocnemius muscle of mice after sub-chronic use of diclofenac. Mice in experimental group received diclofenac (10 mg/kg body wt /day) for 30 days while control group received normal saline. Alkaline phosphatase was assayed in muscle and serum and its activity was localized histochemically in muscle. Results showed that diclofenac induced changes in specific activity of alkaline phosphatase at different periods of treatment variably compared to control group. Specific activity of alkaline phosphatase decreased significantly in gastrocnemius initially (48.74%), increased thereafter (132.96%) and slight decrease (13.97%) was noticed after 30 days. In serum, the specific activity of alkaline phosphatase decreased slightly after 10 days (18.78%), increased in the middle of the treatment period (132.04%) as well as showed increase (109.09%) compared to control group after 30 days stage of investigation. These findings were also confirmed by electrophoretic studies in muscle.

Fish embryo toxicity of carbamazepine, diclofenac and metoprolol

Frequently measured pharmaceuticals in environmental samples were tested in fish embryo toxicity (FET) tests with Danio rerio, based on the draft OECD test protocol. In this FET test 2-h-old zebrafish embryos were exposed for 72 h to carbamazepine, diclofenac and metoprolol to observe effects on embryo mortality, gastrulation, somite formation, tail movement and detachment, pigmentation, heartbeat, malformation of head, otoliths and heart, scoliosis, deformity of yolk, and hatching success at 24, 48 and 72 h. We found specific effects on growth retardation above 30.6 mg/l for carbamazepine, on hatching, yolk sac and tail deformation above 1.5mg/l for diclofenac, and on scoliosis and growth retardation above 12.6 mg/l for metoprolol. Scoring all effect parameters, the 72-h-EC(50) values were: for carbamazepine 86.5mg/l, for diclofenac 5.3mg/l and for metoprolol 31.0mg/l (mean measured concentrations). In conclusion, our results for carbamazepine and metoprolol are in agreement with other findings for aquatic toxicity, and also fish embryos responded in much the same way as rat embryos did. For diclofenac, the FET test performs comparably to Early Life Stage testing.

Pharmacologic targeting or genetic deletion of mitochondrial cyclophilin D protects from NSAID-induced small intestinal ulceration in mice

Small intestinal ulceration is a frequent and potentially serious condition associated with nonselective cyclooxygenase 1/2 inhibitors (nonsteroidal anti-inflammatory drugs, NSAIDs) including diclofenac (DCF). An initial topical effect involving mitochondria has been implicated in the pathogenesis, but the exact mechanisms of NSAID-induced enteropathy are unknown. We aimed at investigating whether DCF caused enterocyte demise via the mitochondrial permeability transition (mPT) and whether inhibition of critical mPT regulators might protect the mucosa from DCF injury. Cultured enterocytes (IEC-6) exposed to DCF readily underwent mPT-mediated cell death. We then targeted mitochondrial cyclophilin D (CypD), a key regulator of the mPT, in a mouse model of NSAID enteropathy. C57BL/6J mice were treated with an ulcerogenic dose of DCF (60 mg/kg, ip), followed (+ 1 h) by a non-cholestatic dose (10 mg/kg, ip) of the CypD inhibitor, cyclosporin A (CsA). CsA greatly reduced the extent of small intestinal ulceration. To avoid potential calcineurin-mediated effects, we used the non-immunosuppressive cyclosporin analog, D-MeAla(3)-EtVal(4)-cyclosporin (Debio 025). Debio 025 similarly protected the mucosa from DCF injury. To exclude drug-drug interactions, we exposed mice genetically deficient in mitochondrial CypD (peptidyl-prolyl cis-trans isomerase F [Ppif(-/-)]) to DCF. Ppif-null mice were largely protected from the ulcerogenic effects of DCF, whereas their wild-type littermates developed typical enteropathy. Enterocyte injury was preceded by upregulation of the proapoptotic transcription factor C/EBP homologous protein (Chop). Chop-null mice were refractory to DCF enteropathy, suggesting a critical role of endoplasmic reticulum stress induced by DCF. In conclusion, mitochondrial CypD plays a key role in NSAID-induced enteropathy, lending itself as a potentially new therapeutic target for cytoprotective intervention.

[Degradation of the mixed pharmaceuticals with low concentration in aqueous by solar/ferrioxalate system and process evaluation through toxicity bioassay]

Under the sunlight irradiation, the four common trace pollutants such as metronidazole, diclofenac, sulfamethoxazole and ibuprofen were degradated and mineralized by the hydroxyl radical (*OH) generated from decomposition of H2O2 catalyzed by ferrioxalate (FeOx), and the toxicity of the water solution containing degradated products and intermediates were evaluated. The factors affecting the removal of the TOC, such as the initial concentration of H2O2, FeOx, and the pH, were investigated through an indicator of total organic carbon. The disappearing rate of pollutants in aqueous solution was explained according to the chemical structure of the pharmaceuticals; the biotoxicity of the pharmaceuticals and the intermediates were evaluated by EC50 value of pharmaceutical solution to the Chlorella. The appropriate operating conditions were achieved at pH 3 with initial concentrations of 300 mg x L(-1) H2O2 and 75 mg x L(-1) FeOx at the conditions such as the initial concentration of four drugs were 20 mg x L(-1), respectively. The order of the degradation rate for the pharmaceuticals is metronidazole > ibuprofen > sulfamethoxazole > diclofenac. During the reaction, the biological toxicity increases with time and then decreases rapidly, along with appearance and disappearance of intermediates. Finally, a model on reaction mechanism was proposed, where Solar/FeOx/H2O2 system was used for the degradation of the pharmaceuticals with low concentration in aqueous solution.

Anti-depressants make amphipods see the light

The effects of serotonin altering parasites, serotonin, the anti-depressant fluoxetine, plus two other highly prescribed pharmaceuticals (carbamazepine and diclofenac) on the behaviour of the marine amphipod, Echinogammarus marinus were investigated. Acanthocephalan parasites are known to alter the swimming behaviour in their amphipod hosts through changes in serotonergic activity resulting in increased predation. Behavioural assays were adapted to record changes in phototaxis and geotaxis behaviour in male E. marinus following 7, 14 and 21 days exposure to serotonin and each pharmaceutical compound at 4 concentrations compared to a control (between 10 ng/L and 10 microg/L). E. marinus infected with acanthocephalans parasites had both significantly higher phototaxis and geotaxis scores than those of uninfected specimens. Phototaxis and geotaxis behaviour increased significantly in a concentration-dependent manner with exposure to serotonin. Fluoxetine significantly altered phototaxis and geotaxis activity in what appeared to be a non-monotonic concentration response curve with the greatest behavioural changes observed at 100 ng/L. The main patterns of these behavioural responses were consistent between two trials and the 3 weeks exposure with specimens spending more time within the light and occurring higher in the water column. No obvious trends could be concluded in the phototaxis and geotaxis scores from individuals exposed to carbamazepine or diclofenac as might be expected from their known mode of action. From this study phototaxis and geotaxis behaviour have been observed to be affected by exposure to serotonin modulators. Parasite studies have shown strong links between changes in behaviour and increased predation risk correlating with changes in serotonergic activity. This study has highlighted the potential for highly prescribed anti-depressant drugs to change the behaviour of an ecologically relevant marine species in ways which could conceivably lead to population level effects.