Metoprolol elicits neurobehavioral insufficiency and oxidative damage in nontarget Nauphoeta cinerea nymphs.

Metoprolol, a drug for hypertension and cardiovascular diseases, has become a contaminant of emerging concern because of its frequent detection in various environmental matrices globally. The dwindling in the biodiversity of useful insects owing to increasing presence of environmental chemicals is currently a great interest to the scientific community. In the current research, the toxicological impact of ecologically relevant concentrations of metoprolol at 0, 0.05, 0.1, 0.25, and 0.5 µg/L on Nauphoeta cinerea nymphs following exposure for 42 consecutive days was evaluated. The insects' behavior was analyzed with automated video-tracking software (ANY-maze, Stoelting Co, USA) while biochemical assays were done using the midgut, head and fat body. Metoprolol-exposed nymphs exhibited significant diminutions in the path efficiency, mobility time, distance traveled, body rotation, maximum speed and turn angle cum more episodes, and time of freezing. In addition, the heat maps and track plots confirmed the metoprolol-mediated wane in the exploratory and locomotor fitness of the insects. Compared with control, metoprolol exposure decreased acetylcholinesterase activity in insects head. Antioxidant enzymes activities and glutathione level were markedly decreased whereas indices of inflammation and oxidative injury to proteins and lipids were significantly increased in head, midgut and fat body of metoprolol-exposed insects. Taken together, metoprolol exposure induces neurobehavioral insufficiency and oxido-inflammatory injury in N. cinerea nymphs. These findings suggest the potential health effects of environmental contamination with metoprolol on ecologically and economically important nontarget insects.

Assessment of the safety of intravitreal injection of metoprolol tartrate in rabbits.

PURPOSE: To verify the safety of different doses of intravitreal metoprolol tartrate (MT) after intravitreal injection in rabbit eyes. METHODS: Animals were randomly assigned into 2 groups: group I received 50 µg of MT and group II 100 µg of MT. A volume of 0.05 mL of the drug solution was administered through an intravitreal injection, while the control eyes received an equal volume of saline solution. Safety was assessed by clinical observation, electroretinography (ERG) and histological evaluation. RESULTS: No evidence of clinical toxicity was observed. ERG waveforms from the MT treated eyes were similar to those recorded from the control eyes in dark-adapted state, amplitude and the implicit time are similar between the groups in light-adapted state, and their retinas had no signs of toxicity by histological evaluation 7 days after intravitreal injection. CONCLUSIONS: The intravitreal use of metoprolol at 50 and 100 µg dosages does not cause short-term retinal toxicity in rabbits.

Influence of pH on the uptake and toxicity of ß-blockers in embryos of zebrafish, Danio rerio.

ß-Blockers are weak bases with acidity constants related to their secondary amine group. At environmental pH they are protonated with the tendency to shift to their neutral species at more alkaline pH. Here we studied the influence of pH from 5.5 to 8.6 on the toxicity of the four ß-blockers atenolol, metoprolol, labetalol and propranolol in zebrafish embryos, relating toxicity not only in a conventional way to external aqueous concentrations but also to measured internal concentrations. Besides lethality, we evaluated changes in swimming activity and heartbeat, using the Locomotor Response (LMR) method and the Vertebrate Automated Screening Technology (VAST) for high throughput imaging. Effects of metoprolol, labetalol and propranolol were detected on phenotype, heart rate and swimming activity. External effect concentrations decreased with increasing neutral fraction for all three pharmaceuticals, attributed by an enhanced uptake of the neutral species in comparison to the corresponding charged form. The LC50 of metoprolol decreased by a factor of 35 from 1.91 mM with almost complete cationic state at pH 7.0 to 0.054 mM with 8% neutral fraction at pH 8.6. For propranolol the LC50 of 2.42 mM at pH 5.5 was even 100 fold higher than the LC50 at pH 8 with 0.023 mM where 3% were neutral fraction. No effects were detected in the zebrafish embryo exposed to atenolol. The internal concentrations for metoprolol and propranolol were quantified at non-toxic concentrations and at the LC10. Apparent bioconcentration factors (BCF) ranged from 1.96 at pH 7.0 to 32.0 at pH 8.6 for metoprolol and from 1.86 at pH 5.5 to 169 at pH 8.0 for propranolol. The BCFs served to predict the internal effect concentrations from the measured external effect concentrations. Internal effect concentrations of metoprolol and propranolol were in a similar range for all pH-values and for all endpoints. Interestingly, the internal effect concentrations were in the internal concentration range of baseline toxicity, which suggests that the effects of the ß-blockers are rather unspecific, even for sublethal effects on heart rate. In summary, our data confirm that the pH-dependent toxicity related to external concentrations can be explained by toxicokinetic effects and that the internal effect concentrations are pH-independent.

Metoprolol induces oxidative damage in common carp (Cyprinus carpio).

During the last decade, ß-blockers such as metoprolol (MTP) have been frequently detected in surface water, aquatic systems and municipal water at concentrations of ng/L to µg/L. Only a small number of studies exist on the toxic effects induced by this group of pharmaceuticals on aquatic organisms. Therefore, the present study aimed to evaluate the oxidative damage induced by MTP in the common carp Cyprinus carpio, using oxidative stress biomarkers. To this end, indicators of cellular oxidation such as hydroperoxide content (HPC), lipid peroxidation (LPX) and protein carbonyl content (PCC) were determined, as well as the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Also, concentrations of MTP and its metabolite O-desmethyl metoprolol were determined in water as well as carp gill, liver, kidney, brain and blood, along with the partial uptake pattern of these compounds. Results show that carp takes up MTP and its metabolite in the different organs evaluated, particularly liver and gill. The oxidative stress biomarkers, HPC, LPX, and PCC, as well as SOD and CAT activity all increased significantly at most exposure times in all organs evaluated. Results indicate that MTP and its metabolite induce oxidative stress on the teleost C. carpio and that the presence of these compounds may constitute a risk in water bodies for aquatic species.

Chronic exposure to the ß-blocker metoprolol reduces growth and alters gene expression of gonadotropins and vitellogenin in Nile tilapia (Oreochromis niloticus).

Knowledge of the occurrence and impacts of human pharmaceuticals in the aquatic environment is increasing since many years. Ecotoxicological studies mainly focus on acute effects though; chronic exposure studies are still rare. ß-adrenergic receptor antagonists (ß-blockers) are widely detected in the aquatic environment and likely alter the physiology of aquatic vertebrates due to a well-conserved adrenergic system. In this study, Nile tilapia (Oreochromis niloticus) were exposed to four different concentrations (4×10-10M, 4×10-9M, 4×10-8M and 4×10-7M) of metoprolol (ß1-blocker) from fertilized egg until 80 days post-hatch. Hatching and survival were not affected but growth was reduced almost dose-dependently after 30 and 80 days post-hatch. Histopathological evaluation of the gills revealed the tendency of mild alterations with proliferation of mucous/chloride cells and infiltration by leucocytes as the main findings. The transcriptional responses of both pituitary gonadotropins (luteinizing hormone and follicle stimulating hormone) as well as the estrogenic biomarker vitellogenin indicated moderately altered endocrine processes due to metoprolol exposure at the concentrations chosen. In contrast, hepatic detoxification mechanisms displayed only little to no effects. Based on this study, the overall toxicity of metoprolol in fish at environmentally relevant concentrations seems to be rather low.

Hazard screening of photo-transformation products from pharmaceuticals: Application to selective ß1-blockers atenolol and metoprolol.

The identification of toxic components in cocktail mixtures of pollutants, their metabolites and transformation products (TPs) generated from environmental and treatment processes remains an arduous task. This study expanded in this area by applying a combination of chemical analytics, a battery of in vitro bioassays and an in silico "testing battery" to UV photolysis mixtures of active pharmaceutical ingredients. The objectives were to understand the toxic nature of the mixtures and to prioritize photo-TPs for risk analysis. The selective ß1-blockers Atenolol (ATL) and Metoprolol (MTL) that are ubiquitous in the aquatic environment were used as an example. The photolysis mixtures were cytotoxic to Vibrio fischeri and mammalian cells but not mutagenic in the Ames test or genotoxic in the in vitro micronucleus and umu tests. Potentially hazardous TPs were proposed by relating the observed effects to the kinetics of TP occurrence and applying in silico toxicity predictions for individual photo-TPs. This model study was done to identify principal mechanisms rather than accurately simulating environmental transformation processes. Several photo-TPs were proposed to present a greater hazard than the selected ß-blockers and therefore fate and toxicity assessments may be required to determine their environmental relevance.

Health effects of metoprolol in epibenthic and endobenthic invertebrates-A basis to validate future in vitro biotests for effect-based biomonitoring.

The aim of this study was to determine the effect data for metoprolol as a model substance for beta-blockers in aquatic invertebrates. The results will be used as a basis for the validation of future mode of action-based in vitro test systems targeting this class of pharmaceuticals. Effects of metoprolol were investigated in two autochthonous species with high relevance in stream ecology: the amphipod Gammarus fossarum and the oligochaete Lumbriculus variegatus. Mortality in G. fossarum was not observed in acute toxicity testing (48 h), and a significant increase of mortality at 45 mg/L was found when amphipods were exposed chronically (40 days). The most sensitive population-relevant endpoints were the juvenile-adult ratio and number of egg-bearing females with NOEC/LOEC-values of 5/15 mg/L. No proteotoxic effects were identified in G. fossarum. The sediment toxicity test with L. variegatus according to the OECD Guideline 225 with an exposure time of 28 days resulted in EC10-values of 92.5 and 126.1 mg/kgdw for the endpoints reproduction and biomass, respectively. In L. variegatus the response kinetics of Hsp70 showed no significant difference between the treatments. A tendency for rising lipid peroxide concentrations was found between 0.03 and 10 mg/kgdw, which were significant between the treatments, but not to the control.

Bioelectro-Fenton: A sustainable integrated process for removal of organic pollutants from water: Application to mineralization of metoprolol.

The relevant environmental hazard related to the presence of pharmaceuticals in water sources requires the development of high effective and suitable wastewater treatment technologies. In the present work, a hybrid process coupling electro-Fenton (EF) process and aerobic biological treatment (Bio-EF process) was implemented for the efficient and cost-effective mineralization of beta-blocker metoprolol (MPTL) aqueous solutions. Firstly, operating factors influencing EF process were assessed. MTPL solutions were completely mineralized after 4h-electrolysis under optimal operating conditions and BDD anode demonstrated its oxidation superiority. The absolute rate constant of MTPL oxidation byOH (kMTPL) was determined by the competition kinetics method and found to be (1.72±0.04)×10(9)M(-1)s(-1). A reaction pathway for the mineralization of the drug was proposed based on the identification of oxidation by-products. Secondly, EF process was used as pre-treatment. An increase of BOD5/COD ratio from 0.012 to 0.44 was obtained after 1h EF treatment, along with 47% TOC removal and a significant decrease of toxicity, demonstrating the feasibility of a post-biological treatment. Finally, biological treatment successfully oxidized 43% of the total TOC content. An overall 90% mineralization of MPTL solutions was achieved by the Bio-EF process, demonstrating its potentiality for treating wastewater containing pharmaceutical residues.

Derivation of water quality standards for carbamazepine, metoprolol, and metformin and comparison with monitoring data.

Environmental quality standards (EQSs) for 3 pharmaceuticals in surface water were derived: carbamazepine (epilepsy), metoprolol (heart failure), and metformin (diabetes). In recent years, these pharmaceuticals have been detected frequently in Dutch surface waters. The proposed standards are based on ecotoxicity data from national and European authorization dossiers and additional information obtained from open literature. The methods used are in accordance with the methodology of the Water Framework Directive and national frameworks for risk limit derivation. Only the exposure route regarding direct ecotoxic effects on ecosystems could be taken into account for deriving EQSs. The exposure route of secondary poisoning of fish-eating animals was not triggered, and not enough data were available or accessible to derive an EQS for the exposure of humans due to consumption of fish. Monitoring data for surface waters worldwide show that the proposed quality standards for carbamazepine may be exceeded. It could be expected that when carbamazepine use increases or effluents are diluted less during dry seasons, standards will be exceeded more often.

Transcriptional Responses in Adult Zebrafish (Danio rerio) Exposed to Propranolol and Metoprolol.

ß-adrenergic receptor blockers (ß-blockers) are widely detected in the aquatic environment; however, the effects of these pharmaceuticals on aquatic organisms remain uncertain. In this study, adult zebrafish were exposed to two different ß-blockers, propranolol and metoprolol, for 96 h. After exposure, the transcriptional responses of genes encoding the ß-adrenergic receptor (i.e., adrb1, adrb2a, adrb2b, adrb3a and adrb3b), genes involved in detoxification and the stress response (i.e., hsp70, tap, mt1 and mt2), and genes related to the antioxidant system (i.e., cu/zn-sod, mn-sod, cat and gpx) were examined in the brain, liver and gonad. Our results show that both propranolol and metoprolol exposure changes the mRNA level of ß-adrenergic receptors, indicating clear pharmacological target engagement of the ß-blockers. The transcription of genes related to antioxidant responses and detoxification process were induced, suggesting that ß-blocker exposure can activate the detoxification process and result in oxidative stress in fish. Moreover, the transcriptional responses displayed substantial tissue- and gender-specific effects. Considering the environmental concentrations of propranolol and metoprolol, these results suggest that these pharmaceuticals are unlikely to pose a risk to fish. However, the impacts in prolonged exposure, along with other possible side effects due to ß-adrenergic receptor blockade, should be further assessed.

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.

A quantitative HPLC-MS/MS method for studying internal concentrations and toxicokinetics of 34 polar analytes in zebrafish (Danio rerio) embryos.

An analytical method using high-performance liquid chromatography-tandem mass spectrometry was developed to determine internal concentrations of 34 test compounds such as pharmaceuticals and pesticides in zebrafish embryos (ZFE), among them, cimetidine, 2,4-dichlorophenoxyacetic acid, metoprolol, atropine and phenytoin. For qualification and quantification, multiple reaction monitoring mode was used. The linear range extends from 0.075 ng/mL for thiacloprid and metazachlor and 7.5 ng/mL for coniine and clofibrate to 250 ng/mL for many of the test compounds. Matrix effects were strongest for nicotine, but never exceeded ±20 % for any of the developmental stages of the ZFE. Method recoveries ranged from 90 to 110 % from an analysis of nine pooled ZFE. These findings together with the simple sample preparation mean this approach is suitable for the determination of internal concentrations from only nine individual ZFE in all life stages up to 96 h post-fertilization. Exemplarily, the time course of the internal concentrations of clofibric acid, metribuzin and benzocaine in ZFE was studied over 96 h, and three different patterns were distinguished, on the basis of the speed and extent of uptake and whether or not a steady state was reached. Decreasing internal concentrations may be due to metabolism in the ZFE.

Toxicity and enantiospecific differences of two ß-blockers, propranolol and metoprolol, in the embryos and larvae of zebrafish (Danio rerio).

The risk presented by ß-blockers on aquatic organisms remains uncertain, particularly given the enantiospecific differences in toxicity of chiral ß-blockers. In this study, the toxicity of two ß-blockers, propranolol and metoprolol, was determined. The 96-h LC50 of propranolol in the zebrafish larvae was 2.48 mg/L, whereas 50 mg/L metoprolol did not result in death. Both ß-blockers decreased the heart rate and hatching rate and increased the mortality of the zebrafish embryos. Among these indicators, the heart rate was the most sensitive. However, the acute larval and embryo toxicity results displayed no enantioselectivity. Additionally, the transcriptional response of the genes encoding the ß-adrenergic receptors and those involved in other physiological processes, including the antioxidant response, detoxification, and apoptosis, in zebrafish larvae exposed to the ß-blockers was examined. Although the changes in gene transcription were fairly minor, significant enantioselectivity was observed for ß-blockers, suggesting that the transcriptional response was more sensitive for the evaluation of enantiospecific toxicity. Based on these results, the pharmaceutical drugs were not expected to pose a risk to fish; however, this conclusion should not be considered final. These results also demonstrated that the enantiospecific toxicity of chiral ß-blockers should be investigated when performing an ecological risk assessment.

Toxicity of the micropollutants Bisphenol A, Ciprofloxacin, Metoprolol and Sulfamethoxazole in water samples before and after the oxidative treatment.

The amount of organic micropollutants detected in surface waters increases steadily. Common waste water treatment plants are not built to remove these substances. Thus there is a need for new technologies. A promising technology is the use of advanced oxidation processes through which organic micropollutants can be removed from waste water. However, the formation of oxidation by-products is likely and needs to be investigated since the by-products not only differ from their parent compounds in regard to their chemical and physical properties but they can also differ in toxicity. Therefore this study was designed to combine chemical and toxicological analyses of the advanced oxidation (O3 [5mg/L] or UV/H2O2 [Hg-LP lamp; 15W; 1g/L H2O2]) of waste water treatment plant effluents and pure water. Effluent samples from conventional activated sludge waste water treatment (mechanical treatment, activated sludge basin, and primary as well as secondary treatment steps) and high-purity deionized water (pure water) were spiked with Bisphenol A, Ciprofloxacin, Metoprolol or Sulfamethoxazole and treated with O3 or UV/H2O2. For the toxicological analyses mammalian cells (CHO-9, T47D) were exposed to the water samples for 24h and were tested for cytotoxicity (MTT Test), genotoxicity (Alkaline Comet Assay) and estrogenicity (ER Calux(®)). The results indicate that the oxidative treatment (O3 or UV/H2O2) of Bisphenol A, Metoprolol, Sulfamethoxazole or Ciprofloxacin in waste water did not result in toxic oxidation by-products, whereas the UV/H2O2 treatment of Bisphenol A and Ciprofloxacin in pure water resulted in by-products with cytotoxic but no estrogenic effects after 60min.

Toxicity assessment of metoprolol and its photodegradation mixtures obtained by using different type of TiO2 catalysts in the mammalian cell lines.

Toxicity of metoprolol (MET) alone and in mixtures with its photocatalytic degradation intermediates obtained by using TiO2 Wackherr and Degussa P25 under UV irradiation in the presence of O2 was evaluated in vitro in a panel of three histologically different cell lines: rat hepatoma (H-4-II-E), human colon adenocarcinoma (HT-29) and human fetal lung (MRC-5). Both catalysts promoted a time-dependent increase in the toxicity of the photodegradation products, and those obtained using Degussa P25 photocatalyst were more toxic. The most pronounced and selective toxic action of MET and products of its photodegradation was observed in the hepatic cell line. The higher toxicity of the mixtures obtained using Degussa P25 catalyst could be explained by a different mechanism of MET degradation, i.e. by the presence or higher concentrations of some intermediates. Although the concentrations of intermediates obtained using TiO2 Wackherr catalyst were higher, they did not affect significantly the growth of the examined cell lines, indicating their lower toxicity. This suggests that a treatment aiming at complete mineralization should be performed bearing in mind that the type of catalyst, the concentration of target molecule, and the duration of the process are significant factors that determine the nature and toxicity of the resulting mixtures. Although the EC50 values of MET obtained in mammalian cell lines were higher compared to the bioassays for lower trophic levels, the time-dependent promotion of toxicity of degradation mixtures should be attributed to the higher sensitivity of mammalian cell bioassays.

Pharmacokinetics, pharmacodynamics and toxicity of a combination of metoprolol succinate and telmisartan in Wistar albino rats: safety profiling.

Metoprolol succinate (MET), a cardioselective ß blocker and telmisartan (TEL), an angiotensin receptor blocker were administered orally, both individually and in combination to Wistar albino rats for evaluation of their pharmacokinetics, pharmacodynamics and repeated dose oral toxicity (28 days). Pharmacokinetic study was performed by analyzing drug concentration in plasma by a developed and validated LC-MS/MS method following oral administration of MET and TEL at 2.5 mg/kg and 2.0 mg/kg dose, respectively, both individually and in combination. Antihypertensive activity of MET and TEL in above dose and manner was evaluated on artificially induced hypertension on laboratory animals. In repeated dose oral toxicity study, MET (60, 120 and 240 mg/kg/day) and/or TEL (12, 24 and 48 mg/kg/day) were administered to animals for 28 days followed by a recovery period of 14 days. Pharmacokinetic data revealed the probable absence of any pharmacokinetic interaction when co-administered. Improved blood pressure lowering effect was observed by combination therapy. Moreover, toxic effects obtained at high dose level of each treatment groups were transient and reversible and no evidence of additive toxic effects were observed due to concomitant administration. So, this combination can primarily be stated as safe which will be confirmed after clinical interaction studies in humans.

Levosimendan infusion improves cardiac output but not blood pressure in a rodent model of severe metoprolol toxicity.

UNLABELLED: Levosimendan (Levo) is an inodilator improving cardiac output (CO) and reducing afterload in heart failure. Previously, we reported that Levo improved CO but not blood pressure (BP) in a rodent model of verapamil poisoning. We theorised that Levo-induced vasodilation should not influence BP to a similar degree in metoprolol poisoning. AIM: To assess the effect of Levo on haemodynamics in a rodent model of metoprolol poisoning. METHOD: Anaesthetized male Wistar rats were infused metoprolol continuously. When the BP dropped to 50% of baseline (time 0) rats received 1 of the 4 treatments: (a) control (0.9% saline bolus + infusion); (b) Levo-l (Levo 36 µm/kg loading dose followed by 0.6 µm/kg/min); (c) Levo-I (Levo infusion only at 0.6 µm/kg/min); and (d) Epi (epinephrine 0.5 µm/kg/min). All groups received comparable fluid volumes. Haemodynamics were recorded every 10 min for 70 min. CO, mean arterial pressure (MAP) and heart rate (HR) of each group were compared to the control. RESULTS: All groups had comparable baseline and time 0 HR, MAP and CO. Levo-L and Levo-I rats showed significantly greater CO at t = 10 min (p > 0.02 and p > 0.04, respectively). CO was higher at all other time points for both Levo groups. This was not statistically significant. Levo did not improve MAP compared to control. Adrenaline increased MAP but not CO compared to control and Levo groups. CONCLUSION: Levo did not improve MAP but moderately improved CO compared to control in this model of metoprolol poisoning. The response was similar to that reported previously in verapamil-poisoned rats. The improvement in MAP seen with epinephrine was most likely vasoconstriction mediated.

Electrochemical degradation of the ß-blocker metoprolol by Ti/Ru 0.7 Ir 0.3 O 2 and Ti/SnO 2-Sb electrodes.

Electrochemical oxidation has been proposed for the elimination of pesticides, pharmaceuticals and other organic micropollutants from complex waste streams. However, the detrimental effect of halide ion mediators and the generation of halogenated by-products in this process have largely been neglected thus far. In this study, we investigated the electrochemical oxidation pathways of the ß-blocker metoprolol in reverse osmosis concentrate (ROC) from a water reclamation plant using titanium anodes coated with Ru(0.7)Ir(0.3)O(2) or SnO(2)-Sb metal oxide layers. The results of liquid chromatography-mass spectrometry analysis indicated that irrespective of the electrode coating the same oxidant species participated in electrochemical transformation of metoprolol in ROC. Although Ti/SnO(2)-Sb exhibited higher oxidizing power for the same applied specific electrical charge, the generation of large fractions of chloro-, chloro-bromo- and bromo derivatives was observed for both electrode coatings. However, degradation rates of metoprolol and its degradation products were generally higher for the Ti/SnO(2)-Sb anode. Chemical analyses of metoprolol and its by-products were complemented with bioanalytical tools in order to investigate their toxicity relative to the parent compound. Results of the bioluminescence inhibition test with Vibrio fischeri and the combined algae test with Pseudokirchneriella subcapitata indicated a substantial increase in non-specific toxicity of the reaction mixture due to the formed halogenated by-products, while the specific toxicity (inhibition of photosynthesis) remained unchanged.

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.