Vânia Calisto

Psychiatric pharmaceuticals in the environment

Psychiatric pharmaceuticals, such as anxiolytics, sedatives, hypnotics, and antidepressants, are among the most prescribed active substances throughout the world. The occurrence of these widely used compounds in environmental matrices (wastewaters, surface, ground and drinking waters, soils, sediments, bio-solids and tissue), as well as the first studies indicating their high persistence and toxicity to non-target organisms, justify the growing concern about these emerging environmental pollutants. Despite this increasing interest, there is a considerable lack of knowledge about the environmental fate of a large number of psychiatric pharmaceuticals and further research about this topic is needed. This paper aims to review the literature data related to the occurrence, persistence, environmental fate and toxicity for non-target organisms of this group of pharmaceuticals. The analytical methods developed for the determination of psychiatric medicines in environmental matrices are also highlighted.

Presence of the pharmaceutical drug carbamazepine in coastal systems: effects on bivalves.

Carbamazepine (CBZ), an antiepileptic drug, is one of the most commonly detected pharmaceutical drugs in aquatic ecosystems, and is used as a marker of urban pollution. Since CBZ is designed to exert a biological effect, when it reaches aquatic environment high probability exist for toxic effects on non-target organisms. The present study evaluated the acute toxicity of environmentally relevant concentrations of CBZ (0.00, 0.03, 0.30, 3.00, 9.00μg/L) in the edible clams Venerupis decussata (a native species) and Venerupis philippinarum (an invasive species) collected from the Ria de Aveiro. The effects on both species were assessed through the use of a battery of biomarkers mainly related with health status and oxidative stress. Furthermore, in this work an alternative and promising tool, the direct competitive immunoassay ELISA, for the direct CBZ quantification in clams tissues, was applied. The results of the present work showed that CBZ in clams tissues increased with the exposure concentration and V. decussata gave slightly higher values than V. philippinarum. Although the clams accumulated lower levels of CBZ than the concentration of exposure, these concentrations were enough to impair the health status and induce oxidative stress. However, a different response to CBZ was observed in the two species. While in V. philippinarum the lipid peroxidation levels increased at the highest CBZ concentration (9.00μg/L), in V. decussata a significant decrease was seen. Moreover, glutathionse S-transferase activity was stimulated in V. decussata and decreased in V. philippinarum. Nevertheless, an induction of glutathione reductase, superoxide dismutase and cytochrome P450 3A4 activities was found in both species as a result of the exposure. The results indicate that, probably, V. philippinarum have a less efficient antioxidant system than V. decussata, and are therefore less capable to neutralize oxidative stress and consequently more sensitive to CBZ. The risk quotient determined for the Ria de Aveiro was higher than 1 indicating that a ecotoxicological risk is suspected. Furthermore, bioaccumulation of CBZ in clams should be taken into consideration since this chemical might be transferred along the food chain and affect non-target organisms.

Direct photodegradation of carbamazepine followed by micellar electrokinetic chromatography and mass spectrometry

Carbamazepine, a widely consumed psychotropic pharmaceutical, is one of the most commonly detected drugs in the environment. To better assess the environmental persistence of carbamazepine in aqueous matrices, the effect of pH and dissolved oxygen on the direct photodegradation rate of this pharmaceutical was evaluated in this study, using simulated solar irradiation. In order to follow the degradation and the emergence of photoproducts, a micellar electrokinetic chromatography based method was developed, consisting on the use of a dynamically coated capillary column. The developed methodology showed good repeatability and efficiency in the separation of carbamazepine and photoirradiation products. Also, seven photodegradation products were identified by electrospray mass spectrometry (ESI-MS), including the known carcinogenic acridine that was produced under all the pH and oxygenation levels studied and one newly identified photoproduct. This paper gives new insights into the role of dissolved oxygen on the photodegradation rate of carbamazepine. The results indicate that acidic pH, combined with the absence of dissolved oxygen in the aqueous matrix, results in very high direct photodegradation rates. At basic pH, dissolved oxygen does not interfere with the process and very low rates were observed. At environmentally relevant conditions, carbamazepine was shown to persist in the environment from 4.5 to 25 days.

Photodegradation of psychiatric pharmaceuticals in aquatic environments--kinetics and photodegradation products.

Benzodiazepines are widely consumed psychiatric pharmaceuticals which are frequently detected in the environment. The environmental persistence and fate of these pharmaceuticals as well as their degradation products is of high relevance and it is, yet, scarcely elucidated. In this study, the relevance of photodegradation processes on the environmental persistence of four benzodiazepines (oxazepam, diazepam, lorazepam and alprazolam) was investigated. Benzodiazepines were irradiated under simulated solar irradiation and direct and indirect (together with three different fractions of humic substances) photodegradation kinetics were determined. Lorazepam was shown to be quickly photodegradated by direct solar radiation, with a half-life time lower than one summer sunny day. On the contrary, oxazepam, diazepam and alprazolam showed to be highly resistant to photodegradation with half-life times of 4, 7 and 228 summer sunny days, respectively. Apparent indirect and direct photodegradation rates are of the same order of magnitude. However, humic acids were consistently responsible for a decrease in the photodegradation rates while fulvic acids and XAD4 fraction caused an enhancement of the photodegradation. Overall, the results highlight that photodegradation might not be an efficient pathway to prevent the aquatic environmental accumulation of oxazepam, diazepam and alprazolam. Also, nineteen direct photodegradation products were identified by electrospray mass spectrometry, the majority of which are newly identified photoproducts. This identification is crucial to a more complete understanding of the environmental impact of benzodiazepines in aquatic systems.

Application of an ELISA to the quantification of carbamazepine in ground, surface and wastewaters and validation with LC–MS/MS

Carbamazepine is a psychiatric pharmaceutical widely detected in aquatic environments. Due to its generalized occurrence and environmental persistence it might be considered as an anthropogenic pollution indicator. In this research, a previously developed enzyme-linked immunosorbent assay (ELISA), based on a commercial monoclonal antibody, was applied to the quantification of carbamazepine in ground, surface and wastewaters and results were validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The performance of the applied ELISA methodology was tested in the presence of high concentrations of sodium chloride and dissolved organic matter. The method was not significantly affected by matrix effects, being adequate for the quantification of carbamazepine in environmental samples, even without sample pre-treatment. This method allows the quantification of carbamazepine in the range of 0.03-10 μg L(-1), with a relative error lower than 30%. Due to a pH dependent cross-reactivity with cetirizine, an antihistaminic drug, the assay also enabled the quantification of cetirizine in the samples. The application of the developed method to the quantification of carbamazepine was performed by using environmental samples with very different matrices, collected in the geographical area of Ria de Aveiro, an estuarine system located in the North of Portugal. Carbamazepine was detected in all analyzed wastewater samples and in one surface water with concentrations between 0.1 and 0.7 μg L(-1). Validation with LC-MS/MS revealed that results obtained by ELISA are 2-28% overestimated, which was considered highly satisfactory due to the absence of sample pre-treatments.

Production of adsorbents by pyrolysis of paper mill sludge and application on the removal of citalopram from water

This work describes the production of alternative adsorbents from industrial residues and their application for the removal of a highly consumed antidepressant (citalopram) from water. The adsorbents were produced by pyrolysis of both primary and biological paper mill sludge at different temperatures and residence times. The original sludge and the produced chars were fully characterized by elemental and proximate analyses, total organic carbon, specific surface area (BET), N₂ isotherms, FTIR, (13)C and (1)H solid state NMR and SEM. Batch kinetic and equilibrium experiments were carried out to describe the adsorption of citalopram onto the produced materials. The fastest kinetics and the highest adsorption capacity were obtained using primary sludge pyrolysed at 800 °C during 150 min. The use of pyrolysed paper mill sludge for the remediation of contaminated waters might constitute an interesting application for the valorization of those wastes.

The effects of carbamazepine on macroinvertebrate species: Comparing bivalves and polychaetes biochemical responses.

In the present study, the bivalve Scrobicularia plana and the polychaete Diopatra neapolitana were exposed to an increasing carbamazepine (CBZ) concentration gradient. Both species are among the most widely used bioindicators, and CBZ is one of the most commonly found drugs in the aquatic environment. After a chronic exposure (28 days), the results obtained revealed that CBZ induced biochemical alterations in both species. Our findings demonstrated that S. plana and D. neapolitana reduced the CBZ accumulation rate at higher CBZ concentrations, probably due to their capacity to decrease their feeding rates at stressful conditions. Nevertheless, this defence mechanism was not enough to prevent both species from oxidative stress. In fact, S. plana and D. neapolitana were not able to efficiently activate their antioxidant defence mechanisms which resulted in the increase of lipid peroxidation, especially at the highest CBZ concentrations. Comparing both species, it seems that S. plana was the most sensitive species since stronger biochemical alterations were observed in this species.

The impacts of pharmaceutical drugs under ocean acidification: New data on single and combined long-term effects of carbamazepine on Scrobicularia plana

Ocean acidification and increasing discharges of pharmaceutical contaminants into aquatic systems are among key and/or emerging drivers of environmental change affecting marine ecosystems. A growing body of evidence demonstrates that ocean acidification can have direct and indirect impacts on marine organisms although combined effects with other stressors, namely with pharmaceuticals, have received very little attention to date. The present study aimed to evaluate the impacts of the pharmaceutical drug Carbamazepine and pH 7.1, acting alone and in combination, on the clam Scrobicularia plana. For this, a long-term exposure (28 days)was conducted and a set of oxidative stress markers was investigated. The results obtained showed that S. plana was able to develop mechanisms to prevent oxidative damage when under low pH for a long period, presenting higher survival when exposed to this stressor compared to CBZ or the combination of CBZ with pH 7.1. Furthermore, the toxicity of CBZ on S. plana was synergistically increased under ocean acidification conditions (CBZ + pH 7.1): specimens survival was reduced and oxidative stress was enhanced when compared to single exposures. These findings add to the growing body of evidence that ocean acidification will act to increase the toxicity of CBZ to marine organisms,which has clear implications for coastal benthic ecosystems suffering chronic pollution from pharmaceutical drugs.

Design of Protonated Polyazamacrocycles Based on Phenanthroline Motifs for Selective Uptake of Aromatic Carboxylate Anions and Herbicides

Three novel large polyazamacrocycles containing two 1,10-phenanthroline units connected by different polyamine spacers have been synthesised and their protonated forms used as receptors for several aromatic carboxylate anions. The receptors bind to the anions in a 1:1 stoichiometry and exhibit remarkable binding selectivity (see figure). Analysis shows that molecular recognition is governed by pi-pi stacking interactions and multiple N--HO==C hydrogen bonds.Three novel large polyazamacrocycles containing two 1,10-phenanthroline (phen) units connected by two polyamine spacers of different length, [32]phen(2)N(4), [30]phen(2)N(6) and Me(2)[34]phen(2)N(6), have been synthesised and their protonated forms used as receptors for binding studies with several aromatic carboxylate anions (benzoate (bzc(-)), 1-naphthalate (naphc(-)), 9-anthracenate (anthc(-)), pyrene-1-carboxylate (pyrc(-)), phthalate, (ph(2-)), isophthalate (iph(2-)), terephthalate (tph(2-)), 2,5-dihydroxy-1,4-benzenediacetate (dihyac(2-)) and, 1,3,5-benzenetricarboxylate (btc(3-))) and three herbicides (4-amino-3,5,6-trichloropyridine-2-carboxylate (ATCP(-)), dichlorophenoxyacetate (2,4-D(-)) and glyphosate (PMG(2-))) in water solution. The [30]phen(2)N(6) receptor was found to be the most suitable for binding the anions considered in a 1:1 stoichiometry. The three receptors exhibit a remarkable binding selectivity towards the extended aromatic anion pyrc(-) at low pH values. Their binding affinities for the monocarboxylate anions decrease with the extension of the aromatic system in the order pyrc(-)>anthc(-)>naphc(-)>bzc(-), which indicates the presence of pi-pi stacking interactions in the molecular recognition of these anions. Molecular dynamics simulations carried out for the binding of {H(4)[30]phen(2)N(6)}(4+) and {H(6)Me(2)[34]phen(2)N(6)}(6+) with pyrc(-), anthc(-), naphc(-), iph(2-) and btc(3-) in water showed that these receptors adopt a folded conformation with the anion inserted between the two phen heads and that the molecular recognition is governed by pi-pi stacking interactions and multiple N--HO==C hydrogen bonds. The binding free energies estimated theoretically are very similar to those found by potentiometric methods, which supports the proposed binding arrangement.

Removal of fluoxetine from water by adsorbent materials produced from paper mill sludge

In this work, three adsorbents were produced by using as precursor primary paper mill sludge and applying KOH, NaOH or ZnCl2 as chemical activating agents (PS800-10KOH, PS800-10NaOH and PS800-10ZnCl2) and subjected to pyrolysis. The produced materials were tested for removal of fluoxetine from water, reported as one of the most persistent pharmaceuticals in the aquatic environment. Also, primary sludge pyrolysed under the same conditions but without activation (PS800-10) and a commercial activated carbon (PBFG4) were studied for comparison. Physical and chemical properties of the materials were determined and adsorption kinetic and equilibrium studies were performed in batch experiments. Equilibrium studies allowed testing the capacity of the produced materials for adsorb fluoxetine-HCl, showing no apparent correlation between the S(BET) areas and the adsorption capacities of the materials. The maximum adsorption capacity (mg g(-1)) was of 191.6±4.8 for PS800-10KOH; 136.6±9.6 for PS800-10NaOH; 28.4±0.3 for PS800-10ZnCl2; 120.4±2.5 for PS800-10 and 96.2±1.0 for PBFG4. It was demonstrated that many factors influence the removal of fluoxetine from solution and that the surface area is not the main factor in the process. Also the activation process did not enhance the properties of the produced materials.