Browsing by Author "Tiritan, Maria Elizabeth"
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- Aerobic granular sludge system under chiral pharmaceutical exposure: insights on nutrient removal performance and microbiome compositionPublication . Miranda, Catarina; Tiritan, Maria Elizabeth; Castro, Paula M. L.; Amorim, Catarina L.
- Chiral analysis of pesticides and drugs of environmental concern: biodegradation and enantiomeric fractionPublication . Maia, Alexandra S.; Ribeiro, Ana R.; Castro, Paula M. L.; Tiritan, Maria ElizabethThe importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF). The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.
- Enantiomeric fraction evaluation of pharmaceuticals in an aerobic granular sludge sequencing batch reactorPublication . Amorim, Catarina L.; Moreira, Irina S.; Ribeiro, Ana Rita; Santos, Lúcia H. M. L. M.; Delerue-Matos, Cristina; Tiritan, Maria Elizabeth; Castro, Paula M. L.
- Enantiomeric fraction evaluation of pharmaceuticals in environmental matrices by liquid chromatography-tandem mass spectrometryPublication . Ribeiro, Ana Rita; Santos, Lúcia H. M. L. M.; Maia, Alexandra S.; Delerue-Matos, Cristina; Castro, Paula M. L.; Tiritan, Maria ElizabethThe interest for environmental fate assessment of chiral pharmaceuticals is increasing and enantioselective analytical methods are mandatory. This study presents an enantioselective analytical method for the quantification of seven pairs of enantiomers of pharmaceuticals and a pair of a metabolite. The selected chiral pharmaceuticals belong to three different therapeutic classes, namely selective serotonin reuptake inhibitors (venlafaxine, fluoxetine and its metabolite norfluoxetine), beta-blockers (alprenolol, bisoprolol, metoprolol, propranolol) and a beta2-adrenergic agonist (salbutamol). The analytical method was based on solid phase extraction followed by liquid chromatography tandem mass spectrometry with a triple quadrupole analyser. Briefly, Oasis® MCX cartridges were used to preconcentrate 250 mL of water samples and the reconstituted extracts were analysed with a Chirobiotic™ V under reversed mode. The effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) was used to validate the method. Linearity (r2 > 0.99), selectivity and sensitivity were achieved in the range of 20–400 ng L−1 for all enantiomers, except for norfluoxetine enantiomers which range covered 30–400 ng L−1. The method detection limits were between 0.65 and 11.5 ng L−1 and the method quantification limits were between 1.98 and 19.7 ng L−1. The identity of all enantiomers was confirmed using two MS/MS transitions and its ion ratios, according to European Commission Decision 2002/657/EC. This method was successfully applied to evaluate effluents of wastewater treatment plants (WWTP) in Portugal. Venlafaxine and fluoxetine were quantified as non-racemic mixtures (enantiomeric fraction ≠ 0.5). The enantioselective validated method was able to monitor chiral pharmaceuticals in WWTP effluents and has potential to assess the enantioselective biodegradation in bioreactors. Further application in environmental matrices as surface and estuarine waters can be exploited.
- Enantiomeric separation of tramadol and Its metabolites: method validation and application to environmental samplesPublication . Silva, Cátia; Ribeiro, Cláudia; Maia, Alexandra S.; Gonçalves, Virgínia; Tiritan, Maria Elizabeth; Afonso, CarlosThe accurate assessment of racemic pharmaceuticals requires enantioselective analytical methods. This study presents the development and validation of an enantioselective liquid chromatography with a fluorescence detection method for the concomitant quantification of the enantiomers of tramadol and their metabolites, N-desmethyltramadol and O-desmethyltramadol, in wastewater samples. Optimized conditions were achieved using a Lux Cellulose-4 column 150 × 4.6 mm, 3 μm isocratic elution, and 0.1% diethylamine in hexane and ethanol (96:4, v/v) at 0.7 mL min-1. The samples were extracted using 150 mg Oasis® mixed-mode cation exchange (MCX) cartridges. The method was validated using a synthetic effluent of a laboratory-scale aerobic granular sludge sequencing batch reactor. The method demonstrated to be selective, accurate, and linear (r2 > 0.99) over the range of 56 ng L-1 to 392 ng L-1. The detection and the quantification limits of each enantiomer were 8 ng L-1 and 28 ng L-1 for tramadol and N-desmethyltramadol, and 20 ng L-1 and 56 ng L-1 for O-desmethyltramadol. The feasibility of the method was demonstrated in a screening study in influent and effluent samples from a wastewater treatment plant. The results demonstrated the occurrence of tramadol enantiomers up to 325.1 ng L-1 and 357.9 ng L-1, in the effluent and influent samples, respectively. Both metabolites were detected in influents and effluents.
- Enantioselective degradation of ofloxacin and levofloxacin by the bacterial strains Labrys portucalensis F11 and Rhodococcus sp. FP1Publication . Maia, Alexandra S.; Tiritan, Maria Elizabeth; Castro, Paula M.L.Fluoroquinolones are a class of antibiotics widely prescribed in both human and veterinary medicine of high environmental concern and characterized as environmental micropollutants due to their ecotoxicity and persistence and antibacterial resistance potential. Ofloxacin and levofloxacin are chiral fluoroquinolones commercialized as racemate and in enantiomerically pure form, respectively. Since the pharmacological properties and toxicity of the enantiomers may be very different, understanding the stereochemistry of these compounds should be a priority in environmental monitoring. This work presents the biodegradation of racemic ofloxacin and its (S)-enantiomer levofloxacin by the bacterial strains Labrys portucalensis F11 and Rhodococcus sp. FP1 at a laboratory-scale microcosm following the removal and the behavior of the enantiomers. Strain F11 could degrade both antibiotics almost completely when acetate was supplied regularly to the cultures. Enrichment of the (R)-enantiomer was observed in FP1 and F11 cultures supplied with ofloxacin. Racemization was observed in the biodegradation of the pure (S)-ofloxacin (levofloxacin) by strain F11, which was confirmed by liquid chromatography - exact mass spectrometry. Biodegradation of ofloxacin at 450 μg L−1 by both bacterial strains expressed good linear fits (R2> 0.98) according to the Rayleigh equation. The enantiomeric enrichment factors were comprised between −22.5% to −9.1%, and −18.7% to −9.0% in the biodegradation of ofloxacin by strains F11 and FP1, respectively, with no significant differences for the two bacteria under the same conditions. This is the first time that enantioselective biodegradation of ofloxacin and levofloxacin by single bacteria is reported.
- Environmental fate of chiral pharmaceuticals: determination, degradation and toxicityPublication . Ribeiro, Ana R.; Castro, Paula M.L.; Tiritan, Maria ElizabethPollution of the aquatic environment by pharmaceuticals is of major concern. Indeed pharmaceutical pollutants have several undesirable effects for many organisms, such as endocrine disruption and bacterium resistance. They are resistant to several degradation processes, making their removal difficult and slow. Pharmaceuticals reach the environment due to their inefficient removal by waste water treatment plants (WWTP), and by improper disposal of unused medicines. In aquatic environments pharmaceuticals reach concentrations at trace levels of ngL-1-μgL-1 range. Many pharmaceutical pollutants are chiral. They occur in nature as a single enantiomer or as mixtures of the two enantiomers, which have different spatial configuration and can thus be metabolized selectively. In spite of similar physical and chemical properties, enantiomers have different interactions with enzymes, receptors or other chiral molecules, leading to different biological response. Therefore they can affect living organisms in a different manner. The fate and effects of enantiomers of chiral pharmaceuticals in the environment are still largely unknown. Biodegradation and toxicity can be enantioselective, in contrast to abiotic degradation. Thus accurate methods to measure enantiomeric fractions in the environment are crucial to better understand the biodegradation process and to estimate toxicity of chiral pharmaceuticals. We review (1) general properties of chiral compounds, (2) current knowledge on chiral pharmaceuticals in the environment, (3) chiral analytical methods to determine the enantiomers composition in environmental matrices, (4) degradation and removal processes of chiral pharmaceuticals in the environment and (5) their toxicity to aquatic organisms. The major analytical methods discussed are gas chromatography (GC), high performance liquid chromatography (HPLC), electrochemical sensors and biosensors. These chiral methods are crucial for the correct quantification of the enantiomers regarding that if an enantiomer with more or less toxic effects is preferentially degraded, the assessed exposure based on measurements of achiral methodologies would overestimate or underestimate ecotoxicity. The degradation and biodegradation is discussed using few examples of important therapeutic classes usually detected in the aquatic environment. Few examples of ecotoxicity studies are also given on the occurrence of enantiomers and their fate in the environment which differs with regard to undesirable effects and to biochemical processes.
- Exploring the fate of chiral pharmaceuticals in an AGS system under saltwater intrusion phenomenaPublication . Miranda, Catarina; Amorim, Catarina; Piccirillo, Clara; Tiritan, Maria Elizabeth; Castro, PaulaAerobic granular sludge (AGS) is a robust technology, largely adopted in wastewater treatment plants (WWTPs) worldwide. However, there is a lack of knowledge regarding how this technology deals with saltwater intrusion and variable daily wastewater salinity loads. With the sea level rise, in coastline WWTPs, seawater infiltration into sewers is a growing problem. In addition, the increase in pharmaceutical production and consumption led to their accumulation in wastewater. Many of these are chiral pharmaceuticals (CPs) whose enantiomers can differ in their degradation ratio and toxicity in the environment. The fate of CPs in AGS systems is scarcely reported, especially if combined with variable salt concentration in wastewater. In this study, an AGS reactor was operated for 132 days for the treatment of urban saline wastewater sporadically containing a mixture of CPs namely: tramadol and venlafaxine and its metabolites o-desmethyltramadol and o-desmetylvenlafaxine, respectively, at concentrations near those found in the environment (8 μg/L). Both daily salinity fluctuations and the presence of CPs in wastewater did not affect the biological removal of COD, N, and P. However, the AGS system was not able to remove the CPs that ended up in the effluent. To address this challenge, a parallel experiment was performed using a bone char material derived from fish-food waste (tuna bones) to adsorb the pharmaceuticals tramadol and venlafaxine. The bone char exhibited removal efficiencies of around 40%, as such in combination with AGS systems it can help to decrease the release of CPs into the environment.
- Exploring the potential of a waste-derived bone char for pharmaceuticals adsorption in saline-based wastewaterPublication . Miranda, Catarina; Scalera, Francesca; Piancastelli, Andreana; Pullar, Robert C.; Tiritan, Maria Elizabeth; Piccirillo, Clara; Castro, Paula M. L.; Amorim, Catarina L.In this study, the effect of salinity in wastewater on the adsorption capacity of a bone char material prepared through pyrolysis of tuna bones at 1000 °C was investigated for two pharmaceuticals, tramadol (TRA) and venlafaxine (VNF), both contaminants of emerging concern. This is the first time that the adsorption efficiency of a bone char-type material was tested in such conditions. The Tuna Bone Char (TBC) was composed of calcium phosphate (hydroxyapatite), and graphitic carbon. The TBC is a nanostructured material (particle size 30–60 nm), with a surface area of 100.67 m2/g (higher than other waste-derived type materials), and a total pore volume of 575.2 mm3/g. TBC capacity to adsorb TRA and VNF, individually or combined, was evaluated in batch experiments using different aqueous matrices: water, non-saline wastewater, and wastewaters with different salinity levels (7.5 and 12 g/L). For individual pharmaceuticals, the TBC had a higher affinity for TRA than VNF. The presence of salts in wastewaters led to a decrease in the TBC adsorption capacity but it was still effective for pharmaceuticals adsorption. Indeed, for the individual pharmaceuticals, the TBC adsorption capacity (qt) was 0.72–2.14 and 0.77–1.70 mg/g for TRA and VNF respectively, depending on the aqueous matrix. With both pharmaceuticals present, lower qt values were experimentally obtained for TRA and VNF. The potential of the TBC, a material derived from a by-product of the fish industry, to be used for environmental remediation in different environments, such as saline wastewaters was demonstrated, widening the range of its potential applications.
- Influence of PDLA nanoparticles size on drug release and interaction with cellsPublication . Cartaxo, Ana Luísa; Costa-Pinto, Ana R.; Martins, Albino; Faria, Susana; Gonçalves, Virgínia M. F.; Tiritan, Maria Elizabeth; Ferreira, Helena; Neves, Nuno M.Polymeric nanoparticles (NPs) are strong candidates for the development of systemic and targeted drug delivery applications. Their size is a determinant property since it defines the NP–cell interactions, drug loading capacity, and release kinetics. Herein, poly(D,L-lactic acid) (PDLA) NPs were produced by the nanoprecipitationmethod, in which the influence of type and concentration of surfactant as well as PDLA concentration were assessed. The adjustment of these parameters allowed the successful production of NPs with defined medium sizes, ranging from 80 to 460 nm. The surface charge of the different NPs populations was consistently negative. Prednisolone was effectively entrapped and released from NPs with statistically different medium sizes (i.e., 80 or 120 nm). Release profiles indicate that these systems were able to deliver appropriate amounts of drug with potential applicability in the treatment of inflammatory conditions. Both NPs populations were cytocompatible with human endothelial and fibroblastic cells, in the range of concentrations tested (0.187–0.784 mg/mL). However, confocal microscopy revealed that within the range of sizes tested in our experiments, NPs presenting amedium size of 120 nmwere able to be internalized in endothelial cells. In summary, this study demonstrates the optimization of the processing conditions to obtain PDLA NPs with narrow size ranges, and with promising performance for the treatment of inflammatory diseases.