Effect of Water pH on the Uptake of Acidic (Ibuprofen) and Basic (Propranolol) Drugs in a Fish Gill Cell Culture Model

In situ self-cleaning removal of emerging organic contaminants with covalent organic framework armed with arylbiguanide

An in situ self-cleaning covalent organic framework featuring arylbiguanide arms (Aryl-BIG-COF) was first developed to remove emerging organic pollutants such as propranolol (PRO) from water. The main breakthroughs addressed the scarcity of functional active sites, the impracticality of ex situ regeneration, and the rapid recombination of electronhole pairs in the application of COFs. Owing to the directional capture ability and electronic structure regulation of the arylbiguanide arms, the adsorption capacity and photocatalytic degradation rate of the newly synthesized COF increased by nearly four and seven times, respectively. Its self-cleaning ability, driven by the photocatalytic regeneration of active sites, enabled in situ removal of PRO and sustained over 90 % removal efficiency after six cycles. Moreover, it demonstrated broad applicability for removing PRO and other emerging pollutants, such as bisphenol A (BPA), tetracycline (TC), and norfloxacin (NOR), across various water matrices with less residual toxicity. The coexisting organic matter and ions in natural water promoted the removal of PRO. The enhancement mechanism involved arylbiguanide arms narrowing the band gap and inducing local charge polarization, thereby increasing the separation efficiency of electronhole pairs. This work provides significant insights into the structural design and practical applications of COFs for purifying water.

Developing an Approach for Integrating Chemical Analysis and Transcriptional Changes to Assess Contaminants in Water, Sediment, and Fish

Pharmaceuticals in aquatic environments pose threats to aquatic organisms because of their continuous release and potential accumulation. Monitoring methods for these contaminants are inadequate, with targeted analyses falling short in assessing water quality's impact on biota. The present study advocates for integrated strategies combining suspect and targeted chemical analyses with molecular biomarker approaches to better understand the risks posed by complex chemical mixtures to nontarget organisms. The research aimed to integrate chemical analysis and transcriptome changes in fathead minnows to prioritize contaminants, assess their effects, and apply this strategy in Wascana Creek, Canada. Analysis revealed higher pharmaceutical concentrations downstream of a wastewater-treatment plant, with clozapine being the most abundant in fathead minnows, showing notable bioavailability from water and sediment sources. Considering the importance of bioaccumulation factor and biota-sediment accumulation factor in risk assessment, these coefficients were calculated based on field data collected during spring, summer, and fall seasons in 2021. Bioaccumulation was classified as very bioaccumulative with values >5000 L kg-1, suggesting the ability of pharmaceuticals to accumulate in aquatic organisms. The study highlighted the intricate relationship between nutrient availability, water quality, and key pathways affected by pharmaceuticals, personal care products, and rubber components. Prioritization of these chemicals was done through suspect analysis, supported by identifying perturbed pathways (specifically signaling and cellular processes) using transcriptomic analysis in exposed fish. This strategy not only aids in environmental risk assessment but also serves as a practical model for other watersheds, streamlining risk-assessment processes to identify environmental hazards and work toward reducing risks from contaminants of emerging concern. Environ Toxicol Chem 2024;43:2252-2273. © 2024 SETAC.

Microfluidic programmable strategies for channels and flow

This review summarizes programmable microfluidics, an advanced method for precise fluid control in microfluidic technology through microchannel design or liquid properties, referring to microvalves, micropumps, digital microfluidics, multiplexers, micromixers, slip-, and block-based configurations. Different microvalve types, including electrokinetic, hydraulic/pneumatic, pinch, phase-change and check valves, cater to diverse experimental needs. Programmable micropumps, such as passive and active micropumps, play a crucial role in achieving precise fluid control and automation. Due to their small size and high integration, microvalves and micropumps are widely used in medical devices and biological analysis. In addition, this review provides an in-depth exploration of the applications of digital microfluidics, multiplexed microfluidics, and mixer-based microfluidics in the manipulation of liquid movement, mixing, and splitting. These methodologies leverage the physical properties of liquids, such as capillary forces and dielectric forces, to achieve precise control over fluid dynamics. SlipChip technology, which branches into rotational SlipChip and translational SlipChip, controls fluid through sliding motion of the microchannel. On the other hand, innovative designs in microfluidic systems pursue better modularity, reconfigurability and ease of assembly. Different assembly strategies, from one-dimensional assembly blocks and two-dimensional Lego®-style blocks to three-dimensional reconfigurable modules, aim to enhance flexibility and accessibility. These technologies enhance user-friendliness and accessibility by offering integrated control systems, making them potentially usable outside of specialized technical labs. Microfluidic programmable strategies for channels and flow hold promising applications in biomedical research, chemical analysis and drug screening, providing theoretical and practical guidance for broader utilization in scientific research and practical applications.

Bridging Machine Learning and Thermodynamics for Accurate pK a Prediction

Integrating scientific principles into machine learning models to enhance their predictive performance and generalizability is a central challenge in the development of AI for Science. Herein, we introduce Uni-pK a, a novel framework that successfully incorporates thermodynamic principles into machine learning modeling, achieving high-precision predictions of acid dissociation constants (pK a), a crucial task in the rational design of drugs and catalysts, as well as a modeling challenge in computational physical chemistry for small organic molecules. Uni-pK a utilizes a comprehensive free energy model to represent molecular protonation equilibria accurately. It features a structure enumerator that reconstructs molecular configurations from pK a data, coupled with a neural network that functions as a free energy predictor, ensuring high-throughput, data-driven prediction while preserving thermodynamic consistency. Employing a pretraining-finetuning strategy with both predicted and experimental pK a data, Uni-pK a not only achieves state-of-the-art accuracy in chemoinformatics but also shows comparable precision to quantum mechanics-based methods.

Cross-Species Extrapolation of Biological Data to Guide the Environmental Safety Assessment of Pharmaceuticals-The State of the Art and Future Priorities

The extrapolation of biological data across species is a key aspect of biomedical research and drug development. In this context, comparative biology considerations are applied with the goal of understanding human disease and guiding the development of effective and safe medicines. However, the widespread occurrence of pharmaceuticals in the environment and the need to assess the risk posed to wildlife have prompted a renewed interest in the extrapolation of pharmacological and toxicological data across the entire tree of life. To address this challenge, a biological "read-across" approach, based on the use of mammalian data to inform toxicity predictions in wildlife species, has been proposed as an effective way to streamline the environmental safety assessment of pharmaceuticals. Yet, how effective has this approach been, and are we any closer to being able to accurately predict environmental risk based on known human risk? We discuss the main theoretical and experimental advancements achieved in the last 10 years of research in this field. We propose that a better understanding of the functional conservation of drug targets across species and of the quantitative relationship between target modulation and adverse effects should be considered as future research priorities. This pharmacodynamic focus should be complemented with the application of higher-throughput experimental and computational approaches to accelerate the prediction of internal exposure dynamics. The translation of comparative (eco)toxicology research into real-world applications, however, relies on the (limited) availability of experts with the skill set needed to navigate the complexity of the problem; hence, we also call for synergistic multistakeholder efforts to support and strengthen comparative toxicology research and education at a global level. Environ Toxicol Chem 2024;43:513-525. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Daphnia magna an emerging environmental model of neuro and cardiotoxicity of illicit drugs

Cocaine, methamphetamine, ectasy (3,4-methylenedioxy amphetamine (MDMA)) and ketamine are among the most consumed drugs worldwide causing cognitive, oxidative stress and cardiovascular problems in humans. Residue levels of these drugs and their transformation products may still enter the aquatic environment, where concentrations up to hundreds of ng/L have been measured. In the present work we tested the hypothesis that psychotropic effects and the mode of action of these drugs in D. magna cognitive, oxidative stress and cardiovascular responses are equivalent to those reported in humans and other vertebrate models. Accordingly we expose D. magna juveniles to pharmacological and environmental relevant concentrations. The study was complemented with the measurement of the main neurotransmitters involved in the known mechanisms of action of these drugs in mammals and physiological relevant amino acids. Behavioural cognitive patters clearly differentiate the 3 psychostimulant drugs (methamphetamine, cocaine, MDMA) from the dissociative one ketamine. Psychostimulant drugs at pharmacological doses (10-200 μM), increased basal locomotion activities and responses to light, and decreased habituation to it. Ketamine only increased habituation to light. The four drugs enhanced the production of reactive oxygen species in a concentration related manner, and at moderate concentrations (10-60 μM) increased heartbeats, diminishing them at high doses (200 μM). In chronic exposures to environmental low concentrations (10-1000 ng/L) the four drugs did not affect any of the behavioural responses measured but methamphetamine and cocaine inhibited reproduction at 10 ng/L. Observed effects on neurotransmitters and related metabolites were in concern with reported responses in mammalian and other vertebrate models: cocaine and MDMA enhanced dopamine and serotonin levels, respectively, methamphetamine and MDMA decreased dopamine and octopamine, and all but MDMA decreased 3 MT levels. Drug effects on the concentration of up to 10 amino acids evidence disruptive effects on neurotransmitter synthesis, the urea cycle, lipid metabolism and cardiac function.

Toxicological effects of diclofenac on signal crayfish (Pacifastacus leniusculus) as related to weakly acidic and basic water pH

The widespread use and continuous discharge of pharmaceuticals to environmental waters can lead to potential toxicity to aquatic biota. Pharmaceuticals and their metabolites are often complex organic and environmentally persistent compounds that are bioactive at low doses. This study aimed to investigate the effects of diclofenac (DCF) on the antioxidant defence system and neurotoxicity biomarkers in signal crayfish (Pacifastacus leniusculus) under weakly acidic and basic conditions. Crayfish were exposed to 200 µg/L of DCF at pH 6 and 8 for 96 h and subsequently underwent the depuration phase for 96 h. Gills, hepatopancreas, and muscle were sampled after the exposure and depuration phases to assess the toxicological biomarker responses of DCF in crayfish by evaluating lipid peroxidation (LPO) levels, activities of antioxidant enzymes and acetylcholinesterase. After the exposure phase, the hemolymph DCF concentration was detected one order higher at pH 6 than at pH 8. The DCF was subsequently fully eliminated from the hemolymph during the depuration phase. Our results showed that DCF caused alteration in the activities of six of the seven tested biomarkers in at least one crayfish tissue. Although exposure to DCF caused imbalances in the detoxification system on multiple tissue levels, it was regenerated to a balanced state after the depuration phase. Integrated biomarker response (IBRv2) showed that the highest toxicological response to DCF exposure was elicited in the gills, whereas the hepatopancreas was the highest-responding tissue after the depuration phase. Exposure to DCF at pH 6 caused higher toxicological effects than at pH 8; however, crayfish antioxidant mechanisms recovered more quickly at pH 6 than at pH 8 after the depuration phase. Our results showed that water pH influenced the toxicological effects of DCF, an ionisable compound in crayfish.

Ultraviolet light spectroscopic characterization of ibuprofen acid aggregation in deionized water

This work provides a description of the aggregation equilibria of ibuprofen acid in deionized water at temperatures between 20 and 40 °C in the 0.1-20.1 ppm concentration range. For this goal, we have made use of UV-Visible spectroscopy. A calculation algorithm was developed to obtain the aggregate orders and thermodynamic parameters from the experimental absorbance values. Monomeric ibuprofen acid was found to be absent in water solutions. In addition to the dimer, two aggregates formed by 32 and 128 monomeric units were found to co-exist in solution at the highest concentration tested. A critical micelle concentration of 7.8 ppm was estimated for this system. The appearance of the first aggregate occurs when the pH drops below the pKa value, which was determined to be 4.62. At higher ibuprofen concentrations, a sudden jump in the electrical conductivity coincides with the onset of formation of the second aggregate. A varied menu of alternatives is offered with respect to the calibration curve of ibuprofen in water, though the linear calibration of ibuprofen concentration with absorbance might be reasonably performed at 224 nm. Finally, the dissolution rate of the commercial ibuprofen used in this work was found to obey the Noyes-Whitney first order equation.

The Influences of Pore Blockage by Natural Organic Matter and Pore Dimension Tuning on Pharmaceutical Adsorption onto GO-Fe3O4

The ubiquitous presence of pharmaceutical pollution in the environment and its adverse impacts on public health and aquatic ecosystems have recently attracted increasing attention. Graphene oxide coated with magnetite (GO-Fe₃O₄) is effective at removing pharmaceuticals in water by adsorption. However, the myriad compositions in real water are known to adversely impact the adsorption performance. One objective of this study was to investigate the influence of pore blockage by natural organic matter (NOM) with different sizes on pharmaceutical adsorption onto GO-Fe₃O₄. Meanwhile, the feasibility of pore dimension tuning of GO-Fe₃O₄ for selective adsorption of pharmaceuticals with different structural characteristics was explored. It was shown in the batch experiments that the adsorbed pharmaceutical concentrations onto GO-Fe₃O₄ were significantly affected (dropped by 2-86%) by NOM that had size ranges similar to the pore dimensions of GO-Fe₃O₄, as the impact was enhanced when the adsorption occurred at acidic pHs (e.g., pH 3). Specific surface areas, zeta potentials, pore volumes, and pore-size distributions of GO-Fe₃O₄ were influenced by the Fe content forming different-sized Fe₃O₄ between GO layers. Low Fe contents in GO-Fe₃O₄ increased the formation of nano-sized pores (2.0-12.5 nm) that were efficient in the adsorption of pharmaceuticals with low molecular weights (e.g., 129 kDa) or planar structures via size discrimination or inter-planar π-π interaction, respectively. As excess larger-sized pores (e.g., >50 nm) were formed on the surface of GO-Fe₃O₄ due to higher Fe contents, pharmaceuticals with larger molecular weights (e.g., 296 kDa) or those removed by electrostatic attraction between the adsorbate and adsorbent dominated on the GO-Fe₃O₄ surface. Given these observations, the surface characteristics of GO-Fe₃O₄ were alterable to selectively remove different pharmaceuticals in water by adsorption, and the critical factors determining the adsorption performance were discussed. These findings provide useful views on the feasibility of treating pharmaceutical wastewater, recycling valuable pharmaceuticals, or removing those with risks to public health and ecosystems.

Factors Determining the Susceptibility of Fish to Effects of Human Pharmaceuticals

The increasing levels and frequencies at which active pharmaceutical ingredients (APIs) are being detected in the environment are of significant concern, especially considering the potential adverse effects they may have on nontarget species such as fish. With many pharmaceuticals lacking environmental risk assessments, there is a need to better define and understand the potential risks that APIs and their biotransformation products pose to fish, while still minimizing the use of experimental animals. There are both extrinsic (environment- and drug-related) and intrinsic (fish-related) factors that make fish potentially vulnerable to the effects of human drugs, but which are not necessarily captured in nonfish tests. This critical review explores these factors, particularly focusing on the distinctive physiological processes in fish that underlie drug absorption, distribution, metabolism, excretion and toxicity (ADMET). Focal points include the impact of fish life stage and species on drug absorption (A) via multiple routes; the potential implications of fish's unique blood pH and plasma composition on the distribution (D) of drug molecules throughout the body; how fish's endothermic nature and the varied expression and activity of drug-metabolizing enzymes in their tissues may affect drug metabolism (M); and how their distinctive physiologies may impact the relative contribution of different excretory organs to the excretion (E) of APIs and metabolites. These discussions give insight into where existing data on drug properties, pharmacokinetics and pharmacodynamics from mammalian and clinical studies may or may not help to inform on environmental risks of APIs in fish.

Investigating the bioaccumulation potential of anionic organic compounds using a permanent rainbow trout liver cell line

Permanent rainbow trout (Oncorhynchus mykiss) cell lines represent potential in vitro alternatives to experiments with fish. We here developed a method to assess the bioaccumulation potential of anionic organic compounds in fish, using the rainbow trout liver-derived RTL-W1 cell line. Based on the availability of high quality in vivo bioconcentration (BCF) and biomagnification (BMF) data and the substances' charge state at physiological pH, four anionic compounds were selected: pentachlorophenol (PCP), diclofenac (DCF), tecloftalam (TT) and benzotriazol-tert-butyl-hydroxyl-phenyl propanoic acid (BHPP). The fish cell line acute toxicity assay (OECD TG249) was used to derive effective concentrations 50 % and non-toxic exposure concentrations to determine exposure concentrations for bioaccumulation experiments. Bioaccumulation experiments were performed over 48 h with a total of six time points, at which cell, medium and plastic fractions were sampled and measured using high resolution tandem mass spectrometry after online solid phase extraction. Observed cell internal concentrations were over-predicted by KOW-derived predictions while pH-dependent octanol-water partitioning (DOW) and membrane lipid-water partitioning (DMLW) gave better predictions of cell internal concentrations. Measured medium and cell internal concentrations at steady state were used to calculate RTL-W1-based BCF, which were compared to DOW- or DMLW-based model approaches and in vivo data. With the exception of PCP, the cell-derived BCF best compared to DOW-based model predictions, which were higher than predictions based on DMLW. All methods predicted the in vivo BCF for diclofenac well. For PCP, the cell-derived BCF was lowest although all BCF predictions underestimated the in vivo BCF by ≥ 1 order of magnitude. The RTL-W1 cells, and all other prediction methods, largely overestimated in vivo BMF, which were available for PCP, TT and BHPP. We conclude that the RTL-W1 cell line can supplement BCF predictions for anionic compounds. For BMF estimations, however, in vitro-in vivo extrapolations need adaptation or a multiple cell line approach.

Active Pharmaceutical Ingredient Uptake by Zebrafish (Danio rerio) Oct2 (slc22a2) Transporter Expressed in Xenopus laevis Oocytes

Uptake of active pharmaceutical ingredients (APIs) across the gill epithelium of fish is via either a passive or facilitated transport process, with the latter being more important at the lower concentrations more readily observed in the environment. The solute carrier (SLC) 22A family, which includes the organic cation transporter OCT2 (SLC22A2), has been shown in mammals to transport several endogenous chemicals and APIs. Zebrafish oct2 was expressed in Xenopus oocytes and the uptake of ranitidine, propranolol, and tetraethylammonium characterized. Uptake of ranitidine and propranolol was time- and concentration-dependent with a k_m and V_max for ranitidine of 246 µM and 45 pmol/(oocyte × min) and for propranolol of 409 µM and 190 pmol/(oocyte × min), respectively. Uptake of tetraethylammonium (TEA) was inhibited by propranolol, amantadine, and cimetidine, known to be human OCT2 substrates, but not quinidine or ranitidine. At external media pH 7 and 8 propranolol uptake was 100-fold greater than at pH 6; pH did not affect ranitidine or TEA uptake. It is likely that cation uptake is driven by the electrochemical gradient across the oocyte. Uptake kinetics parameters, such as those derived in the present study, coupled with knowledge of transporter localization and abundance and API metabolism, can help derive pharmacokinetic models. Environ Toxicol Chem 2022;41:2993-2998. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Characterization of Plant Accumulation of Pharmaceuticals from Soils with Their Concentration in Soil Pore Water

Predicting plant uptake of pharmaceuticals from soils is very challenging because many pharmaceuticals are ionizable compounds, which experience highly variable sorption/desorption and transformation processes in soils. This study aimed to elucidate how the equilibrium between sorbed and dissolved phases influences radish uptake of 15 pharmaceuticals from three soils with different properties. After 30 days of uptake, the accumulation of acetaminophen, carbamazepine, lamotrigine, carbadox, trimethoprim, and triclosan in radish ranked as Riddles > Capac > Spinks soil. In contrast, radish accumulation of caffeine, lincomycin, monensin, tylosin, sulfadiazine, and sulfamethoxazole exhibited the opposite order of Riddles < Capac < Spinks soil. Oxytetracycline and estrone demonstrated similar accumulation in radish grown in the three soils. Accumulation of pharmaceuticals in radish demonstrated no apparent relation with their concentration in soils. However, we identified strong positive correlation between pharmaceutical accumulation in radish and their corresponding concentration in soil pore water. These results reveal that pharmaceutical in soil pore water is the dominant fraction bioavailable to plant uptake. Relatively constant root concentration factors (RCFs) on the basis of pharmaceutical concentration in soil pore water, compared to the highly variable RCFs derived from soils, suggest that pore water-based RCF is superior for describing pharmaceutical accumulation in plants grown in soils. We recommend that pharmaceuticals in soil pore water should be evaluated and included in modeling their uptake by plants.

Biodegradation of L-Valine Alkyl Ester Ibuprofenates by Bacterial Cultures

Nowadays, we consume very large amounts of medicinal substances. Medicines are used to cure, halt, or prevent disease, ease symptoms, or help in the diagnosis of illnesses. Some medications are used to treat pain. Ibuprofen is one of the most popular drugs in the world (it ranks third). This drug enters our water system through human pharmaceutical use. In this article, we describe and compare the biodegradation of ibuprofen and ibuprofen derivatives-salts of L-valine alkyl esters. Biodegradation studies of ibuprofen and its derivatives have been carried out with activated sludge. The structure modifications we received were aimed at increasing the biodegradation of the drug used. The influence of the alkyl chain length of the ester used in the biodegradation of the compound was also verified. The biodegradation results correlated with the lipophilic properties (log P).

Developing in vitro models to assess fish gill excretion of emerging contaminants

Advances in analytical methods have enabled the detection of emerging contaminants at ever lower concentrations in freshwaters. However, such measurements need to be linked to effect-based assays to identify risks. The bioconcentration factor (BCF) forms part of a chemical's environmental risk assessment (ERA), and current regulatory testing guidelines to calculate fish BCFs use hundreds of fish per chemical. Due to ethical concerns a reduction in the numbers of animals used is desired, and there is a need to identify in vitro or in silico alternatives which meet regulatory acceptance. This study describes the successful demonstration of a FIsh Gill Cell culture System (FIGCS) to assess an often overlooked parameter in pharmacokinetics: the excretion of drugs across the gill. The FIGCS tolerates the application of natural waters on its apical surface, mimicking the situation of the live fish, and thus in combination with advanced analytical methods, offers an opportunity to take lab-based testing used for ERA, such as compound uptake, biotransformation or excretion directly into field for validation with natural waters. Here we used the basic drug propranolol and the acidic ibuprofen as a demonstration of the FIGCS utility in three separate experiments. Excretion across the apical membrane showed saturation kinetics, suggesting the involvement of carrier-mediated processes. Both propranolol and ibuprofen were excreted across the epithelium from the media (internal blood equivalent) to the water, with ibuprofen excretion being considerably slower than propranolol excretion. Further studies indicate that ibuprofen may be complexing with fetal bovine serum (FBS) reducing bioavailability; in contrast propranolol efflux rate was unaffected, indicating that drugs behave differently in the presence of FBS and other plasma proteins. A key issue in future ERA is to better understand the effects of mixtures of different pollutant classes found in environmental samples, and this model offers an ethical path to do this.