Approaches to the Development of Human Health Toxicity Values for Active Pharmaceutical Ingredients in the Environment

Bioaccumulation of Organic and Inorganic Pollutants in Fish from Thermaikos Gulf: Preliminary Human Health Risk Assessment Assisted by a Computational Approach

The monitoring of contaminants in fish species is pivotal for fishes' health and reproduction, as well as for human health. In the specific work, three major categories of contaminants, pesticides, pharmaceuticals, and macro and trace elements, were investigated in two major fish species, Dicentrarchus labrax and Solea solea, collected from Thermaikos Gulf, in Greece. To achieve this goal, three analytical methods using LC-MS/MS, GC-MS/MS, and ICP-MS were developed, validated, and applied to the collected fish samples. The results indicated a very low prevalence of caffeine and acetaminophen, both not exceeding 3.8 μg/kg fish. Similarly, thiabendazole, cypermethrin, and tricyclazole (pesticides) were found in a concentration range of 0.9 to 13.7 μg/kg fish, while in one D. labrax sample, traces of the metabolite of organochlorine pesticide DDT, o,p'-DDE were detected. Al, Mn, Fe, Zn, and Sr were the predominant trace elements in a concentration range of 500-20,000 μg/kg fish. Macro elements levels varied from 280 to 5405 mg/kg fish. Health risk assessment did not unveil an unacceptable risk for the human health of adults, apart from one sample presenting Hg above the regulatory levels. On the contrary, for children, the calculated hazard quotient values for Hg in all cases and for two As detections were higher than the threshold value of 1, indicating a potential risk.

Computational study of nitro-benzylidene phenazine as dengue virus-2 NS2B-NS3 protease inhibitor

According to the World Health Organisation (WHO), as of week 23 of 2022, there were more than 1,311 cases of dengue in Malaysia, with 13 deaths reported. Furthermore, there was an increase of 65.7% during the same period in 2021. Despite the increase in cumulative dengue incidence, there is no effective antiviral drug available for dengue treatment. This work aimed to evaluate several nitro-benzylidene phenazine compounds, especially those that contain 4-hydroxy-3,5-bis((2-(4-nitrophenyl)hydrazinylidene)-methyl)benzoate through pharmacophore queries selection method as potential dengue virus 2 (DENV2) NS2B-NS3 protease inhibitors. Herein, molecular docking was employed to correlate the energies of selected hits' free binding and their binding affinities. Pan assay interference compounds (PAINS) filter was also adopted to identify and assess the drug-likeness, toxicity, mutagenicity potentials, and pharmacokinetic profiles to select hit compounds that can be considered as lead DENV2 NS2B-NS3 protease inhibitors. Molecular dynamics assessment of two nitro-benzylidene phenazine derivatives bearing dinitro and hydroxy groups at the benzylidene ring showed their stability at the main binding pocket of DENV2 protease, where their MM-PBSA binding energies were between -22.53 and -17.01 kcal/mol. This work reports those two nitro-benzylidene phenazine derivatives as hits with 52-55% efficiency as antiviral candidates. Therefore, further optimisation is required to minimise the lead compounds' toxicity and mutagenicity.

2-Phenoxyacetamide derivatives as SARS-CoV-2 main protease inhibitor: In silico studies

2-Phenoxyacetamide group has been identified as one of markers in the discovery and development of SARS-CoV-2 antiviral agent through its main protease (M^pro) inhibition pathway. This study aims to study a series of 2-phenoxyacetamide derivatives using in silico method toward SARS-CoV-2 M^pro as the protein target. The study was initiated by employing structure-based pharmacophore to virtually screen and to select the ligands, which have the best fit score (hits) along with the common pharmacophore features being matched. The result shows that from the 11 ligands designed, four ligands are selected as the hits by demonstrating fit score in the range of 56.20 to 65.53 to the pharmacophore model, employing hydrogen bond acceptor (HBA) and hydrophobic (H) as the common features. The hits were then docked into the binding site of the M^pro to see the binding mode of the corresponding hits as well as its affinity. The docking results free energy of binding (ΔG_bind) of the hits are in agreement with the pharmacophore fit score, in the range of −6.83 to −7.20 kcal/ mol. To gain the information of the hits as a potential drug to be developed, the in silico study was further proceed by predicting the mutagenic potency, toxicity and pharmacokinetic profiles. Based on the efficiency percentage, all hits meet the criteria as drug candidates by showing 84–88% leading to a conclusion that 2-phenoxyacetamide derivatives are beneficial to be marked as the lead compound for SARS-CoV-2 M^pro inhibitor.

Ecotoxicity and photodegradation of Montelukast (a drug to treat asthma) in water

The present work focuses on the ecotoxicological effects of montelukast sodium (MTL) and its photoproducts, obtained under environmentally-like conditions. Despite of the potential presence in surface waters and the common use of MTL as asthma drug, limited data has been published for its photodegradation, while no information is available for its ecotoxicity. Light-induced degradation is an effective way for drugs to degrade in aquatic environments, and MTL is highly photosensitive, even by exposure to sunlight. In this study, solar-simulated irradiation of the drug in water was investigated. The drug was quickly converted into a series of photoproducts that were spectroscopically characterized. The possible photoreaction pathways were proposed. Ecotoxicity tests were performed on parent compound and mixture of photoproducts towards two bioindicators (Raphidocelis subcapitata and Daphnia magna). Results evidenced that effects of MTL on D. magna (EC50 = 16.4 mg/L) were greater than effects on R. subcapitata (EC50 = 195.7 mg/L). Microscopy observations revealed that MTL had mainly accumulated in the gut of daphnia. Toxicity data on photolysed solutions highlighted the presence of residual toxicity in all samples, evidencing that no complete mineralization occurred. Future research should focus on monitoring of MTL concentrations in the environment and study its effects in bioaccumulation tests.

Occurrence, Fate, Effects, and Risks of Dexamethasone: Ecological Implications Post-COVID-19

The recent outbreak of respiratory syndrome-coronavirus-2 (SARS-CoV-2), which causes coronavirus disease (COVID-19), has led to the widespread use of therapeutics, including dexamethasone (DEXA). DEXA, a synthetic glucocorticoid, is among the widely administered drugs used to treat hospitalized COVID-19 patients. The global COVID-19 surge in infections, consequent increasing hospitalizations, and other DEXA applications have raised concerns on eminent adverse ecological implications to aquatic ecosystems. Here, we aim to summarize published studies on DEXA occurrence, fate, and effects on organisms in natural and engineered systems as, pre-COVID, the drug has been identified as an emerging environmental contaminant. The results demonstrated a significant reduction of DEXA in wastewater treatment plants, with a small portion, including its transformation products (TPs), being released into downstream waters. Fish and crustaceans are the most susceptible species to DEXA exposure in the parts-per-billion range, suggesting potential deleterious ecological effects. However, there are data deficits on the implications of DEXA to marine and estuarine systems and wildlife. To improve DEXA management, toxicological outcomes of DEXA and formed TPs should entail long-term studies from whole organisms to molecular effects in actual environmental matrices and at realistic exposure concentrations. This can aid in striking a fine balance of saving human lives and protecting ecological integrity.

A study on catalytic and non-catalytic sites of H5N1 and H1N1 neuraminidase as the target for chalcone inhibitors

The H1N1 pandemic in 2009 and the H5N1 outbreak in 2005 have shocked the world as millions of people were infected and hundreds of thousands died due to the infections by the influenza virus. Oseltamivir, the most common drug to block the viral life cycle by inhibiting neuraminidase (NA) enzyme, has been less effective in some resistant cases due to the virus mutation. Presently, the binding of 10 chalcone derivatives towards H5N1 and H1N1 NAs in the non-catalytic and catalytic sites was studied using molecular docking. The in silico study was also conducted for its drug-like likeness such as Lipinski Rule, mutagenicity, toxicity and pharmacokinetic profiles. The result demonstrates that two chalcones (1c and 2b) have the potential for future NA inhibitor development. Compound 1c inhibits H5N1 NA and H1N1 NA with IC₅₀ of 27.63 µM and 28.11 µM, respectively, whereas compound 2b inhibits NAs with IC₅₀ of 87.54 µM and 73.17 µM for H5N1 and H1N1, respectively. The in silico drug-like likeness prediction reveals that 1c is 62% better than 2b (58%) in meeting the criteria. The results suggested that 1c and 2b have potencies to be developed as non-competitive inhibitors of neuraminidase for the future development of anti-influenza drugs.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s13765-021-00639-w.

Disposal practice and factors associated with unused medicines in Malaysia: a cross-sectional study

Background

The improper disposal of unused medicines is a worldwide concern because of its impact on the environment, economy, and health. This study aims to describe the disposal practice of unused medicine and identify factors associated with unused medicines in Malaysia.

Methods

This was a cross-sectional, face to face interview-based survey using a structured questionnaire. We used a convenience sampling method to recruit participants from Kuala Lumpur and Selangor in Malaysia.

Results

We interviewed 1184 participants, and the response rate was 96%. Out of the total respondents, 995 (84%) reported having unused medicines. About a quarter of respondents kept unused medicines in the cabinet, and another quarter disposed of them into the trash or toilet. Only half of the respondent who used medicines for chronic illnesses had unused medicines compared to about 90% of respondents who used medicines for acute illnesses. The main reason for having unused medicines among those who used medicines for chronic illness was non-adherence (69%, p <  0.05). Only 27% of these respondents returned unused medicines under the “Medicine Return Programme (MRP)”. The other group who used medicines for acute illnesses had unused medicines because their health conditions improved. Thus, most of the unused medicines will eventually end up in household waste. A multivariate logistic regression analysis identified respondents who used medicines for acute illnesses as the strongest predictor of having unused medicines (Odds Ratio (OR) = 29.8; p <  0.001), followed by those who pay for their medicines (OR = 6.0; p < 0.001) and those who were willing to participate the Medicine Return Programme (OR = 2.5; p = 0.009).

Conclusion

The prevalence of unused medicines and their improper disposal were high in Malaysia. Unused medicines are associated with people who use medicines for acute illnesses, pay for their medication, and are willing to participate in an MRP. Rationale prescription and optimal dispensing practice, together with a broader MRP facilities coverage, could reduce unused medicine possession.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11676-x.

Effectiveness of an intervention to increase the knowledge, attitude, and practice regarding the return and disposal of unused medications

This study aimed to evaluate the effectiveness of an educational intervention (Safe D.U.M.P) to improve the knowledge, attitude, and practice regarding the return and disposal of unused medications. Community-dwelling adults in Malaysia who could understand English were recruited from two healthcare events. Participants were asked to fill out the validated Return and Disposal of Unused Medications (ReDiUM) questionnaire (pre-intervention), view six educational intervention posters on how to dispose of unused medications (Safe D.U.M.P), then answer the ReDiUM questionnaire immediately after viewing the posters (post-intervention). A total of 390 out of 456 participants participated (response rate=85.5%). Most were female (71%) with a median age of 42 years. The overall knowledge of participants significantly increased from 60% to 80% (p<0.001). However, no improvement was seen regarding their overall attitude and practice. This outcome was as expected as it may be more difficult to improve attitude and practice (when compared to knowledge) with a single educational session.

Optimized production and safety evaluation of hispidin-enriched Sanghuangporus sanghuang mycelia

Phellinus linteus, also known as the sanghuang mushroom, is a medicinal mushroom that has been recognized as beneficial to health for more thousands of years. Among its diverse valuable secondary metabolites, the yellow-brown styrylpyrone pigment hispidin has garnered significant attention due to its various pharmacological effects. However, recently after detailed morphological and molecular phylogenetic studies, the correct scientific name of the true sanghuang strains was shown not to be P. linteus but Sanghuangporus sanghuang. As the incorrect binomial name P. linteus has long been misleadingly referred, there is a need to evaluate the safety of S. sanghuang. Moreover, the growing conditions can impact the secondary metabolite profile of the fungi. Hence, this study is the first to optimize hispidin production and to investigate the genotoxic and oral toxic effects of hispidin-enriched S. sanghuang mycelia. In order to induce the biosynthesis of hispidin, 15 different culture media consisting of five carbon sources, five nitrogen sources, and five initial pH conditions were screened. Glucose and yeast extract at an initial pH of 5 were found to be the most suitable carbon and nitrogen sources, respectively, for the optimal growth and production of hispidin. Moreover, the production of hispidin was 3 mg/g in a 20-ton bioreactor under optimal conditions. Furthermore, the ames test, in vitro chromosome aberration test, acute oral toxicity test, and bone marrow micronucleus test were used to detect toxicological properties of 3 mg/g hispidin-enriched S. sanghuang mycelia. In all tests, there was no statistically significant difference between the mycelia and the negative control. Based on the results obtained, the present study demonstrates that 3 mg/g hispidin-enriched S. sanghuang mycelia has a very low order of toxicity, which supports its safety for human consumption.

Toxicity of pharmaceuticals in binary mixtures: Assessment by additive and non-additive toxicity models

Current risk assessment in many countries, including European Union, is still placing focus on single substances rather than their mixtures, although mixtures are commonly found in the environment. To overcome this problem and gain new insights, six pharmaceuticals, namely: azithromycin (AZM), erythromycin (ERM), carbamazepine (CBA), oxytetracycline (OTC), dexamethasone (DXM), and diclofenac (DCF), were selected in order to analyze their combined toxicity in binary mixtures. Overall, 45 binary mixtures were analyzed. Single component toxicities were determined as well, for modelling purpose. Two most common mathematical models for the description of mixture toxicities were applied: concentration addition (CA) and independent action (IA) model. Comparison of the predicted and experimentally obtained toxicities provided information about the modes of toxicity action in the mixtures. OTC-DCF binary mixture indicated synergism with respect to additive behavior (CA model). All other binary combinations containing OTC or DCF were acting very similarly: the synergism with respect to additive behavior was observed for OTC-CBA and DCF-CBA combinations, while OTC-AZM, OTC-ERM, DCF-AZM and DCF-ERM exhibited antagonistic behavior with respect to CA model. All the remaining binary mixtures indicated additive behavior. The applicability of IA model as a proof of independent toxic action of the components was confirmed in cases of DCF-AZM, DCF-ERM, and OTC-AZM mixtures.

Development and Validation of the Return and Disposal of Unused Medications Questionnaire (ReDiUM) in Malaysia

The aim of our study was to develop and validate the return and disposal of unused medications (ReDiUM), as there are currently no validated tools available (worldwide) to assess this. The ReDiUM was developed by an expert panel. It was then administered to community-dwelling adults, who could understand English, at baseline and 2 weeks later. A total of 338/354 participants agreed to participate (response rate = 95.4%). Flesch reading ease was 60. The overall Cronbach's α was 0.703 (range = 0.609-0.762). At test-retest, κ values ranged from 0.244 to 0.523. Median total knowledge score was 60% (interquartile range = 40% to 70%). The majority of participants (94.4%) knew that improper drug disposal has harmful effects on the environment. However, their knowledge was low (11.2%) regarding the disposal of pressurized metered-dose inhalers in the garbage. The ReDiUM was found to be a valid and reliable instrument to assess the knowledge, attitude, and practice on the ReDiUM in Malaysia.

Caffeine and paraxanthine in aquatic systems: Global exposure distributions and probabilistic risk assessment

This study presents one of the most complete applications of probabilistic methodologies to the risk assessment of emerging contaminants. Perhaps the most data-rich of these compounds, caffeine, as well as its main metabolite (paraxanthine), were selected for this study. Information for a total of 29,132 individual caffeine and 7442 paraxanthine samples was compiled, including samples where the compounds were not detected. The inclusion of non-detect samples (as censored data) in the estimation of environmental exposure distributions (EEDs) allowed for a realistic characterization of the global presence of these compounds in aquatic systems. EEDs were compared to species sensitivity distributions (SSDs), when possible, in order to calculate joint probability curves (JPCs) to describe the risk to aquatic organisms. This way, it was determined that unacceptable environmental risk (defined as 5% of the species being potentially exposed to concentrations able to cause effects in>5% of the cases) could be expected from chronic exposure to caffeine from effluent (28.4% of the cases), surface water (6.7% of the cases) and estuary water (5.4% of the cases). Probability of exceedance of acute predicted no-effect concentrations (PNECs) for paraxanthine were higher than 5% for all assessed matrices except for drinking water and ground water, however no experimental effects data was available for paraxanthine, resulting in a precautionary deterministic hazard assessment for this compound. Given the chemical similarities between both compounds, real effect thresholds, and thus risk, for paraxanthine, would be expected to be close to those observed for caffeine. Negligible Human health risk from exposure to caffeine via drinking or groundwater is expected from the compiled data.

Rapid determination of the emerging contaminant oxypurinol in surface water using solid phase extraction followed by ultra high-performance liquid chromatography with fluorescence detection

A method has been developed for the trace analysis of oxypurinol that is considered as an active pharmaceutical ingredient and an emerging environmental contaminant. The method achieved the identification and quantification of oxypurinol in surface water samples utilizing solid phase extraction and ultra high-performance liquid chromatography with diode array and fluorescence detection for the first time. Four principal parameters of solid phase extraction were optimized to obtain maximum extraction efficiency. Under the isocratic elution of methanol/water (5:95, v/v) and the excitation/emission wavelength of 254/359 nm, a rapid determination was achieved in 2.0 min with good linearity of 1.05-351 μg/L (coefficient of determination above 0.9998). The limit of detection and method detection limit were 0.210 μg/L and 1.34 ng/L, respectively. Precision of the method was evaluated and a relative standard deviation value of 3.3% was obtained for analyses of six replicate spiking blank samples (200 mL, 176 ng/L) according to the overall proposed procedure. The method showed a great anti-interference ability and average spiked recoveries of oxypurinol in five surface water samples were in the range of 94.5-111%. The ability of the method to detect and correctly identify oxypurinol can significantly promote investigation on the occurrence of oxypurinol in water and its potential (eco-)toxicological effects. Graphical abstract Quantification of the emerging contaminant oxypurinol in s urface water using SPE/UHPLC-FLD.

U.S. News Media Coverage of Pharmaceutical Pollution in the Aquatic Environment: A Content Analysis of the Problems and Solutions Presented by Actors

Pharmaceutical pollution in the aquatic environment is an issue of concern that has attracted attention by the news media. Understanding the factors that contribute to media framing of pharmaceutical pollution may lead to a better understanding of the management and governance of this issue, including why these pollutants are generally unregulated at this time. This study conducted a content analysis of 405 newspaper articles (81 had substantive information on the topic) from 2007 to 2014, using the search terms "water" and "pharmaceuticals" in the Chicago Tribune, Denver Post, Los Angeles Times, New York Daily News, New York Times, USA Today, Wall Street Journal, and Washington Post. We sought to analyze the factors that contributed to the news media presentation of pharmaceutical pollution in the United States, including the presentation of the risks/safety and solutions by various actors. We found that the primary issues in the news media were uncertainty regarding public health and harm to the environment. The primary solutions recommended within the news media were implementing additional water treatment technologies, taking unused pharmaceuticals to predetermined sites for disposal (take-back programs), and trash disposal of unused pharmaceuticals. Water utilities and scientists presented improved water treatment technology, government actors presented take-back programs, and pharmaceutical representatives, while sparsely involved in the news media, presented trash disposal as their primary solutions. To advance the understanding of the management of pharmaceutical pollution, this article offers further insight into the debate and potential solutions within the news media presentation of this complex scientific topic.