Development of a novel naphthoic acid ionic liquid and its application in "no-organic solvent microextraction" for determination of triclosan and methyltriclosan in human fluids and the method optimization by central composite design

A holistic review on triclosan and triclocarban exposure: Epidemiological outcomes, antibiotic resistance, and health risk assessment

Triclosan (TCS) and triclocarban (TCC) are antimicrobials that are widely applied in personal care products, textiles, and plastics. TCS and TCC exposure at low doses may disturb hormone levels and even facilitate bacterial resistance to antibiotics. In the post-coronavirus disease pandemic era, chronic health effects and the spread of antibiotic resistance genes associated with TCS and TCC exposure represent an increasing concern. This study sought to screen and review the exposure levels and sources and changes after the onset of the coronavirus disease (COVID-19) pandemic, potential health outcomes, bacterial resistance and cross-resistance, and health risk assessment tools associated with TCS and TCC exposure. Daily use of antimicrobial products accounts for most observed associations between internal exposure and diseases, while secondary exposure at trace levels mainly lead to the spread of antibiotic resistance genes. The roles of altered gut microbiota in multi-system toxicities warrant further attention. Sublethal dose of TCC selects ARGs without obviously increasing tolerance to TCC. But TCS induce persistent TCS resistance and reversibly select antibiotic resistance, which highlights the benefits of minimizing its use. To derive reference doses (RfDs) for humans, more sensitive endpoints observed in populational studies need to be confirmed using toxicological tests. Additionally, the human equivalent dose is recommended to be incorporated into the health risk assessment to reduce uncertainty of extrapolation.

Triclosan and related compounds in the environment: Recent updates on sources, fates, distribution, analytical extraction, analysis, and removal techniques

Triclosan (TCS) has been widely used in daily life because of its broad-spectrum antibacterial activities. The residue of TCS and related compounds in the environment is one of the critical environmental safety problems, and the pandemic of COVID-19 aggravates the accumulation of TCS and related compounds in the environment. Therefore, detecting TCS and related compound residues in the environment is of great significance to human health and environmental safety. The distribution of TCS and related compounds are slightly different worldwide, and the removal methods also have advantages and disadvantages. This paper summarized the research progress on the source, distribution, degradation, analytical extraction, detection, and removal techniques of TCS and related compounds in different environmental samples. The commonly used analytical extraction methods for TCS and related compounds include solid-phase extraction, liquid-liquid extraction, solid-phase microextraction, liquid-phase microextraction, and so on. The determination methods include liquid chromatography coupled with different detectors, gas chromatography and related methods, sensors, electrochemical method, capillary electrophoresis. The removal techniques in various environmental samples mainly include biodegradation, advanced oxidation, and adsorption methods. Besides, both the pros and cons of different techniques have been compared and summarized, and the development and prospect of each technique have been given.

Smartphone-based colorimetric determination of triclosan in aqueoussamples after ultrasound assisted-dispersive liquid-liquid microextraction under optimized response surface method conditions

In the present study, a simple and low cost methodology based on ultrasonic assisted-dispersive liquid-liquid microextraction (UA-DLLME) followed by smartphone-based colorimetric measurement was introduced for the separation and determination of Triclosan (TCS) from contaminated waters. This method is based on the formation of an azo compound from the alkaline reaction of TCS with a diazonium ion, resulting from the reaction of sodium nitrite and p-sulfanilic acid in an acidic medium. The orange-brown color product was extracted into a low volume of organic phase by UA-DLLME method and RGB values were recorded with free Android app Color Grab. The effective parameters in this procedure, namely solution pH, p-sulfanilic acid and nitrite concentration, reaction time and volume of the extraction solvent were investigated and optimized by response surface methodology (RSM) based on a Box-Behnken design (BBD) model. Under optimum conditions, the calibration graph was linear in the range of 3.0 and 200 μg L^-1 of TCS. The limit of detection (LOD) and limit of quantification (LOQ) were 0.8 and 2.7 μg L^-1, respectively. The proposed method was successfullyused for the analyses of triclosan in several water and wastewater samples and satisfactory results were obtained.

A novel and affordable bioaugmentation strategy with microbial extracts to accelerate the biodegradation of emerging contaminants in different media

This study describes a new bioaugmentation alternative based on the application of aqueous aerated extracts from a biomixture acclimated with ibuprofen, diclofenac and triclosan. This bioaugmentation strategy was assayed in biopurification systems (BPS) and in contaminated aqueous solutions to accelerate the removal of these emerging contaminants. Sterilized extracts or extracts from the initial uncontaminated biomixture were used as controls. In BPS, the dissipation of 90% of diclofenac and triclosan required, respectively, 60 and 108 days less than in the controls. The metabolite methyl-triclosan was determined at levels 12 times lower than in controls. In the bioaugmented solutions, ibuprofen was almost completely eliminated (99%) in 21 days and its hydroxylated metabolites were also determined to be at lower levels than in the controls. The plasmidome of acclimated biomixtures and its extract appeared to maintain certain types of plasmids but degradation related genes became less evident. Several dominant OTUs found in the extract identified as Flavobacterium and Fluviicola of the phylum Bacteroidetes, Thermomicrobia (phylum Chloroflexi) and Nonomuraea (phylum Actinobacteria), may be responsible for the enhanced dissipation of these contaminants. This bioaugmentation strategy represents an advantageous tool to facilitate in situ bioaugmentation.

Advances Brought by Hydrophilic Ionic Liquids in Fields Involving Pharmaceuticals

The negligible volatility and high tunable nature of ionic liquids (ILs) have been the main drivers of their investigation in a wide diversity of fields, among which is their application in areas involving pharmaceuticals. Although most literature dealing with ILs is still majorly devoted to hydrophobic ILs, evidence on the potential of hydrophilic ILs have been increasingly provided in the past decade, viz., ILs with improved therapeutic efficiency and bioavailability, ILs with the ability to increase drugs' aqueous solubility, ILs with enhanced extraction performance for pharmaceuticals when employed in biphasic systems and other techniques, and ILs displaying low eco/cyto/toxicity and beneficial biological activities. Given their relevance, it is here overviewed the applications of hydrophilic ILs in fields involving pharmaceuticals, particularly focusing on achievements and advances witnessed during the last decade. The application of hydrophilic ILs within fields involving pharmaceuticals is here critically discussed according to four categories: (i) to improve pharmaceuticals solubility, envisioning improved bioavailability; (ii) as IL-based drug delivery systems; (iii) as pretreatment techniques to improve analytical methods performance dealing with pharmaceuticals, and (iv) in the recovery and purification of pharmaceuticals using IL-based systems. Key factors in the selection of appropriate ILs are identified. Insights and perspectives to bring renewed and effective solutions involving ILs able to compete with current commercial technologies are finally provided.

Hormesis Effect of Methyl Triclosan on Cell Proliferation and Migration in Human Hepatocyte L02 Cells

Methyl triclosan (mTCS) is a methylated derivative of triclosan (TCS), which is extensively used as an antimicrobial component of various nursing products and disinfectants. Current research studies of mTCS mainly focused on the environmental persistence and bioaccumulation potential. Knowledge regarding the toxicity and carcinogenicity of mTCS is limited until now. In this study, the human hepatocyte L02 cells were used to investigate the cellular effects of mTCS under different concentrations (0.1-60 μM). The hormesis effect was observed where a low dose of mTCS (≤5 μM) exposure stimulated the cell proliferation ability, while high-dose exposure (≥20 μM) inhibited cell proliferation. In the same time, low doses of mTCS (0.5 and 1 μM) induced enhanced anchorage-independent proliferation ability and cell migration ability, indicating a positive effect on malignant transformation in L02 cells. Moreover, reactive oxygen species productions were significantly increased after mTCS exposure (≥1 μM), as compared with the control group. Furthermore, expressions of tumor-related genes, mouse double minute 2 (MDM2), matrix metalloproteinase 9 (MMP9), and proliferating cell nuclear antigen (PCNA), and proto-oncogene MYC (c-Myc), Jun, and FosB were significantly upregulated, while no significant changes were observed on expressions of apoptosis-related and cell cycle-related genes in L02 cells after exposure of low-dose mTCS. In conclusion, these results indicated that a low dose of mTCS had a hormesis effect in L02 cells on cell proliferation and malignant transformation in vitro, which might be mediated through oxidative stress response.

Combined toxicity of triclosan, 2,4-dichlorophenol and 2,4,6-trichlorophenol to zebrafish (Danio rerio)

Triclosan (TCS), 2,4,6-trichlorophenol (2,4,6-TCP) and 2,4-dichlorophenol (2,4-DCP) are the most prevalent chlorinated phenolic pollutants in aquatic environments. Our results showed LC₅₀ and EC₅₀ values of 0.51, 1.11, 2.45mg/L, and 0.36, 0.74, 1.53mg/L for TCS, 2,4,6-TCP and 2,4-DCP, respectively, to 120hpf zebrafish. The highest TCSD (the mixture of TCS, 2,4,6-TCP and 2,4-DCP) toxicity was observed at a TCS:2,4,6-TCP:2,4-DCP concentration ratio of 1:2:4. LC₅₀ and EC₅₀ values of TCSD mixtures for 120-hpf zebrafish were 2.28 and 1.16mg/L, respectively. Two toxicity assessment methods (Toxic Unit and Mixture Toxicity Index) indicated that TCSD interactions produced partly additive toxicity. TCSD exposure decreased zebrafish hatching rate and led to a series of malformations. Following alkaline phosphatase staining, a large area of vascular ablation was observed with almost complete disappearance of vascular branches and a smaller coverage range. Prominent reddening of the yolk sac and visceral mass after oil red O staining implied that TCSD exposure severely affected fat metabolism. Following acridine orange staining, cell death occurred in eyes while high TCSD concentrations (0.84mg/L) induced cardiovascular circulation dysfunction. Alcian blue staining increased the α angle between Meckel's cartilages and β angle between two ceratobranchial. Basihyal and palatoquadrate became shorter and developmental abnormality or defects occurred in the fifth ceratobranchial. Overall, these results provide a theoretical basis for systematically evaluating the combined toxicity of the prevalent chlorinated phenolic pollutants in real-world aquatic environments.

Inhibitory effects of natural organic matter on methyltriclosan photolysis kinetics

This study evaluated the effects and related mechanisms of natural organic matter (NOM) on the photolysis of methyltriclosan (MTCS), a metabolite of triclosan. Addition of two representative NOM isolates, Pony Lake fulvic acid (PLFA-microbial origin) and Suwannee River fulvic acid (SRFA-terrestrial origin), significantly inhibited the direct photolytic rate of MTCS by ∼70%. The MTCS photolytic rate in the presence of PLFA was greater than for SRFA. NOM not only suppressed photolysis by light-shielding, but also produced ROS to oxidatively degrade MTCS and/or triplet NOM (³NOM*) to sensitize degradation. The dual effects of light-screening and photo-sensitization led to an overall decrease in photolysis of MTCS with a positive concentration-dependence. Upon addition of NOM, EPR documented the occurrence of ¹O₂ and ˙OH in the photolytic process, and the bimolecular k value for the reaction of ¹O₂ with MTCS was 1.86 × 10⁶ M⁻¹ s⁻¹. ROS-quenching experiments indicated that the contribution of ˙OH (19.1–29.5%) to indirect photolysis of MTCS was lower than for ¹O₂ (38.3–58.7%). Experiments with D₂O further demonstrated that ¹O₂ participated in MTCS photodegradation. Moreover, the addition of sorbic acid and O₂ gas to the reaction confirmed the participation of ³NOM* as a key reactant in the photochemical transformation of MTCS. This is the first comprehensive analysis of NOM effects on the indirect photolysis of MTCS, which provides new insights for understanding the environmental fate of MTCS in natural environments.

We demonstrate that PLFA and SRFA inhibit the MTCS photolysis by synergistic effects of light-shielding and photo-sensitization.

Vortex assisted-supramolecular solvent based microextraction coupled with spectrophotometric determination of triclosan in environmental water samples

A simple, fast and environmental friendly vortex assisted-supramolecular solvent based microextraction (VA-SSME) method was developed for the preconcetration of triclosan in wastewater prior to UV spectrophotometric determination. To achieve maximum sensitivity and accuracy for the target analyte, the experimental parameters affecting the VA-SSME procedure were optimized using response surface methodology (RSM). Under optimised conditions, the correlation coefficient (R2) and recoveries were 0.9994 and 100.31-118.5%, respectively. The intra-day (repeatability) and inter-day (reproducibility) precisions expressed in terms of relative standard deviation (RSD) were 2-4% and 5.2%, respectively. The preconcentration factor and limits of detection (LOD) and quantification (LOQ) were found to be 90, 0.28 μg L−1 and 0.92 μg L−1, respectively. The developed VA-SSME/UV method was applied for the determination of triclosan in real samples collected over a period of three months. The analytical results obtained showed that triclosan was frequently detected in influent wastewater samples but was not detected in effluent samples.