Risk assessment of phthalates in pharmaceuticals

Are pharmaceutical residues in crops a threat to human health?

The application of biosolids, manure, and slurry onto agricultural soils and the growing use of treated wastewater in agriculture result in the introduction of human and veterinary pharmaceuticals to the environment. Once in the soil environment, pharmaceuticals may be taken up by crops, resulting in consequent human exposure to pharmaceutical residues. The potential side effects of pharmaceuticals administered in human medicine are widely documented; however, far less is known regarding the risks that arise from incidental dietary exposure. The aim of this study was to evaluate human exposure to pharmaceutical residues in crops and assess the associated risk to health for a range of pharmaceuticals frequently detected in soils. Estimated concentrations of carbamazepine, oxytetracycline, sulfamethoxazole, trimethoprim, and tetracycline in soil were used in conjunction with plant uptake and crop consumption data to estimate daily exposures to each compound. Exposure concentrations were compared to Acceptable Daily Intakes (ADIs) to determine the level of risk. Generally, exposure concentrations were lower than ADIs. The exceptions were carbamazepine, and trimethoprim and sulfamethoxazole under conservative, worst-case scenarios, where a potential risk to human health was predicted. Future research therefore needs to prioritize investigation into the health effects following exposure to these compounds from consumption of contaminated crops.

Indicator displacement-based colorimetric assay for dibutyl phthalate in pharmaceutical products with titanium(IV)-pyridylazo resorcinol (PAR)

Taking advantage of the competitive binding affinity towards Ti(IV) between 4-(2-pyridylazo) resorcinol (PAR) and phthalate, a simple indicator displacement (ID)-based colorimetric assay was designed for indirect determination of a well-known phthalic acid ester, dibutyl phthalate (DBP). The indicator PAR and Ti(IV) formed a purplish-red-colored Ti(IV)-PAR complex (λmax = 540 nm) at a 1:1 ratio. In the presence of pre-hydrolyzed DBP, colorless complex formation of phthalate ion (emerging from alkaline hydrolysis of DBP) with Ti(IV) resulted in a hypsochromic shift in absorbance maximum, accompanying a color change from purplish-red to yellowish-orange (λmax = 390 nm) by the release of PAR from Ti(IV)-PAR system. Based on this mechanism, the linear response range of the system for DBP was found to lie between 0.16 and 0.37 mmol L-1 with an experimental detection limit of 11.6 µmol L-1. The recommended Ti(IV)-PAR system was successfully applied to DBP-containing pharmaceutical products (as real sample) after a simple clean-up process for removing possible water-soluble interferents. The analytical results obtained from the recommended method (by applying the standard addition approach) and the reference liquid chromatography-tandem mass spectrometric (LC-MS/MS) method were statistically compared using DBP-extract of the drug samples. Consequently, a simple and selective colorimetric ID strategy was proposed for the analysis of DBP in pharmaceuticals for the first time.

Diethyl phthalate and dibutyl phthalate disrupt sirtuins expression in the HepG2 cells

Background

Phthalates are additives used as plasticizers among other uses, classified as endocrine disruptors and may contribute to some metabolic disorders. The aim of this work was to determine the effect of the exposure of diethyl phthalate (DEP) and dibutyl phthalate (DBP) on cell viability and reactive oxygen species (ROS) production, as well as the regulation of sirloins in HepG2 cells.

Methods

HepG2 cells were exposed to DEP or DBP at 0.1, 1, 10 and 100 μg/mL, and after 48 or 72 h the gene and protein expression of sirtuins was quantified by qRT-PCR and Western-Blot, respectively.

Results

Results showed that even at a low concentration of 0.1 μg/mL DEP affected the expression of Sirt3 and Sirt4, whereas DBP at 0.1 μg/mL affected Sirt3 and Sirt5 gene expression. Protein analysis showed a reduction in Sirt1 levels at a DEP concentration of 1 μg/mL and higher, while DBP at higher dose (100 μg/mL) decreased Sirt3 protein levels. Cell viability decreased by 20% only at higher dose (100 μg/mL) and ROS production increased at 10 and 100 μg/mL for both phthalates.

Conclusion

These findings indicate that exposure to low concentrations (0.1 μg/mL) of DEP or DBP can negatively influence the expression of some sirtuins.

Human skin absorption of three phthalates

Population studies reveal widespread exposure to phthalates. Understanding their absorption, distribution, metabolism, and excretion is vital to reduce exposure. However, data on skin absorption remain limited. We thus aim to characterize the skin permeation of three phthalates in a mixture, neat or in emulsion; di(2-ethylhexyl) phthalate (d4-DEHP), dibutyl phthalate (d4-DBP), and diethyl phthalate (d4-DEP), by comparing in vitro human skin (800 µm) permeation (24 hours) results using flow-through diffusion cells with urine results obtained from volunteers exposed to the same mixture applied to a forearm (40 cm2). Metabolites were analyzed in receptor fluids and urine. Phthalates crossed the skin barrier and metabolized into monoesters before elimination. Increased permeation was observed for phthalates in emulsion compared to neat substances, with polyethylene glycol (PEG) in the receptor fluid enhancing emulsion permeation, but not affecting neat substances. In vitro results mirrored in vivo findings: DEP showed rapid permeation (J: ∼2 ug/cm2/h) and urinary excretion peaking at six hours post-application, whereas DBP exhibited slower kinetics (J: ∼0.1 ug/cm2/h), with a urinary peak at 15-17 hours post-application. DEHP had minimal permeation (J: ∼0.0002 ug/cm2/h) with no observable urinary peak. These findings underscore the importance of comprehending phthalate skin absorption for effective exposure mitigation strategies.

Xenoestrogen concentration in women with endometriosis or leiomyomas: A case-control study

BACKGROUND

Xenoestrogens are synthetic or naturally occurring chemicals capable of altering the endocrine system of humans and animals owing to their molecular similarity to endogenous hormones. There is limited data regarding their effects on women´s health. Chronic exposure to xenoestrogens can promote the development of estrogen-related diseases.

OBJECTIVES

To examine xenoestrogen concentration (TEXB-α) differences between women with leiomyomas or endometriosis and control women, and to study the relationship between the clinical and sociodemographic characteristics of these patients and their xenoestrogen levels.

METHODS

Prospective case-control study. We selected 221 women who underwent surgery at Quironsalud Madrid University Hospital between 2017 and 2021. The cases included 117 patients: 74 women who underwent surgery for uterine leiomyomas, 21 with endometriosis, and 22 with both pathologies. The control group comprised 104 healthy women who underwent surgical procedures for other reasons. TEXB-α was determined in the omental fat of all patients. Using a questionnaire and reviewing the patients' medical records, we collected sociodemographic data and other relevant variables.

RESULTS

A significant majority of study participants (68.8%) had detectable levels of xenoestrogens. We found no association between TEXB-α levels in omental fat and the presence of myomas or endometriosis. In the case group, women living or working in Madrid Community exhibited, on average, 3.12 Eeq pM/g higher levels of TEXB-α compared to those working in other areas (p = 0.030). Women who referred to the use of estrogen-containing hormonal contraceptives had, on average, 3.02 Eeq pM/g higher levels of TEXB-α than those who had never used them (p = 0.022).

CONCLUSIONS

This study found no association between omental xenoestrogen levels and leiomyomas or endometriosis. However, their presence in most participants and their association with highly polluted areas emphasizes the importance of limiting environmental exposure to these substances. We also identified an association between hormonal contraceptive use and xenoestrogen concentration.

Screening of Environmental Chemicals to Characterize Exposures in Participants With Systemic Lupus Erythematosus

OBJECTIVE

There is a need to characterize exposures associated with the pathogenesis of systemic lupus erythematosus (SLE). In this pilot study, we explore a hypothesis-free approach that can measure thousands of exogenous chemicals in blood ("exposome") in patients with SLE and unaffected controls.

METHODS

This cross-sectional study analyzed a cohort of patients with prevalent SLE (n = 285) and controls (n = 106). Plasma was analyzed by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). Mass spectrometry features present in at least 25% of all samples were selected for association analysis (n = 2,737). Features were matched to potential chemicals using available databases. Association analysis of abundances of features with SLE status was performed, adjusting for age and sex. We also explored features associated with SLE phenotypes, sociodemographic factors, and current medication use.

RESULTS

We found 30 features significantly associated with SLE status (Bonferroni P < 0.05). Of these, seven matched chemical names based on databases. These seven features included phthalate metabolites, a formetanate metabolite, and eugenol. The abundance of acid pesticides differed between patients with SLE and controls (Bonferroni P < 0.05). Two unmatched features were associated with a history of lupus nephritis, and one with anti-double-stranded DNA antibody production (Bonferroni P < 0.05). Seventeen features varied by self-reported race and ethnicity, including a polyfluoroalkyl substance (analysis of variance P < 1.69 × 10-5). Eleven features correlated with antimalarials, 6 with mycophenolate mofetil, and 29 with prednisone use.

CONCLUSION

This proof-of-concept study demonstrates that LC-QTOF/MS is a powerful tool that agnostically detects circulating exogenous compounds. These analyses can generate hypotheses of disease-related exposures for future prospective, longitudinal studies.

Occurrence of phthalates in facemasks used in India and its implications for human exposure

Synthetic polymers with additives are used in the manufacturing of face masks (FMs); hence, FMs could be a potential source of exposure to phthalic acid esters (PAEs). India stands second in the world in terms of the FMs usage since the beginning of Covid-19 pandemic. However, little is known about the PAEs content of FMs used in India. Some PAEs, such as DEHP and DBP are suspected endocrine disrupting chemicals (EDCs); hence, wearing FM may increase the risk of exposure to these EDCs. In this study, we collected 91 samples of FMs from eight Indian cities and analyzed for five PAEs viz. DMP, DEP, DBP, BBP, and DEHP. The PAEs contents in FMs ranged from 101.79 to 27,948.64 ng/g. The carcinogenic risk of N 95 with filter, N-95, and cloth masks was higher than the threshold levels. The findings indicate the need to control PAEs in FMs through regulatory actions.

Phthalate toxicity mechanisms: An update

Phthalates are one of the most widely used plasticizers in polymer products, and they are increasingly being exposed to people all over the world, generating health concerns. Phthalates are often used as excipients in controlled-release capsules and enteric coatings, and patients taking these drugs may be at risk. In both animals and human, phthalates are mainly responsible for testicular dysfunction, ovarian toxicity, reduction in steroidogenesis. In this regard, for a better understanding of the health concerns corresponding to phthalates and their metabolites, still more research is required. Significantly, multifarious forms of phthalates and their biomedical effects are need to be beneficial to investigate in the various tissues or organs. Based on these investigations, researchers can decipher their toxicity concerns and related mechanisms in the body after phthalate's exposure. This review summarizes the chemical interactions, mechanisms, and their biomedical applications of phthalates in animals and human.

Plastic particles in medicine: A systematic review of exposure and effects to human health

Single-use plastics (SUPs) have become an essential constituent of our daily life. It is being exploited in numerous pharmaceutical and healthcare applications. Despite their advantages and widespread use in the pharma and medical sectors, the potential clinical problems of plastics, especially the release of micro-nanoplastics (MNPs) and additives from medical plastics (e.g. bags, containers, and administrative sets) and sorption of drugs remain understudied. Certainly, the MNPs are multifaceted stressors that cause detrimental effects to the ecosystem and human health. The origin and persistence of MNPs in pharmaceutical products, their administration to humans, endurance and possible health implication, translocation, and excretion have not been reviewed in detail. The prime focus of this article is to conduct a systematic review on the leaching of MNPs and additives from pharmaceutical containers/administrative sets and their interaction with the pharmaceutical constituents. This review also explores the primary and secondary routes of MNPs entry from healthcare plastic products and their potential health hazards to humans. Furthermore, the fate of plastic waste generated in hospitals, their disposal, and associated MNPs release to the environment, along with preventive, and alternative measures are discussed herein.

High exposure to phthalates is associated with HbA1c worsening in type 2 diabetes subjects with and without edentulism: a prospective pilot study

BACKGROUND

Phthalates exposure and complete edentulism are related to both low socioeconomic status. No study by far has verified if and to what extent these two conditions are related. We aimed to explore their potential association and interplay in the metabolic control and cardiovascular risk profile.

METHODS

In our small (n = 48) prospective pilot study twenty-four patients with type 2 diabetes (DnE) and twenty-four patients with type 2 diabetes and edentulism (DE) followed for 19 ± 2 months were treated according to best clinical standards. Phthalates' exposure was evaluated by urinary concentration of di-2-ethylhexylphthalate (DEHP), metabolites, i.e. mono 2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) and mono 2-ethyl-5-hydroxyhexyl phthalate (MEHHP).

RESULTS

No association between phthalates and edentulism was found, nor did edentulism affect glucose control. Higher phthalates exposure was associated with a glycated haemoglobin worsening. This association was found for all the measured phthalates metabolites, both as a whole (DEHP; r = 0.33, p = 0.0209) and individually: MEHP (r = 0.41, p = 0.0033), MEHHP (r = 0.32, p = 0.028), MEOHP (r = 0.28, p = 0.0386).

CONCLUSIONS

Phthalates are not associated with edentulism but predict the worsening of glucose control in subjects with type 2 diabetes. These findings might prove relevant in identifying novel biomarkers of cardiometabolic risk. Further studies are needed to validate our results and estimate the true potential of phthalates in terms of risk assessment.

Skin models for dermal exposure assessment of phthalates

Phthalates are a class of compounds that have found widespread use in industrial applications, in particular in the polymer, cosmetics and pharmaceutical industries. While ingestion, and to a lesser degree inhalation, have been considered as the major exposure routes, especially for higher molecular weight phthalates, dermal exposure is an important route for lower weight phthalates such as diethyl phthalate (DEP). Assessing the dermal permeability of such compounds is of great importance for evaluating the impact and toxicity of such compounds in humans. While human skin is still the best model for studying dermal permeation, availability, cost and ethical concerns may preclude or restrict its use. A range of alternative models has been developed over time to substitute for human skin, especially in the early phases of research. These include ex vivo animal skin, human reconstructed skin and artificial skin models. While the results obtained using such alternative models correlate to a lesser or greater degree with those from in vivo human studies, the use of such models is nevertheless vital in dermal permeation research. This review discusses the alternative skin models that are available, their use in phthalate permeation studies and possible new avenues of phthalate research using skin models that have not been used so far.

Urinary Phthalate Biomarkers during Pregnancy, and Maternal Endocrine Parameters in Association with Anthropometric Parameters of Newborns

Adverse birth outcomes present risk factors resulting in neonatal morbidity and mortality. Sufficient maternal hormonal concentrations are crucial for normal foetal development. Previous studies have shown a relationship between phthalate exposure and maternal hormonal levels during pregnancy. This study aims to investigate if neonatal anthropometric parameters are associated with maternal endocrine parameters during the ≤15th week of gestation and the third trimester of pregnancy concerning phthalate exposure in pregnant women from Nitra, Slovakia. We used high-performance liquid chromatography, tandem mass spectrometry (HPLC-MS/MS), and electro-chemiluminescence immunoassay to quantify urinary concentrations of phthalates and serum concentrations of hormones and sex hormone-binding globulin (SHBG), respectively. We observed a mostly positive correlation between neonatal anthropometric parameters (gestational age, birth length, birth weight, head circumference) and maternal concentration of phthalate metabolites (p ≤ 0.05). The hierarchical multivariate regression results showed a statistically significant association between Apgar score at 5 min after delivery, gestational age, birth weight, head circumference, and maternal endocrine parameters during pregnancy (p ≤ 0.05), adjusted to phthalate metabolites. To the best of our knowledge, our study is the first to indicate that prenatal exposure to phthalates may also affect birth outcomes through interaction with the maternal endocrine system.

Di-n-butyl phthalate disrupts neuron maturation in primary rat embryo neurons and male C57BL/6 mice

Di-n-butyl phthalate (DBP) is commonly used as a plasticizer and its usage continues to increase in conjunction with plastic consumption. DBP is readily released into air, drinking water, and soil, and unfortunately, is a potent endocrine disrupter that impairs central nervous system functions. Previously DBP was found to (1) arrest the cell cycle of C17.2 neural progenitor cells (NPCs) at the G1 phase, (2) reduce numbers of newly generated neural stem cells in the mouse hippocampus, and (3) adversely affect learning and memory. Other investigators also noted DBP-mediated neurotoxic effects, but as yet, no study has addressed the adverse effects of DBP on neuronal differentiation. Data demonstrated that at 200 μM DBP induced apoptosis in rat embryo primary neurons by increasing reactive oxygen species levels and inducing mitochondrial dysfunction. However, no significant effect was detected on neurons at concentrations of ≤100 μM. In contrast, doublecortin/microtubule associated protein-2 (DCX/MAP2) immunocytochemistry showed that DBP at 100 μM delayed neuronal maturation by increasing protein levels of DCX (an immature neuronal marker), without markedly affecting cell viability. Further in vivo studies confirmed that DCX⁺ cell numbers were significantly elevated in the hippocampus of DBP-treated mice, indicating that DBP delayed neuronal maturation, which is known to be associated with impaired memory retention. Data demonstrated that DBP might disrupt neuronal maturation, which is correlated with reduced neurocognitive functions.

Toxicokinetic studies of di-isobutyl phthalate focusing on the exploration of gender differences in rats

Due to the use of di-isobutyl-phthalate (DiBP) in the production of soft-polyvinyl chloride articles, it is currently a hazardous substance prevalent in human daily life. However, reports on DiBP's toxicokinetics are still very scarce. And no studies have been reported on gender differences in DiBP toxicokinetics. Therefore, this study was conducted in accordance with these research needs. DiBP of 100 mg/kg has been exposed to male and female rats single or multiple times. DiBP and its major metabolite, mono-isobutyl-phthalate (MiBP), were quantified from various biological samples obtained from rats administered with DiBP. Based on these results, several toxicokinetic parameters were estimated. Toxicokinetic results between genders were compared, and from this, existence and extent of gender differences in DiBP's toxicokinetics were explored. Investigation of presence and extent of subacute toxicity in male and female rats following multiple exposures to DiBP were also conducted. This study provided comprehensive information on DiBP toxicity and gender differences that have not been reported in detail. Results of these studies imply that subacute toxicity in liver, kidney, lung, and testis of rats at 100 mg/kg of DiBP is modest and that there is little difference in toxicokinetics between genders. And in both male and female rats, the metabolism of DiBP (to MiBP) was significant, and excretion of MiBP into urine was a major indicator of DiBP exposure.

Associations between medication use and phthalate metabolites in urine and follicular fluid among women undergoing in vitro fertilization

BACKGROUND

Phthalates, which are used as excipients of drugs, have been related to adverse reproductive outcomes. However, the relationships between medication use and phthalate exposure among women undergoing in vitro fertilization (IVF) have not been studied.

OBJECTIVE

To investigate the associations between the medication intake and phthalate metabolites in urine and follicular fluid (FF).

METHOD

Eight phthalate metabolites were measured in urine and FF samples from 274 women undergoing IVF using liquid chromatography-tandem mass spectrometry. Information on recent medication intake was obtained via interview by trained staff. We constructed generalized linear regression models to examine the associations of medication intake with phthalate metabolite concentrations and dose-response relationships between the number of medicines used and metabolite concentrations in two matrices.

RESULTS

Four of 10 drugs were used by more than 10% of the participants, including vitamins (23.0%), traditional Chinese medicine (TCM, 22.3%), antioxidants (12.4%) and amoxicillin (10.2%). Participants who had used TCM had 26.0% (95% CI: 0.0, 58.8%), 32.6% (95% CI: 4.2, 68.8%) and 32.3% (95% CI: 2.6, 70.6%) higher urinary mono-n-butyl phthalate (MBP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) concentrations, respectively, than those who had not. Antioxidant intake was associated with a 30.6% (95% CI: -48.5, -6.6%) decrease in the urinary MBP concentration. Compared with non-users, women who reported the use of medicines had 53.2% (95% CI: 2.7, 128.5%) higher concentrations of MMP and a 37.7% (95% CI: -60.7, -1.5%) lower level of MBP in FF, respectively.

CONCLUSION

Our data suggest that the intake of some medications may increase phthalate exposure among women undergoing IVF.

Chemophobia and knowledge of toxicological principles in South-Korea: perceptions of trace chemicals in consumer products

Many consumer products are manufactured or synthesized from chemicals. However, consumers may be hesitant to purchase consumer products that are perceived as synthetic or derived with chemical substances. Prior studies suggested a preference for chemicals of natural origin and an irrational fear of synthetic chemicals, a phenomenon that is referred to as chemophobia. The aim of this study was two-fold as follows: to (1) investigate the levels of knowledge with respect to toxicological principles, chemophobia, and trust in stakeholders in South Korea and (2) experimentally test the effect of information provision on acceptance and willingness-to-buy for the specific case of trace chemicals in consumer products. For this purpose, an online survey and experiment was conducted with consumers in South Korea. Data suggested that in South Korea chemophobia correlated with an individual's knowledge regarding toxicological principles. Accordingly, a small intervention providing information on the dose-response mechanism increased consumers' acceptance of the presence of trace chemicals and subsequent willingness to purchase the products in this study. In conclusion, this investigation stresses the importance of educating the public regarding basic principles of toxicology to avoid chemophobia, while simultaneously discussing other factors that need to be taken into account such as attitudes and trust in communicators.

Design of Catalase Monolithic Tablets for Intestinal Targeted Delivery

Several studies confirmed a correlation between elevated hydrogen peroxide (H₂O₂) levels in patients with intestinal bowel diseases (IBD) and the negative effects caused by its presence. The objective of this study was to explore the potential use of catalase (CAT) to diminish the level of H₂O₂ and its deleterious action on intestinal mucosa. Oral dosage forms of a CAT bioactive agent targeted to the intestines were designed and tested in various simulated gastric and intestinal media. Monolithic tablets (30% loading) were prepared using commercial CarboxyMethylCellulose (CMC) or synthesized CarboxyMethylStarch (CMS) and TriMethylAmineCarboxyMethylStarch (TMACMS) as matrix-forming excipients. For starch derivatives, the presence of the ionic groups (carboxymethyl and trimethylamine) was validated by spectral analysis. In vitro studies have shown that tablets formulated with TMACMS and 30% CAT resisted the acidity of the simulated gastric fluid and gradually released the enzyme into the simulated intestinal fluid. The investigation of the CAT release mechanism revealed the role of anionic and cationic groups of polymeric excipients and their involvement in the modulation of the CAT dissolution profile. The proposed drug delivery system can be considered an efficient solution to target CAT release in the intestine and contribute to the reduction of H₂O₂ associated with intestinal inflammation.

SGLT2 inhibitors and thiazide enhance excretion of DEHP toxic metabolites in subjects with type 2 diabetes: A randomized clinical trial

OBJECTIVE

Phthalates are non-persistent pollutants related to impaired metabolism and high cardiovascular risk. Their toxic metabolites are eliminated through urine and feces. Prevention policies are considered by the governments, although no therapeutic strategy to facilitate their elimination from the human body has been proposed so far. Aim of the present study was to verify, for the first time in humans, whether diuretics might be able to enhance phthalates' toxic metabolites urinary output.

DESIGN AND METHODS

We conducted a two-armed, parallel-design, randomized clinical trial. Thirty patients with type 2 diabetes and hypertension received a four week-treatment with Dapagliflozin 10 mg or Hydrochlorothiazide 12.5 mg. 24-hours urine were collected to measure urinary excretion of three major 2-ethylhexyl-phthalate (DEHP) metabolites, i.e. mono 2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) and mono 2-ethyl-5-hydroxyhexyl phthalate (MEHHP).

RESULTS

24-h urinary excretion of DEHP and MEHP was increased (+44%, p = 0.036; +49%, p = 0.0016) while MEOHP e MEHHP showed only a positive trend (+25%, p = 0.016; +36%, p = 0.062). Irrespective of the specific treatment, induced variations of daily urinary eliminations of MEHP metabolites were related with the 24-h urinary sodium (r = 0.42, p = 0.0226) and potassium (r = 0.54, p = 0.0026) excretion. Also, DEHP and MEOHP were related to sodium (r = 0·43, p = 0.0205; r = 0·44, p = 0.0168 respectively) but not to potassium.

CONCLUSIONS

Urinary phthalates excretion seems to occur mainly through sodium- and potassium-related mechanisms, apparently independent from the different diuretic effect. Both thiazide diuretics and SLGT2 inhibitors are effective into the removal of phthalates metabolites from the human body, reducing the human tissues' exposure to their toxicity.

The associations between personal care products use and urinary concentrations of phthalates, parabens, and triclosan in various age groups: The Korean National Environmental Health Survey Cycle 3 2015-2017

Phthalates and parabens are ubiquitous chemicals of public concern. This study aimed to investigate the use of personal care products (PCPs) as predictors of exposure to phthalates, parabens, and triclosan (TCS) among various age groups in a nationally representative population. The concentrations of eight phthalate metabolites, three parabens, and TCS were measured in a random spot urine sample in 5962 study participants (age range: 3-86 years). The information on PCPs use was obtained in seven categories over previous three months. The exposure risks to phthalates, parabens, and TCS were different according to the pattern of PCPs use in different age groups and gender. In adolescents and adults, females used all categories of PCPs more frequently than males, with statistical significance. The use rates of PCPs and the significant exposure risks to phthalates, parabens, and TCS associated with PCP use were more clearly observed in adults. The least square geometric means (LSGMs) of urinary methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) steadily increased, as the cumulative number of used PCPs increased with statistical significance. The exposure risks to MeP were consistently observed with various PCPs use and showed a significant increase as the cumulative number of PCPs use increased in adults. Furthermore, the use of fragrance products, makeup, and air fresheners significantly increased the exposure risk to EtP in preschoolers. The significant exposure risk to mono-(3-carboxypropyl)- phthalate (MCPP) associated with nail polishes use was observed in preschoolers and adults. This study showed the associations between PCPs use and urinary concentrations of phthalates, parabens, and TCS in various age groups. Environmental health policies to reduce exposure to phthalates and parabens should be widely implemented, including industry regulations and increasing public awareness. Future studies are needed to explore other important exposure sources of these chemicals and their related adverse health effects.

Development of a physiologically based pharmacokinetic model of diisononyl phthalate (DiNP) in pregnant rat and human

A physiologically based pharmacokinetic (PBPK) model for di-isononyl phthalate (DiNP) was developed by adapting the existing models for di(2-ethylhexyl) phthalate (DEHP) and di-butylphthalate (DBP). Both pregnant rat and human time-course plasma and urine data were used to address the hydrolysis of DiNP in intestinal tract, plasma, and liver as well as hepatic oxidative metabolism and conjugation of the monoester and primary oxidative metabolites. Data in both rats and humans were available to inform the uptake and disposition of mono-isononyl phthalate (MiNP) as well as the three primary oxidative metabolites including hydroxy (7-OH)-, oxo (7-OXO)-, and carboxy (7-COX)-monoisononyl phthalate in plasma and urine. The DiNP model was reliable over a wide range of exposure levels in the pregnant rat as well as the two low exposure levels in humans including capturing the nonlinear behavior in the pregnant rat after repeated 750 mg/kg/day dosing. The presented DiNP PBPK model in pregnant rat and human, based upon an extensive kinetic dataset in both species, may provide a basis for assessing human equivalent exposures based upon either rodent or in vitro points of departure.

Citrate ester substitutes for di-2-ethylhexyl phthalate: In vivo reproductive and in vitro cytotoxicity assessments

Di-2-ethylhexyl phthalate (DEHP) is frequently used as a plasticizer for wrapping films, in toys, and in medical devices. Previous studies demonstrated that DEHP in mouse reduced testicular and epididymis weights, suppressed levels of serum testosterone, luteinizing hormone, and follicle-stimulating hormone, and decreased synthesis of testosterone by Leydig cells. Due to these anti-androgenic effects of DEHP on the reproductive system, the aim of this study was to examine whether substitutes such as acetyl triethyl citrate (ATEC) and acetyl tributyl citrate (ATBC) also damaged the reproductive system. In particular, this study investigated the anti-androgenic effects and cytotoxicity of DEHP substitutes using castrated male Sprague--Dawley rats employing the in vivo Hershberger assay and in vitro mouse Leydig (TM3) cells and mouse fibroblast (NIH-3T3) cell lines. In the Hershberger assay, rats were administered testosterone propionate and ATEC or ATBC at 20, 100, or 500 mg/kg b.w./day or DEHP (500 mg/kg b.w./day). Controls received testosterone antagonist flutamide (positive control), testosterone only (negative control), or corn oil only (vehicle control). ATEC/ATBC treatment produced no significant differences compared with testosterone in 5-androgen-dependent tissues weights including ventral prostate, seminal vesicles, levator ani-bulbocavernosus muscle, Cowper's glands, and glans penis. In the 500 mg/kg ATBC group, there was a significant reduction in liver weight. The MTT assay revealed that cell viability of both TM3 and NIH-3T3 cells treated with ATEC was not markedly altered. However, ATBC significantly reduced TM3 and NIH-3T3 cell viability in a concentration-dependent manner. Further, ATBC reduced cell viability to greater extent in TM3 versus NIH-3T3 cells. Based upon the observed effects of citrate ester substitutes on reproductive tissue responses and cytotoxicity, ATEC compared to ATBC may be a better alternative to DEHP for potential commercial uses.

ABBREVIATIONS

ATEC: acetyl triethyl citrate; ATBC: acetyl tributyl citrate; CG: Cowper's glands; DEHP: di-2-ethylhexyl phthalate; DMEM: Dulbecco's modified Eagle's medium; DMSO: dimethyl sulfoxide; GP: glans penis; LABC: levator ani-bulbocavernosus muscle; MTT: methyl tetrazolium; NC: negative control; NT: untreated control; PC: positive control; SV: seminal vesicle; TP: testosterone propionate; VC: vehicle control; VP: ventral prostate.

Risk communication for labeling all ingredients in consumer products

The labeling of all ingredients contained in consumer products has been requested by consumers concerned regarding their safety. Consequently, regulatory agencies have set guidelines for industries on how to provide safety information regarding the ingredients in their products. However, discordant opinions were raised from stakeholders, resulting in the formation of a risk communication forum among industries, regulatory agencies, consumer groups, and academia. There are several methods that might be utilized to provide ingredient information to consumers: (1) listing all ingredients on the label of products, (2) providing major ingredients on the label of products, (3) presenting all ingredients on the websites of each manufacturer, and (4) listing major ingredients on the label of products and the remainder of ingredients (not on the label) on the websites. Each method might have its own advantages and disadvantages with respect to providing the information regarding the names of the ingredients used in consumer products to the consumers. A continuous risk communication forum might be an effective tool to facilitate an improved understanding of chemical information, toxicological science, regulatory guidelines, labeling methods, and consumers' concern. This study suggests that risk communication efforts may be helpful and a good opportunity for stakeholders to exchange opinions and reach a harmonious conclusion on labeling of consumer products ingredients.

Risk assessment of volatile organic compounds (VOCs) detected in sanitary pads

Disposable sanitary pads are a necessity for women's health, but safety concerns regarding the use of these products have created anxiety. The aim of this study was to conduct a risk assessment of 74 volatile organic compounds (VOCs), which were expected to be contained within sanitary pads. Of the 74 VOCs, 50 were found in sanitary pads retailed in Korea at concentrations ranging from 0.025 to 3548.09 µg/pad. In order to undertake a risk assessment of the VOCs, the toxicological database of these compounds in the United States Environmental Protection Agency (USEPA), Agency for Toxic Substances and Disease Registry (ATSDR), National Toxicology Program (NTP) and World Health Organization (WHO) was searched. Ethanol was found to exhibit the highest reference dose (RfD) while 1,2-dibromo-3-chloro-propane displayed the lowest RfD. Consequently, a worst-case exposure scenario was applied in this study. It was assumed that there was the use of 7.5 sanitary napkins/day for 7 days/month. In the case of panty liners or overnight sanitary napkins, the utilization of 90 panty liners/month or 21 overnight sanitary napkins/month was assumed, respectively. In addition, 43 kg, the body weight of 12 to 13-year-old young women, and 100% VOCs skin absorption were employed for risk assessment. The systemic exposure dose (SED) values were calculated ranging from 1.74 (1,1,2-trichloroethane) ng/kg/day to 144.4 (ethanol, absolute) µg/kg/day. Uncertainty factors (UFs) were applied ranging from 10 to 100,000 in accordance with the robustness of animal or human experiments. The margin of exposure (MOE) of 34 VOCs was more than 1 (acceptable MOE > 1). Applicable carcinogenic references reported that the cancer risk of five VOCs was below 10^-6. Based on our findings, evidence indicates that the non-cancer and cancer risks associated with VOCs detected in sanitary pads currently used in South Korea do not pose an adverse health risk in women.