Isothiazolinones in cleaning products: Analysis with liquid chromatography tandem mass spectrometry of samples from sensitized patients and market

Impact of the rearing environment on the metabolism of shrimps and tracing the origins and species of shrimps using specific metabolites

Herein, the link between rearing environmental condition and metabolism was explored. Metabolite fingerprint datasets of black tiger shrimp (Penaeus monodon) from three production sites were collected and studied using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and HPLC-MS/MS. Two compounds, benzisothiazolinone and hippuric acid, were identified to be potentially related to pollution in the rearing environment and showed different abundances in the analysed shrimp samples with different origins. Furthermore, metabolomic analysis on three shrimp species, black tiger shrimp, kuruma shrimp (Penaeus japonicus) and sword shrimp (Parapenaeopsis hardwickii), under an identical rearing environment was also conducted. Two compounds, diethanolamine and benzisothiazolinone, potentially linked with pollution in the rearing environment were identified. The present protocol holds promise to be extended to the studies of exploring the relationship between rearing environmental conditions and metabolism. Furthermore, the analysis of single-blind samples was conducted. The results show that specific metabolites can be utilized as markers for tracing the origins of shrimp samples. The present protocol holds potential for application in tracing the origin and species of certain seafoods.

Benzisothiazolinone: Pharmacokinetics, Tissue Distribution, and Mass Balance Studies in Rats

Humans are continuously exposed to benzisothiazolinone (BIT), which is used as a preservative, through multiple routes. BIT is known to be a sensitizer; in particular, dermal contact or aerosol inhalation could affect the local toxicity. In this study, we evaluated the pharmacokinetic properties of BIT in rats following various routes of administration. BIT levels were determined in rat plasma and tissues after oral inhalation and dermal application. Although the digestive system rapidly and completely absorbed orally administered BIT, it underwent severe first-pass effects that prevented high exposure. In an oral dose escalation study (5-50 mg/kg), nonlinear pharmacokinetic properties showed that C_max and the area under the curve (AUC) increased more than dose proportionality. In the inhalation study, the lungs of rats exposed to BIT aerosols had higher BIT concentrations than the plasma. Additionally, the pharmacokinetic profile of BIT after the dermal application was different; continuous skin absorption without the first-pass effect led to a 2.13-fold increase in bioavailability compared with oral exposure to BIT. The [¹⁴C]-BIT mass balance study revealed that BIT was extensively metabolized and excreted in the urine. These results can be used in risk assessments to investigate the relationship between BIT exposure and hazardous potential.

Occupational contact allergy: The European perspective-Analysis of patch test data from ESSCA between 2011 and 2020

BACKGROUND

Occupational skin diseases have led the occupational disease statistics in Europe for many years. Especially occupational allergic contact dermatitis is associated with a poor prognosis and low healing rates leading to an enormous burden for the affected individual and for society.

OBJECTIVES

To present the sensitization frequencies to the most relevant allergens of the European baseline series in patients with occupational contact dermatitis (OCD) and to compare sensitization profiles of different occupations.

METHODS

The data of 16 022 patients considered having OCD after patch testing within the European Surveillance System on Contact Allergies (ESSCA) network between January 2011 and December 2020 were evaluated. Patients (n = 46 652) in whom an occupational causation was refuted served as comparison group.

RESULTS

The highest percentages of OCD were found among patients working in agriculture, fishery and related workers, metal industry, chemical industry, followed by building and construction industry, health care, food and service industry. Sensitizations to rubber chemicals (thiurams, carbamates, benzothiazoles) and epoxy resins were associated with at least a doubled risk of OCD. After a decline from 2014 onwards, the risks to acquire an occupation-related sensitization to methyl(chloro)isothiazolinone (MCI/MI) and especially to methylisothiazolinone (MI) seem to increase again. Sensitization rates to formaldehyde were stable, and to methyldibromo glutaronitrile (MDBGN) slightly decreasing over time.

CONCLUSIONS

Among allergens in the European Baseline Series, occupational relevance is most frequently attributed to rubber accelerators, epoxy resins and preservatives.

Contact sensitization to benzisothiazolinone: IVDK-data of the years 2002 to 2021

BACKGROUND

Benzisothiazolinone (BIT; CAS no. 2634-33-5) is used as a biocide in various products, including water-based paints, metalworking fluids, and household products. In recent years, increasing sensitization rates have been observed in Europe.

OBJECTIVE

To describe a time trend of sensitization to BIT, analyse concomitant reactions, and identify patients with increased risk of BIT sensitization.

METHODS

Retrospective analysis of data from 26 739 patients patch tested with BIT, sodium salt, 0.1% petrolatum as part of several special test series within the Information Network of Departments of Dermatology (IVDK), 2002 to 2021.

RESULTS

Positive reactions to BIT were noted in 771 patients (2.9%). Sensitization frequency varied over time and increased in recent years, peaking at 6.5% in 2020. Painters and metalworkers handling metalworking fluids, but not cleaners, had a significantly increased risk of BIT sensitization. From our data, there is no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

CONCLUSION

The increasing frequency of sensitization justifies adding BIT to the baseline series. More research on the clinical relevance of positive patch test reactions to BIT and the cause for the rising numbers of BIT sensitization is needed.

HIGHLIGHTS

Frequency of sensitization to BIT has increased in recent years. The increasing frequency of sensitization justifies adding BIT to the baseline series. Painters and metalworkers handling metalworking fluids, but not cleaners, has a significantly increased risk of BIT sensitization. We found no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation

BACKGROUND

Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known.

OBJECTIVES

To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones.

MATERIALS AND METHODS

We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC).

RESULTS

A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI.

CONCLUSIONS

Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon.

Analytical Method Development of Benzisothiazolinone, a Biocide, Using LC-MS/MS and a Pharmacokinetic Application in Rat Biological Matrices

Benzisothiazolinone (BIT), a biocide widely used as a preservative in household cleaning and personal care products, is cytotoxic to lung cells and a known skin allergen in humans, which highlights the importance of assessing its toxicity and pharmacokinetics. In this study, a simple, sensitive, and accurate LC−MS/MS method for the quantification of BIT in rat plasma, urine, or tissue homogenates (50 μL) using phenacetin as an internal standard was developed and validated. Samples were extracted with ethyl acetate and separated using a Kinetex phenyl−hexyl column (100 × 2.1 mm, 2.6 μm) with isocratic 0.1% formic acid in methanol and distilled water over a run time of 6 min. Positive electrospray ionization with multiple reaction monitoring transitions of m/z 152.2 > 134.1 for BIT and 180.2 > 110.1 for phenacetin was used for quantification. This assay achieved good linearity in the calibration ranges of 2−2000 ng/mL (plasma and urine) and 10−1000 ng/mL (tissue homogenates), with r ≥ 0.9929. All validation parameters met the acceptance criteria. BIT pharmacokinetics was evaluated via an intravenous and dermal application. This is the first study that evaluated BIT pharmacokinetics in rats, providing insights into the relationship between BIT exposure and toxicity and a basis for future risk assessment studies in humans.

Effects of slime toy poisoning in children and teenagers

Abstract Objective: The aim of this study was to identify which types of skin reactions are associated with slime toys and which of their ingredients are most frequently involved in cases of poisoning. Data source: Between January and July 2021, articles were selected using PubMed, SciELO, and LILACS databases. The following descriptors were used: (dermatitis OR rash OR eczema OR inflammation) AND slime. Inclusion criteria were articles available in full, in either Portuguese, English, or Spanish, published between January 2000 and July 31, 2021, and articles reporting cases of contact dermatitis or eczema potentially or directly attributed to slime toys. Articles not meeting these criteria and duplicate texts in the databases were excluded. Data synthesis: In total, 65 publications were identified, of which 16 were included in this review. This resulted in a total of 22 children (2 males, 20 females), aged between 4 and 13 years, who were reportedly intoxicated by slime toys, most of these being linked to homemade preparations. Studies reported the occurrence of contact or allergic dermatitis on hands, fingers, nails, forearms, and cheeks. The most allergenic and/or irritant ingredients included liquid detergent and soap. Additionally, patch tests identified positive reactions to methylisothiazolinone and methylchloroisothiazolinone, the preservatives used by chemical industries on preparation of glue, soap, detergents, etc. Conclusions: Although slime toys might be important for improving motor development and parental relationships, homemade slime toy recipes include several allergenic and irritant ingredients which might be exposed to vulnerable children and cause intoxications. Therefore, homemade slime toys preparations should be used cautiously and under the supervision of adults.

Thyroid hormone disrupting potentials of benzisothiazolinone in embryo-larval zebrafish and rat pituitary GH3 cell line

Benzisothiazolinone (BIT), one of the most widely used antimicrobial agents in consumer products, has frequently been detected in the water environment. The present study was conducted to determine the adverse effects of BIT on the thyroid neuroendocrine system of zebrafish embryos/larvae. Rat pituitary (GH3) cell line was employed to support the underlying mechanism of thyroid hormone disrupting effects. Significant coagulation and hatching delay were observed in embryos exposed to 30 μg/L of BIT, which in turn remarkably decreased hatchability and larval survival. In BIT-exposed larvae, tshβ, tshr, and trh genes were significantly upregulated along with a decrease in thyroxine and triiodothyronine content, indicating that BIT decreased thyroid hormones and increased thyrotropin-releasing hormone and thyroid stimulating hormone secretion through a feedback circuit. The downregulation of trα and deio2 genes in the zebrafish larvae suggests the inhibition of thyroid hormone receptors and deiodination. Similar to the results in zebrafish, upregulation of tshβ and downregulation of trα, trβ, deio1, and deio2 genes were observed in GH3 cells. Our observations suggest that BIT can decrease the level of thyroid hormones by influencing central regulation, receptor binding, and deiodination.

Identification of combinations of endocrine disrupting chemicals in household chemical products that require mixture toxicity testing

People are exposed to various chemicals contained in consumer products for which the risks are poorly characterized. There is growing evidence that exposure to endocrine disrupting chemicals (EDCs) through product use potentially affects development, behavior, and reproduction. However, limited information is available about common combinations of chemicals based on their appearance and potential health effects. The present study listed the ingredients contained in 11064 household chemical products from a publicly available database, and identified EDCs related to estrogenicity, androgenicity, thyroid hormone disruption, and changes in steroidogenesis. Association rule mining was applied to the dataset to identify frequent combinations of chemicals or commonly occurring EDCs contained in a single product. Among the target products, ingredient names were matched with 1241 chemical identifiers. A total of 293 chemicals were related to endocrine disruption, and nearly two-thirds of the products contained more than one of these chemicals. Cleaning products, synthetic detergents, fabric softeners, air fresheners, and deodorants have several hotspots for fragrances, isothiazolinones, glycol ethers, and parabens. The three most prevalent EDCs in household chemical products were added to act as fragrances and preservatives. The present study demonstrated that commonly occurring chemical combinations can be derived using an association rule mining algorithm. The results of this study will be useful in prioritizing chemical combinations and developing management plans for EDC mixture in consumer products.

Development and validation of a UPLC-MS/MS method for the quantification of isothiazolinones in the composition and emissions from consumer products

Isothiazolinones, a family of biocides, are used as preservatives for their fungicidal, bactericidal, and algacidal properties. These compounds can be found in a wide range of consumer and building products, such as paints, varnishes, shampoos, and liquid detergents. A robust analytical UPLC-MS/MS method to identify and quantify seven isothiazolinones (MIT, CMI, BIT, MBIT, BBIT, OIT, and DCOIT) in consumer products and their emissions was developed and validated according to ISO/IEC 17025. The limits of detection (LODs) ranged from 0.14 μg L^-1 (BIT) to 0.54 μg L^-1 (CMI). The method was applied for the quantification of the seven isothiazolinones in four types of consumer products (i.e., cosmetics, air fresheners, cleaning products, and building products) and the indoor emissions from a paint. Matrix effects were observed for the shampoo (63-74%), the shower gel (67-84%), and the ceramic glass cleaner (53-57%). All isothiazolinones indicated by the manufacturer (i.e., MIT, CMI, BIT, OIT, and DCOIT) were detected in the products and successfully quantified by the UPLC-MS/MS method.

Trends in preservative allergy: Benzisothiazolinone emerges from the pack

BACKGROUND

Preservatives are used widely in cosmetic, household, and industrial products to prevent microbial growth and spoiling of the products. There has been a recent epidemic of contact allergy to methylisothiazolinone (MI).

OBJECTIVES

To establish emerging trends in preservative contact allergy as MI is replaced.

METHODS

We performed a retrospective study on consecutively patch-tested patients at our center from January 2011 to December 2019.

RESULTS

A total of 7846 consecutively patch-tested patients were included who were patch tested between January 2011 and December 2019. The prevalence of allergy to MI fell from a peak of 9.39% in 2013 to 1.98% in 2019. MI/methylchloroisothiazolinone (MCI) followed a similar trend, with a peak prevalence of 7.85% in 2014 and falling to 1.39% in 2018. The prevalence of contact allergy to benzisothiazolinone (BIT) has increased steadily increased in 2014 from 0.26% (confidence interval [CI] 0.03-0.93) to 3.42% (CI 2.43-4.66) in 2019.

CONCLUSIONS

Our data show a significant increase in the prevalence of contact allergy to BIT over the last 6 years, probably as a consequence of increased use in household products. It is essential to continue to look for emerging trends in contact allergy to enable prompt preventative measures to be taken.

What Is New in Occupational Allergic Contact Dermatitis in the Year of the COVID Pandemic?

Purpose of Review

This article aims to summarize some recent trends in occupational allergic contact dermatitis (ACD), including dermatitis related to pandemic-level personal protective equipment in healthcare workers, hazards patients may experience when working from home, and occupational perspectives on the recent American Contact Dermatitis Society (ACDS) allergens of the year and ACDS Core Allergen Series updates.

Recent Findings

Recent ACDS Allergens of the Year may be particularly relevant to healthcare workers, including isobornyl acrylate, which is present in glucose sensors and propylene glycol present in hand cleansers and disinfectants. Lavender, limonene, and linalool, all of which are new additions to the ACDS Core Allergen Series, have been reported as causes for occupational ACD in massage therapists and aromatherapists. Isothiazolinone allergy continues to rise in both consumer and occupational settings. Finally, the COVID-19 pandemic has resulted in a wave of occupational ACD in healthcare workers to personal protective equipment, and revealed new potential allergens for individuals working from home.

Summary

Occupational allergic contact dermatitis continues to exert a significant occupational disease burden. Remaining aware of the current trends in allergens may allow for earlier recognition, diagnosis, and treatment, subsequently helping our patients to work in healthier and safer environments.

A Commonly Used Biocide 2-N-octyl-4-isothiazolin-3-oneInduces Blood-Brain Barrier Dysfunction via Cellular Thiol Modification and Mitochondrial Damage

Isothiazolinone (IT) biocides are potent antibacterial substances commonly used as preservatives or disinfectants, and 2-n-Octyl-4-isothiazolin-3-one (OIT; octhilinone) is a common IT biocide that is present in leather products, glue, paints, and cleaning products. Although humans are exposed to OIT through personal and industrial use, the potentially deleterious effects of OIT on human health are still unknown. To investigate the effects of OIT on the vascular system, which is continuously exposed to xenobiotics through systemic circulation, we treated brain endothelial cells with OIT. OIT treatment significantly activated caspase-3-mediated apoptosis and reduced the bioenergetic function of mitochondria in a bEnd.3 cell-based in vitro blood–brain barrier (BBB) model. Interestingly, OIT significantly altered the thiol redox status, as evidenced by reduced glutathione levels and protein S-nitrosylation. The endothelial barrier function of bEnd.3 cells was significantly impaired by OIT treatment. OIT affected mitochondrial dynamics through mitophagy and altered mitochondrial morphology in bEnd.3 cells. N-acetyl cysteine significantly reversed the effects of OIT on the metabolic capacity and endothelial function of bEnd.3 cells. Taken together, we demonstrated that the alteration of the thiol redox status and mitochondrial damage contributed to OIT-induced BBB dysfunction, and we hope that our findings will improve our understanding of the potential hazardous health effects of IT biocides.

Pediatric allergic contact dermatitis. Part I: Clinical features and common contact allergens in children

Allergic contact dermatitis (ACD), a delayed hypersensitivity skin reaction to environmental allergens, has a prevalence that is similar in children and adults. However, diagnostic testing for ACD in pediatric populations accounts for less than one tenth of all patch tests. The relative infrequency of pediatric patch testing may be attributed to the difficulty in testing in this population, which includes a smaller surface area for patch test placement and maintaining cooperation during patch testing, especially in younger children. Diagnosis can be difficult in children because the appearance of ACD can mimic other common pediatric skin conditions, particularly atopic dermatitis and irritant contact dermatitis. Comprehensive history taking, guided by patient presentation, age group, and location of dermatitis, helps build clinical suspicion. Such clinical suspicion is one of the major reasons behind patch testing, with additional indications being recalcitrant dermatitis and dermatitis with atypical distribution. US pediatric data have shown the top allergens to be metals, fragrances, topical antibiotics, preservatives, and emollients. These trends are important to recognize to guide management and accurate diagnosis, because ACD tends to persist if the allergen is not identified and can affect patients' quality of life.

Persistence of Isothiazolinones in Clothes After Machine Washing

BACKGROUND

Sensitization to methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) is a worldwide problem. Washing machine detergents are suspected to cause cutaneous symptoms in highly sensitized patients. Little is known about the persistence of isothiazolinones in clothes that have been washed.

OBJECTIVE

The aim of the study was to analyze the possible persistence of MI, MCI, benzisothiazolinone, and octylisothiazolinone in common fabrics after machine washing.

METHODS

Different clothes (cotton, polyester, linen, and wool) were collected, and 4 types of wash were done (control, standard, standard + conditioner, and standard + double rinse). The samples were analyzed using ultrahigh-performance liquid chromatography.

RESULTS

The results showed that the concentrations of isothiazolinones were very low, independent of the type of material or wash. The highest levels were found in the control wash (hand wash), reaching a maximum of 0.4 ppm in the linen.

CONCLUSIONS

Our findings suggest that it is not necessary to recommend that patients sensitized to MI avoid isothiazolinones in machine detergents or fabric conditioners or to double rinse. However, after using the detergent for hand washing (the control in our study), there may remain sufficient concentrations of isothiazolinones in clothes to produce symptoms in highly sensitized patients.

A review of contact dermatitis

OBJECTIVE

To familiarize the reader with the mechanisms and causes of contact dermatitis.

DATA SOURCES

Recent research articles, relevant review articles, and case series/reports in English from PubMed database, mostly from 2010 onwards.

STUDY SELECTIONS

Most data were in the form of retrospective studies. Efforts were made to include clinical trials; however, for newer allergens and data on biologics, case series and case reports were included. Older studies regarding the mechanism were included if they were of particular importance.

RESULTS

An understanding of this review should enable the reader to approach the patient with unknown dermatitis with a better understanding of the cause and management.

CONCLUSION

Clinical suspicion for relevant allergens combined with the interpretation of patch tests are important in the diagnosis and treatment of patients with contact dermatitis.