captax and dibenzothiazyl-disulfide

Benzothiazole (BTHs) are environmental contaminants of emerging concern for which little toxicological information is available. Therefore the toxic potential of twelve BTHs was evaluated with two rainbow trout epithelial cell lines, RTgill-W1 and RTL-W1. The BTHs were benzothiazole (BTH), 3,3'-diethylthia dicarbocyanine iodide (DTDC), C.I. sulphur orange 1 (SO), 2-mercaptobenzothiazole (2MBTH), zinc 2-mercaptobenzothiazole (ZnMBTH), sodium 2-mercaptobenzothiazole (NaMBTH), 2-hydroxy-benzothiazole (OHBTH), 2- aminobenzothiazole (2ABTH), C.I. vat yellow 2 (VY), N,N-dicyclohexyl-2-benzothiazolsulfene amide (NNA), 2,2'-dithiobis (benzothiazole) (DBTH) and 2-(p-aminophenyl)-6-methylbenzothiazole-7-sulfonic acid (MBTHS). All BTHs, except for NNA, DBTH, and MBTHS, caused both cytotoxicity and a transitory elevation in reactive oxygen species (ROS) levels. Yet, neither N-acetyl cysteine (NAC) nor IM-54 inhibited cytotoxicity, suggesting that ROS imbalance did not contribute to cell death. Cell death was not blocked by Necrostatin-1 nor accompanied by DNA laddering, suggesting that neither necroptosis nor apoptosis took place. The comet assay revealed DNA strand breaks after exposures to 2ABTH and OHBTH for 1 day and to BTH for 12 days. In RTL-W1, cytochrome P4501A was induced noticeably by 2ABTH, OHBTH, and MBTHS and weakly by NaMBTH, ZnMBTH, SO, VY, and NNA, suggesting that these BTHs have the potential to alter xenobiotic metabolism and activate the aryl hydrocarbon receptor. In summary, several toxic actions were initiated in vitro by some but not all BTHs, warranting further study of these BTHs in vivo.

Topics: Animals; Benzothiazoles; Cell Death; Cell Line; Comet Assay; DNA Damage; Hydrazones; Imidazoles; Indoles; Oncorhynchus mykiss; Reactive Oxygen Species; Toxicity Tests; Water Pollutants, Chemical

The rubber accelerator, 2-mercaptobenzothiazole (MBT), is known to cause allergic contact dermatitis (ACD), but the mechanism is unknown. The role of the thiol group in MBT's allergenicity was investigated in the present study. Guinea pigs were sensitized to MBT using a modified guinea pig maximization test (GPMT) and reactivity was assessed toward 2-mercaptobenzothiazole disulfide (MBTS), 2-hydroxybenzothiazole (HBT; thiol-substituted), 2-(methylthio)benzothiazole (MTBT; thiol-blocked), and benzothiazole (BT; thiol-lacking). MBT and MBTS, but not BT, HBT, or MTBT, elicited ACD in MBT-sensitized animals, demonstrating that the thiol group is critical to MBT's allergenicity. In addition, both MBT and MBTS were shown to inhibit both glutathione reductase and thioredoxin reductase, and thus contribute to the stability of MBT-protein mixed disulfides. It is concluded that the probable haptenation mechanism of MBT is through initial oxidation to MBTS with subsequent reduction to form mixed disulfides with proteins.

Topics: Analysis of Variance; Animals; Benzothiazoles; Cross Reactions; Dermatitis, Allergic Contact; Disulfides; Dose-Response Relationship, Drug; Female; Glutathione Reductase; Guinea Pigs; Haptens; Immunization; Oxidation-Reduction; Rubber; Skin; Sulfhydryl Compounds; Thioredoxin-Disulfide Reductase

At evaluation of contact dermatitis caused by solid material, patch testing is usually performed with the material as such and with extracts of it. In this study, optimization of the extraction technique monitored by quantitative HPLC analysis of the extracted haptens is described for mercaptobenzothiazole derivatives. Several solvents with different properties are included. Acetone has traditionally been a solvent widely used for the extraction of organic haptens from solid products. However, acetone and other ketones are not inert solvents. The rubber accelerators 2-(4-morpholinyl mercapto) benzothiazole (MMBT) and N-cyclohexyl-2-benzothiazyl sulfenamide (CBS) react with acetone, yielding 2 new compounds, which were isolated and characterised by NMR and MS. For the extraction of solid rubber products, methyl tert-butyl ether (MTBE) was found to be a more suitable solvent which is unreactive to most common haptens.

Topics: Antifungal Agents; Benzothiazoles; Chromatography, High Pressure Liquid; In Vitro Techniques; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Weight; Patch Tests; Rubber; Sensitivity and Specificity; Solvents; Thiazoles

5 cases of allergic contact dermatitis from rubber footwear were investigated by a combination of patch testing in patients and chemical analysis of causative rubber products. Our studies revealed 2-mercaptobenzothiazole (MBT) and benzothiazyl disulfide (MBTS) (typical allergenic accelerators) as causative chemicals in 3 cases from children's rubber shoes, ladies' rubber boots and ladies' canvas shoes. These 3 patients reacted to mercaptobenzothiazole-type accelerators including MBT and MBTS. MBT and MBTS were determined in each item of causative footwear by chemical analysis, including extraction by shaking with acetone-chloroform (1:1) mixture at room temperature and determination using reversed-phase high-performance liquid chromatography (RP-HPLC). Subsequently, we identified styrenated phenol (SP), a newly found allergenic antioxidant, as a causative chemical in a case from ladies' canvas shoes. The patient reacted to SP but not to MBT and MBTS, though SP, MBT and MBTS were determined in the causative shoes by gas chromatography (GC), GC-mass spectrometry (GC-MS) and HPLC. We also identified p-tert-butylphenol-formaldehyde resin (PTBP-F-R), (a known allergenic adhesive ingredient) as a causative chemical in a case from ladies' sneakers. The patient reacted to PTBP-F-R but not to p-tert-butylphenol (PTBP), MBT and MBTS. These 4 compounds were determined in the causative sneakers by GC, GC-MS and HPLC. Thus, our studies revealed that not only known allergens, such as MBT, MBTS and PTBP-F-R, but also a newly found one, such as SP, were important causes of allergic contact dermatitis from rubber footwear.

Topics: Adhesives; Adolescent; Antioxidants; Benzothiazoles; Dermatitis, Allergic Contact; Female; Foot Dermatoses; Formaldehyde; Humans; Male; Middle Aged; Patch Tests; Phenol; Phenols; Resins, Synthetic; Rubber; Shoes; Thiazoles

We studied 3 contact sensitizers present in rubber products, ethylbutyl thiourea (EBT), 2-mercaptobenzothiazole (MBT) and 2,2-dithio-bis-benzothiazole (MBTS), to relate the amount of sensitizer eliciting allergic contact dermatitis to the quantity leaching from a product into various biological fluids: normal saline, human plasma and 3 synthetic sweat solutions of pH 5.5 to 7.5. To determine the amount of sensitizer remaining after leaching, Soxhlet extraction with acetonitrile was subsequently performed. High-performance liquid chromatography was used for chemical analysis. 12 MBT-sensitive patients were patch tested with serial dilutions of MBT and MBTS in petrolatum. A Latin Square design was used in statistical analysis of variance of the patch test results. Large amounts of thioureas leached from 2 rubber articles eliciting thiourea dermatitis, the literature suggesting that these would have been well above the elicitation threshold. Leaching of MBTS was relatively greater than MBT into most media, whereas MBT was a more potent elicitor than MBTS at equivalent concentrations. The lowest eliciting concentration of MBT in 1 subject was 0.01%. Such information should prove helpful to manufacturers in designed products that do not release allergens sufficiently to cause reactions in consumers.

Topics: Adolescent; Adult; Aged; Benzothiazoles; Dermatitis, Allergic Contact; Diving; Dose-Response Relationship, Drug; Female; Gloves, Protective; Humans; Male; Maximum Allowable Concentration; Middle Aged; Plasma; Protective Devices; Rubber; Shoes; Skin; Sodium Chloride; Sweat; Thiazoles; Thiourea

An analytical quantitative high-pressure liquid chromatography (HPLC) method was developed for simultaneous determination of all mercaptobenzothiazole derivatives in the mercapto mix patch testing standard. The stability of the mercaptobenzothiazoles constituting the mercapto mix was studied both in petrolatum and in buffer solution at pH 6.5, with and without glutathione. In petrolatum vehicle, dibenzothiazyl disulfide was the dominant compound found in stored mercapto mix. In buffer solution at pH 6.5, 2-mercaptobenzothiazole and the sulfenamide derivatives morpholinyl mercaptobenzothiazole and N-cyclohexyl-2-benzothiazyl sulfenamide were converted into dibenzothiazyl disulfide. In the presence of glutathione, both the sulfenamide derivatives and the dibenzothiazyl disulfide were rapidly converted into 2-mercaptobenzothiazole. The findings explain the "cross-sensitivities" reported for the mercaptobenzothiazole group as a result of chemical reactions resulting in one main hapten. The use of a single substance for patch testing for mercaptobenzothiazole hypersensitivity is proposed.

Topics: Antimetabolites; Benzothiazoles; Chromatography, High Pressure Liquid; Drug Stability; Morpholines; Patch Tests; Pharmaceutical Vehicles; Sulfhydryl Compounds; Thiazoles

To determine the metabolic disposition of [14C]-2-mercaptobenzothiazole (MBT) and [14C]-2-mercaptobenzothiazole disulfide (MBTS), male and female rats were dosed topically. Topical doses were 36.1 micrograms/animal for [14C]MBT and 33.6 micrograms/animal for [14C]MBTS. Although more MBT passed through the skin than MBTS and although, relative to rats, guinea pigs absorbed a greater percentage of the dose (33.4% compared to 16.1-17.5% of the MBT and 12.2% compared to 5.94-7.87% for MBTS), the disposition of radioactivity derived from the two compounds was similar. Washing of the skin removed more of the radioactivity from guinea pigs than from rats. For both sexes of rats dosed intravenously with [14C]MBT (0.602 mg/kg) or [14C]MBTS (0.571 mg/kg), disposition of the compounds was similar. In 72 h, 90.9-101% of the dose appeared in the urine and 3.79-15.1% in the feces. At this time, a small portion of the administered radioactivity (1.52-1.96% of the dose) remained associated with erythrocytes. Oral dosing of rats for 14 d with unlabeled MBT (0.510 mg/kg.d) prior to a single dose of [14C]MBT (0.503 mg/kg) or with unlabeled MBTS (0.521 mg/kg.d) prior to a single dose of [14C]MBTS (0.730 mg/kg). For both sexes, disposition of the compounds was similar. At 96 h after dosing, a small portion of the administered radioactivity (1.20-1.69% of the dose) remained associated with erythrocytes, most of which was bound to the membranes. For both compounds and sexes, 60.8-101% of the radioactivity administered appeared in the urine and 3.46-9.99% in the feces in 96 h. At the time, only trace amounts of radioactivity remained in tissues other than blood. Of these tissues, thyroid contained the highest concentration. In the urine, there was a detectable MBT or MBTS, but there were two metabolites, one of which was identified as a thioglucuronide derivative of MBT. The other was possibly a sulfonic acid derivative of MBT. In conclusion, there were similarities in absorption, distribution, and metabolism of [14C]MBT and [14C]MBTS in rats and in guinea pigs, indicating that [14C]MBTS was readily converted to [14C]MBT.

Topics: Absorption; Administration, Oral; Administration, Topical; Animals; Benzothiazoles; Carbon Radioisotopes; Environmental Exposure; Female; Guinea Pigs; Injections, Intravenous; Male; Rats; Rats, Inbred F344; Thiazoles; Tissue Distribution

Although contact dermatitis from shoes is common, the causative allergen is frequently not known. Reliance cannot be placed on standard screening trays because such testing can be negative when testing to shoe materials is positive. Furthermore, the relevance of positive screening tests is almost never proven by extracting that allergen from the patient's shoes. We present a case of insole dermatitis to tennis shoes in which we directly isolated the causative allergens by step-by-step patch-test monitoring of active fractions. Chromatographic separation of the active fractions led to the isolation of 2 allergens, mercaptobenzothiazole (Captax) (MBT) and its dimer, dibenzothiazyl disulfide (Altax) (DBTD). Patch tests to DBTD were noticeably more potent than those to MBT. In what might be considered an obvious case of contact sensitivity to MBT, the actual allergen is DBTD. Using this method, unknown shoe allergens can be isolated, identified, and added to the shoe test tray of potential allergens.

Topics: Benzothiazoles; Chemical Fractionation; Child; Chromatography; Dermatitis, Contact; Humans; Male; Patch Tests; Rubber; Shoes; Thiazoles

Embryonal lethality (EL) in rats was examined after administration of the rubber accelerators (RA), captax, altax, santocure, santocure-mor and thiurams D and E. Administration of RA to non-pregnant females caused the increase in the estrous cycle and diminished the rate of conception. The total EL increased after administering all the RA, while the postimplantation one only after altax administration. The index of altax mutagenicity is comparable with those of cancerogens or alkylating agents. Administration of RA to pregnant females leads to the increase in the total EL, with altax being the single agent that produces the rise in all the types of lethality. Inhibition of reproduction function of white rats is a consequence of mutagenic, embryotic and gonadotropic actions of RA, with altax being found the most active agent.

Topics: Animals; Benzothiazoles; Estrus; Female; Fetal Death; Mutagens; Pregnancy; Rats; Thiazoles; Thiocarbamates; Thiram; Time Factors