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Description of key information

Short description of key information on bioaccumulation potential result: 
Based on physical-chemical characteristics, particularly water solubility, octanol-water partition coefficient and vapour pressure, very limited absorption by the dermal route is expected, which is further supported by dermal absorption and dermal acute toxicity studies results. Due to its polar character the substance is not expected to become systemically available to a high extent after inhalation of dust. For the oral route uptake is more likely compared to dermal application. Bioaccumulation is not likely to occur based on the physical-chemical properties. Excretion is expected to occur rapidly via the urine and the faeces. No sex differences with regard to toxicity are expected based on data from repeated dose toxicity tests.
Short description of key information on absorption rate:
Two studies were available investigating the dermal absorption of pharmacokinetics of 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonatesodium in different cosmetic formulations. Both studies indicated a very low dermal penetration rate, which is below or only slightly above the detection limit of the analytical methods. No dermal accumulation of the test substance occurred.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

Toxicological profile of Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate

 

Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was tested for acute toxicity by oral and dermal application to the rat according to OECD guideline 401 and 402. The LD50 (oral) was greater than 5000 mg/kg bw and the LD50 (dermal) was greater than 2000 mg/kg bw.

Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was tested in a primary skin irritation study according to OECD guideline 404 and EU method B.4. The test item was not irritating to rabbit’s skin. Furthermore, a phototoxicity test was carried out according to the CTFA Safety Testing Guidelines with 15 female Albino Hartley guinea pigs. It can be concluded that the test article sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate does not exhibit a photoirritating potential in the guinea pig.Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was tested in two primary eye irritation studies according to OECD giudeline 405 and EU method B.5. In both studies, the test item was severly damaging to rabbit’s eyes.

Two maximisation tests in guinea pigs were performed to determine the contact allergenic potency of the test article. In the first test none of the control and test group animals were observed with skin reactions after challenge treatment with a non-irritant test article concentration of 10 % in bi-distilled water. In the other test 10% and 5% of the animals of the test group (25 % test article in physiological saline) showed skin reactions 24 and 48 hours after removing the dressings, respectively. The test substance is, therefore, considered not to be a sensitizer when used under the given test conditions. Additionally, a Local Lymph Node Assay (LLNA) was performed according to the OECD Guideline 429. Also in this study the test substance is not considered to be a potential skin sensitizer.One photosensitisation test (photoallergenicity) was performed according to the CTFA Safety Testing Guidelines. In this study the test substance did not exhibit a photoallergenic or phototoxic potential in the guinea pig under the given study conditions.

Sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzene did not reveal any indication for mutagenicity in the Ames test or in a gene mutation test in cultured mammalian cells (HGPRT assay) with and without metabolic activation. In an in vitro chromosomal aberration test in cultured V79 cells, positive effects were noted in the presence and absence of metabolic activation. However, in an in vivo mouse micronucleus assay the test substance does not induce cytogenetic damage in bone marrow cells of NMRI mice. In addition in an UDS assay in vivo the test article did not induce DNA-damage leading to repair synthesis in the hepatocytes of treated rats. In conclusion, the test substance is not considered to be mutagenic in vivo.

A 28-day oral (gavage) toxicity study was performed with sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate in male and female Wistar rats according to OECD 407 Guideline and EC Method B.7. Dose levels administered in this study were selected based on data obtained during a 5-day dose-range-finding toxicity study. A control, four dose groups and a high dose and control recovery group (n= 5 animals per group and sex) were involved in the study. The test item was administered at concentrations of 0, 20, 50, 200 and 800 mg/kg bw prepared in carboxymethyl cellulose (4 %), at a 10 mL/kg bw treatment volume. There were no changes in the animal clinical condition, body weight or food consumption. A statistically significant increase in absolute and relative liver weights were observed in male and female rats at termination of the treatment period at 200 mg/kg bw/day. However, no histopathological correlation or changes in enzymes activities indicating aphysiological damage of the liver were found. Thus, these findings were considered to be adaptive and not adverse. No other effects were observed at 200 mg/kg bw/day. Additionally, the absolute weights of the adrenals were statistically significant decreased in males at termination of the treatment and treatment free (recovery) period at 800 mg/kg bw/day. There was no evidence of abnormal histopathological findings and no effects at clinical laboratory investigations (haematology, clinical biochemistry, urinanalysis) or any other parameter at any test dose investigated. In conclusion, based upon the results obtained in this study, the "no adverse effect level" (NOAEL) of sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate is 200 mg/kg bw for male and females rats when administered orally by gavage for a period of 28 days.

     Toxicokinetic analysis of Sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate

 

Sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonateis a solid powder at room temperature with a molecular weight of 370.385g/mol. The substance is soluble in water (9.8 g/L). The logPow ofthe substancewas measured to be -0.24, indicating a rather polar compound. A BCF of 15.01 L/kg wet-wt (Log BCF = 1.176) was calculated by EPIWIN (v.4.00).The substancehas a very low vapour pressure of 6.06E-018 Pa at 25 °C (calculated value).

The substance is hydrolytically stable, as shown in a hydrolysis screening test according to OECD 111 at 50°C.

 

Absorption

Oral

Oral absorption is favoured for molecular weights below 500 g/mol. The substance contains ionisable groups, which do not favour absorption via the GI tract. Nevertheless, based on the water solubility and the very low logPow valuethe substance is favourable for absorption by passive diffusion. Absorption of very hydrophilic substances by passive diffusion may be limited by the rate at which the substance partitions out of the gastrointestinal fluid. As the substances molecular weight is higher than 200,the substanceis very unlikely to pass through aqueous pores or be carried through the epithelial barrier by the bulk passage of water. Sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate showed only mild adverse effects at concentration of 800 mg/kg bw/day in a 28-day repeated dose study when administered orally. Administered in an acute studythe substance caused mortalities only at extremely high doses of 5000 mg/kg bw. Therefore, it can be assumed that limited direct absorption across the gastrointestinal tract epithelium will occur when applied orally.

Inhalation

Based on the low vapour pressure of 6.06E-018 Pa inhalation exposure towards vapour is not likely. However, based on results of particle size determinations inhalable/respirable dust cannot be excluded (MMAD, D50 = 6.7 µm). If the substance reaches the lung, is not expected to easily become systemic available due to its high hydrophilic and polar nature.

Dermal

Similarly, based on physical – chemical properties,the substance is not likely to penetrate skin to a large extent as the low logPow value of <0 suggest a substance with poor lipophilicity which limits penetration into the stratum corneum and hence dermal absorption. Water solubilities between 100-10,000 mg/l together with the log P value below 0 further indicate that the substance may be too hydrophilic to cross the lipid rich environment of the stratum corneum. Dermal uptake for these substances will be low.

In addition, two studies were available investigating the dermal absorption of pharmacokinetics ofSodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonatein different cosmetic formulations. Both studies support the predicted skin penetration as a very low dermal penetration rate was observed. Most fractions analysed were below the detection limits of the analytical methods.

A first in-vitro percutaneous penetration study of sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxy- benzenesulfonate was performed under "in-use" conditions over a 24 hour period according to COLIPA guidelines for percutaneous penetration of cosmetic ingredients (COLIPA, 1995). The test substance was applied in a representative oxidative hairdye formulation consisting of a hairdye solution (containing 0.67 % test substance) mixed 1:1 with developer. Thus the applied formulation contained 0.33 % test substance. Permeation of the test substance through the skin was not detected in ten cells, suggesting that it was below the limit of detection, which equated to permeation of less than about 5 ng/cm2or about 0.08 % of the applied dose in 24 hours (amount in receptor fluid). The average dose of formulation applied to the skin was 2.1 ± 0.07 mg/cm2which represented 7.1 ± 0.22 µg/cm2of the test substance. The average total amount of the test substance recovered from the wash, wipe, tape strips, remaining skin and receptor phase was 7.2 ± 0.2 µg/cm2which represented an overall recovery of 101 ± 1.2 %. Of the recovered material, the majority (99.7 ± 1.1 % of the applied dose) was found in the 30 minute wash. A small amount of the test substance was recovered in the 24 hour wipe and strips 1-3 (total 0.032 µg/cm2) and this may be considered as surface material. The total amount of the test substance recovered from the deeper layers of the skin amounted to 0.026 µg/cm2(< 0.4 % of the applied dose) So based on a worst case assumption summing up the residues on the skin and the upper skin layers (24 h wipe and stripping), the amount in the deeper skin layers and theoretically amount (based on LOD) in the receptor fluid (0.032 + 0.026 + 0.005 µg/cm2result in a skin penetration of less than 1% (0.9 %) of the applied dose(An-eX analytical services ltd., 1988).

A second percutaneous absorption pharmacokinetics study of sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was performed with three formulations according to COLIPA guidelines for in vitro assessment of dermal absorption and percutanous penetration of cosmetic ingredients (COLIPA, 1999). The data show that very little (< 100 ng) of the test substance penetrated the skin over the 48 hour test period. The lower limit of detection for this compound was approximately 50 ng/mL (neat standard), which is approximately 1.5 ng per receptor solution sample (the average recovery from concentrated receiver solution samples was found to be 100.8%). The surface wash content is very high, indicating that the vast majority of the applied dose remains on the surface of the skin. This study supports the findings noted in the first skin penetration study (DermPharm, 2003).

Furthermore, application ofthe substanceto skin of rats did not cause irritation or corrosion nor systemic effects (mortality) in skin irritation/corrosion studies and an acute dermal toxicity study.

 

Distribution and Metabolism

When reaching the body Sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate will be distributed in body liquids due to its high water solubility and very low Pow. Based on its very low BCF valuethe substanceis very unlikely to bioaccumulate in the human body.

Based on the structure of the molecule and its nature, metabolism in the human body will mainly consist on phase-II metabolising steps, leading to an even better water solubility for excretion. This is in compliance with the results obtained in the genotoxic tests showing no difference in results in samples with and without metabolising system. Metabolic activation leading to more toxic metabolites is thus not very likely. In addition available studies do not indicate any sex difference with regard to the toxicity of the substance.


Excretion

Based on the water solubility and the logPow value, excretion via the urine is likely. As the substance has a molecular weight above 300 g/mol the excretion of a considerable amount via the bile is also possible, especially if phase-II conjugation takes place e.g. with formation of glucoronid derivates.

 

Summary

Based on physical-chemical characteristics, particularly water solubility, octanol-water partition coefficient and vapour pressure, very limited absorption by the dermal route is expected, which is further supported by dermal absorption and dermal acute toxicity studies results. Due to its polar character the substance is not expected to become systemically available to a high extent after inhalation of dust. For the oral route uptake is more likely compared to dermal application. Bioaccumulation is not likely to occur based on the physical-chemical properties. Excretion is expected to occur rapidly via the urine and the faeces. No sex differences with regard to toxicity are expected based on data from repeated dose toxicity tests.

 

        References

 

An-eX analytical services ltd. (1998). IN VITRO HUMAN SKIN PENETRATION AND DISTRIBUTION OF CIBAFAST H (CG4499) UNDER "IN-USE" CONDITIONS. Testing laboratory: An-eX analytical services ltd.,Redwood, Cardiff CFI 3XF,. Report no.: CSC/3b/98. Owner company: Ciba Spezialitatenchemie Grenzach GmbH.Report date: 1998-10-27.

 

ECHA (2008),Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance

 

DermPharm (2003). CHARACTERIZATION OF THE PERCUTANEOUS ABSORPTION OF FAT 75'309, IN VITRO, USING THE HUMAN CADAVER SKIN MODEL. Testing laboratory: DermPharm, A Division of DermTech International,15222-B Avenueof Science,,,. Report no.: DP03-659. Owner company: Ciba Specialty Chemicals, Home Personal Care Segment, Postfach Basel, 4002.Report date: 2003-12-12.

 

Marquardt H., et al., (1999). Toxicology. Academic Press,,, 1999

 

Mutschler E., et al., (2001). Arzneimittelwirkungen. Lehrbuch der Pharmakologie und Toxikologie. Wissenschaftliche Verlagsgesellschaft,, 2001

Discussion on absorption rate:

A first in-vitro percutaneous penetration study of sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxy- benzenesulfonate was performed under "in-use" conditions over a 24 hour period according to COLIPA guidelines for percutaneous penetration of cosmetic ingredients (COLIPA, 1995).

The test substance was applied in a representative oxidative hairdye formulation consisting of a hairdye solution (containing 0.67 % test substance) mixed 1:1 with developer. Thus the applied formulation contained 0.33 % test substance. The formulation was applied to human epidermal skin membranes mounted in Franz type diffusion cells at a target dose of 2 mg/cm2. After a 30 minute exposure period the skin surface was rinsed with warm water. Twelve replicates were conducted.

Of the twelve skin samples treated with the test substance, only two showed permeation of the active after 24 hours. However, data from both of these cells was excluded from further consideration (in one case anomolously high and early levels of permeation suggested that the integrity of the membrane had been compromised, and in the other, an unreasonably high recovery (-140%) implied that the applied dose was incorrectly measured). Permeation of the test substance through the skin was not detected in the remaining ten cells, suggesting that it was below the limit of detection, which equated to permeation of less than about 5 ng/cm2or about 0.08 % of the applied dose in 24 hours. The average dose of formulation applied to the skin was 2.1 ± 0.07 mg/cm2which represented 7.1 ± 0.22 µg/cm2 of the test substance. The average total amount of the test substance recovered from the wash, wipe, tape strips, remaining skin and receptor phase was 7.2 ± 0.2 µg/cm2which represented an overall recovery of 101±1.2 %. Of the recovered material, the majority (99.7 ± 1.1 % of the applied dose) was found in the 30 minute wash. A small amount of the test substance was recovered in the 24 hour wipe and strips 1-3 (total 0.032 µg/cm2) and this may be considered as surface material. The total amount of the test substance recovered from the deeper layers of the skin amounted to 0.026 µg/cm2(< 0.4 % of the applied dose).

A second percutaneous absorption pharmacokinetics study of sodium 3(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate was performed with three formulations according to COLIPA guidelines for in vitro assessment of dermal absorption and percutanous penetration of cosmetic ingredients (COLIPA, 1999). Absorption was measured in human cadaver skin, in vitro, using the finite dose technique and Franz Diffusion Cells. The products were tested on a minimum of six replicate sections, when possible, from three different cadaver skin donors for the percutaneous absorption of the test substance over a 48-hour dose period. At pre-selected times after dosing, the dermal receptor solution was removed in its entirety, replaced with fresh receptor solution, and an aliquot saved for subsequent analysis. The samples were analyzed for the test substance using high performance liquid chromatography (HPLC).

The data show that very little (< 100 ng) of the test substance penetrated the skin over the 48 hour test period. The lower limit of detection for this compound was approximately 50 ng/mL(neat standard), which is approximately 1.5 ng per receptor solution sample (the average recovery from concentrated receiver solution samples was found to be 100.8%).

The data also indicate that whether the test formulation is in contact with the skin for 30 minutes (Formulation "A") or 48 hours (Formulations "B" and "C"), essential the same amount of the test substance penetrates into and through the skin. There was no statistical difference (Student's t-Test) between the formulations in their ability to delivery the test substance into or through the skin (p>0.5). The surface wash content is very high, indicating that the vast majority of the applied dose remains on thesurface of the skin. Further, there is no evidence of dermal accumulation of test compound that may have penetrated the stratum corneum and become bioavailable at a later time point.

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