Reaction mass of 3-(4-hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde and 4-(4-hydroxy-4-methylpentyl)cyclohex-3-ene-1-carbaldehyde

Endpoint summary

Description of key information

Skin sensitisation: In a well conducted LLNA test substance showed to be skin sensitising at an EC3 of 17 %, a NOEL of 10 % was derived in this study. Also two HRIPT studies are available, showing no sensitisation up to 15 %.

The test substance has no structural alert for respiratory sensitisation.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Test substance has been tested in an LLNA test and two well conducted HRIPT test which will be used for the DNEL derivation. In addition, the present risk assessment will also take into account the DNEL derived by the Research Institute for Fragrance Materials (RIFM) and the maximum concentration in the end product established by the International Fragrance Association.

 

LLNA study: A study, performed according to OECD Guideline 429 (Local Lymph Node Assay in mice) in compliance with GLP, was available for assessment (RCC Ltd., 2001). Five groups of 4 female mice were treated by topical application to the dorsal surface of each ear lobe with 1, 2.5, 5, 10 and 25 % solution of test substance in acetone/olive oil (4:1 v/v) for three consecutive days. A positive control group of four mice was treated with alpha-hexylcinnamaldehyde (25%) and a vehicle control group was treated with the vehicle alone. Five days after the first topical application the mice were injected intravenously into a tail vein with 3H-thymidine, the draining auricular lymph nodes excised, pooled per group and their proliferative capacity measured by the incorporation of 3H-thymidine in a β-scintillation counter. The stimulation indices were 0.6, 0.7, 0.6, 1.3, and 4.9 for 1, 2.5, 5, 10 and 25 % solution of test substance, respectively. For the positive control a stimulation index of 7.2 was obtained. Based on the results of the study, the test substance is considered to give a positive result in the LLNA test. An EC3 value of 17.1% and a NOEL of 10% were calculated based on the study results. This value can be converted to an EC3 figure expressed as μg/cm2 using EC3 (μg/cm2 ) = 17.1 % x 250 x 1 g/mL = 4275 μg/cm2.

 

Skin sensitising properties of test substance were extensively investigated in a number of studies with human volunteers. Two most recent human repeated insult patch tests, using the largest numbers of volunteers, will be summarised here.

 

First HRIPT test: In the assay conducted by Harrison Research Laboratories, Inc. (2003) 235 volunteers (63 males, 172 females, aged from 18 to 70 years) were challenged occlusively with 0.3 mL of the test material for 24 hours on Monday, Wednesday and Friday, for 3 consecutive weeks, for a total of 9 applications. After a ca. 2 weeks rest period they were challenged at a virgin site for 24 hours and reactions were scored immediately after the patch removal, 24, 48 and 72 hours later. The test substance was applied as a 5.3% solution in 75% DEP:25% ethanol. Vehicle control and normal saline were used as negative controls. 201 subjects completed the study. The applied amount of the test substance corresponded to a total dose of 4000 μg/cm2 (rounded off figure). During the induction phase, one of the subjects exhibited a 1-level plus oedema reaction; the test site was changed. Other subjects exhibited low-level, transient (±/1) reactions. At the challenge, low-level, transient (±) reactions were exhibited. Low-level, transient reactions (±/1) were also observed in several subjects upon exposure to control substances. No effect was observed at a concentration of 5.3 %. Though the application site area was not reported, it is assumed that this area is based on a standard site, which is 3.63 cm2. The NOEL in this study is considered to be 5.3 %, corresponding with 4000 ug/cm2.

 

Second HRIPT test: In an assay conducted by Consumer Product Testing Co. (1999) a dose of 0.2 mL of a 15 % solution of the substance in 75 % alcohol SD39C/25% DEP was applied to a 3.63 cm2 area patch (equivalent to 8264 μg/cm2). The patches were applied under occlusion to the upper back of 119 volunteers (18 males, 91 females, 18-77 years) for 24 hours with a 24 - 48 hours rest period on Monday, Wednesday and Friday for 3 consecutive weeks, for a total of 9 applications. 109 volunteers completed the study. Approximately 2 weeks after the last application the subjects were challenged with 24 hr application of the same patch at a virgin site. Subjects that reacted to a challenge were rechallenged approximately 5 - 6 weeks after the primary challenge. In case of a positive reaction, a second rechallenge was performed after a 5 weeks rest period. Scattered, barely perceptible (+) to moderate (2-level) patch test responses were observed in 4/119 test panellists during the induction phase. Positive reactions were observed in two subjects in the challenge phase. These subjects were rechallenged after a 5 - 6 weeks rest period. One of these subjects exhibited no reactions to the treatment and was considered to be not sensitised. The other subject exhibited a positive reaction and was rechallenged again after 5 weeks of rest. The reaction was again positive. This subject had psoriasis and had participated in several patch tests a year before the study. He also showed a mild positive response (1-level) to a deodorant product. It was concluded that the subject reactivity appeared to have been elicited by the material itself and was not indicative of pre-sensitisation. Thus no sensitisation reactions were considered to be observed in the study. No effect was observed at a concentration of 15 %. This NOEL value of 15 % can be converted to a value expressed as μg/cm2 based on an application volume of 0.2 mL, an application area of 3/4" x 3/4" (3.63 cm2) and the relative density of the substance of ca. 1 (0.9908) g/mL will become ).15 x 200 mg/ 3.63 cm2 = 8264 μg/cm2.

 

According to the REACH Guidance on information requirements and chemical safety assessment, the EU Expert group on skin sensitization nominated by the Technical Committee on Classification and Labelling concluded that it would not be appropriate to derive a DNEL for skin sensitization based on elicitation (see Chapter R.8 of the REACH Guidance on information requirements and chemical safety assessment, Appendix 8-10, page 128). Therefore data on induction of skin sensitisation are used for DNEL derivation. This also means that information on elicitation from amongst others the study of Schnuch et al. (2009) or Scientific Committee on Consumer Safety (SCCS) (http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_074.pdf) will not be used to establish the NOAEL.

 

The test substance was only sensitising in the LLNA test and therefore the NOEL established in this test will be used as a starting point to derive a DNEL.

 

RIFM also has established a DNEL for skin sensitisation, calling it a NESIL using a Weight of Evidence approach:

All data on the induction of sensitisation presented in this submission show that the weight of evidence No Expected Sensitisation Induction Level (NESIL) for induction is 4000 μg/cm2. This is supported by the robustness of the scientific data and highlighted by:

1) the murine local lymph node assay showed an EC3 value of 17.1 % (4275 μg/cm2);

2) a human repeated insult patch test with 201 subjects that confirms that a dose of 4000 μg/cm2 does not induce sensitisation;

3) HMPCC, which collectively show that doses between 938 and 1592 μg/cm2 did not induce sensitisation in 749 subjects; and 4) The test substance alone did not induce sensitisation in predictive human sensitisation studies.

 

This derived NESIL has led to the following maximum concentration in the end products (www.ifraorg.org, 49th Amendment). IFRA has identified several categories for consumer exposure (https://www.rifm.org/downloads/RIFM-IFRA%20Guidance-for-the-use-of-IFRA-Standards.pdf). Only the categories relevant for REACH are presented below:

Category 5A: 0.2% (Insect repellent intended to be applied to the skin)

Category 8: 0.067% Products with significant anogenital exposure (intimate wipes, baby wipes)

Category 9: 0.2% Rinse off products with body and hand exposure (soap, shampoo)

Category 10: 0.2% Household care products with mostly hand contact (Detergents: all types, air fresheners (spray), insecticides (spray))

Category 11: 0.067% Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate (toiler paper, napkins)

Category 12: 91% (candles, shoe polishes, toilet blocks, fuels, paints)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The substance is not a respiratory sensitiser in absence of human data indicating such effects. In addition, the respiratory sensitisation is assessed using the integrated evaluation strategy for respiratory sensitisation data in the ECHA guidance (R7A, Fig. 7.3-4, 2017).

1) The substance is a skin sensitiser;

2) The substance does not belong to the di-isocyanates;

3) The substance has no structural alerts or is structurally related to chemicals causing respiratory sensitisation as presented in Table R.7.3-1 in the ECHA guidance of 2008 or those provided in the following document: http://ec.europa.eu/health/scientific_committees/docs/annex6_respiratory.pdf.

Therefore, the substance is not considered to be a respiratory sensitiser.

Justification for classification or non-classification

Based on the positive results in the LLNA study, the substance has to be classified for skin sensitisation,Category 1A, H317: 'May cause an allergic skin reaction' according to EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

Based on the absence of structural alerts indicating a respiratory sensitisation potential, the substance does not need to be classified as respiratory sensitiser.