Reaction mass of 3,7-dimethyl-1-octyl acetate and citronellyl acetate

Endpoint summary

Description of key information

Skin sensitisation: The substance is a sensitiser, based on read-across from Geranyl Acetate tested in an OECD TG 429

Respiratory sensitisation: not respiratory sensitising, in absence of human data and absence of respiratory sensitisation alerts.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Skin sensitisation of Citronellyl Acetate multi is based on read-across from Geranyl Acetate EXTRA (trans-pure). The executive summary of the source information is presented below followed by the read-across rationale.

Skin sensitisation of Geranyl Acetate EXTRA:

A local lymph node assay was performed according to OECD TG 429 with Geranyl Acetate EXTRA. Mean disintegrations per minute (dpm)/animal (2 lymph nodes) were 380.9, 1885.1, 2791.1 and 2879.3 for control group and groups exposed to 25, 50 and 100% test substance, respectively. This correlates to SI values of 4.95, 7.33 and 7.56 for the groups dosed at 25, 50 and 100%. These data indicate that the substance has skin sensitizing properties. Based on the calculation method described in NIH Publication Number 11-7709, an EC3 of 13.74 can be derived on which bases it classified as Skin sensitizing Category 1B.

The skin sensitizing properties of Citronellyl Acetate Multi using read across from Geranyl Acetate EXTRA (CAS# 105-87-3)

Introduction and hypothesis for the analogue approach

Citronellyl Acetate Multiis a multi-constituent. The main constituent of Citronellyl Acetate Multi isCitronellyl Acetate mono. It has an unsaturated hydrocarbon backbone to which an acetic ester is attached. The minor constituent is Dihydro-Citronellyl Acetate is the same structure except it has a saturated hydrocarbon backbone.

For this substance no skin sensitisation data are available. In accordance with Article 13 of REACH, lacking information can be generated by means other than experimental testing, i.e. applying alternative methods such as QSARs, grouping and read-across. For assessing the skin sensitising properties of Citronellyl Acetate Multi the analogue approach is selected because for one analogue, which is also an impurity, Geranyl Acetate, information on skin sensitizing properties is available which can be used for read across.

Hypothesis: Citronellyl Acetate Multi has the same skin sensitisation potential as Geranyl Acetate EXTRA.

Available information: For Geranyl Acetate EXTRA and LLNA was performed according to OECD TG 429) with 25, 50, or 100% test substance in acetone/olive oil (4:1). SI values were 4.95, 7.33 and 7.56, respectively. Based on the calculation method described in NIH Publication Number 11-7709, an EC3 of 13.74 can be derived. Based on these data the substance is classified as Skin sensitizing Category 1B (calculation included below).

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemicals are shown in the data matrix, including physico-chemical properties and toxicological information, thought relevant for acute dermal toxicity, of all substances.

Purity / Impurities

The purity and impurities of the target chemical do not indicate acute oral toxicity potential other than indicated by the parent substance. The impurities are all below < 10%.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: For Citronellyl Acetate Multi its impurity Geranyl Acetate EXTRA is considered the key representative analogue for the key constituents because reliable information on skin sensitisation is available, which can be used conservatively.

Structural similarities and differences: Citronellyl Acetate Multi’s constituents and Geranyl Acetate EXTRA have a similar backbone and functional group, i.e. an alkane/alkene chain with an acetate ester on C1. The key constituent has one double bond, the minor constituent has no double bond, while Geranyl Acetate has two double bonds in its alkyl backbone.

Skin absorption:Citronellyl Acetate Multi’s constituent has the same skin absorption as Geranyl Acetate based on chemical structure, MW, and physico-chemical properties.

Skin sensitisation reactivity: Citronellyl Acetate Multi’s terpene type constituents are expected to have the same or less reactivity compared to Geranyl Acetate. The unsaturated bonds attached to methyl groups have some reactivity and may generate hydroperoxide which evoke a skin sensitisation reaction. Especially in the LLNA is sensitive for reacting on hydroperoxides. The skin sensitisation reactivity of Geranyl Acetate EXTRA can be related to this hydroperoxide forming. Geranyl Acetate also has a double bond conjugated with the ester which presents additional reactivity and therefore the skin sensitisation of this analogue is considered conservative when compared to Citronelly Acetate Multi constituents, which do not have this conjugated ester bond.

In the OECD Toolbox this terpene – hydroperoxide formation is not recognised as an alert for Geranyl Acetate an alert is fired based on the conjugated ester bond.

Uncertainty of the prediction: There are indications that the key constituent of Citronellyl Acetate Multi, which is the mono, is not a skin sensitiser based on a recent carried out Buehler test with this substance (ECHA dissemination site). In view of the presence of 1-10% Geranyl Acetate among other conjugated ester impurities, also Citronellyl Acetate Multi would need to be classified for skin sensitisation.

Data matrix

The relevant information on physico-chemical properties and toxicological characteristics are presented in the Data Matrix.

Conclusions on skin sensitisation for hazard

For Citronellyl Acetate Multi no skin sensitisation information is available. However, for one of its impurities (1-10%) such information is available which can be used for read across and which can be adequately and reliably documented. For Geranyl Acetate EXTRA an EC3 of 13.7 can be calculated and is therefore a skin sensitiser 1B. This result can be applied to Citronellyl Acetate Multi.

Final conclusion: Citronellyl Acetate Multi is considered to have an EC3 of 13.7 and therefore it is a Skin sensitiser Cat. 1B.

References:

ICCVAM Test Method Evaluation Report: Usefulness and Limitations of the Murine Local Lymph Node Assay for Potency Categorization of Chemicals Causing Allergic Contact Dermatitis in Humans, NIH Publication Number 11-7709 (2011)

Data matrixpresenting the information relevant for read across toCitronellyl Acetate Multi from Geranyl Acetate

Substance	Citronellyl Acetate Multi	Citronellyl Acetate mono constituent	Dihydro-Citronellyl Acetate constituent	Geranyl Acetate EXTRA impurity
Read-across	Target	Target	Target	Source
Structure *	See constituents
% in product	See constituents	60-75	10-20	<10
CAS	See constituents	150-84-5	20780-49-8	105-87-3
EC number	908-114-0	205-775-0	244-034-4	203-341-5
REACH	Registered	Registered	Registered	Registered
MW	See constituents	198	200	196
Phys-chem
Appearance	Liquid	Liquid (ECHA site0	Liquid (ECHA site)	Liquid (ECHA site)
Log Kow	4.6 (exp)	4.6 (ECHA site)	4.6 (ECHA site)	4.5
Ws (mg/L)	12.1 (exp)	5.7(ECHA site)	4.7(ECHA site)	18.2
Vp (Pa)	2.6 (exp)	7.0(ECHA site)	12.9 (ECHA site)	6.2
Human health
Skin sensitisation	EC3 is 13.7 Skin sensitizing Cat. 1B (RA)	Negative in Buehler (OECD TG 406, 100% (ECHA site)	Negative (ECHA site)	EC3 is 13.7 Skin sensitizing Cat. 1B (OECD 429)

RA = read-across.

Calculation EC3 according to NIH Publication Number 11-7709 (2011)

 

Data used for the calculation:

 

Concentration	SI value
25%	4.95
50%	7.33
100%	7.26

 

As all SI values are >3, the following calculation is used:

Where

a = dose concentration for next to lowest SI above 3                   here: 50

b = next to lowest SI above 3                                                                  here: 7.33

c = dose concentration for lowest SI above 3                                   here: 25

d = lowest SI above 3                                                                                  here: 4.95

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. 7.3-2, 2014).

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 considered to be not a respiratory sensitiser.

Justification for classification or non-classification

The substance is considered a skin sensitiser and needs to be classified for Skin sensitisation Category 1B and shall be labelled with 'H317: May cause an allergic skin reaction', according to EU CLP (EC No. 1272/2008, and its amendments).

In absence of human data indicating respiratory sensitisation and using the ITS in the ECHA guidance (R.7a, 2014) the substance is not considered to be a respiratory sensitiser in accordance with the criteria outlined in the EU CLP (EC 1272/2008, and its amendments).