Registration Dossier

Administrative data

Description of key information

Skin corrosion: Not corrosive based on absence of acid and based groups indicating corrosion. In a HRIPT test up to 75% no corrosion and no irritation was seen. Absence of skin corrosion is further supported in the in vitro skin irritation test where the substance is borderline irritant/non-irritant:

- Skin (OECD TG 439): irritating  (borderline irritant/non irritant)

- Eye (QSAR): not irritating

- Respiratory irritation (expert reasoning): Based on absence of human data and absence of other data indicating such an effect.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08 June - 26 July 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Two independent tests were run which are combined in the present record.
Qualifier:
according to
Guideline:
other: OECD Guideline 439; In vitro skin irritation: Reconstructed human epidermis method
GLP compliance:
yes (incl. certificate)
Species:
other: EPISKIN human epidermis skin constructs.
Strain:
other: Commercial test kit
Details on test animals and environmental conditions:
Not applicable
Type of coverage:
not specified
Preparation of test site:
not specified
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µL
- Concentration (if solution): 100%

Duration of treatment / exposure:
15 minutes
Observation period:
not applicable
Number of animals:
not applicable
Details on study design:
See any other information below
Irritation / corrosion parameter:
other:
Run / experiment:
1
Value:
59.1
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
2
Value:
41.6
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
3
Value:
45.5
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
Mean of 3
Value:
48.8
Remarks on result:
other:
Remarks:
Borderline result: 45-55%, but substance is considered an irritant
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
4
Value:
58.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
5
Value:
57.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
6
Value:
49.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of 3
Value:
55
Remarks on result:
other:
Remarks:
Less irritancy is seen compared to the first test but final conclusion is that the substance is an irritant

Table 1 EPISKIN Results Repeat Study (key study)

 

Sample

Tissue viability as percentage of mean OD negative

control

Prediction MTT endpoint

 

Replicate Tissues

Mean ± SD

 

a

b

c

 

 

Negative Control

101.6

99.3

99.1

100.0 ± 1.4

Non-irritant

Positive control

19.3

28.4

12.1

19.9 ± 8.2

Irritant

IFF TM 09 -221

59.1

41.6

45.5

48.8 ± 9.2

Irritant

As the mean tissue viability was less than 50% of the negative control value in the repeat study (48.8% +/- 9.2%), it was decided to classify the test-substance conservatively as Irritant R38 (EU DSD) / Irritant H315 (EU CLP) and not to run another repeat study.

Table 2 EPISKIN Results Original Study

 

Sample

Tissue viability as percentage of mean OD negative

control

Prediction MTT endpoint

 

Replicate Tissues

Mean ± SD

 

a

b

c

 

 

Negative Control

114.5

87.0

98.5

100.0 ± 13.8

Not applicable

Positive control

10.8

11.3

13.9

12.0 ± 1.7

Irritant

IFF TM 09 -221

58.2

57.2

49.5

55.0 ± 4.8

Non-irritant

As the tissue viability of 55.0% was a borderline result in the range 45-55%, it was proposed to repeat the test in a further study, although the OECD guideline does not have an absolute requirement for a repeat test.

Methodology

The mean Optical Density (OD) for the 6 replicate blanks was subtracted from the individual substance and control tissues OD.

The viability of each tissue was expressed as a percentage of the mean negative control value.

Assay acceptance criteria

The OD from the negative control tissue in the MTT assay is an indicator of tissue viability after the shipping and storage procedure and under the specific conditions of the assay. The mean absorbance of the triplicate negative control values should be >=0.6 and the Standard Deviation (SD) value of the % viability should be ≤18. The OD of the positive control is an indicator of the sensitivity of the tissues. The mean viability should be ≤30% of the negative control and the SD ≤18.

Data interpretation - Prediction model

If the mean tissue viability was less than 50% of the negative control value, the sample was classed as Irritant

If the mean tissue viability was greater than 50% of the negative control value, the sample was classed as non-irritant.

Interpretation of results:
other: skin irritant Cat 2
Remarks:
according to EU CLP (EC 1272/2008 and its amendments)
Conclusions:
Two skin irritation test showed tissue viability between 45 and 55%. To be conservative the substance is considered an irritant to the skin Cat 2.
Executive summary:

An in vitro skin irritation study was performed in accordance with OECD 439. As the tissue viability presented borderline result in the range 45 -55%, with a mean of 48% tissue viability. In a second test the mean tissue viability was 55%. A conservative approach has been taken and result in the substance being a skin irritant.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation
Remarks:
other: QSAR
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
1 September 2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The QSAR prediction is fully adequate. A QSAR is allowed methodology and the uncertainty of the prediction is within the OECD test method of eye irritation, and the potential mechanisms of eye irritation are covered too. The prediction and validity of the model fulfil the 5 OECD principles of the validation of (Q)SARs (REACH Guidance on Information Requirements and Chemical Safety Assessment Chapter R6.1 Guidance on (Q)SARs). A Klimisch rating of 2 was assigned based on Practical guidance #5 on the reporting of (Q)SARs in IUCLID (ref: ECHA-10-B-10-EN).
Justification for type of information:
The adequacy of the information is presented in the Endpoint summary
Guideline:
other: Guidance on information requirements and chemical safety assessment, Chapter R.6: QSARs and grouping of chemicals, May 2008.
Principles of method if other than guideline:
General model for the presence or absence of eye irritation according to EU C&L for organic liquids.
GLP compliance:
no
Remarks:
N/A
Controls:
no
Number of animals or in vitro replicates:
Not relevant
Details on study design:
The presence or absence of eye irritation following EU C&L rules was predicted based on molecular weight according to the method of Worth and Cronin (2003) and on the basis of structural analogue substances. The experimental data of substances in the training set used usually originates from tests carried out according to OECD guideline 405.

TYPE OF MODEL
- Structure Activity Relationship (SAR) using Classification tree analysis
- Descriptor values: molecular weight (calculated with ACDChemsketch) and molecular structure
Irritation parameter:
other: N/A
Time point:
other: 0
Score:
0
Irritant / corrosive response data:
The substance has a MW of 234 g/mol, which is higher than the models' threshold value (137 g/mol) for prediction of eye irritation indicating that the substance is not an eye irritant. Additionally, two structural analogues (2,6-dimethyl-4-heptanone, 6,10,14-trimethyl-2-pentadecanone) of OTNE are classified as not irritating to the eyes.

Test material is within the applicability domain of the model (see details on test material):

- Model is about organic liquids

- Training set has MW range of 30-268.5 g/mol

- Training set of the model contains 5/119 substances with ketons

- Model hypothesis: smaller molecules are more likely to penetrate into eye and cause irritation than larger chemicals

- Model does not discuss the metabolic domain (parent compound is expected to cause the effect)

Considerations on structural analogues (2,6-dimethyl-4-heptanone and 6,10,14-trimethyl-2-pentadecanone):

The presented analogues are aliphatic organics containing C, H, O atoms, and the difference with the predicted chemical OTNE is that the chemical cyclic features and has one unsaturated bond. This dissimilarity is not expected to cause other properties, because the longer aliphatic chain is expected to bend and may have similar cyclic features as OTNE. The bioavailability of the chemicals is expected to be the highest for the smaller molecule with the lowest log Kow. The bioavailability of OTNE and the other analogue are suspected to be similar. The cyclic structure may be somewhat less bioavailable than the aliphatic chains. At the other hand the log Kow of the aliphatic chain is somewhat higher. The keton group of OTNE is expected to be somewhat less electrophilic than the two analogues presented due to some hindrance of a methyl group.

The uncertainty of the prediction:

The uncertainty of the prediction is within the uncertainty of the model: 98% correct predictions for negatives. It is unlikely that this prediction is a false negative because of additional applicability domain reasoning considering physical state, bioavailability, structural alert and reactivity considerations are strengthening the prediction besides OTNE being within the applicability domain of the model. Also the false negative chemical, polyethylene glycol butyl ether, is not similar to OTNE.

The chemical and biological mechanisms according to the model underpinning the predicted result:

The model is based on the hypothesis that smaller chemicals are more likely to penetrate into the eye and cause irritation than larger chemicals. Consistent with this hypothesis was the finding of Rosenkranz that the mean MW of irritants is significant lower than the mean MW of non-irritants (Worth and Cronin, 2003).

Interpretation of results:
other: Not an eye irritant
Remarks:
according to EU CLP (EC 1272/2008 and its amendments)
Conclusions:
Based on the predicted values in the model, the substance OTNE does not need to be classified as irritant (molecular weight higher than threshold value and non-irritating property of structural analogues).
Executive summary:

The model of AP Worth and MTD Cronin as published in Journal of Molecular Structure (TheoChem) 622 (2003) 97-111 ("The use of discriminant analysis, logistic regression and classification tree analysis in the development of classification models for human health effects") was used to predict the irritating potential of OTNE based on its molecular weight and structural analogues.

The substance has a MW of 234 g/mol, which is higher than the model's threshold value (137 g/mol) for prediction of eye irritation. Additionally, two structural analogues (2,6-dimethyl-4-heptanone, 6,10,14-trimethyl-2-pentadecanone) of OTNE are classified as not irritating to the eyes.

Based on the predicted values in the model, the substance OTNE does not need to be classified as irritant (molecular weight higher than threshold value and non-irritating property of structural analogues)

Tabulated summary on the QSAR prediction, the (Q)SAR methodology and the relevance for REACH:

 

Reliability of prediction

Scientific validity of

 method

Relevance for REACH C&L

Defined Endpoint

QSAR based on OECD TG 405 information and DSD criteria

QSAR based on OECD TG 405 information and DSD criteria

REACH requires information similar to OECD TG 405

The algorithm

Prediction according to algorithm: OTNE has MW of 234, which is much > 137 and therefore not an eye irritant

Liquid organic substances with MW >137 are not eye irritants

(Q)SARs are allowed methodology when used according to Annex XI

Applicability domain

OTNE is within the domain, considering i) being a liquid; ii) MW range used in the model and; iii) other cyclic ketons are present in the training set

See substances in training set, cyclic ketons are included

Eye irritation hazards for OTNE has to be assessed under REACH

Uncertainty

Limited, because OTNE does not have additional groups which may lead to higher eye irritation e.g. higher electrophilicity

Limited, see paper of Worth and Cronin, 2000

The uncertainty of the result is limited, because OTNE is within the domain

Mode of action explanation

OTNE has insufficient reactive properties to cause eye irritation or corrosion

Not explained, but liquids with MW > 137 are expected to limitedly penetrate the eye barriers

The QSAR result of OTNE covers the mode of actions in OECD TG 405 because the training set is based on this type of tests

KC

1

Sufficiently valid

Sufficiently relevant

Translation into

Not an eye irritant according to DSD

Uses DSD criteria

Result is based on DSD criteria

Actual use into

Not an eye irritant

Adequacy

Sufficiently adequate, no further information needed

 

 

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Additional information

Skin corrosion:

Not corrosive based on absence of acid and based groups indicating corrosion. The functional ketone group is not very reactive in absence of adjacent (beta position) electrophilic groups such as halogens, oxygens and/or double bonds. Absence of skin corrosion is further supported in the in vitro skin irritation test where the substance is borderline irritant/non-irritant. Also in a HRIPT study no corrosion was found up to 75%.

Skin irritation

In vitro skin irritation according to OECD TG 439: The key study was an in vitro skin irritation study that was performed in accordance with OECD TG 431 (EPISKIN). The key study indicated that OTNE is irritating to the skin, based on a mean tissue viability of <50% (48%). The key study was performed as a repeat of a supporting in vitro skin irritation study, in which a mean tissue viability of 55% was measured, which would lead to non-classification. As the tissue viability was a borderline result in the range 45 -55% a conservative approach is applied and the substance is considered a skin irritant.

Skin irritation: Human patch test

Another supporting study is a human skin irritation patch test. In this occlusive patch test, 0.3 ml OTNE in 3:1 diethyl phthalate:ethanol or 3:1 ethanol:diethyl phthalate at concentrations of 20, 40, 60, and 75% was applied to the backs of male and female subjects for two 24-hour periods over a 96-hour study period. Sites were assessed approximately 48 hours after each treatment period. Under these conditions, OTNE elicited negligible dermal irritation potential in humans.

In vivo skin irritation in a 90 -day repeated dose dermal toxicity studies: Skin irritation observed in subchronic (90 -day) dermal toxicity studies performed in rats and mice are included in the present section. Solutions of OTNE in ethanol were applied to the skin of rat and mice for 5 days per week for 3 months, without occlusion. 10 rodents were tested in each dose group. Doses were 6.25%, 12.5%, 25% and 50% OTNE in ethanol and 100% OTNE, on approx. 10% of body surface area.

In rats these doses correspond approximately to 31.25 to 500 mg/kg bw in rats. In all male and female rats (except in 62.5 mg/kg bw/day OTNE males) the incidences of minimal to mild hyperplasia and hyperkeratosis at the site of application were significantly greater than those in their respective control groups. Therefore the NOEC in rats is 6.25%.

In mice these dosed correspond to 125 to 2.000 mg/kg bw. All exposure groups developed skin hyperkeratosis, hyperplasia, chronic active inflammation, fibrosis, epidermal suppurative inflammation, and hair follicle hyperplasia. No corrosion was observed but a clear NOAEC in mice is not found. The LOEC is 6.25%.

Both rats and mice were dermally exposed to OTNE in ethanol without occlusion of the treated site. Therefore, the local effects observed as a result of dermal exposure may have been confounded, as grooming by the animals can have influenced the skin effects, actual dermal dose and/or dermal exposure time. The effects seen may be an under or over-estimation of repeated dose skin irritation. As a result of these methodological limitations, the derivation of a dose descriptor (NOAEC or LOAEC) for local effects via the dermal exposure route is deemed inappropriate. Nevertheless, the skin irritant effects reported in this study are considered to support the conclusion for the skin irritation endpoint.

Eye irritation

The key information available for the eye irritating potential of OTNE was a fully adequate QSAR. The model of AP Worth and MTD Cronin as published in Journal of Molecular Structure (TheoChem) 622 (2003) 97-111 ("The use of discriminant analysis, logistic regression and classification tree analysis in the development of classification models for human health effects") was used to predict the irritating potential of OTNE based on its molecular weight and structural analogues.

The substance has a MW of 234 g/mol, which is higher than the model's threshold value (137 g/mol) for prediction of eye irritation. Additionally, two structural analogues (2,6-dimethyl-4-heptanone, 6,10,14-trimethyl-2-pentadecanone) of OTNE are classified as not irritating to the eyes.

Based on the predicted values in the model, the substance does not need to be classified as irritant (molecular weight higher than threshold value and non-irritating property of structural analogues).

Tabulated summary on the QSAR prediction, the (Q)SAR methodology and the relevance for REACH:

 

Reliability of prediction

Scientific validity of

 method

Relevance for REACH C&L

Defined Endpoint

QSAR based on OECD TG 405 information and DSD criteria

QSAR based on OECD TG 405 information and DSD criteria

REACH requires information similar to OECD TG 405

The algorithm

Prediction according to algorithm: OTNE has MW of 234, which is much > 137 and therefore not an eye irritant

Liquid organic substances with MW >137 are not eye irritants

(Q)SARs are allowed methodology when used according to Annex XI

Applicability domain

OTNE is within the domain, considering i) being a liquid; ii) MW range used in the model and; iii) other cyclic ketons are present in the training set

See substances in training set, cyclic ketons are included

Eye irritation hazards for OTNE has to be assessed under REACH

Uncertainty

Limited, because OTNE does not have additional groups which may lead to higher eye irritation e.g. higher electrophilicity

Limited uncertainty, see paper of Worth and Cronin, 2000

The uncertainty of the result is limited, because the QSAR is based on OECD TG 405. In addition OTNE is within the domain

Mode of action explanation

OTNE has insufficient reactive properties to cause eye irritation or corrosion

Not explained, but liquids with MW > 137 are expected to limitedly penetrate the eye barriers

The QSAR result of OTNE covers the mode of actions in OECD TG 405 because the training set is based on this type of tests

Klimisch code

1

Sufficiently valid

Sufficiently relevant

Translation into

Not an eye irritant according to DSD and therefore also not CLP

Uses DSD criteria: CLP criteria are very similar to DSD

Result is based on DSD criteria which are very similar to CLP

Actual use into DSD and CLP

Not an eye irritant

Adequacy

Sufficiently adequate, no further information needed

 

Respiratory irritation

For respiratory irritation mostly human data are used for the assessment because no suitable in vitro or in vivo tests are available that can identify respiratory irritation (REACH guidance R.7.2.3). There are no human data such as indicated in R7.2.3 the ECHA guidance that indicate respiratory reactions of the substance e.g. from consumer experience or occupational exposure. Also in view of the borderline skin irritation potential, the substance is not corrosive or severely irritating which further minimizes the respiratory irritation hazard (ECHA guidance: R.7.2.4.1, 2014).

Justification for classification or non-classification

Based on the available information OTNE needs to be classified as a skin irritant (Skin Irrit. Cat 2) according to EU CLP (EC 1272/2008 and its updates: H315 and the phrase -Causes skin irritation-, needs to be assigned.

Based on the available information the substance does not need classified for eye and respiratory irritation, according to EU CLP (EC 1272/2008 and its updates).