Ethyl 2-methyl-1,3-dioxolane-2-acetate

Endpoint summary

Description of key information

SKIN

Not irritating, OECD 439, EU Method B.46, Warren (2013)

EYE

Not irritating, Hopf (1978) and DEREK prediction (2013)

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:

10 July 2013 to 15 July 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Remarks:

EPISKIN™

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: collagen type I matrix coated with type IV collagen

Vehicle:

unchanged (no vehicle)

Amount/concentration applied:

10 µL of test material was applied to the epidermis surface.

Duration of treatment / exposure:

15 minutes.

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

95.5

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

2

Value:

83

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

103.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- Direct MTT Reduction
The MTT solution containing the test material did not turn blue which indicated that the test material did not directly reduce MTT.

- Test Material, Positive Control Item and Negative Control Item
The individual and mean OD562 values, standard deviations and tissue viabilities for the test material, negative control and positive control are given in Table 1. The mean viabilities and standard deviations of the test material and positive control, relative to the negative control are also given in Table 1.

The relative mean viability of the test material treated tissues was 94.0 % after a 15-minute exposure period and 42 hours post-exposure incubation period.

It was considered unnecessary to perform IL-1α analysis as the results of the MTT test were unequivocal.

Table 1: Mean OD₅₆₂ Values and Percentage Viabilities for the Negative Control Item, Positive Control Item, and Test Material

Substance	OD562 of Tissues	Mean OD562 of Triplicate Tissues	± SD of OD562	Relative Individual Tissue Viability (%)	Relative Mean Viability (%)	± SD of Mean Relative Viability (%)
Negative Control Item	1.006	0.842	0.144	119.5	100*	17.1
	0.787			93.5
	0.734			87.2
Positive Control Item	0.113	0.080	0.028	13.4	9.5	3.4
	0.067			8.0
	0.061			7.2
Test material	0.804	0.792	0.087	95.5	94.0	10.4
	0.699			83.0
	0.872			103.6

* = The mean viability of the negative control tissue is set at 100 %

SD = Standard Deviation.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the test the test material was considered to be a non-irritant.

Executive summary:

A test was carried out to evaluate the skin irritation potential of the test material in vitro, using the EPISKIN™ reconstructed human epidermis model. The study was conducted under GLP conditions and in accordance with the standardised guidelines OECD 439 and EU Method B.46.

The test consisted of a treatment period of 15 minutes followed by a post-exposure incubation period of 42 hours. The principle of the assay is based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test material by means of the colourimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt to a blue formazan salt (with the mitochondria of viable cells) in the test material treated tissues relative to the negative controls.

The relative mean viability of the test material treated tissues was 94.0 % after the 15-minute exposure period and 42 hour post-exposure incubation period.

As a result of this, the test material is not considered to be classified as a skin irritant according to EU criteria.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation, other

Remarks:

QSAR

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

26 July 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

The Derek Nexus software is a well established and recognised software system for predicting this type of endpoint. As such, despite the brief nature of the available report, the lack of irritating effects predicted by the software can be considered to be reliable with some restrictions.

Justification for type of information:

QSAR prediction

Qualifier:

no guideline available

Principles of method if other than guideline:

QSAR method. Program version: Derek Nexus: 3.0.1, Nexus: 1.5.1

GLP compliance:

no

Species:

other: QSAR

Details on study design:

- Average molecular mass: 174.19 (Lhasa Limited, version 1.0)
- Exact molecular mass: 174.0892 (Lhasa Limited, version 1.0)
- Log Kp: -2.96 (Potts & Guy, version 1.0 (LogP: BioByte Corp., version 5.3; Average Molecular Mass: Lhasa Limited, version 1.0))
- Log P: 1.16 (BioByte Corp., version 5.3)

- KnowledgeBase name: Derek KB 2012 1.0
- KnowledgeBase version: 1.0
- KnowledgeBase last modified: 29 November 2012 11:56:30
- KnowledgeBase certified by: Lhasa Limited, Leeds, Yorkshire, UK

Irritation parameter:

in vitro irritation score

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Remarks on result:

no indication of irritation

No eye-irritant effects predicted

Interpretation of results:

GHS criteria not met

Conclusions:

No eye-irritant effects predicted

Executive summary:

A summary of a computer prediction carried out on the molecular structure of methyl dioxolan using the predictive software, Derek Nexus: 3.0.1, did not predict and eye-irritant effects for the molecule.

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

not reported

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The substance used in the study is not representative of the substance to be registered; rather it is a diluted mixture containing the registered substance at 50 % in olive oil. The duration of treatment, and the period of observation, was not reported. There are a number of reporting deficiencies, however, overall it can be seen that the study was performed to sound scientific principles.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

GLP compliance:

no

Remarks:

study pre-dates GLP

Species:

rabbit

Strain:

not specified

Details on test animals or tissues and environmental conditions:

TEST ANIMALS (white rabbits)
- Weight at study initiation: 1.5 - 2.0 kg
- Housing: Individually housed
- Diet: standard diet, ad libitum
- Water: ad libitum from automatic drinkers

ENVIRONMENTAL CONDITIONS
- Temperature (°C): approximately 20 °C
- Humidity (%): aproximately 50 %
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark

Vehicle:

other: olive oil

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
The test material was tested at 50% in olive oil.

Duration of treatment / exposure:

- Dose administration: 0.1 mL of the test material formulation was applied into the conjunctival sac of one eye of each rabbit. The lids were then gently held together for one minute after which the animal was released. The other eye was treated with water (control eye).

Observation period (in vivo):

Not reported.

Number of animals or in vitro replicates:

4 males and 4 females

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): After 1 minute the treated eyes of half of the animals were washed with 10 - 20 mL lukewarm saline.

SCORING SYSTEM
The reactions, following treatment, were observed.

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritant / corrosive response data:

The test material formulation was concluded not to be irritating to the mucous membranes of eyes.

The test material formulation was concluded not to be irritating to the mucous membranes of eyes under the conditions of the test..

Interpretation of results:

GHS criteria not met

Conclusions:

The test material formulation was concluded not to be irritating to the mucous membranes of eyes.

Executive summary:

The eye irritation potential of the test material formulation was assessed in a study which was conducted according to a methodology which was similar to that which is outlined in the standardised guideline OECD 405. 0.1 mL of test material formulation was instilled into one eye of each of eight rabbits, the other eye was treated with water and acted as the control eye. One minute after instillation, the treated eyes of half of the animals was rinsed with 10 - 20 mL lukewarm saline. Any adverse effects were noted. Under the conditions of the study the test material formulation was concluded not to be irritating to the mucous membranes of eyes.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin In the key study, the skin irritation potential of the test material was investigated in vitro, using the EPISKIN™ reconstructed human epidermis model. The study was conducted under GLP conditions and in accordance with the standardised guidelines OECD 439 and EU Method B.46. The test consisted of a treatment period of 15 minutes followed by a post-exposure incubation period of 42 hours. The principle of the assay was based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test material by means of the colourimetric MTT reduction assay. The relative mean viability of the test material treated tissues was 94.0 % after the 15-minute exposure period and 42 hour post-exposure incubation period. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt to a blue formazan salt (with the mitochondria of viable cells) in the test material treated tissues relative to the negative controls. As a result of this, the test material is not considered to be classified as an irritant according to EU criteria. This study was assigned a reliability score of 1 in accordance with the principle of assessing data quality as defined by Klimisch (1997).Supporting information on the skin irritation potential of the test material is considered in a weight of evidence approach by evaluating two irritation studies in which the test material was administered as a diluted mixture in vehicle. Furthermore, skin irritation parameters were included as part of two acute dermal toxicity studies and two skin sensitisation studies; these are included in the evaluation.In the first irritation study, reported by Wolven & Levenstein, the skin irritation of the test material was investigated in a study whereby three rabbits were dermally exposed to test material at 15% in alcohol. 0.5 mL of the formulation was applied to an intact area of skin and 0.5 mL of the formulation was applied to an abraded area of skin. The formulations were held in contact with the skin for a period of 24 hours under an occlusive dressing. Observations were made on patch removal and again 72 hours following administration. Three rabbits were treated, as above, with 15% water in alcohol; these animals are regarded as control animals. No signs of dermal irritation were noted in any of the animals in the treatment and control groups at either time point. Therefore, under the conditions of the study, the test material did not elicit any reaction in any of the animals during the course of the study that meant the test material required classification as a skin irritant.In the second irritation study, reported by Hopf, the skin irritation of the test material was investigated in a study in which 30 human volunteers received a single, occlusive, dermal application of test material. The test material was applied as a 50% formulation in olive oil. Skin reactions were recorded 24 and 48 hours following administration. Under the conditions of the study no signs of skin irritation were noted. The test material is therefore not considered to require classification for skin irritation.Both studies were conducted on a diluted mixture of the registered substance, however, since the test material is marketed and used at lower concentrations, the results of these studies are regarded as being conservative for human exposure. Although there are a number of reporting deficiencies, overall the studies were performed to sound scientific principles. Bearing these points in mind, the studies have been assigned a reliability score of 3 in accordance with the criteria of Klimisch (1997). Together they are deemed adequate for assessment as an accurate reflection of the substance. To further substantiate the overall conclusion, that the substance is not a skin irritant, information from the acute dermal toxicity studies and skin sensitisation studies are included below. In the acute dermal toxicity studies, 10 rabbits each received a dermal application of 5.0 g/kg test material. Skin irritation parameters were observed on day 1. In the first study (Moreno, 1979), none of the animals died. Skin irritation on day 1 was observed to be absent to slight. In the second dermal toxicity study (Moreno, 1978), none of the animals died. Slight redness was observed in eight animals and moderate redness was observed in one animal; the other treated animal was observed to have no redness. Slight edema was noted on 4 animals, moderate edema on 2 animals and no edema on the remaining 4 animals. In the skin sensitisation studies, a Maximisation Test was conducted in line with the method described in the Journal of Investigative Dermatology, Volume 47, No. 5; 1966; 393-409. Prior to conducting the Maximisation Test, the test material was pretested on all human subjects in order to determine whether sodium lauryl sulphate pretreatment was required. A patch of test material was therefore applied to normal sites on the backs of the subjects for 48 hours under occlusion. Skin irritation parameters were examined upon patch removal. In the first study (Epstein 1979), no significant evidence of irritation was observed during the pre-test. The test material was therefore considered to be non-irritating and all subjects were pretested with 5% sodium lauryl sulphate during the proceeding Maximisation Test. In the second study (Epstein, 1978), no significant evidence of irritation was observed during the pre-test. The test material was therefore considered to be non-irritating and all subjects were pretested with 3% sodium lauryl sulphate during the proceeding Maximisation Test. Since, in each of these studies, the methodology and results were reported in very limited detail it was not possible to assess the quality of the reported results from the data presented. Furthermore, the aim of each study was not specifically to determine skin irritation. Therefore, these studies were assigned a reliability score of 4. The available data are considered to be complete and the conclusion for skin irritation, not irritating, was taken forward for risk assessment. Eye The eye irritation potential of the test material is considered in a weight of evidence approach by the available study in which the test material was administered as a diluted mixture in vehicle in conjunction with the results of a QSAR prediction performed using the Derek Nexus software. In the study, the eye irritation potential of the test material formulation which consisted of the substance at 50% concentration in olive oil was assessed following a methodology which was similar to that which is outlined in the standardised guideline OECD 405. 0.1 mL of test material formulation was instilled into one eye of each of eight rabbits, the other eye was treated with water and acted as the control eye. One minute after instillation, the treated eyes of half of the animals were rinsed with 10 - 20 mL lukewarm saline. Any adverse effects were noted. Under the conditions of the study the test material formulation was concluded not to be irritating to the mucous membranes of eyes. Whilst this study was conducted on a diluted mixture of the registered substance, since the test material is marketed and used at lower concentrations, the results of these investigations are regarded as being conservative for human exposure. Although there are a number of reporting deficiencies, overall the study was performed to sound scientific principles. Bearing these points in mind, the study has been assigned a reliability score of 3 in accordance with the criteria of Klimisch (1997). Together with the result of the Derek Nexus prediction which did not indicate cause for concern with regards to the eye irritancy potential of the substance and the negative result and low cytotoxicty that is seen in thein vitroskin irritation study, the data are deemed adequate for assessment as an accurate reflection of the substance. The available data are considered to be complete and the conclusion for eye irritation, not irritating, was taken forward for risk assessment.

Justification for selection of skin irritation / corrosion endpoint:

The study was conducted under GLP conditions and in accordance with standardised guidelines.

Justification for selection of eye irritation endpoint:

No single study is selected as the key study. The two available studies were considered together in a weight of evidence approach.

Justification for classification or non-classification

Skin

In accordance with the criteria for classification as defined in Annex I, Regulation 1272/2008, the test material does not require classification for skin irritation.

Eye

In accordance with the criteria for classification as defined in Annex I, Regulation 1272/2008, the test material does not require classification for eye irritation.