Diisopropyl ether

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with detailed documentation.

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

-reliability scoring based on 2002 guideline

Deviations:

yes

Remarks:

During the acclimation period, relative humidity in the animal room was between approximately 20-65% for a maximum of 15 hours.

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

During the acclimation period, relative humidity in the animal room was between approximately 20-65% for a maximum of 15 hours.

GLP compliance:

yes (incl. QA statement)

Remarks:

Germany

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories B.V., Postbus 6174, 5960 AD Horst/The Netherlands
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 17.6 to 22.1 g
- Housing: Single caging in Makrolon Type II with wire mesh top and granulated soft wood bedding
- Diet (e.g. ad libitum): pelleted standard diet, ad libitum (from Harlan Laboratories B.V., 5960 AD Horst/The Netherlands)
- Water (e.g. ad libitum): tap water, ad libitum (Gemeindewerke, 64380 Rossdorf, Germany)
- Acclimation period: at least 5 days prior to the start of the dosing under test conditions


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2 ºC
- Humidity (%): 20-65%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

25, 50, or 100%

No. of animals per dose:

4 females per group

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: The highest test item concentration, which can be technically used was 100% of the undiluted test item.
- Irritation: To determine the highest non-irritant test concentration, a pre-test was performed in two animals. Two mice were treated with concentrations of 50 and 100% each on three consecutive days. Clinical signs were recorded within 1 hour and 24 ± 4 hours after each application, as well as on Day 7. At the tested concentrations, the animals did not show any signs of irritation or systemic toxicity.
- Lymph node proliferation response: Not reported.


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: a test item is regarded as a sensitizer if (1) the exposure to at least one concentration of the test item resulted in an incorporation of 3-Hmethyl thymidine (3HTdR) at least 3-fold or greater than that recorded in control mice, as indication by the stimulation index, and (2) that the data are comparable with a conventional dose response


TREATMENT PREPARATION AND ADMINISTRATION:

Topical Application - Each test group of mice was treated by a topical (epidermal) application to the dorsal surface of each ear (left and right) with different test item concentrations of 25, 50, or 100% in acetone:olive oil (4:1). The application volume, 25 µl, was spread over the entire dorsal surface of each ear once daily for three consecutive days. A further group was treated with the vehicle alone.

Five days after the first topical application, all mice were administered with 250 µl of 78.3 microCi/ml 3HTdR (corresponds to 19.6 µCi 3HTdR per mouse) by intravenous injection via a tail vein. Approximately 5 hours after treatment with 3HTdR all mice were euthanized buy intraperitonal injection of Pentobarbial-Natrium. The draining lymph nodes were excised and pooled. Single-cell suspensions were prepared and washed with phosphate buffered saline twice and then suspended in 5% tricholoracetic acid. Then the cells were incubated at approximately 4 ºC for 18 hours and the precipatates were resuspended in 5% tricholoracetic acid and transfered to plastic scintillation vials and mixed. The level of 3HtdR incorporation was measured on a beta-scintillation counter as disintegrations per minute (DPM).

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

The mean values and standard deviations were calculated in the body weight tables.

Positive control results:

See attached Annex II of study report for positive control results

Parameter:

SI

Remarks on result:

other: 25% group - 0.75 50% group - 0.71 100% group - 0.80

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Control group - 5932 25% group - 4442 50% group - 4242 100% group - 4753

No deaths occurred during the study period. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. The body weights of animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age.

Interpretation of results:

GHS criteria not met

Conclusions:

In this study, Stimulation Indices of 0.75, 0.71, and 0.80 were determined with the test item at concentrations of 25, 50, and 100% in acetone:olive oil (4 +1), respectively. The test item diisopropyl ether was not a skin sensitizer under the test conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The skin sensitisation potential of diisopropyl ether was assessed in a GLP-compliant study performed according to OECD Guideline for the Testing of Chemicals No. 429 (local lymph node assay) (Vogel, 2010). In the main study, groups of 4 female mice were tested with the undiluted test material or diluted test material at concentrations of 50 or 25% in acetone/olive oil (4:1 v/v). The mice were treated daily with an application of 25 µL of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days. Another group of four mice received the vehicle alone in the same manner. Five days following the first topical application of the test material, all mice were injected via the tail vein with 250 µL of 3H-methyl thymidine (3HTdR). Five hours following the administration of 3HTdR, all mice were killed. A single cell suspension of pooled lymph node cells was prepared by gentle mechanical disaggregation. The incorporation of 3HTdR was counted by beta-scintillation. Since treatment with the test material did not result in at least a 3-fold or greater increase in 3HTdR incorporation compared to control values, the test substance was considered to be non-sensitising under the conditions of the test. In addition, there were no deaths and no signs of systemic toxicity reported, and body weight changes between Day 1 and Day 6 were within the range commonly recorded for animals of this strain and age. Therefore, no skin sensitisation potential is expected for diisopropyl ether.

Migrated from Short description of key information:

Diisopropyl ether was reported to be non-sensitising to skin in a local lymph node assay conducted in mice in a GLP-compliant study performed according to the OECD test guideline (No. 429).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

There is no information available concerning respiratory sensitisation.

 

According to OECD TG 429 the submission substance is not a skin sensitizer. As a result, the substance does not meet the criteria for classification according to Regulation (EC) No 1272/2008, Annex I section 3.4.