Diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1)

Endpoint summary

Description of key information

A total of 3 studies on skin sensitisation are available. The results of the studies is not homogenous. The substance is classified as Skin Sens. 1B as a precautionary measure.

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:

2018-05-24 to 2018-06-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The LLNA was required as the in vitro skin sensitisation studies OECD 442C and 442D did not gave adequate information for uniformly convincing substance classification.

Qualifier:

according to guideline

Guideline:

OECD Guideline 442B (Skin Sensitization: Local Lymph Node Assay: BrdU-ELISA)

Version / remarks:

2010-07-22

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA): BrdU-ELISA

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: R-127, lot 170825
- Expiration date of the lot/batch: 2019-06-19

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: InVivos Pte Ltd
9 Perahu Road,
Lim Chu Kang,
Singapore 718793
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 16.7 - 20.6 g
- Housing: OptiMICE Caging Systems
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 1 week
- Indication of any skin lesions: none

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 - 26 °C
- Humidity (%): 30 - 70 %
- IN-LIFE DATES: From: 2018-05-17 To: 2018-06-27

Vehicle:

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

Concentration:

1 %, 0.5 %, 0.25 %

No. of animals per dose:

3

Details on study design:

Administration of test substances

Administration Topical application on dorsum of both ears
Dose level 25 µl for each ear
Dose Interval Topical application of 25 µl of test substances/negative control/positive control on the dorsum of each ear once a day for 3 consecutive days
Dosing Date 21 Jun 2018 – 23 Jun 2018

Administration of BrdU (10 mg/ml)

Administration Intraperitoneal injection (IP)
Dose level 5 mg (0.5ml of 10 mg/ml solution) per mice
Dose Interval Single Dose
Dosing Date 25 Jun 2018

Positive control substance(s):

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

Statistics:

Results for each test and control group were expressed as mean Stimulation Index (SI). The SI was derived by dividing the mean BrdU labelling index of test or positive control group by the mean BrdU labelling index of negative control group. The SI for negative control group was defined as 1.


BrdU labelling index (LI) = (Mean ABS450-Mean ABSblank 450) – (Mean ABS690-Mean
ABSblank 690)
SI = LI test (positive control) / LI negative control

Based on OECD Guideline 442B, SI of 1.6 or more (≥ 1.6) is considered positive for designating a test sample as a sensitizer. The positive control usually produces a SI of ≥ 1.6.

Positive control results:

Valid

Key result

Parameter:

SI

Value:

1.742

Test group / Remarks:

0.25 % test item

Parameter:

SI

Value:

1.955

Test group / Remarks:

0.5 %

Parameter:

SI

Value:

2.89

Test group / Remarks:

1 %

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

Based on the above study, using 1%, 0.5% and 0.25% (v/v) of the test item – diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1), as test substances and acetone : Olive oil (4:1, v/v) as vehicle and negative control, skin sensitization was produced in mice.

Executive summary:

The potential of diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1) to cause skin sensitisation was examined in a study according to OECD 442B.

Based on the above study, using 1%, 0.5% and 0.25% (v/v) of the test item – diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1), as test substances and acetone : Olive oil (4:1, v/v) as vehicle and negative control, skin sensitization was produced in mice.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The potential of diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1) to cause skin sensitisation was examined in a study according to OECD 442B. Based on this study, using 1%, 0.5% and 0.25% (v/v) of the test item skin sensitization was produced in mice.

Justification for classification or non-classification

The substance is classified as Skin Sens. 1B as a precautionary measure.