Isodecyl acrylate

Endpoint summary

Description of key information

The murine Local Lymph Node Assay (LLNA, OECD 429) was performed to evaluate the skin sensitization potential of isodecyl acrylate. The substance gave a positive result in this test, indicative of a potential of skin sensitization.

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:

31 July 2012 to 09 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd, Margate
- Age at study initiation: approx. 8 to 10 weeks old
- Weight at study initiation: 17 to 19 g
- Housing: Individually housed in cages that conformed to 'Code of Practice for the Housing and Care of Animals Used in Scientific Procedures'
- Diet (e.g. ad libitum): SQC(E) Rat and Mouse Maintenance Diet No 1, ad libitum
- Water (e.g. ad libitum):Mains water, ad libitum
- Acclimation period: 7 to 16 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 24°C
- Humidity (%): 45 to 65%
- Air changes (per hr): 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light): Illuminated by flourescent strip lights for 12 hours daily

IN-LIFE DATES: From: 14 August 2012 To: 04 September 2012

Vehicle:

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

Concentration:

Low test concentration- 10% v/v
Intermediate concentration - 25% v/v
High concentration - 50% v/v

No. of animals per dose:

4 animals per dose

Details on study design:

TREATMENT PREPARATION AND ADMINISTRATION:
Formulations were freshly prepared as required using 80% v/v acetone in olive oil on Day s1, 2 and 3. The formulations were stored at room temperature, in sealed, air-tight containers prior to dosing and were used within two hours of preperation.
Concentrations of test article were expressed volumetrically and in terms of test article received (without regard to purity or active content).
Each mouse was manually restrained with both auditory pinnae left free. The outer aspect of both pinnae of each mouse was treated by direct application of the appropriate test or control formulation (0.025 mL/pinna) dispensed from an automatic micro pipette.

Positive control substance(s):

other: The sensitivity and reliability of the test system are checked at least every six months. Preferred substances are alpha-hexylcinnamaldehyde (CAS Number 101-86-0) and mercaptobenzothiazole (CAS Number 149-30-4).

Statistics:

no

Positive control results:

Positve control not included in this study but checked at least every six months.

Key result

Parameter:

EC3

Value:

14.9

Parameter:

SI

Value:

1.9

Test group / Remarks:

low dose

Parameter:

SI

Value:

5.3

Test group / Remarks:

mid dose

Parameter:

SI

Value:

4.4

Test group / Remarks:

high dose

Cellular proliferation data / Observations:

per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0. Low dose group = 1.9 Intermediate dose group = 5.3 High dose group = 4.4 The calculated EC3 value was found to be 14.9%.
Scintillation fluid with 5% w/v trichloroacetic acid: 53 DPM Vehicle control: 2788 DPM Isodecyl Acrylate (10% v/v): 5180 DPM Isodecyl Acrylate (25% v/v): 14908 DPM Isodecyl Acrylate (50% v/v): 12235 DPM

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The Local Lymph Node Assay demonstrated that Isodecyl Acrylate has the potential to cause skin sensitisation.

Executive summary:

This study was conducted to assess the potential of the test article, Isodecyl Acrylate, to cause skin sensitisation in the mouse (OECD 429). Following a preliminary screening test using a 50% v/v formulation, the test article was prepared for administration at 10, 25 and 50% v/v in 80% v/v acetone in olive oil. Groups of four female CBA/CaCrl mice were subjected to topical applications of vehicle or of one of the test formulations to the outer aspect of the auditory pinnae once daily on Days 1, 2 and 3. On Day 6 a 20 µCi dose of tritiated 3H-methyl thymidine was injected intravenously into each mouse. Approximately five hours later the auricular lymph nodes were recovered from each animal. The nodes from mice subjected to the same treatment were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/v trichloroacetic acid and processed through a scintillation counter. Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0. The stimulation index were: 1.9, 5.3 and 4.4 for the concentrations 10, 25 and 50% v/v respectively. The calculated EC3 value was found to be 14.9%.The Local Lymph Node Assay demonstrated that Isodecyl Acrylate has the potential to cause skin sensitisation.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

This study was conducted to assess the potential of the test article, Isodecyl Acrylate, to cause skin sensitisation in the mouse (OECD 429).

Following a preliminary screening test using a 50% v/v formulation, the test article was prepared for administration at 10, 25 and 50% v/v in 80% v/v acetone in olive oil. Groups of four female CBA/CaCrl mice were subjected to topical applications of vehicle or of one of the test formulations to the outer aspect of the auditory pinnae once daily on Days 1, 2 and 3. On Day 6 a 20 µCi dose of tritiated 3H-methyl thymidine was injected intravenously into each mouse. Approximately five hours later the auricular lymph nodes were recovered from each animal. The nodes from mice subjected to the same treatment were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/v trichloroacetic acid and processed through a scintillation counter.

Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

The stimulation index were: 1.9, 5.3 and 4.4 for the concentrations 10, 25 and 50% v/v respectively.

The calculated EC3 value was found to be 14.9%.

The Local Lymph Node Assay demonstrated that Isodecyl Acrylate has the potential to cause skin sensitisation.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the positive results obtained in the skin sensitisation study performed on isodecyl acrylate, the test susbtance must be classified as skin sensitizer.

Skin.Sens.1B "May cause an allergic skin reaction"(H317) according to the Regulation EC n°1272/2008.

Justification of the category: an EC3 of 14.9 was calculated in the LLNA. This value is higher than 2, therefore the category B is selected.