N-ethyl-N-(3-methylphenyl)propionamide

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

At the time of study performance, the LLNA method was not adopted.

Test material

Test material information

Constituent 1

Reference substance name:

N-ethyl-N-(3-methylphenyl)propionamide

EC Number:

423-640-6

EC Name:

N-ethyl-N-(3-methylphenyl)propionamide

Cas Number:

179911-08-1

Molecular formula:

C12H17NO

IUPAC Name:

N-ethyl-N-(3-methylphenyl)propanamide

Test material form:

liquid

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Ltd
- Weight at study initiation:
- Housing: 308 and 394g
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22± 3°C
- Humidity (%): 50% +/- 20%.
- Photoperiod (hrs dark / hrs light): 12 hours light and 12 hours dark

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal and epicutaneous

Vehicle:

physiological saline

Remarks:

DOBS Saline

Concentration / amount:

Induction: injection 0.3% in DOBS saline and 100% dermally

Day(s)/duration:

Day 1 and 7 / 48 hours

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Challenge

Route:

epicutaneous, occlusive

Vehicle:

other: Alembicol D

Concentration / amount:

50%

Day(s)/duration:

Day 20 / 24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

20 (ten males and ten females)

Details on study design:

lntradermal injection
The hair was clipped from a 2cm x 4cm area of skin in the dorsal shoulder area and three pairs of intradermal injections were made within the clipped area as follows:

1. Two 0.1ml injections of 1:1 FCA and saline.

2. Two 0.1ml injections of 0.3% test item in DOBS saline.

3. Two 0.1ml injections of 1:1 0.6% test item in DOBS saline and FCA to give a resultant concentration of 0.3%

The injection sites were scored 24 hours after treatment

Occluded patch application
Seven days after the injections the same 2cm x 4cm area was clipped and shaved. A 2cm x 4cm filter paper patch, attached by double-sided adhesive tape to 4 4cm x 6cm piece of thin polythene, was saturated with 100.0% test item (as supplied) and placed over the shaved site. The patch was held in place for 48 hours by adhesive plaster wrapped around the trunk behind the forelimbs. The occluded patch site was scored 24 hours after removal of the bandage.

Challenge
Thirteen days after the application of the induction patch the guinea pigs were challenged on the clipped and shaved flank by occluded patch. For each animal, two 8mm diameter filter paper patches in two 11mm aluminium patch test cups were applied to the shaved flank, one saturated with 50.0% test item in Alembicol D and the other saturated with the solvent. The patches were held in place for 24 hours by adhesive plaster wound around the trunk.
The treatment sites were examined for evidence of sensitization 24 and 48 hours after removal of the patches

Challenge controls:

At the same time as the test animals were selected, ten (five male and five female) guinea pigs were selected as treated controls (Group B) for challenge. The control guinea pigs were selected so that their body weights were similar to those of the test guinea pigs at challenge. The guinea pigs received two intradermal injections of 1:1 mixture of FCA and saline, two 0.1ml injections of DOBS saline and two 0.1ml injections of a 1:1 mixture of FCA and DOBS saline in exactly the same way as the test animals. This was followed seven days later by a 48 hour occluded "blank" patch over the injection sites. The animals were assessed after both induction procedures as described for the test animals.
The control animals were challenged with the test material at the same time and in the same manner as the test animals.

Positive control substance(s):

yes

Remarks:

Hexyl Cinnamic Aldehyde

Results and discussion

Positive control results:

90% positive

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Results 5

Reading:

1st reading

Hours after challenge:

48

Group:

positive control

Dose level:

10%

Remarks on result:

positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the test item was classed as a non-sensitiser and does not require labelling according to Part Il(B) of Annex VI of Directive 67/548/EEC relating to the classification of dangerous substances and preparations, "(Official Journal of the European Communities, No L383 A131 B.6. - 29.12.1992)".

Executive summary:

Magnusson and Kligman guinea pig maximisation test. This method is similar to that described in the Official Journal of the EuropeanCommunities No. L383 Al31 B.6. Acute Toxicity (Skin Sensitization), 29.12.1992 and OECD Guideline 406 for Testing of Chemicals(1993).

 

Sensitization was induced in guinea pigs by intradermal injections of both test substance and Freund's Complete Adjuvant. Seven days later the induction process was supplemented by application of the test substance to the shoulder injection sites under occlusion for 48 hours.

Thirteen days later the guinea pigs were challenged by a 24 hour occluded patch of the test substance, the treatment sites were then examined for evidence of sensitization 24 and 48 hours after removal of the challenge patch.

Induction (intradermalinjection):

 

1)                       A 1:1 mix of Freund's Complete Adjuvant (FCA) with 0.9% (w/v) physiological saline (saline).

 

2)                       0.3% (w/v) test item in 0.01% dodecylbenzene sulphonate in 0.9% physiologic alsaline (DOBS saline)

3) 0.6% (w/v) Agarbois in DOBS saline mixed 1:1with FCA to give a final concentration of 0.3% (w/v) of test item

Induction (occluded patch application): 100% (as supplied) test item

Challenge (occluded patch application): 50.0% (w/v) Agarbois in Alembicol D.

Results:

There was no evidence of any sensitization reactionsinany of the twenty test guinea pigs challenged with 50.0% test item.

Conclusion:

Under the conditions of this study, test item was classed as a non-sensitiser and does not require labelling according to Part Il(B) of Annex VI of Directive 67/548/EEC relating to the classification of dangerous substances and preparations. "(Official Journal of the European Communities, No L383 A131 B.6. - 29.12.1992)".