ethyl N2-dodecanoyl-.sc.l.sc.-argininate hydrochloride

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 8, 2000 to February 2, 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

A guideline study with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The study was performed before the entry into force of REACH Regulation.

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

434-630-6

EC Name:

-

Cas Number:

60372-77-2

Molecular formula:

Hill formula: C20H41N4O3Cl

IUPAC Name:

ethyl N2-dodecanoyl-l-argininate hydrochloride

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material: Nα-Lauroyl-L-arginine ethyl ester monohydrochloride
- Substance type: Dehydrated LAE
- Physical state: Granular white powder
- Lot/batch No.: 2625
- Purity: 92-94%
- Storage condition of test material: 4ºC, protected from light

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Nossan S.r.l., Correzzana (MI), Italy
- Age at study initiation: 4 to 5 weeks
- Weight at study initiation: 300-350 g
- Housing: in groups of up to 5 animals, in stainless steel cages measuring 48 x 63 x 41 cm with a grid floor
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 24°C
- Humidity (%): 45 to 65%.
- Photoperiod (hrs dark / hrs light): artificial cycle of 12 hours light/12 hours dark

IN-LIFE DATES: From: May 2, 2000 To: May 25, 2000

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

water

Concentration / amount:

0.1 %

Adequacy of induction:

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

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

20%

Day(s)/duration:

48 hours

Adequacy of induction:

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

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

5%

Day(s)/duration:

24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Number of animals in test group: 10
Number of animals in negative control group: 5

Details on study design:

RANGE FINDING TESTS:
- Intradermal injection tolerance test: Two animals were selected from those available. Six sites were selected on each animal and these injected intradermally with 0.1 ml single concentration of the test item. The 2 animals were treated with the substance at concentrations of 50%, 20%, 10%, 5%, 1% and 0.5% in sterile water. The treated sites were examined 5 days later for any signs of reaction to treatment. Observed irritation was recorded using the Draize scoring scale (below) and any response not covered by the scoring scale was separately described.
- Topical application tolerance test: Five animals were selected from those available and each of them injected intradermally at the prepared site with two injections, each of 0.1 ml, of emulsified Freund's complete adjuvant. Seven days later, the flanks of each animal were clipped free of hair and dosed with 2 concentrations of the test item, 1 on either flank. All animals were treated in this manner such that a total of 5 concentrations of the test item (50%, 20%, 10% 5% and 1% in sterile water). Within the group, each concentration was duplicated. The adhesive dressings and gauze patches were removed after 24 hours contact with the skin.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2: Intradermal injectionand topical application
- Exposure period: 7 days intradermal injection; 48 hours topical application
- Test group: 1 test group of 10 animals
- Control group: 5 animals
- Site: scapular region
- Frequency of applications: Intradermal injection (day 0); topical application (day 8)
- Duration: 21 days
- Concentrations: 0.1% intradermal injection; 20% topical application

B. CHALLENGE EXPOSURE
- No. of exposures: Challenge exposure topical application (1)
- Day(s) of challenge: 2
- Exposure period: 24 hours
- Test group: 1 test group of 10 animals
- Control group: 5 animals
- Site: flanks
- Concentrations: 5%
- Evaluation (hr after challenge): 3, 24 and 48 hours

Positive control substance(s):

yes

Remarks:

(mercaptobenzothiazole)

Results and discussion

Positive control results:

70% response in test group and 0% response in control group at challenge. Incidence at challenge is acceptable. Test system is regarded as valid.

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0 %

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Results 5

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

0

Remarks on result:

not measured/tested

Results 6

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0%

No. with + reactions:

0

Total no. in group:

0

Remarks on result:

not measured/tested

Any other information on results incl. tables

Maximum concentration not causing irritating effects in preliminary test: 5 %

Signs of irritation during induction:

Intradermal injection: Well defined erythema was apparent following administration of Freund's complete adjuvant, the vehicle or the test substance mixed with Freund's complete adjuvant.  Slight reaction was seen in five animals at both sites treated with the test substance.  No reaction was observed at those sites following 48 hours topical exposure to test item or vehicle alone.

Topical application: No reaction was observed around the injection sites of animals following topical exposure to the test substance or the vehicle alone.

Evidence of sensitisation of each challenge concentration:
No response was observed in any animal.

Other observations:
Changes in bodyweight of animals during the study period were generally similar in animals from both the test and control groups.

Table 1. Details on main study Challenge individual results:

			Dermal response
			Vehicle		Test item
Group function	Animal	Sex	24 h	48 h	24 h	48 h
CONTROL	221	Female	0	0	0	0
	223		0	0	0	0
	225		0	0	0	0
	227		0	0	0	0
	229		0	0	0	0
TEST	231		0	0	0	0
	233		0	0	0	0
	235		0	0	0	0
	237		0	0	0	0
	239		0	0	0	0
	241		0	0	0	0
	243		0	0	0	0
	245		0	0	0	0
	247		0	0	0	0
	249		0	0	0	0

Erythema and Eschar Formation Value
No erythema	0
Very slight erythema (barely perceptible)	1
Well-defined erythema	2
Moderate to severe erythema	3
Severe erythema (beet redness) to slight eschar formation
(injuries in depth)	4
Oedema Formation
No oedema	0
Very slight oedema (barely perceptible)	1
Slight oedema (edges of area well-defined by definite raising)	2
Moderate oedema (raised approximately 1 millimetre)	3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure)	4

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The results obtained in this study indicate that LAE does not elicit a sensitisation reponse in the guinea pig, as no reaction was observed at challenge.

Executive summary:

The study was performed according to OECD 406 guideline and in agreement with those of B.6 detailed in Commision Directive 96/54/EEC.

The results obtained in this study indicate that LAE does not elicit a sensitisation response in the guinea pig, there being no reaction observed at challenge. LAE is not sensitising to skin and has not to be classified for skin sensitisation.