Dl-Proline, 5-oxo-, compd. with N2-coco acyl-l-arginine Et ester

Endpoint summary

Description of key information

Gouda, 1996

Under the conditions of the study, there was no dermal sensitisation potential in guinea pigs for the test material, therefore, the test material was determined to be non-sensitising.

In addition there have been no incidences of sensitisation in humans during worldwide use of the substance since its introduction in 1979, mainly in Japan and Europe.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 February 1996 to 18 March 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A non GLP study performed to sound scientific principles with a sufficient level of detail to assess the quality of the submitted data.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study was conducted for worker safety purposes prior to adoption of the OECD 429 Guideline for the Local Lymph Node Assay.

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
The test material was prepared immediately before use.
- Preliminary study: The test material was weighed, added with distilled water (Otsuka, Lot No. K5L88), sonicated for 20 minutes, warmed for 1 minute at 30 °C, then made into 1.0 (w/w)% solution.
- Intradermal induction: The test material was weighed, added with distilled water (Otsuka, Lot No. 4B83), sonicated for 20 minutes, warmed for 1 minute at 30 °C, then made into 1.0 and 2.0 (w/w) % solutions. In addition, this 2.0 (w/w) % solution was pipetted and mixed with FCA (Difco Laboratories, Lot No. 64542LA) to prepare an emulsion (1:1).
- Epidermal induction: The test material 1.0 (w/w)% solution was made in the same way as intradermal induction.
- Challenge: The test material 1.0 (w/w)% solution was made in the same way as intradermal induction and epidermal induction.
- Preparation of emulsion (1:1) of Freund’s complete adjuvant and physiological saline: Freund’s complete adjuvant (FCA: Difco Laboratories, Lot No. 64542LA) was pipetted and mixed with physiological saline (Otsuka, Lot No. 4F85N) to prepare an emulsion (1:1).

Species:

guinea pig

Strain:

Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 5 weeks
- Weight at study initiation: 295.3 - 350.0 g
- Housing: Five animals were accommodated in each stainless-steel cage.
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 7 days. During the quarantine/acclimation period, the animals were observed for clinical signs once every day.

ENVIRONMENTAL CONDITIONS
- Temperature: 23 ± 3 °C
- Humidity: 55 ± 15 %
- Air changes: 10-15 times per hour
- Photoperiod: 12 hours lighting

Route:

intradermal and epicutaneous

Vehicle:

water

Concentration / amount:

1.0 %, 0.05 mL

Day(s)/duration:

Day 1(intradermal) and Day 8 (epidermal for 48 hours)

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

1 %

Day(s)/duration:

Day 22 for 24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 per test material group, 5 per control group

Details on study design:

PRELIMINARY STUDY
- Two animals without abnormalities were selected. Fur of both flanks (approximately 5 x 10 cm) was clipped and shaved. On the next day, two patches of 2 x 2 cm were saturated with 0.2 mL of test material and applied to the clipped/shaved flank skin and covered occlusively with a bandage tape. The patches were removed 24 hours after application.
- The patch application sites were observed immediately after removing the patch and then 24 hours later. The skin reactions were scored according to the following scale:
No visible change = 0
Discrete or patchy erythema = 1
Moderate and confluent erythema = 2
Intense erythema and swelling = 3
- The concentration for the challenge was set at 1.0 (w/w) % (the maximum non-irritating concentration)

MAIN STUDY
INDUCTION
- Intradermal induction (Day 1): One day before intradermal induction, an area approximately 4 x 6 cm of the scapular region was clipped with electric clippers and shaved with an electric shaver. On the next day, 0.05 mL of each substance was intradermally administered to Areas 1 to 3 within an area of 2 x 4 cm. The substances and administration sites were as follows:
Area 1: 1:1 (v/v) mixture emulsion of physiological saline and FCA
Area 2: 1.0 % test material solution
Area 3: 1:1 (v/v) mixture emulsion of 2.0 % test material solution and FCA
- Epidermal induction (Day 8): On Day 6 after the intradermal induction, the same area as on Day 1 was clipped and shaved, and Vaseline containing 10 % sodium lauryl sulphate was applied thoroughly. On the next day, a patch of 2 x 4 cm was saturated with 0.5 mL of 1.0 (w/w)% substance, applied to the induction area and covered occlusively with a plastic film tape (Plasupport, HOGY Medical Co., Ltd.). The patch was removed 48 hours after application.

CHALLENGE (DAY 22)
- 20 days after the intradermal induction, fur of the right flank (approximately 5 x 10 cm) of animals was clipped and shaved. On the next day, the patch of 2 x 2 cm was saturated with 0.2 mL of 1.0 (w/w) % test material and fixed in place with a bandage tape for 24 hours for occlusive application of the challenge.

OBSERVATIONS
- Clinical signs: Clinical signs of all animals were observed once daily from delivery of the animals to the termination of the animal test.
- Body weight measurement: All animals were weighed on Day 1 (intradermal induction), Day 8 (epidermal induction), Day 22 (challenge), Day 24 and Day 25 (observation period).
- Skin reactions: Observation of skin reactions was performed 24 and 48 hours after removing the applied patch for the challenge. The skin reactions were scored and recorded according to the following scale:
No visible change = 0
Discrete or patchy erythema = 1
Moderate and confluent erythema = 2
Intense erythema and swelling = 3
- For each application site, the skin reaction of individual animals was scored and the mean score of each test group at each observation period was calculated, and the positive reaction rate [(number of animals with skin reactions of score 1 or greater) / (number of animals used) x 100] was determined.
The test material was assigned to one of the following five grades of allergenic potency according to Magnusson and Kligman, ranging from weak to extreme:
Positive reaction rate (%): 0 – 8 = Grade I (Weak)
Positive reaction rate (%): 9 – 28 = Grade II (Mild)
Positive reaction rate (%): 29 – 64 = Grade III (Moderate)
Positive reaction rate (%): 65 – 80 = Grade IV (Strong)
Positive reaction rate (%): 81 – 100 = Grade V (Extreme)

Challenge controls:

No-induction control group.

Positive control substance(s):

not specified

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1.0 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1.0 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

other: control group

Dose level:

1.0 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

other: control group

Dose level:

1.0 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Clinical signs

- There were no mortalities, or abnormal clinical signs observed during the study period.

 

Body weights

- Seven animals in the test material group and 2 animals in the control group at the challenge observation period (Day 24), and 1 animal in the test material sensitisation group at the challenge observation period (Day 25) showed a loss of body weight. This was judged to be unrelated to the test material, although the cause of the decrease was unclear.

 

Skin reactions

- No skin reactions were observed at the 1.0 (w/w) % test material application site in the test group and the control group. Thus, the mean score was 0 and the positive reaction rate was 0 %.

Interpretation of results:

other: Not classified according to EU criteria.

Conclusions:

Under the conditions of the study, the test material was determined to be non-sensitising to skin.

Executive summary:

The potential of the test material to cause skin sensitisation was assessed in guinea pigs in accordance with the maximisation test.

The skin sensitization study was conducted in female Hartley strain guinea pigs with the Maximization Test Method. The maximum non-irritating concentration of the test material was determined to be 1.0 % (w/w) in the preliminary study.

In the induction phase of the study the animals were treated intradermally on Day 1 on a clipped area on the scapular region of the animals. On Day 8 they were treated with an epidermal induction under an occlusive patch for 48 hours. The challenge was performed on Day 22 with an occlusive application of the test material for 24 hours. Clinical signs, body weight measurements and skin reactions were recorded.

None of the test group or control group showed skin reactions after the challenge treatment with the test material at 1.0 % in distilled water.

Under the conditions of the study, there was no dermal sensitisation potential in guinea pigs for the test material, therefore, the test material was determined to be non-sensitising.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Gouda (1996)

The potential of the test material to cause skin sensitisation was assessed in guinea pigs in accordance with the maximisation test. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

The skin sensitization study was conducted in female Hartley strain guinea pigs with the Maximization Test Method. The maximum non-irritating concentration of the test material was determined to be 1.0 % (w/w) in the preliminary study.

In the induction phase of the study the animals were treated intradermally on Day 1 on a clipped area on the scapular region of the animals. On Day 8 they were treated with an epidermal induction under an occlusive patch for 48 hours. The challenge was performed on Day 22 with an occlusive application of the test material for 24 hours. Clinical signs, body weight measurements and skin reactions were recorded.

None of the test group or control group showed skin reactions after the challenge treatment with the test material at 1.0 % in distilled water.

Under the conditions of the study, there was no dermal sensitisation potential in guinea pigs for the test material, therefore, the test material was determined to be non-sensitising.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to skin sensitisation.