L-Threonine, N-coco acyl derivs., monosodium salts

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

An experimental study on the skin irritation of the test item itself is not available.
According to REACH Regulation Annex XI, 1.5, obligatory endpoints recommended for REACH registration according to REACH Annexes VII – X can be covered by the concept of „Grouping of substances and read-across approach“, in case the respective substances, selected for read-across, exhibit similar physicochemical, toxicological and ecotoxicological properties.
The test item Acylthreoninate TH-CS-11-T and the read-across substance Acylglycinate GCS-11-T are structurally closely related substances, which differ predominantly in the in the amino acid anion (Alaninate vs. Glycinate). According to available experimental studies, both substances exhibit results on major relevant endpoints (physico-chemical properties, environmental fate and behavior, ecotocicity, human toxicity) that are in a comparable range. Moreover, the kind of natural amino acid anion is not expected to have any significant adverse effect contributing to overall substance toxicity of either of the compounds.
Therefore, it can be assumed that the results obtained with these structurally related substances are appropriate according to criteria of REACH Annex XI, 1.5, to serve for read-across for uncovered obligatory endpoints of the test item Acylthreoninate TH-CS-11-T recommended for REACH registration according to REACH Annexes VII and VIII.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium cocoyl glycinate (SCG) [INCI]

IUPAC Name:

Sodium cocoyl glycinate (SCG) [INCI]

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Netherlands BV
- Age at study initiation: 14 weeks (males, females)
- Weight at study initiation: 2.2 kg (male); 2.5 kg (females)
- Housing: individually in stainless steel cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: yes

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 - 23 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): 10 - 15 per hour
- Photoperiod (hrs dark / hrs light): 12 hour cycle dark / light

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL / animal
- Concentration (if solution): undiluted

Duration of treatment / exposure:

4 hour

Observation period:

14 days

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: approx. 10 cm x 10 cm
- % coverage: 100
- Type of wrap if used: surgical gauze patch

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 4 hours

SCORING SYSTEM: Irritation scoring according to Council Regulation (EC) No 440/2008

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

all animals

Time point:

other: 24h / 48h / 72h/

Score:

1.67

Max. score:

2

Reversibility:

fully reversible

Results 2

Irritation parameter:

erythema score

Basis:

animal #1

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

1.33

Max. score:

2

Reversibility:

fully reversible

Results 3

Irritation parameter:

erythema score

Basis:

animal #2

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

1.67

Max. score:

2

Reversibility:

fully reversible

Results 4

Irritation parameter:

erythema score

Basis:

animal #3

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

2

Max. score:

2

Reversibility:

fully reversible

Results 5

Irritation parameter:

edema score

Basis:

mean

Remarks:

all animals

Time point:

other: 24h / 48h / 72h

Score:

1.11

Max. score:

2

Reversibility:

fully reversible

Results 6

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

1

Max. score:

1

Reversibility:

fully reversible

Results 7

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

1.33

Max. score:

2

Reversibility:

fully reversible

Results 8

Irritation parameter:

edema score

Basis:

animal #3

Remarks:

mean

Time point:

other: 24h / 48h / 72h

Score:

1

Max. score:

1

Reversibility:

fully reversible

Other effects:

Scaling noted

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Hostapon SG as applied is not irritating to skin.

Executive summary:

The primary skin irritation potential of an aqueous solution of the registered UVCB substance (active content 25%) was investigated according to OECD test guideline no. 404. The test item was applied by topical semi-occlusive application of 0.5 mL to the intact left flank of each of three young adult New Zealand White rabbits. The duration of treatment was four hours. The scoring of skin reactions was performed 1, 24, 48 and 72 hours, as well as 7, 10 and 14 days after removal of the dressing. The mean score was calculated across 3 scoring times (24, 48 and 72 hours after patch removal) for each animal for erythema/eschar grades and for oedema grades, separately. The mean erythema/eschar score of the three animals was 1.33, 1.67 and 2.00, respectively and the mean oedema score was 1.00, 1.33 and 1.00, respectively. The application of Hostapon SG to the skin resulted in mild to moderate signs of irritation. These included erythema, oedema, scaling and dry / inelastic skin. In the male, these effects were reversible and were no longer evident 14 days after treatment. Both females were still observed with scaling of the skin on day 14 post treatment, the end of the observation period. The test item caused no staining of the treated skin. No corrosive effects were noted on the treated skin of any animal at any of the measuring intervals and no clinical signs were observed. Based on the results, the registered substance is not regarded a skin irritant according to EU classification criteria.