Methyl (R)-lactate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

June 26, 1995 - July 10, 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl (S)-2-hydroxypropionate

EC Number:

211-694-1

EC Name:

Ethyl (S)-2-hydroxypropionate

Cas Number:

687-47-8

IUPAC Name:

ethyl 2-hydroxypropanoate

Constituent 2

Reference substance name:

Ethyl lactate

EC Number:

202-598-0

EC Name:

Ethyl lactate

Cas Number:

97-64-3

IUPAC Name:

ethyl 2-hydroxypropanoate

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF bred New Zealand White albino rabbits were obatined from the Broekmans Institue, Someren, the Netherlands
- Age at study initiation: males, young adult
- Weight at study initiation: 2130-2220 g
- Housing:individually in stainless steel cages, fitted with perforated floor
- Diet (e.g. ad libitum): standard laboratory rabbit diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 6/7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3°C
- Humidity (%): 52.5-75%
- Air changes (per hr): ca 10 air changes/hours
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark cycle

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipping

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

an amount of 0.5 ml of the test substance was distributed over a patch measuring 2.5 x 2.5 cm.

Duration of treatment / exposure:

4 hours

Observation period:

14 days

Number of animals:

3

Details on study design:

Three or four days prior to the start of the study, the hair was removed from the back and flanks of the animals using electric clippers in a way as to avoid abrasions. One day prior to application of the test material, the skin site was inspected for hair growth and the clipping was repeated. Just prior to application, a skin site suitable for application was selected on the clipped back and flanks of the animal. An amount of 0.5 ml of the test substance was distributed over a patch measuring 2.5 x 2.5 cm. The patch loaded with the test substance was fixed tot the selected apllication site by means of adhesive tape. Subsequently, the entire trunk of the rabbit was wrapped with self-adhesive-gauze to maintain the patch in postion and to retard evaporation of volatile substances. The gauze was additionaly fastened with two stripes of tape. After a 4-hour exposure period, the test substance and patch were removed and the test site was cleaned with a moistened tissue. Circa 1 hour later, the resulting skin reactions wer evaluated by the method of Draize et al. (J. Pharmacol. Exp. Ther. 82 (1994) 377-390). Further skin readings were made at approximately 24, 48 and 72 hours, and at 7 and 14 days after treatment.

Results and discussion

In vivo

Results

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 1

Score:

0

Max. score:

0

Irritant / corrosive response data:

Table 1 - Skin irritation scores of ethyllactate , after a single 4-hour dermal exposure

Animal no. Hours or days after removal of the test material:
1 hr 24 hr 48 hr 72 hr 7 d
A-B A-B A-B A-B A-B
12 0-0 (1-1) 0-0 (2-2) 0-0 (2-2) 0-0 (2-1) 0-0
8 0-0 (1-1) 0-0 (2-2) 0-0 (2-2) 0-0 (2-1) 0-0
14 0-0 (1-1) 0-0 (1-1) 0-0 0-0
Erythema (A): 0.0 0.0 0.0 0.0 0.0
Oedema (B): 0.0 0.0 0.0 0.0 0.0

() Skin effects were located on a very small skin area on the edge of the application area (width less than 1 mm), most probably caused by pressure of the bandage on the test patch underneath. Therefore, the toxicological significance of these skin effects is considered dubious.

Other effects:

At 7 days after treatment, slight scaliness was observed in the two rabbits that showed skin irritation during the first days on the edges of the application area (<1 mm) only. At 14 days after treatment, the scaliness had cleared.

Any other information on results incl. tables

Table 1 - Skin irritation scores of ethyllactate, after a single 4-hour dermal exposure

Animal no.	Hours or days after removal of the test material:
	1 hr	24 hr	48 hr	72 hr	7 d
	A-B	A-B	A-B	A-B	A-B
12	0-0 (1-1)	0-0 (2-2)	0-0 (2-2)	0-0 (2-1)	0-0
8	0-0 (1-1)	0-0 (2-2)	0-0 (2-2)	0-0 (2-1)	0-0
14	0-0 (1-1)	0-0 (1-1)	0-0	0-0
Erythema (A):	0.0	0.0	0.0	0.0	0.0
Oedema (B):	0.0	0.0	0.0	0.0	0.0

 

() Skin effects were located on a very small skin area on the edge of the application area (width less than 1 mm), most probably caused by pressure of the bandage on the test patch underneath. Therefore, the toxicological significance of these skin effects is considered dubious.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Ethyl lactate is not irritating or corrosive to (human) skin

Executive summary:

In a acute dermal irritation study, 3 young adult male SPF bred New Zealand White albino rabbits (weight 2130 -2220 g) were dermally exposed to 0.5 ml of undiluted ethyllactate to an area of 2.5 x 2.5 cm. Test sites were covered with an occlusive dressing for 4 hours. Animals were the observed for 14 days. Irritation was scored by the method of Draize et al.. Only mild skin effects were observed on a very small skin area on the edge of the application area, most probably by pressure of the bandage on the test patch underneath. Since normally these kind of exposure conditions will not occur in humans, the toxicological significance of these skin effects is considered dubious. In this study, ethyl lactate is not a dermal irritant.