(R)-lactic acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

L-(+)-lactic acid

EC Number:

201-196-2

EC Name:

L-(+)-lactic acid

Cas Number:

79-33-4

Molecular formula:

C3H6O3

IUPAC Name:

(2S)-2-hydroxypropanoic acid

Test animals

Species:

guinea pig

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: applied neat

Controls:

not required

Amount / concentration applied:

Concentration: 88 % aqueous solution

Duration of treatment / exposure:

3 min, 1h, 4 h

Observation period:

72h after patch removal

Number of animals:

6

Details on study design:

The animals were divided into 2 groups of 3. The hair was clipped from both flanks of all animals approximately 24 h prior to patch application. Care was taken to avoid abrading the skin. In Group l, 0.5 mL of the test material was applied under 2 gauze patches each measuring 2.5 cm x 2.5 cm (6 cm²). The patches were applied to the intact skin and covered with Micropore tape. The whole trunk was then bound with Elastoplast elastic bandage to give a semi-occlusive covering.
Group 2 animals were treated in a similar fashion except that the material was applied under one patch.
For Group l animals the first patch was removed 3 min after application and the skin gently washed with water to remove any residual test material. Reactions were scored. One hour after application the second patch was removed, the skin washed and reactions scored. The patch for Group 2 animals was left in place for 4 h before removal and scoring.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 1h

Score:

1

Max. score:

8

Reversibility:

fully reversible within: 24h

Remarks on result:

other: Only observed with 4h exposure

Results 2

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24h

Score:

0

Max. score:

8

Results 3

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 48h

Score:

0

Max. score:

8

Results 4

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 72h

Score:

0

Max. score:

8

Results 5

Irritation parameter:

erythema score

Basis:

mean

Time point:

other: 1h

Score:

1

Reversibility:

fully reversible within: 24 h

Remarks on result:

other: Only observed with 4h exposure

Results 6

Irritation parameter:

erythema score

Basis:

mean

Time point:

24 h

Score:

0

Results 7

Irritation parameter:

erythema score

Basis:

mean

Time point:

48 h

Score:

0

Results 8

Irritation parameter:

erythema score

Basis:

mean

Time point:

72 h

Score:

0

Results 9

Irritation parameter:

edema score

Basis:

mean

Time point:

other: 1h

Score:

0

Results 10

Irritation parameter:

edema score

Basis:

mean

Time point:

24 h

Score:

0

Results 11

Irritation parameter:

edema score

Basis:

mean

Time point:

48 h

Score:

0

Results 12

Irritation parameter:

edema score

Basis:

mean

Time point:

72 h

Score:

0

Irritant / corrosive response data:

No irritation was noted in Group l animals at either 3 min or 1 h at the exposed sites. In Group 2, for which expsoure was 4h, very slight erythema was noted in all animals. By 24 h after exposure, skin appeared normal. It is concluded from the test results that Lactic Acid Q88 is not corrosive to guinea pig skin. It is also noted that irritation after 4 h exposure was transient and limited to very mild erythema.

Applicant's summary and conclusion

Interpretation of results:

other: not irritating

Conclusions:

Under the given conditions, the test item is not irritating to the skin.

Executive summary:

The corrosivity potential of a test material, Lactic Acid Q88, was investigated by means of a test in guinea pigs. The test was designed to assess irritancy and/or corrosivity by means of topical application of the test material to intact skin under semi occlusive conditions for various exposure times: 3 min, 1h and 4h. Two groups of 3 animals were used. In group 1 exposures of 3 min and 1h were investigated while 4 h exposures were investigated in group 2.

No irritation or corrosion were noted in animals exposed to Lactic Acid Q88 for 3 min and 1h. Responses in animals exposed to the test material for 4 h were limited to very slight erythema which was noted at patch removal and 1 h after patch removal. Skin appeared normal at 24 h after patch removal.