L-(+)-lactic acid

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference Type:

review article or handbook

Title:

Final report on the safety assessment of glycolic acid, ammonium, calcium, potassium, and sodium glycolates, methyl, ethyl, propyl, and butyl glycolates, and lactic acid, ammonium, calcium, potassium, sodium, and TEA-lactates, methyl, ethyl, isopropyl, …

Author:

Andersen, F.A.

Year:

1998

Bibliographic source:

International Journal of Toxicology 17 (Suppl. 1)

Materials and methods

Study type:

study with volunteers

Test material

Test material information

Constituent 1

Reference substance name:

Lactic acid

EC Number:

200-018-0

EC Name:

Lactic acid

Cas Number:

50-21-5

Molecular formula:

C3H6O3

IUPAC Name:

2-hydroxypropanoic acid

Method

Route of administration:

dermal

Details on study design:

A RIPT was completed using 99 of 115 initial subjects to determine the primary or cumulative irritation and/or sensitization potential of anhydrous emulsions containing 2.0, 3.0, 4.0, or 5.0% Lactic Acid (Consumer Product Testing Co., 1993c). Approximately 0.2 mL of each test material was applied for 24 h to the upper back (between the scapulae) of each subject using semi-occlusive patches three times/week for a total of 10 applications. Around 14 days after the last application, an open patch challenge application was made to the original site and to a previously untreated site on the volar forearm. The sites were scored 24 and 48 h after application.

Results and discussion

Results of examinations:

One subject had a response of mild erythema at the original test site 48 h after application of the formulation containing 2.0% Lactic Acid; another subject had the same response to the 3.0% formulation at the test site after 48 h. A third subject had a response of mild erythema to the 3.0, 4.0, and 5.0% Lactic Acid formulations at the previously untreated site. No responses were recorded for nthe other subjects. The three subjects that had a reaction were rechallenged as previously described for the original challenge. A reaction of nmild erythema was recorded after 24 h, but not 48 h, at the previously untreated site for the subject that had a reaction to the 2.0% formulation ; the response was considered weak and transitory and clinically ninsignificant. No reaction was observed upon rechallenge of the subject that had a reaction to the 3% formulation. Upon rechallenge of the subject that reacted to the 3.0, 4.0, and 5.0% Lactic Acid formulations, a response to the test materials of mild erythema was observed at the previously untreated site after 24 and 48 h; the researchers stated that the response could be due to hypersensitivity and could probably be considered clinically insignificant. The researchers concluded that studies with anhydrous microemulsions containing 2.0, 3.0, 4.0, and 5.0% Lactic Acid do not indicate a significant potential for dermal irritation or sensitization.

Applicant's summary and conclusion

Conclusions:

Based on the results presented in the review publication by Andersen, lactic acid in concentrations of up to 5% is not sensitizing to the skin in repeated insult patch tests.

Executive summary:

Based on the results presented in the review publication by Andersen, lactic acid in concentrations of up to 5% is not sensitizing to the skin in repeated insult patch tests.