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Diss Factsheets

Administrative data

Description of key information

There are no reliable studies available for the assessment of the skin sensitisation endpoint with the target substance, lactic acid. Therefore, data from a suitable read-across partner, L(+)-lactic acid was used to assess the skin sensitisation potential of lactic acid. For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

In a GLP-compliant Buehler test conducting according to EPA OPP 81-6 with L(+)-lactic acid, at all concentrations tested ( 3, 10, 30 and 100 % (w/w)), skin response to challenge is qualitatively and quantitatively indistinguishable from skin response to initial induction, or to skin response in a naive control which is not an indication of sensitization. Therefore, classification for skin sensitisation according to the CLP Regulation 1272/2008 is not warranted.

Supporting evidence is derived from the results presented in the review publication by Andersen, 1998. The author presented results from a guinea pig maximization and human repeated insult patch test (see IUCLID section 7.10.4). Both tests showed, that the tested substance lactic acid (CAS 50-21-5) is not inducing skin sensitization.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.
Reason / purpose for cross-reference:
read-across source
Positive control results:
Erythema and edema according to Draize (1979) and for other dermal reactions at 24 and 48 hours following each induction and challenge application. Results are presented for testing on 3 groups of 10 guinea pigs. In the first 24 hrs of the challenge test, 8, 8 and 10 out of 10 animals showed positive sensitization reaction to the positive control (DNCB), and 48 hours after the beginning of the test, 8, 8 and 9 out of 10 animals still presented positive reaction to DNCB.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100% test material
No. with + reactions:
9
Total no. in group:
10
Clinical observations:
All effects observed were deemed irritation, not sensitization
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100% test material
No. with + reactions:
8
Total no. in group:
10
Clinical observations:
All effects observed were deemed irritation, not sensitization
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100% test material
No. with + reactions:
9
Total no. in group:
10
Clinical observations:
All effects observed were deemed irritation.
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100% test material
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
All effects observed were deemed irritation.
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.5 mL of 0.1% DCNB
No. with + reactions:
28
Total no. in group:
30
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.5 mL of 0.1% DCNB
No. with + reactions:
25
Total no. in group:
30
Remarks on result:
positive indication of skin sensitisation
Interpretation of results:
other: CLP criteria not met
Conclusions:
Based on the result the test item is not considered to be sensitising to the skin. Therefore, classification for skin sensitisation according to the CLP Regulation 1272/2008 is not warranted.
Executive summary:

This study was conducted to evaluate the contact dermal sensitization potential of L(+)-lactic acid using a method described in the EPA Guidelines, 1982 (modification of the Buehler Closed Patch Technigue) as described in American Biogenics Corporation (ABC) protocol A330. No mortalities occurred and all animals gained body weight. The test article (100%) produced very slight erythema at 3 sites and very slight edema at l site after the Ist induction. Erythema grades increased in severity after the 2nd induction application. One site was graded as severe erythema, however, this grade was given a 4 due to pinpoint pitting of the skin and scab formation, not for redness. Due to the increase of severity of the reactions, the concentration of the test article was reduced to 30% and the induction site was changed to the left flank. Very slight erythema was noted after the 5th induction application. Grades ranging from very slight to severe erythema were noted from the 7th to the 9th induction applications. Again, the severe (grade 4) reactions were given this grade due to pinpoint pitting of the skin and the eschar formation, not for redness.

After the challenge application, the test article (100%) produced grade 4 erythema in up to 6 test animals. These gradings were very sirnilar in character as those seen during the induction pplications, that is, pinpoint pitting of the skin and eschar formation, very little redness. These reactions were considered to be irritation reactions, not sensitization reactions. Other reactions noted at challenge for the test animals were very slight to moderate erythema, and very slight to moderate edema. The test article (100%) produced grade 4 erythema in up to 8 naive control animals. These gradings were also pinpoint pitting of skin and eschar formation with very little redness. These reactions were considered to be irritation reactions, not sensitization reactions. Other reactions noted for the naive control animals were very slight to moderate erythema and very slight to moderate edema. The reactions seen in the naive control animals at the challenge application were similar to the reactions seen for the test group animals and L(+)-lactic acid was not considered to be a contact dermal sensitizer.

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Species:
guinea pig
Remarks on result:
no indication of skin sensitisation

Based on the results from a maximization study using guinea pigs, lactic acid at a concentration of 10% can be considered as non-sensitizer.

Interpretation of results:
other: not sensitizing
Conclusions:
Based on the results from a maximization study using guinea pigs, lactic acid at a concentration of 10% can be considered as non-sensitizer.
Executive summary:

Based on the results from a maximization study using guinea pigs, lactic acid at a concentration of 10% can be considered as non-sensitizer.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

There are no reliable studies available for the assessment of the skin sensitisation endpoint with the target substance, lactic acid. Therefore, data from a suitable read-across partner, L(+)-lactic acid was used to assess the skin sensitisation potential of lactic acid. For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

The contact dermal sensitization potential of L(+)-lactic acid was investigated using a modified Buehler Closed Patch Test. No mortalities occurred and all animals gained body weight. The test article (100%) produced very slight erythema at 3 sites and very slight oedema at 1 site after the 1st induction. Erythema grades increased in severity after the 2nd induction application. One site was graded as severe erythema, however, this grade was given a 4 due to pinpoint pitting of the skin and scab formation, not for redness. Due to the increase of severity of the reactions, the concentration of the test article for induction was reduced to 30% and the induction site was changed to the left flank. Very slight erythema was noted after the 5th induction application. Grades ranging from very slight to severe erythema were noted from the 7th to the 9th induction applications. Again, the severe (grade 4) reactions were given this grade due to pinpoint pitting of the skin and the eschar formation, not for redness.

After the challenge application, the test article (100%) produced grade 4 erythema in up to 6 test animals. These gradings were very similar in character as those seen during the induction applications, that is, pinpoint pitting of the skin and eschar formation, very little redness. These reactions were considered to be irritation reactions, not sensitization reactions. Other reactions noted at challenge for the test animals were very slight to moderate erythema, and very slight to moderate oedema. The test article (100%) produced grade 4 erythema in up to 8 naive control animals. These gradings were also pinpoint pitting of skin and eschar formation with very little redness. These reactions were considered to be irritation reactions, not sensitization reactions. Other reactions noted for the naive control animals were very slight to moderate erythema and very slight to moderate oedema. The reactions seen in the naive control animals at the challenge application were similar to the reactions seen for the test group animals and the test substance was not considered to be a contact dermal sensitizer.

Supporting evidence is derived from the data presented in the review publication by Andersen, 1998. The author presented results from a guinea pig maximization and human repeated insult patch test. Both tests showed, that the tested substance lactic acid (CAS 50-21-5) is not inducing skin sensitization.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available data,classification for skin sensitisation is not warranted according to CLP Regulation 1272/2008.