Methanesulphonic acid

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

modified grading timings for evaluation

GLP compliance:

yes

Type of study:

Buehler test

Species:

guinea pig

Strain:

Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley Inc. (P.O. Box 29176, Indianapolis, Indiana 46229)
- Weight at study initiation: 429.6±18.8 g (males), 400.5±27.6 g (females)
- Housing: single
- Diet (e.g. ad libitum): Teklad Guinea Pig Diet
- Water (e.g. ad libitum): tap water
- Acclimation period: 4 days


ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12/12

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

Induction: 35 % MSA
Challenge: 17.5 % MSA

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

Induction: 35 % MSA
Challenge: 17.5 % MSA

No. of animals per dose:

10 males, 10 females (controls: 5 males, 5 females)

Details on study design:

RANGE FINDING TESTS:
A preliminary study was conducted in order to determine the concentrations to be tested in the main study. The irritation potential of methane sulfonic acid (MSA) 70 % at levels of undiluted, 50 %, 25 %, 10 %, 5 %, 2.5 %, 1.0 % and 0.5 % was evaluated in 2 groups of 4 animals each. Four levels of test substance were evaluated per animal. Dilutions were obtained with distilled water (w/v). 0.3 ml of the different concentrations were applied into 25 mm Hill Top Chambers, which were placed on the animals clipped back for 6 hours. On the next day the animals were depilated and two hours later examined for irritation, according to the grading scores (0: no reaction; : slight, patchy erythema; 1: slight but confluent or moderate patchy erythema; 2: moderate erythema; 3: severe erythema with or without edema). Another examination was performed 40 hours after exposure. Undiluted 70 % produced grades of 2,1 and ± with edema, blanching, and scabbing on two sites, 50 %, 25 %, 10 %, 5 %, 2.5 %, 1.0 % produced grades of ±, while 0.5% produced grades of ± and 0. A 50 % w/v concentration of MSA 70% in distilled water was chosen for use at induction for the test group. The level was chosen as the highest concentration causing no greater than mild to moderate primary irritation.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test groups: 0.3 ml of the test substance
- Control group: 0.3 ml vehicle
- Site: left shoulder
- Frequency of applications: on day 1, 7 and 14
- Duration: 14 days
- Concentrations: 50 % (w/v of MSA 70%)


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 28
- Exposure period: 24 hours
- Test groups: 0.3 ml of test substance
- Control group: 0.3 ml of test substance
- Site: right flank
- Concentrations: 25 % (w/v of MSA 70%)
- Evaluation (hr after challenge): 24 hours

Challenge controls:

No extra group necessary: control group was challenged with test substance, as well, because induction exposure with distilled water is not expected to induce any sensitization.

Positive control substance(s):

no

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

17.5 %

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no clinical signs

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 17.5 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no clinical signs.

Reading:

2nd reading

Hours after challenge:

40

Group:

test chemical

Dose level:

17.5%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no clinical signs

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 40.0. Group: test group. Dose level: 17.5%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no clinical signs.

None of the test animals responded with a skin grade that would have been suggestive of sensitization. No data on clinical signs was revealed.

Interpretation of results:

not sensitising

Remarks:

Migrated information

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

According to the information requirements for REACH (column 2 of Annex VIII) in vivo testing for skin sensitisation does not need to be conducted because the substance is classified as corrosive to the skin (pH <2).

Nevertheless, key information is available from a study (ElfAtochem 1995) stating that the substance did not cause skin sensitisation in guinea-pigs in the Buehler Test following the OECD test guideline 406. Ten male and ten female guinea pigs received 3 induction exposures via topical dermal application with 0.3 ml of 35 % methanesulfonic acid on their left shoulder for 6 hours on day 1, 7 and 14. On day 28, the animals were epicutaneously treated for 24 hours with 0.3 ml of 17.5 % methanesulfonic acid on their right flank as challenge exposure. None of the test animals responded with a skin grade that was suggestive of sensitization.

Summerising the substance is not a skin sensitizer in an animal test.

Migrated from Short description of key information:
Methanesulphonic acid (MSA) is not sensitizing in a OECD 406 (Bühler Test).

Respiratory sensitisation

Endpoint conclusion

Additional information:

This information is not available.

Justification for classification or non-classification

Based on the information available, no further classification for sensitisation is needed.

EU classification according to Annex I of Directive 67/548/EEC: no classification required

GHS classification (GHS UN rev.3, 2009): no classification required