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Diss Factsheets

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report date:
1995

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
This study was performed before the implementation of the REACH regulation.

Test material

Constituent 1
Chemical structure
Reference substance name:
Methanesulphonic acid
EC Number:
200-898-6
EC Name:
Methanesulphonic acid
Cas Number:
75-75-2
Molecular formula:
CH4O3S
IUPAC Name:
methanesulfonic acid
Test material form:
liquid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ORGANISMS:
- Strain: Hartley
- Sex: male and female
- Source: Harlan Sprague Dawley (P.O. Box 29176, Indianapolis, Indiana 46229)
- Age: no data
- Weight at study initiation: 429.6 ± 18.8 (males), 400.5 ± 27.6g (females)

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
35%
Day(s)/duration:
days 1, 7 and 14
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
17.5%
Day(s)/duration:
Day 28
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Test group: 10 males and 10 females
Control group: 5 males and 5 females
Details on study design:
ADMINISTRATION:
- Induction schedule:
- On day 1, dermal application with 0.3 ml of test substance (treated group) or with the vehicle (control group) on the left shoulder.
- On day 7, the same region received another topical application
- On day 14, this same site was treated by a last topical application
All these applications lasted approximately 6 hours.
- Concentration in Freunds Complete Adjuvant (FCA): not used here
- Challenge schedule: On day 28, all the animals received 0.3 ml of the test substance at the concentration of 25% (of the 70% solution) in their right flank.
- Challenge exposure duration : 24h
- Rechallenge: no
- Positive control: no
- Other:

EXAMINATIONS:
- Examination schedule: 24h after each induction an challenge application.
- Grading system:
0: no reaction
±: slight, patchy erythema
1: slight but confluent or moderate patchy erythema
2: moderate erythema
3: severe erythema with or without oedema.

- Pilot study: Yes
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 70% at levels of undiluted, 50%, 25%, 10%, 5%, 2.5%, 1% and 0.5% was evaluated in two groups of four animals each. Four levels of test material were evaluated per animals.
Dilutions were obtained with distilled water (w/v).
0.3 ml of different solutions was applied into a 25 mm Hill Top Chamber, which were placed on animals clipped back for 6 hours. The day after, animals were depilated and two hours later, examined for irritation, according the previously described scale.
Another score was performed 40h after exposure.
Positive control substance(s):
yes
Remarks:
alpha-Hexylcinnamaldehyde

Results and discussion

Positive control results:
alpha-Hexylcinnamaldehyde at 5% in acetone induced skin reactions of sensitization in 7/10 guine pigs

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
17.5% aqueous methane sulfonic acid
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 17.5% aqueous methane sulfonic acid. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
17.5% aqueous methane sulfonic acid
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 17.5% aqueous methane sulfonic acid. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
17.5% aqueous methane sulfonic acid
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 17.5% aqueous methane sulfonic acid. No with. + reactions: 0.0. Total no. in groups: 9.0.
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
17.5% aqueous methane sulfonic acid
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 17.5% aqueous methane sulfonic acid. No with. + reactions: 0.0. Total no. in groups: 9.0.
Group:
positive control
Remarks on result:
not measured/tested

Any other information on results incl. tables

RESULTS OF PILOT STUDY:
Undiluted methane sulfonic acid 70% produced grades of 2, 1 and ±, with oedema, blanching and scabbing on two sites.
Dilutions at 50%, 25%, 10%, 5%, 2.5% and 1% produced grades of ±, while 0.5% produced grades of ± and 0.
Consequently, the 50% dilution was chosen for use at induction for the test group, since it caused no greater than mild to moderate primary irritation. Moreover, the 25% dilution was selected for challenge, because it caused no more than slight irritation.

RESULTS OF TEST
- Sensitization reaction: None of the test animals responded with a skin grade that would have been suggestive of sensitization.
- Clinical signs: no data

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
20 guinea-pigs were induced by 50% of methane sulfonic acid 70% solution (i.e. 35% of methane sulfonic acid) and challenged by 25% of methane sulfonic acid 70% solution (i.e. 17.5% of methane sulfonic acid). None of the test animals responded with a skin grade that would have been suggestive of sensitization.
Executive summary:

The potential of 70% aqueous methane sulfonic acid, to produce delayed contact hypersensitivity in guinea pigs was evaluated using an adaptation of the method of Ritz and Buehler. 70% aqueous methane sulfonic acid was evaluated for primary irritation at levels of undiluted, 50%, 25%, 10%, 5%, 2.5%, 1%, and 0.5%. All formulations were prepared w/v in distilled water. Undiluted 70% aqueous methane sulfonic acid produced grades of 2, 1, and ± with edema, blanching, and scabbing on two sites, 50%, 25%, 10%, 5%, 2.5%, and 1% produced grades of ±, while 0.5% produced grades of ± and 0. A 50% w/v concentration of 70% aqueous methane sulfonic acid in distilled water was chosen for use at induction for the test group. This level was chosen as the highest concentration causing no greater than Mild to moderate primary irritation. Undiluted distilled water was utilized at induction for the vehicle control group. An 25% w/v concentration of 70% aqueous methane sulfonic acid in distilled water was chosen for use at primary challenge for the test group and the vehicle control group. This level was chosen as the highest concentration causing no more than slight primary irritation. None of the test animals or control animals responded with a skin grade that would have been suggestive of sensitization.