Metam-sodium

Endpoint summary

Description of key information

The skin sensitization potential of target chemical Metam-sodium (CAS no: 137-42-8) was assessedin various experimental studies which were conducted on guinea pigs.Based on the available key data and supporting studies,it can be concluded thatchemical Metam-sodium (CAS no: 137-42-8) is able to cause skin sensitization and considered as sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Skin Sensitizer”.

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:

data from handbook or collection of data

Justification for type of information:

data from handbook or collection of data

Qualifier:

according to guideline

Guideline:

other: not fully in agreement with Dir 96/54/EEC Annex IV C or 92/69-84/449 or OECD 406 (1981-92).

Principles of method if other than guideline:

The skin sensitization study was conducted on guinea pigs to determine delayed contact hypersensitivity of test chemical Metam-sodium (CAS no: 137-42-8).

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

not specified

Specific details on test material used for the study:

- Name of test material : Metam-sodium
- Common name: Sodium methyldithiocarbamate
- Molecular formula : C2H4NNaS2
- Molecular weight : 129.1826 g/mol
- Smiles notation : C(=S)(NC)[S-].[Na+]
- InChl : 1S/C2H5NS2.Na/c1-3-2(4)5;/h1H3,(H2,3,4,5);/q;+1/p-1
- Substance type: Organic
- Physical state: Solid

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

not specified

Route:

intradermal and epicutaneous

Vehicle:

other: distilled water

Concentration / amount:

- Induction phase: metam sodium at 5% in water and metam sodium at 5% in a 50:50 mixture of Freund’s complete adjuvant and
water.
-Topical application of 2.5% v/v in water.

Day(s)/duration:

No data available

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: distilled water

Concentration / amount:

1% and 0.5%

Day(s)/duration:

72 hours

Adequacy of challenge:

not specified

No. of animals per dose:

20

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and topical)
- Exposure period: no data
- Test groups: 20
- Control group: no data
- Site: no data
- Frequency of applications: no data
- Duration: no data
- Concentrations: - Induction phase: metam sodium at 5% in water and metam sodium at 5% in a 50:50 mixture of Freund’s complete adjuvant and
water.
-Topical application of 2.5% v/v in water.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: after 2 weeks
- Exposure period:no data
- Test groups: no data
- Control group: no data
- Site: at two sites of each animal
- Concentrations: 1% or 0.5%
- Evaluation (hr after challenge): 24/48/72 hours

Vehicle:

not specified

Reading:

1st reading

Hours after challenge:

72

Group:

test chemical

Dose level:

1% and 0.5%

No. with + reactions:

19

Total no. in group:

20

Clinical observations:

Metam sodium produced evidence of delayed contact hypersensitivity in 19 guinea pigs.

Remarks on result:

positive indication of skin sensitisation

Cellular proliferation data / Observations:

Metam sodium produced evidence of delayed contact hypersensitivity in 19 guinea pigs.

Interpretation of results:

other: Sensitizing

Conclusions:

The test chemical Metam-sodium (CAS no: 137-42-8) was considered to be sensitizing to the skin of guinea pigs.

Executive summary:

The skin sensitization study was conducted on 20 female Dunkin-Hartley guinea pigs to determine delayed contact hypersensitivity of test chemical Metam-sodium (CAS no: 137-42-8).

 

During the induction phase, the Guinea pigs were treated at 5% in water and metam sodium at 5% in a 50:50 mixture of Freund’s complete adjuvant and water intradermally and at 2.5% v/v in water topically.

After a rest period of 2 weeks, the animals were challenged using metam sodium at 1% and 0.5% v/v in water applied at two sites of each animal. The challenge sites were evaluated 24, 48, and 72 h after removal of the patches.

 

Metam sodium produced evidence of delayed contact hypersensitivity in 19 guinea pigs. Therefore, thechemicalMetam-sodium (CAS no: 137-42-8)was considered to be sensitizing to the skin of guinea pigs.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Various studieshas been investigated for the test chemicalMetam-sodium (CAS no: 137-42-8)to observe the potential for skin sensitization to a greater or lesser extent. The studies are based on in vivo experiments in guinea pigs for target chemicalMetam-sodium (CAS no: 137-42-8) which have beensummarized as below;

 

The skin sensitization study was conducted by authoritative databases on 20 female Dunkin-Hartley guinea pigs to determine delayed contact hypersensitivity of test chemical Metam-sodium (CAS no: 137-42-8). During the induction phase, the Guinea pigs were treated at 5% in water and metam sodium at 5% in a 50:50 mixture of Freund’s complete adjuvant and water intradermally and at 2.5% v/v in water topically. After a rest period of 2 weeks, the animals were challenged using metam sodium at 1% and 0.5% v/v in water applied at two sites of each animal. The challenge sites were evaluated 24, 48, and 72 h after removal of the patches. Metam sodium produced evidence of delayed contact hypersensitivity in 19 guinea pigs. Therefore, thechemicalMetam-sodium (CAS no: 137-42-8)was considered to be sensitizing to the skin of guinea pigs.

 

A Buehler test was conducted by same authoritative databases on guinea pigs to assess the skin sensitization potential of test chemical Metam-sodium (CAS no: 137-42-8). A solution of 1%Metam-sodiumtechnical (technical formulation containing 32.9% methylcarbamodithionic acid monosodium salt as active ingredient; in bidistilled water) was used for the 10 induction applications over a period of 4 weeks.Later, the animals were challenged with 1% or 0.1% test chemical on day 35, 42 and 49.Since the chemical induced skin sensitization, the chemicalMetam-sodium (CAS no: 137-42-8) was considered to be sensitizing to the skin of guinea pigs.

 

The above results were supported by anotherBuehler testconducted by other review articles on guinea pigs to determine the skin sensitization potential of test chemical Metam-sodium (CAS no: 137-42-8). The treated guinea pigs showed contact sensitization when the chemical was applied dermally at dose of 32.5%. Therefore, thechemicalMetam-sodium (CAS no: 137-42-8)was considered to be sensitizing to the skin of guinea pigs.

 

The overall results were further supported by the Buehler test conducted on guinea pigs to assess the skin sensitization potential of test chemical Metam-sodium (CAS no: 137-42-8).Approximately 1% was used for the 10 induction applications of 6 hours for a 3-week period. Later on day 35, 42 and 49, animals were challenged with 1% and reachallenged with 0.1%.The chemical caused skin sensitization in treated animals. Hence the test chemicalMetam-sodium (CAS no: 137-42-8)was considered to be sensitizing to the skin of guinea pigs.

 

Based on the available key data and supporting studies,it can be concluded thatchemical Metam-sodium (CAS no: 137-42-8) is able to cause skin sensitization and considered as sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Skin Sensitizer”.

 

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitization potential of test substance Metam-sodium (CAS no: 137-42-8) were observed in various studies. From the results obtained from these studies it is concluded that the chemical Metam-sodium (CAS no: 137-42-8) is likely to cause skin sensitization and hence can be classified as skin sensitizer.