Registration Dossier

Administrative data

Description of key information

Based on read-across from the GPMT results for DMPT, HIDT would not appear to be a skin sensitizer.

However, this is superseded by company data on skin sensitisation due to occupational human exposure to the main component DMDS. The category hypothesis for ‘Mercaptocarboxilic acids, their salts and derived esters’ suggests that DMDS is a strong sensitizer by virtue of its two thiol groups.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
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:
see attached justification
Reason / purpose:
read-across source
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The LLNA was not yet validated at the time of the study.
Species:
guinea pig
Route:
intradermal
Vehicle:
paraffin oil
Concentration / amount:
0.2%
Day(s)/duration:
Day 0
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
1.0%
Day(s)/duration:
Day 7, 48 h
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
0.005%
Day(s)/duration:
Day 21, 24 h
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
22
Challenge controls:
22 naive (sham-induced) animals
Positive control substance(s):
yes
Remarks:
DNCB, 0.1% (ethanol), 1.0% (petrolatum), 0.025% (petrolatum) for intradermal induction, topical induction, and challenge, respectively.
Positive control results:
22/22 of animals showed skin reactions
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.005%
No. with + reactions:
0
Total no. in group:
22
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.005%
No. with + reactions:
0
Total no. in group:
22
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
0.005%
No. with + reactions:
0
Total no. in group:
22
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
0.005%
No. with + reactions:
0
Total no. in group:
22
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.025%
No. with + reactions:
22
Total no. in group:
22
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.025%
No. with + reactions:
22
Total no. in group:
22
Remarks on result:
positive indication of skin sensitisation
Interpretation of results:
Category 1A (indication of significant skin sensitising potential) based on GHS criteria
Conclusions:
Based on read-across from the GPMT results for DMPT, DMDS would not appear to be a skin sensitizer.
However, this is superseded by company data on skin sensitisation due to occupational exposure. The category hypothesis for ‘Mercaptocarboxilic acids, their salts and derived esters’ suggests that DMDS is a strong sensitizer by virtue of its two thiol groups.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification