2-methylpentane-1,5-diamine

Endpoint summary

Description of key information

There is no need for skin sensitisation studies to be conducted because the substance is classified for skin corrosion (Category 1A). Yet, the skin sensitisation potential of MPMD was assessed using guinea pigs, which revealed clear negative results. From one occupational exposure case report no clear conclusion can be drawn. In a further case report of patch testing 102 occupationally exposed patients towards components of epoxy resin systems no sensitisation against MPMD was found.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In general, there is no need for skin sensitisation testing in case of corrosive substances. This is due to reasons of animal protection and because testing for skin sensitisation proves to be challenging as well as interpretation of results is difficult. Nevertheless, available data on MPMD are presented.  

There are two skin sensitization tests (intracutaneous induction treatment) on guinea pigs with MPMD as test material. And observations on humans after occupational exposure are reported.

In an intracutaneous test 5 male and 5 female guinea pigs per dose group (5% or 0.5% of test substance) were subject to a skin sensitisation assay. First Primary irritation was tested (1 drop open epikutan). Two days thereafter 4 intradermal injections with 0.1 ml of 1% (v/v) emulsion (1 injection per week) followed. After challenge (done open epicutaneous; two weeks after last induction injection) with MPMD the animals in the 5% group showed mild erythema in the 24 and 48 h reading (5/10 and 2/10 animals). In the 0.5% test group no effects were observed. Positive control substance showed the expected positive result. According to the authors MPMD is no skin sensitiser.

In another intracutaneous guinea pig test (conducted as described above) 10 male guinea pigs were treated with two concentrations of MPMD each (10% or 1% of test substance). After challenge with the test substance animals in the 10% group showed very slight erythema in the 24 and 48 h reading (i.e. 8/10 and 10/10 animals). In the corresponding control group (animals were only treated once with the test substance during challenge) 8/10 animals showed also slight erythema in the 24 and 48 h reading, revealing the irritant potential of the test substance at this concentration level. In the 1% test group no effects were observed. According to the authors MPMD is no skin sensitiser.

 

 

There are two publications which deal with sensitisation to MPMD in humans:

 

Darr-Foit et al. (2016) report a positive patch test reaction to MPMD of a 63-year old male worker with a 4-year history of work-related contact dermatitis due to handling of epoxy resin systems. However, the authors state that it was probable that the patient was co-sensitized by co-exposure to MPMD and m-xylene diamine, as he handled an epoxy resin system containing both substances. Therefore, no clear conclusion can be drawn from this publication.

 

Another publication is from Suomela et al. (2022). In this analysis the authors searched patch test files from 102 patients that were examined between January 2017 and December 2020 regarding occupational contact allergy to epoxy compounds at The Finnish Institute of Occupational Health (FIOH). No sensitisation against MPMD was found in any of the 102 patients. The patch tests were conducted according to the European Society of Contact Dermatitis guideline for diagnostic patch testing (Johansen et al., 2015).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

As described in the section on skin irritation/corrosion and eye irritation, the substance is very alkaline and therefore exhibits corrosive properties. Due to these substance properties, testing for skin sensitisation proves somewhat challenging and interpretation of results is difficult, as indicated by the supporting studies presented. No clear conclusions can be drawn from the case study with occupational exposure to MPMD, but patch testing results of the FIOH of allergic dermatitis patients against substances of epoxy resin systems did not reveal any sensitisation potential of MPMD. Together with the negative results from the guinea pig studies with MPMD, no classification for skin sensitizing properties according to Regulation (EC) No 1272/2008 is proposed.