Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

For risk assessment purposes, the oral absorption is set at 50% and the dermal and inhalation absorption is set at 100%.

Key value for chemical safety assessment

Absorption rate - oral (%):
Absorption rate - dermal (%):
Absorption rate - inhalation (%):

Additional information

MMDS is a solid and is hydrolytically unstable in water and aqueous solutions. Physical chemical characteristics of MMDS requiring studies in aqueous surroundings (as water solubility, octanol/water partition coefficient and surface tension) can therefore not be determined on MMDS. MMDS will decompose rapidly in formaldehyde and MSDA. As the assessment will be performed for MMDS, the toxicokinetic behavior of MSDA and formaldehyde is not further considered.


As the physical chemical properties of the substance determine the toxicokinetic properties of MMDS for a toxicokinetic assessment, and the essential values for MMDS are not available, worst-case estimates are proposed for MMDS, according to REACH guidance (1,2).


For oral absorption, the worst-case value is considered 50% (2). The results of the toxicity studies do not provide reasons to deviate from this proposed oral absorption factor.


Based on the particle size of MMDS, the mass median aerodynamic diameter of MMDS is 192.481 µm. Particles < 100μm which have a potential to be inhaled, are present (10% < 59.316 µm and 2.26% < 10 µm). For risk assessment purposes in the scope of EU REACH,the inhalation absorption of MMDS is set at 100%, as a worst-case estimate (1,2).


Based on the relatively low molecular weight (188.179)and in the absence of a logPow, the criteria for 10% dermal absorption as given in the guidance (1) (MW > 500 and logPo/w > 4) are not met and hence 100% dermal absorption is proposed. The results of the toxicity studies do not provide reasons to deviate from this proposed dermal absorption factor.

Normally, it is generally accepted that dermal absorption is lower compared to oral absorption. However, since the 50% oral absorption is set in absence of further data, the 100% dermal absorption should therefore be considered a worst case assumption.