Reaction mass of [(2-substituted-4-nitroaryl)diazenyl]methyl(arylamino)-[(2-arylethyl)amino]pyridinecarbonitrile and [(2-substituted-4-nitroaryl)diazenyl]methyl(arylamino)-[(2-arylethyl)amino]pyridine-3-carbonitrile

Particle size distribution (Granulometry)

Description of key information

The particle size distribution of laboratory material of FAT 41030 is approximately 0.3 µm to 20 µm with a mass median diameter (MMD) of 4.4 µm, whereas of the material placed on the market, the majority of particles is > 100 µm thus belonging to the fraction non-inhalable by humans. The remaining particles placed on the market will not significantly reach the thoracic areas of the respiratory tract and therefore are not considered to be respirable by humans. The same is concluded for the target substance FAT 41045.

Additional information

The commercial product of FAT 41045 is imported into the EU in a standardized dust suppressed formulation in analogy to FAT 41030.

Particle size determinations by laser diffraction were performed according to test guideline in compliance with GLP with FAT 41030 a structural analogue of FAT 41045. Both substances are very similar in their chemical structure and, as demonstrated, in a number of physicochemical properties. In addition, their industrial production processes are analogous. Therefore, these studies are used for read-across thus avoiding duplicate tests.

Three samples of FAT 41030 were investigated:

1. FAT 41030/A, a laboratory sample used for performing the analytical, phys-chem, tox- and ecotox-tests

2. FAT 41030/B, a sample as placed on the market

3. FAT 41030/C a sample as placed on the market.

The results indicated the particle size distribution of the lab sample (FAT 41030/A) was found to range from approximately 0.3 µm to 20 µm and the mass median diameter (MMD) was determined to be 4.4 µm.

However, the two representative samples of the product from regular production as placed on the market were found to be of much coarser particle size:

FAT 41030/B: D10 = 62.9 µm, D50 = 130.5 µm, D90 = 250.9 µm

FAT 41030/C: D10 = 81.7 µm, D50 = 139.5 µm, D90 = 235.1 µm

For both regular samples (FAT 41030/B and FAT 41030/C) no particles smaller or equal to 10 µm were found.

In conclusion, the majority of particles placed on the market is > 100 µm thus belonging to the fraction non-inhalable by humans. The remaining particles placed on the market will not significantly reach the thoracic areas of the breathing apparatus and therefore are not considered to be respirable by humans.