Ferrate(2-), [[N,N'-1,2-ethanediylbis[N-[(carboxy-.kappa.O)methyl]glycinato-.kappa.N,.kappa.O]](4-)]-, (OC-6-21)-

Endpoint summary

Description of key information

No data are available with EDTA-FeHNa. However the following information is extrapolated from the analogue EDTA-Fe(III)Na (See See Section 13 for justification of read-across):
In summary, most iron absorbed after EDTA-FeHNa is ingested is released to the physiological mucosal uptake system before absorption.
Only a very small fraction of the EDTA-FeHNa complex (less than 1%) is absorbed intact, and it is completely excreted in the urine.
An additional small fraction (probably less than 5%) of the EDTA moiety itself is absorbed, presumably bound to other metals in the gastrointestinal tract, and it is also completely excreted in the urine. Although the absorption of the EDTA moiety from administered EDTA-FeHNa has not been measured directly in humans, physicochemical considerations indicate that EDTA absorption from EDTA-FeHNa would be similar to that from other metal complexes, such as CaNa2EDTA and CrEDTA. As described above, poor absorption of the intact EDTA-FeNa can be inferred from measurements of urinary radio iron excretion after the oral administration of Na59-FeEDTA.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

With regard to EDTA:

According to the dissociation equilibrium of edetic acid, administration of different sodium salts will result in dependence on the intestinal pH-value to the formation of various anionic species of EDTA. In whatever salt EDTA is administered it is likely to chelate metal ions in vivo. It can be assumed that the oral and dermal absorption of sodium salts of EDTA and of the free acid is comparable to the low absorption of CaNa2EDTA. Calcium salts of EDTA are poorly absorbed from the gastrointestinal tract (2 to 18% within 24 h), a maxium of 5% was detected in the urine. Only 0.001% is absorbed after dermal application. Intravenously injected EDTA is excreted within 24 h in the urine, 50% of the substance in the first h and 90% within 7 h.

With regard to EDTA-FeNa:

After ingestion, based on the data available, a low bioaccumulation potential for EDTA-FeNa is concluded (see also section 7.1).

For EDTA-FeNa, intestinal absorption was estimated to be 5%, and dermal absorption 0.001%. Based on the particle size distribution of EDTA-FeNa, it is expected that 90% of the inhaled substance will be deposited in the upper respiratory tract, which will finally be taken up orally. Of this, only 5% will be absorbed in the gastrointestinal tract and become available systematically, i.e. 0.9 x 0.05 = 0.045 (4.5%). The other 10% may reach the alveoli and it is assumed that this will be absorbed completely (worst case). Therefore, the total inhalation absorption factor will be 0.045 + 0.10 = 0.145 (14.5%). Neither the iron nor the EDTA moiety of EDTA-FeNa undergoes biotransformation.

These conclusions are applicable to EDTA-FeHNa (See See Section 13 for justification of read-across).