Glycine, N,N'-1,2-ethanediylbis-, reaction products with formaldehyde, iron chloride (FeCl3) and phenol, potassium salts

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In an extended oral OECD 422 study with Fe-HBED - with a 10-wk pre-mating period and all 90-day parameters included - no parental, reproduction or developmental toxicity was noted up to an including 1000 mg/kg bw/day. In a key one-generation oral toxicity study in rats (Reijnders, 1996) with the structurally related UVCB Fe-EDDHMA, the NOAEL for parental toxicity was set at 50 mg/kg bw, the NOAEL for fertilty at at least 750 mg/kg bw and the NOAEL for developmental effects at 50 mg/kg bw. Developmental toxicity was seen in the presence of maternal toxicity. 

 

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

One well performed and reported study extended OECD 422 study (with 10-wk premating period).

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In the extended oral OECD 422 study with Fe-HBED - with a 10-wk pre-mating period and all 90-day parameters included - no parental, reproduction or developmental toxicity was noted up to an including 1000 mg/kg bw/day. In a one-generation reproduction toxicity study (Reijnders, 1997), the structurally related UVCB Fe-EDDHMA was administered to 28 Wistar rats/sex/dose level by single oral gavage at dose levels of 50, 200 or 750 mg/kg bw/day. A concurrent control group was treated with the vehicle only. Treatment commenced 10 weeks prior to mating for males and 2 weeks prior to mating for females and continued for both sexes until at least the end of the lactation period. Pregnant females were allowed to litter normally. On day 4 of lactation, each litter was adjusted to 4 males and 4 females or as near as possible. The surviving offspring was euthanised after weaning.

The primary effect on parental animals was poor physical condition, resulting in premature mortality, growth reduction and reduced food consumption in both sexes at 750 mg/kg bw/day. These signs were seen with reduced severity at 200 mg/kg bw/day in males only. Thus, the NOAEL for systemic toxcity in parental animals was 50 mg/kg bw/day under the conditions of this study.

Examination of the reproduction performance of males and females revealed a slight decrease of the fertility and conception indices in the 750 mglkg Fe-EDDHMA dose group. However, the fertility and conception indices in the control group were also low. Oral administration of EDDHMA-Fe to parental rats at dose levels up to 750 mg/kg bw/day produced no histopathological evidence of toxicity to reproduction or infertility. As such the NOAEL for reproductive performance/fertility was established at 750 mg/kg bw/day.

In the offspring, increased post natal loss and reduced viability were noted during PND 0-4 at 200 and 750 mg Fe-EDDHMA/kg bw/day, and with lower incidence at 50 mg/kg bw/day. With special regard to the low incidence and unusual distribution pattern of findings noted at 50 mg/kg bw/day, the NOAEL for developmental toxicity was 50 mg/kg bw/day under the conditions of this study. Effects at higher levels were considered to be closely related to (subclinical) maternal toxicity.

To support read across from Fe-EDDHMA to Fe-HBED (bridging), an extended OECD 422 study was performed with Fe-HBED. Because the number of animals in OECD 422 is at least 10 animals/sex/group, the OECD 422 is carried out with a 10-wk pre-mating period so that animals were exposed for at least 13 weeks, and all repro parameters were included. Based on the results of both studies it can be concluded that at very high dose levels of both Fe-HBED and Fe-EDDHMA of 1000 and 750 mg/kg bw/day, respectively, adverse effects on reproduction are absent.  

Data Waiving for an EOGRTS with HBED-Fe:

The performance of an EOGRTS with Fe-HBED is scientifically unjustified. There were no adverse findings on reproduction for Fe-HBED and Fe-EDDHMA at high doses (1000 and 750 mg/kg bw/day, respectively) and no signs of developmental toxicity for Fe-HBED at a high dose of 1000 mg/kg bw/day. Signs of developmental toxicity were only found in the one-generation study with the structurally related UVCB Fe-EDDHMA but only at dose levels showing clear parental toxicity. No parental toxicity was seen for Fe-HBED up to and including 1000 mg/kg bw/day. In the developmental toxicity study with Fe-EDDHMA no adverse effects on development were observed up to an exposure level of 1000 mg/kg bw/day (see below and see also the read across document in section 13). In addition, in three repeated dose toxicity studies with oral administration (two 28-day studies and one 90-day study) with Fe-EDDHMA, no adverse effects on the reproduction organs were seen (no organ weight changes and no adverse histopathological findings). 

In summary, it is very unlikely that Fe-HBED will cause adverse reproductive and/or developmental toxicity effects at 1000 mg/g bw day in an EOGRTS as the only difference between the two studies would consist of a different number of animals group (viz. 10-12 animals/group in the extended OECD 422 versus 20-24 animals/group in the EOGRTS) and conducting such a study is thus scientifically not justified. The available one-generation study and developmental toxicity studies with Fe-EDDHMA are therefore sufficient for hazard assessment and risk characterisation.

 

Effects on developmental toxicity

Description of key information

In a key developmental oral toxicity study (Reijnders, 1996) with the structurally related UVCB Fe-EDDHMA, the NOAEL for developmental effects was established as at least 1000 mg/kg bw/day based on the absence of embryo-/foetotoxic or teratogenic effects.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Study duration:

subacute

Species:

rat

Quality of whole database:

Well performed study and results corroborated by those from the one-generation study and the study with the structurally related UVCB Fe-EDDHA. In addition, no developmental toxicity was observed in the extended OECD 422 study with Fe-HBED.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In a developmental toxicity study (Reijnders, 1996) the structurally related UVCB Fe-EDDHMA was administered once daily to groups of mated female rats by oral gavage at 0, 50, 200 or 1000 mg/kg bw/day from day 6 through day 16 of gestation. Control group females received the vehicle only. All dams were sacrificed on day 21 of the gestation period and foetuses removed for examination. In dams, there were no treatment-related clinical signs or incidences of mortality. The body weight gain and food intake was reduced at 1000 mg/kg bw/day. No adverse effects on pregnancy and no embryo-/foetotoxic effects were observed. There was no indication of teratogenic potential. On the basis of these results, the NOAEL was 200 mg/kg bw/day for maternal toxicity and 1000 mg/kg bw/day for develomental toxicity and teratogenicity. Although the duration of treatment was short, the results of this study are corroborated by the results of the one-generation study. The effects seen in fetuses in the one-generation study, consisting of mortality or reduced viability were related to the poor physical condition of the mothers that had been treated for a much longer period.

The NOAEL in a developmental study with the structurally related substance EDDHA-Fe resulted in a NOAEL of at least 500 mg/kg bw (highest level tested).

In the extended OECD 422 study with Fe-HBED no developmental toxicity was noted. 

Mode of Action Analysis / Human Relevance Framework

The intrinsic property of chelating agents is binding metal ions. So if high doses of empty chelates are orally administered, metal ions such as zinc will be bound in the gut which will not be bioavailable anymore, leading to a potential zinc deficieny in the mother and fetuses. Because HBED has already bound iron, for which it has a high affinity, there will be no or limited exchange to other metal ions, and as such no zinc deficiency will occur, which was shown in the extended OECD 422 study with Fe-HBED and in the rat studies with the read across substances Fe-EDDHMA and Fe-EDDHA. As the MoA is known, as well as the effects of zinc deficiency are, there is no need to show developmental toxicity is also absent in rabbits like in rats. A rabbit study has been included with Mn-EDTA to show the absence of developmental effects of metal chelating agents in the rabbit (see section 13).

Justification for classification or non-classification

Fe-HBED did not show parental, reproduction or developmental toxicity in an extended OECD 422 study with a 10-wk premating priod up to and including 1000 mg/kg bw/day. The structurally related UVCB Fe-EDDHMA also caused no developmental toxicity and no teratogenicity in the rat in a key developmental toxicity study according to test guideline OECD 414. Effects on reproductive performance/fertility of Fe-EDDHMA were assessed using a one generation toxicity study according to test guideline OECD 415. Only a slight decrease of the fertility and conception indices were seen in the high dose group of 750 mg/kg bw/day. However, the fertility and conception indices in the control group were also low. In the absence of concomitant histopathological findings, this slight change in reproductive performance was considered to be secondary to the poor clinical condition of the animals at this dose level. Similarly, developmental effects were seen in this one-generation study only at dose levels that produced pronounced maternal toxicity.

Accordingly, Fe-HBED is not considered to be subject to classification for toxicity to reproduction or development according to Regulation 1272/2008/EC.