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Key value for chemical safety assessment

Effects on fertility

Description of key information
- Oral: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity
- Dermal: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity
- Inhalation: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity
- Huang (2001) describes an in vitro study with human semen exposed to with ferrous nitrate (Fe(NO3)2 x 9H2O). Exposure to Fe2+ resulted in a decrease of sperm motility. However, it is concluded that this study is only of minor relevance for living organisms.
Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
200 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
Two reliable screening studies with FeCl2 and FeSO4x7H2O. In the both cases Fe seems to be not toxic to reproduction. Supporting studies similar to OECD TG 414 using Iron(III)-hydroxide sucrose complex and Ferric carboxymaltose (NN 1999, study no. VFR026/983656 and NN 2000, study no. VFR049/004349, respectively) are availabe.
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

This endpoint is covered by the category approach for dissociating, inorganic and non-toxic iron compounds (please see the section on toxicokinetics, metabolism and distribution for the category justification/report format).

Oral:

 • animal data:

 - For FeCl3 no reliable studies are available on this endpoint. Loewit 1971 reports pre-implantation toxicity of FeCl3 after intravaginal application in rats. This result is disregarded as the application route is irrelevant for humans. Kamboj applied FeCl3 solutions into rat testis and saw adverse effects on spermatogenesis; testes, epididymis and sperm duct. Again this result is disregarded as the application route is irrelevant for humans. Accordingly a read across is applied from FeCl2 and FeSO4 and FeCl3 is deemed not to be a reproductive toxicant.

 - For Fe2(SO4)3 no studies are available for this endpoint. Accordingly a read across is applied from FeCl2 and FeSO4 and Fe2(SO4)3 is deemed not to be a reproductive toxicant.

- For FeCl2 exactly one study is available that is fully reliable (Beom 2004) where rats have been orally exposed to up to 500 mg FeCl2/kg bw/d following OECD TG 422 and GLP. The results of the pre- and post-implantation loss rates did not show a treatment related effect. No treatment-related effects were observed on mean live neonates, birth rates, survival rates.

Accordingly the NOAEL for subacute reproduction toxicity is >= 500 mg FeCl2/kg bw/d (equivalent to 220.5 mg Fe/kg bw/d).

 - For FeSO4 one study is available that is fully reliable (Furuhashi 2002) where rats have been orally exposed to up to 1000 mg FeSO4 x 7 H2O/kg bw/d following OECD TG 422 and GLP.

No effects on oestrous cycle were seen, all 12 pairs of each dose group copulated successfully (copulation index 100%) and all females except one female became pregnant (fertility index: 100). The gestation index was 100% for all dose groups and no adverse findings on the offspring viability was seen. No significant changes between treatment groups and controls were observed (number, number of stillbriths, numbers of live pups on day 0 of lactation, sex ratio, delivery index, birth index, live birth index, general signs, number of live pups on day 4 of lactation, viability index on day 4 of lactation, external observation, body weight change, necropsy findings). Accordingly the NOAEL for subacute reproduction toxicity is >= 1000 mg FeSO4 x 7 H2O/kg bw/d (equivalent to 200 mg Fe/kg bw/d).

 - FeClSO4: no studies are available for this endpoint. Accordingly a read across is applied from FeCl3 and FeClSO4 is deemed not carcinogenic.

 • human data: No human data available for this endpoint

 • general: Only for FeCl2 and FeSO4 reliable studies (conducted according to OECD TG 422) are available. For reproduction effects only systemic effects are relevant. As the bioavailability of ferrous iron is assumed to be higher than that of ferric iron, a read across from these two substances to the ferric salts of this category is deemed valid and conservative. For both substances no adverse effects were seen at the highest tested dose levels where moderate to strong parental toxicity was already present. Based on the available data it can therefore be assumed that the iron salts of this category are not reproductive toxicants. The lowest NOAEL with regard to iron based on these studies would be >= 200.9 mg Fe/kg bw/d.

Dermal

No study is available for any member of the iron salt category.

Inhalation

No study is available for any member of the iron salt category.

Intravenous injection

Supporting studies similar to OECD TG 414 using Iron(III)-hydroxide sucrose complex and Ferric carboxymaltose (NN 1999, study no. VFR026/983656 and NN 2000, study no. VFR049/004349, respectively) are available.

Pregnant rabbits were treated intravenously with iron sucrose at the doses of 3, 6.5 and 13 mg Fe/kg /day from day 6 to 19 of pregnancy. The animals were sacrificed on day 29. The highest dose of 13 mg/kg bw was considered as MTD due to the severity of local irritation. Animals of group 1, 2, 3 and 4 were treated daily with i.v. infusion of test substance or control on day 6-19. Following completion of treatment of the first 5 animals of group 4 the remaining 17 animals and additional 22 animals were assigned to two subgroups designated for treatment on alternative days. This was done in response of the marked local irritating effect of the test substance in group 4. After sacrifice section was performed on dams and fetuses. Five rabbits from dose group 3, 4, 4a and 4b aborted after a short period of body weight loss. Aborting animals showed changes including accentuated lobular pattern in liver, swollen spleen, enlarged kidneys. One moribund animal of group 4 was sacrificed after heavy weight loss and reduced food intake. Necropsy revealed also changes in liver, spleen and kidneys, additionally to fetus resorption. In group 4 food consumption was reduced by 23-47 %. In fetuses dilatation of umbilical artery was observed in group 4a. Other treatment related abnormalities were found in group 3, 4a and 4b (fluid in abdomen). Malformation observed in treatment groups included fused sternebrae and vertebrae, and misaligned vertebrae. Since bw gain was unaffected in the individual females that delivered the affected fetuses and therefore these results are assumed not secondary to maternal toxicity. The fetal incidence of fused sternebrae was 3/121 in group 4b but 0/102 and 0/18 in groups 4a and 4, respectively. There was one occurrence in group 2 and no in group 3. The incidence of fused sternebrae in group 4b is with 2.48% greater than the historical control value of 1.26 % from NZW rabbits performed in the same laboratory. But when treating group 4a and 4b as one group with 223 animals the incidence is with 1.34 % comparable with the historical control value and therefore in the normal range. Misaligned vertebrae were observed in non-dose-related manner in control and treatment groups. These findings lead to the overall conclusion that iron sucrose is not teratogenic in the rabbit under the conditions of this test.

Pregnant rabbits were treated intravenously with ferric carboxymaltose (CAS 9007-72-1) at the doses of 4.5, 9, 13.5 and 18 mg Fe/kg /day from day 6 to 19 of pregnancy. After sacrifice or premature death section was performed on dams and fetuses. Two dams per dose group died or were sacrificed. Prior to death/sacrifice dams in group 13.5 and 18 mg/kg suffered from weight loss and reduced food intake and showed a liver tinged orange with accentuated lobular pattern. Orange/brown discoloration in various organs were noted it dose group 9 mg/kg upwards. Several dams starting at dose group 4.5 mg/kg onwards aborted. Preimplantation loss was marked in high dose group (33 %) compared to control (18 %). Three fetuses at high dose and two fetuses in 13.5 mg/kg developed marked domed craniums. Both 13.5 mg fetuses had additionally internal hydrocephaly or suspected hydrocephaly (major malformations). One fetus in 9 mg group had moderately domed cranium (minor malformation). The domed cranium was in incidence and severity dose related. All fetal effects appeared at maternal toxic dose. Therefore, ferric carboxymaltose is assumed to be not teratogenic under the conditions of this test.

In conclusion these studies confirm the absence of teratogenicity.


Short description of key information:
- Oral:
• FeCl3: no reliable studies available. Accordingly a read across is applied from FeCl2 and FeSO4. FeCl3 is deemed not toxic to reproduction.
• Fe2(SO4)3: no studies are available for this endpoint. Accordingly a read across is applied from FeCl2 and FeSO4. Fe2(SO4)3 is deemed not toxic to reproduction.
• FeCl2: not toxic to reproduction, NOAEL >= 500 mg FeCl2/kg bw/d for reproductive toxicity (OECD TG 422); study "FeCl2_Beom 2004/K1 KS/Toxicity to reproduction: oral - OECD 422, rat"
• FeSO4: not toxic to reproduction, NOAEL >= 1000 mg FeSO4 x 7 H2O/kg bw/d for reproductive toxicity (OECD TG 422); study "FeSO4_Furuhashi 2002/K1 KS/Toxicity to reproduction - OECD 422, rat"
• FeClSO4: no studies are available for this endpoint. Accordingly a read across is applied from FeCl2 and FeSO4. FeClSO4 is deemed not toxic to reproduction.
- Dermal: no study available for any member of the iron salt category
- Inhalation: no study available for any member of the iron salt category

Justification for selection of Effect on fertility via oral route:
The most critical NOAEL for reproductive toxicity calculated as Fe for FeSO4x7H2O

Effects on developmental toxicity

Description of key information
• FeCl3: no developmental toxicity/teratogenicity, one reliable studies available (Nolen 1972), though with only one dose tested where no adverse effects were seen. Accordingly a read across is applied from FeCl2, FeSO4 and two i.v. rabbit studies with Fe(III)-sucrose and -carboxymaltose. FeCl3 is deemed not toxic to reproduction in concentrations without maternal toxicity.
• Fe2(SO4)3: no developmental toxicity/teratogenicity, no studies are available for this endpoint. Accordingly a read across is applied from FeCl2, FeSO4 and two i.v. rabbit studies with Fe(III)-sucrose and -carboxymaltose. Fe2(SO4)3 is deemed not toxic to reproduction.
• FeCl2: no developmental toxicity/teratogenicity, NOAEL >= 500 mg FeCl2/kg bw/d for developmental toxicity/teratogenicity (OECD TG 422); study "FeCl2_Beom 2004/K1 KS/Toxicity to reproduction: oral - OECD 422, rat"
• FeSO4: not classifiable, NOAEL >= 1000 mg FeSO4 x 7 H2O/kg bw/d for developmental toxicity/teratogenicity (OECD TG 422); study "FeSO4_Furuhashi 2002/K1 KS/Toxicity to reproduction - OECD 422, rat", no conflicting results from available studies with low reliability.
• FeClSO4: no studies are available for this endpoint. Accordingly a read across is applied from FeCl2 and FeSO4. FeClSO4 is deemed not toxic to reproduction.
- Dermal: no study available for any member of the iron salt category
- Inhalation: no study available for any member of the iron salt category
Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
200 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
Three reliable studies with FeCl2, FeSO4x7H2O and FeCl3 are available. In the all cases Fe seems to be not teratogen.
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

Justification for read-across

This endpoint is covered by the category approach for soluble iron salts (please see below for the category justification/report format).

In addition to the category members, the surrogate materials Iron(III) sucrose and Ferric carboxymaltose were used for read-across (NN 1990 & Joseph 2000 and NN 2000 & Chopra 2006 & Center for Drug Evaluation and Research (CDER) 2013a, 2013b and 2013c, respectively). These substances also dissociate at physiological pH to the same species produced by the ferric (iron III) salts. As discussed in the category justification section, the equilibrium to iron II species is quickly established. In result the iron species burden is assumed to be comparable to equimolar exposure to the iron category member salts. The additional Sucrose or Carboxymaltose are considered non-toxic and neglected so far as the whole effects were assigned to the iron dose. This establishes an additional safety margin.

- Oral:

 • animal data:

 - For FeCl3 a reliable studies is available on this endpoint. Unfortunately Nolen 1972 (conducted comparable to OECD TG 414 in rats) has only used one relatively low dose level of 7.8 mg/kg at which no adverse effects indicative for developmental toxicity or teratogenicity were seen. So a solid assessment the toxicity of FeCl3 with regard to this endpoint is not possible. Accordingly a read across is applied from FeCl2, FeSO4 and two i.v. rabbit studies with Fe(III)-sucrose and -carboxymaltose, respectively. FeCl3 is deemed not toxic to reproduction.

 - For Fe2(SO4)3 no studies are available for this endpoint. Accordingly a read across is applied from FeCl2, FeSO4 and two i.v. rabbit studies with Fe(III)-sucrose and -carboxymaltose, respectively. Fe2(SO4)3 is deemed not to be a reproductive toxicant.

- For FeCl2 exactly one study is available that is fully reliable (Beom 2004) where rats have been orally exposed to up to 500 mg FeCl2/kg bw/d following OECD TG 422 and GLP. No treatment-related effects were observed on mean live neonates, birth rates, survival rates and sex ratios on days 0 and 4 post-partum. The only abnormality found in the external appearance examinations is an acaudate observed in one neonate at 500 mg/kg. Crown Rump Length (CRL) of female neonates showed a significant decrease at 125 mg/kg on Day 4 post-partum. This is regarded as a secondary effect to maternal poisoning. Accordingly the NOAEL for subacute developmental toxicity/teratogenicity is >= 500 mg FeCl2/kg bw/d (equivalent to 220.3 mg Fe/kg bw/d).

 - For FeSO4 one study is available that is fully reliable (Furuhashi 2002) where rats have been orally exposed to up to 1000 mg FeSO4 x 7 H2O/kg bw/d following OECD TG 422 and GLP. No adverse findings on the offspring viability were seen. No significant changes between treatment groups and controls were observed (number, number of stillbirths, number of live pups on day 0 of lactation, sex ratio, delivery index, birth index, live birth index, general signs, number of live pups on day 4 of lactation, viability index on day 4 of lactation, external observation, body weight change, necropsy findings). Accordingly the NOAEL for developmental toxicity is >= 1000 mg FeSO4 x 7 H2O/kg bw/d (equivalent to 200.9 mg Fe/kg bw/d). No conflicting results are reported in the studies with lower reliability (Food and Drug Research Laboratories, Inc. 1974 a & b, Verret 1980)

 - FeClSO4: no studies are available for this endpoint. Accordingly a read across is applied from FeCl3 and FeClSO4 is deemed not toxic to reproduction.

 - other iron species:

Two i.v. teratogenicity studies in the rabbit were reported by US-FAD in the drug approval process. One with Fe(III)sucrose and one with Fe(III)carboxymaltose as iron replacement product indicated for the treatment of iron deficiency anaemia. No clear effect on the fetuses could be observed in the study with Fe(III)sucrose. Maternal and teratogenic NOAEL was 3 mg/kg be/day. In the study with Fe(III)carboxymaltose in incidence and severity dose related increase of fetuses with domed cranium was found only at maternal toxic doses. No maternal NOAEL could be determined. Maternal LOAEL and NOAEL for developmental toxicity was 4.5 mg/kg bw/day. The NOAEL’s are very low compared to the no effect levels observed in oral toxicity studies with iron ions. Since the absorption rate in an i.v. study is 100% and therefore much higher than in an oral study the derived NOAEL’s are deemed to be of low relevance for the iron salts of this category. Fe(III)sucrose and Fe(III)carboxymaltose are deemed not to be teratogenic.

Fredriksson 1999 reports effects of developmental neurotoxicity in the mouse (LOAEL (developmental neurotoxicity) = 3.7 mg/kg bw/day test material) when iron succinate was orally applied (gavage) on post-natal days 10 – 12. In the two behavioural tests (activity chamber and radial maze), deficits in habituation and deficits in performance increments over successive test trials were seen in both Fe2+ dose groups. Since the absorption of chelated iron is usually higher than that of ionic iron these results are deemed to be of low relevance for the iron salts of this category.

Lucesoli & Fraga 1999 and Whittaker 1997 treated rats with a very fine powder of iron (carbonyl iron) in the diets (6 and 12 wks respectively). Lucesoli & Fraga 1999 looked specifically for oxidative stress in the test and reported that the only tested concentration of 25 mg carbonyl iron/g diet is a NOAEC. Whittaker 1997 report that degeneration of the germinal epithelium of the testis, formation of multinucleated giant cells and lack of mature sperm were observed in rats at the highest dose (10 mg carbonyl iron/g diet) resulting in a NOAEC of 5 mg carbonyl iron/g diet. The relevance of these two studies for the iron salt category is very questionable as very fine elemental Fe mixed with diet most probably has an absorption behaviour that is very different from that of the members of this iron salt category.

Huang (2001) describes an in vitro study with human semen exposed to with ferrous nitrate (Fe(NO3)2x 9H2O). Exposure to Fe2 + resulted in a decrease of sperm motility. However, it is concluded that this study is only of minor relevance for living organisms.

 

 • human data:

Two reports are available on the effect of (accidental) iron overdosing in pregnant women. Tran 2000 conducted a literature search for relevant English language publications between 1966 and 1998. After exclusion of articles and their references which appeared in peer reviewed publications 14 papers were identified describing 61 incidences of obstetric iron overdose by ingestion. From the data extracted the patients were grouped according to maternal serum iron level either < 400 µg/dL (4000 µg/L) or >= 400 µg/dL (4000 µg/l) and by stage of iron toxicity. Blood for peak levels was drawn at a mean 4.3 and 3.1 hours after ingestion for low and high exposure groups respectively. Stages of iron toxicity were described as 0 = asymptomatic, 1 = gastrointestinal symptoms, 2 = metabolic disturbance, 3 = organ failure, 4 = gastrointestinal scarring. Groups were compared for maternal-foetal outcomes which included spontaneous abortion, perinatal death, preterm delivery, congenital abnormalities or maternal death. The same groups were compared for aspects of deferoxamine use. Statistical comparisons were performed using the student t-test, Fischer exact test or ANOVA, with significance p<0.05. The iron formulations ingested by the individuals in the study were described as 'simple' iron (26 individuals), 'simple' iron with folate (23), ferrous sulphate (9), ferrous gluconate (1), iron supplement (1). There was no relationship between peak iron level and frequency of spontaneous abortion, preterm delivery, congenital anomalies or perinatal or maternal death. Peak iron levels were available for 23 patients. However patients with peak levels greater than 400 µg/dL were more frequently symptomatic than women with lower peak levels (12/13 compared to 5/10). Patients from both groups were treated similarly for the iron overdose. Iron toxicity could be staged in 59 patients. Patients with stage 3 iron intoxication (organ failure) were more likely to spontaneously abort (1/3 vs 1/56), deliver preterm (2/3 vs 6/56), or experience maternal death 3/3 vs 0/56). There was a tendency for symptomatic patients to receive a higher mean deferoxime dose than asymptomatic patients (6.9 g vs 4.0 g). McElhatton carried out a study that was based on follow-up of iron overdose patients reported to the UK National Poisons Information Centre and the Teratology Information Service. From 68 enquiries to the above agencies, 49 patients were eventually included in the study, in all of these the outcome of pregnancy was known. For each patient a questionnaire was sent to the physician and the information in the publication is based entirely on information provided by the physician. Overdose was defined as any non-therapeutic dose of a drug. The dose of iron taken was known in 48/49 patients. 28 reportedly took more than 1.2 g (equivalent to 20 mg/kg in a 60 kg woman) while 21 took less than 1.2 g. There were no maternal or neonatal deaths. In 36 patients the serum iron level was known, all had iron levels above normal while 20/36 had measured serum iron levels > 60 mol/l. Of these, 14 cases had iron levels of 60-89 µmol/l consistent with moderate toxicity with 6 cases >90 µmol/l compatible with severe toxicity. There was no correlation between stated dose taken and highest serum iron level. 25 of these 49 patients were treated with desferrioxamine (DFO). The authors comment that the time at which serum iron levels were taken was variable and it was not known when DFP treatment was started so that serum iron levels give only an approximate guide to toxicity in this study. Information on each patient is presented. Of the 49 pregnancies, 43 resulted in live babies, 2 had spontaneous abortions (one following abdominal trauma), 4 elective terminations. Of the live babies, 3 were premature and another 3 had abnormalities. However, the authors concluded that, as all babies with malformations were associated with overdoses after the first trimester, the malformations could not be directly related to the iron overdose (or to desferrioxamine therapy, given in 2 cases where abnormalities occurred). Thus, there was no evidence from this study that iron causes developmental malformations. Birth weights of babies in relation to serum iron and antidote treatment were presented, although numbers were too small to draw general conclusions, all fell within the expected range and there was no correlation between serum iron and birth weight. There was no evidence to suggest that DFO caused toxicity in the mother or baby.

• general:

Only for FeCl2 and FeSO4 fully reliable studies (conducted according to OECD TG 422) are available. For developmental toxicity/teratogenicity only systemic effects are relevant. As the bioavailability of ferrous iron is assumed to be higher than that of ferric iron, a read across from these two substances to the ferric salts of this category is deemed valid and conservative. For both substances no adverse effects were seen at the highest tested dose levels where moderate to strong parental toxicity was already present. Based on the available data it can therefore be assumed that the iron salts of this category are not reproductive toxicants and a classification is not necessary to date. Human data available from two studies support this conclusion. In both studies there was no evidence from this study that iron causes developmental malformations. In Tran 2000 spontaneously abort (1/3 vs 1/56) or preterm delivery (2/3 vs 6/56) was only seen at doses that were highly toxic to the mother. Based on the available data it can therefore be assumed that the iron salts of this category are not reproductive toxicants and a classification is not necessary to date.

 

- Inhalation: no study available for any member of the iron salt category

- Dermal: no study available for any member of the iron salt category

 


Justification for selection of Effect on developmental toxicity: via oral route:
The most critical NOAEL for reproductive toxicity calculated as Fe for FeSO4x7H2O

Toxicity to reproduction: other studies

Additional information

Justification for read-across

This endpoint is covered by the category approach for soluble iron salts (please see the section Toxicokinetics, metabolism and distribution for the category justification/report format).

In addition to the category members, the surrogate materials Ferrous succinate and Ferrous nitrate were used for read-across (Fredriksson et al. 1999 and Huang et al. 2001, respectively). These substances also dissociate at physiological pH to the same species produced by the ferrous (iron II) salts. As discussed in the category justification section, the equilibrium to iron III species is quickly established. In result the iron species burden is assumed to be comparable to equimolar exposure to the iron category member salts. The additional Butanedioic acid or Nitrate are regarded as non-toxic and neglected so far as the whole effects were assigned to the iron dose. This establishes an additional safety margin.

Available data

- Oral: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity

- Dermal: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity

- Inhalation: no study available for any member of the iron salt category or it is already discussed under reproductive toxicity or developmental toxicity/teratogenicity

- one in vitro study (Huang et al. 2001, listed in IUCLID section “Exposure related observations in humans: other data”) with human semen exposed to with ferrous nitrate (Fe(NO3)2 x 9H2O) is available. Exposure to Fe2+ resulted in a decrease of sperm motility. However, it is considered of minor relevance for living organisms.

Justification for classification or non-classification

- Effects on fertility:

Based on the above stated assessment of the reproduction toxicity potential of the members of the iron salt category they are deemed not to be toxic to the reproduction and accordingly do not need to be classified according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

 

- Effects on developmental toxicity/teratogenicity:

Based on the above stated assessment of the developmental toxicity/teratogenicity potential of the members of the iron salt category they are deemed not to be toxic to the developmental toxicity/teratogenic and accordingly do not need to be classified according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.