Calcium 3,5,5-trimethylhexanoate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Calcium 3,5,5-trimethylhexanoate is not expected to be toxic for reproduction.

Additional information

Read-across approach

Selected endpoints for the human health hazard assessment are addressed by read-across, using a combination of data on the metal cation and the organic acid anion. This way forward is acceptable, since metal carboxylates are shown to dissociate to the organic anion and the metal cation upon dissolution in aqueous media. No indications of complexation or masking of the metal ion through the organic acid were apparent during the water solubility and dissociation tests (please refer to the water solubility and dissociation in sections 4.8 and 4.21 of IUCLID). Once the individual transformation products of the metal carboxylate become bioavailable (i.e. in the acidic environment in the gastric passage or after phagocytosis by pulmonary macrophages), the “overall” toxicity of the dissociated metal carboxylate can be described by a combination of the toxicity of these transformation products, i.e. the metal cation and carboxylate anion according to an additivity approach.

 

Calcium 3,5,5-trimethylhexanoate is the calcium salt of 3,5,5-trimethylhexanoic acid and readily dissociates to the corresponding divalent calcium cation and monovalent 3,5,5-trimethylhexanoate anions. The calcium cation and the 3,5,5-trimethylhexanoate anion are considered to represent the overall toxicity of calcium 3,5,5-trimethylhexanoate in a manner proportionate to the free acid and the metal (represented by one of its readily soluble salts). 

 

A detailed justification for the read-across approach is added as a separate document in section 13 of IUCLID.

 

Toxicity for reproduction – effects on fertility

No toxicity data on adverse effects on sexual function and fertility with calcium 3,5,5-trimethylhexanoate are available, thus the reproductive toxicity will be addressed with existing data on the dissociation products as detailed in the table below. Further details on the genetic toxicity of the individual constituents are given below.

 

Table: Summary of toxicity data on adverse effects on sexual function and fertility of calcium 3,5,5-trimethylhexanoate and the individual constituents.

	calcium substances	3,5,5-trimethylhexanoic acid (CAS# 3302-10-1)	calcium 3,5,5-trimethylhexanoate (CAS# 64216 -15 -5)
Two-generation reproductive toxicity study	not reprotoxic (weight of evidence, human data) not classified	NOAEL(rat, P and F1) = 79-228 mg/kg bw/day (one-generation reproductive toxicity study) not classified	no data   not classified (read-across)

 

Calcium

Only limited data are available on effects of calcium compounds on the reproductive performance of male and female mice and rats, respectively. A preliminary NOAEL for calcium effects on reproduction and development of offspring may be derived from a CaCO₃ feeding study in mice (Richards and Greig, 1952). The study design was similar to that of a one-generation reproductive toxicity study. The highest dose of 2 % CaCO₃ (corresponding to 1.1 % Ca) resulted in reduced numbers and total weight of litters, and increased both the number and proportion of litter deaths, hence being considered as LOAEL for effects on reproductive performance. The dose level of 0.73 % Ca may be established as NOAEL although there were some sporadic effects without statistical significance. However, no daily dose levels could be calculated due to lack of data on daily food intake.

 

However, with respect to potential hazards of calcium for reproduction the following aspects have to be taken

into account:

 

i) Calcium, released as calcium cations in aqueous media is a physiologically essential element and nutrient for all mammals including humans. Comprehensive evaluations of possible adverse health effects of individual nutrients at intakes in excess of dietary requirements have been presented in the scientific opinions of the Scientific Committee on Food (SCF). Where possible, tolerable upper intake levels (UL) for different human populations have been established. The UL is an estimate of the highest level of intake entailing no appreciable risk of adverse health effects. In the opinion on calcium (EFSA 2006), the sources, properties and effects of calcium on animals as well as on different subgroups of the human population have been re-evaluated and a tolerable upper intake level for calcium has been defined. The SCF decided to base the derivation of an UL for calcium on the evidence of different interventional studies of long duration in adults, some of which were placebo-controlled and in which total daily calcium intakes of 2500 mg from both the diet and supplements were tolerated without any adverse effects. Based on the findings, a tolerable upper intake level of 2500 mg of calcium per day for calcium intake from all sources is proposed for adults, corresponding to a dose of about 36 mg calcium/kg bw/d taking into account an average body weight of 70 kg/person. The UL is considered to also cover any potential reproductive effects.

 

ii) Supportive information is available in section 7.12 of the technical dossier (Mortimer, 1988) showing that calcium is essential for the function of human spermatozoa (acrosome reaction), i.e. calcium has a beneficial effect on reproductive performance.

 

iii) Supportive information is available in section 7.12 of the technical dossier (Han, 2000) showing that calcium has a protective effect against lead accumulation in dams and their offspring, i.e. acts beneficially.

 

3,5,5-trimethylhexanoic acid

In a reliable one-generation range-finding study, the test substance was administered to rats in the diet in concentrations of 0.06, 0.12, 0.25 and 0.5% for at least ten weeks prior to mating, during the mating gestation and postpartum periods until weaning of the F1 offspring. The male P1 animals were sacrificed at the end of the mating period, the females and the offspring after weaning.

No effects were observed with respect to fertility (NOAEL 0.5%, 289-477 mg/kg bw/day in males, 336-970 mg/kg bw/d in females).

Other effects in the P generation were decreases in food consumption in the 0.5% group dams during the postpartum period, decreases in body weights in females of the 0.25% group at postpartum day (PPD) 4 as well as in 0.5% females at gestation days (GD) 7 and 21 and at PPD 4, 7, and 14. Liver weights were increased in dams at dietary concentrations of 0.25% and above, in males at 0.5%.

The LOAEL for systemic paternal effects was 0.25% (165-500 mg/kg bw/d for females), the NOAEL 0.12% (79 -228 mg/kg bw/d for females)

 

Calcium 3,5,5-trimethylhexanoate

Since no toxicity data on adverse effects on sexual function and fertility is available for calcium 3,5,5-trimethylhexanoate, information on the individual constituents calcium and 3,5,5-trimethylhexanoic acid will be used for the hazard assessment and, when applicable, for the risk characterisation of calcium 3,5,5-trimethylhexanoate. For the purpose of hazard assessment of calcium 3,5,5-trimethylhexanoate, the point of departure for the most sensitive endpoint of each constituent will be used for the DNEL derivation.

Justification for selection of Effect on fertility via oral route:

Information from read-across substances:

• human data for calcium: not reprotoxic (weight of evidence)


• animal data for 3,5,5 -trimethylhexanoic acid: NOAEL(rat, P)=79-228mg/kg bw/day

Effects on developmental toxicity

Description of key information

Calcium 3,5,5-trimethylhexanoate is not expected to be a developmental toxicant.

Additional information

Read-across approach

Selected endpoints for the human health hazard assessment are addressed by read-across, using a combination of data on the metal cation and the organic acid anion. This way forward is acceptable, since metal carboxylates are shown to dissociate to the organic anion and the metal cation upon dissolution in aqueous media. No indications of complexation or masking of the metal ion through the organic acid were apparent during the water solubility and dissociation tests (please refer to the water solubility and dissociation in sections 4.8 and 4.21 of IUCLID). Once the individual transformation products of the metal carboxylate become bioavailable (i.e. in the acidic environment in the gastric passage or after phagocytosis by pulmonary macrophages), the “overall” toxicity of the dissociated metal carboxylate can be described by a combination of the toxicity of these transformation products, i.e. the metal cation and carboxylate anion according to an additivity approach.

 

Calcium 3,5,5-trimethylhexanoate is the calcium salt of 3,5,5-trimethylhexanoic acid and readily dissociates to the corresponding divalent calcium cation and monovalent 3,5,5-trimethylhexanoate anions. The calcium cation and the 3,5,5-trimethylhexanoate anion are considered to represent the overall toxicity of calcium 3,5,5-trimethylhexanoate in a manner proportionate to the free acid and the metal (represented by one of its readily soluble salts). 

 

A detailed justification for the read-across approach is added as a separate document in section 13 of IUCLID.

 

Toxicity for reproduction – developmental toxicity

No toxicity data on adverse effects on development of the offspring with calcium 3,5,5-trimethylhexanoate are available, thus the reproductive toxicity will be addressed with existing data on the dissociation products as detailed in the table below. Further details on the reproductive toxicity of the individual constituents are given below.

 

Table: Summary of toxicity data on adverse effects on development of the offspring of calcium 3,5,5-trimethylhexanoate and the individual constituents.

	calcium substances	3,5,5-trimethylhexanoic acid (CAS# 3302-10-1)	calcium 3,5,5-trimethylhexanoate (CAS# 64216 -15 -5)
Pre-natal developmental toxicity study	not reprotoxic (weight of evidence, human data) not classified	testing proposal	no data   not classified (read-across)

 

Calcium

Only limited data are available on effects of calcium compounds on the reproductive performance of male and female mice and rats, respectively. A preliminary NOAEL for calcium effects on reproduction and development of offspring may be derived from a CaCO₃ feeding study in mice (Richards and Greig, 1952). The study design was similar to that of a one-generation reproductive toxicity study. The highest dose of 2 % CaCO₃ (corresponding to 1.1 % Ca) resulted in reduced numbers and total weight of litters, and increased both the number and proportion of litter deaths, hence being considered as LOAEL for effects on reproductive performance. The dose level of 0.73 % Ca may be established as NOAEL although there were some sporadic effects without statistical significance. However, no daily dose levels could be calculated due to lack of data on daily food intake.

 

However, with respect to potential hazards of calcium for reproduction the following aspects have to be taken

into account:

 

i) Calcium, released as calcium cations in aqueous media is a physiologically essential element and nutrient for all mammals including humans. Comprehensive evaluations of possible adverse health effects of individual nutrients at intakes in excess of dietary requirements have been presented in the scientific opinions of the Scientific Committee on Food (SCF). Where possible, tolerable upper intake levels (UL) for different human populations have been established. The UL is an estimate of the highest level of intake entailing no appreciable risk of adverse health effects. In the opinion on calcium (EFSA 2006), the sources, properties and effects of calcium on animals as well as on different subgroups of the human population have been re-evaluated and a tolerable upper intake level for calcium has been defined. The SCF decided to base the derivation of an UL for calcium on the evidence of different interventional studies of long duration in adults, some of which were placebo-controlled and in which total daily calcium intakes of 2500 mg from both the diet and supplements were tolerated without any adverse effects. Based on the findings, a tolerable upper intake level of 2500 mg of calcium per day for calcium intake from all sources is proposed for adults, corresponding to a dose of about 36 mg calcium/kg bw/d taking into account an average body weight of 70 kg/person. The UL is considered to also cover any potential reproductive effects.

 

ii) Supportive information is available in section 7.12 of the technical dossier (Mortimer, 1988) showing that calcium is essential for the function of human spermatozoa (acrosome reaction), i.e. calcium has a beneficial effect on reproductive performance.

 

iii) Supportive information is available in section 7.12 of the technical dossier (Han, 2000) showing that calcium has a protective effect against lead accumulation in dams and their offspring, i.e. acts beneficially.

 

 

Two pre-natal developmental toxicity studies establishing a dose- response relationship of potential adverse effects of calcium after oral administration of calcium carbonate to rats were identified (Shackelford et al., 1993, 1994). The design of these studies was comparable to the OECD guideline 414. In all studies no adverse developmental, foetotoxic or teratogenic effects were noticed up to and including the highest dose levels tested. These studies allow the derivation of a NOAEL value for developmental effects of calcium.

From the study on rats given CaCO₃ in feed (Shackelford et al., 1993) the highest dose of 1.25 % Ca is established as the NOAEL for developmental effects, corresponding to a daily dose of 938 mg Ca/kg bw/d.

However, with respect to potential hazards of calcium for developmental toxicity the following aspects have to be taken into account:

 

i) Calcium, released as calcium cations in aqueous media is a physiologically essential element and nutrient for all mammals including humans. Comprehensive evaluations of possible adverse health effects of individual nutrients at intakes in excess of dietary requirements have been presented in the scientific opinions of the Scientific Committee on Food (SCF). Where possible, tolerable upper intake levels (UL) for different human populations have been established. The UL is an estimate of the highest level of intake entailing no appreciable risk of adverse health effects. In the opinion on calcium (EFSA 2006), the sources, properties and effects of calcium on animals as well as on different subgroups of the human population have been re-evaluated and a tolerable upper intake level for calcium has been defined. The SCF decided to base the derivation of an UL for calcium on the evidence of different interventional studies of long duration in adults, some of which were placebo-controlled and in which total daily calcium intakes of 2500 mg from both the diet and supplements were tolerated without any adverse effects. Based on the findings, a tolerable upper intake level of 2500 mg of calcium per day for calcium intake from all sources is proposed for adults, corresponding to a dose of about 36 mg calcium/kg bw/d taking into account an average body weight of 70 kg/person. The UL is considered to also cover any potential developmental effects and will be used further in the risk assessment.

 

ii) Lack of developmental/teratogenic effects or even beneficial effects of calcium supplementation on foetal development is further supported by human data (Villar, 1990; Levine, 1997; Koo, 1999; Section 7.10.1 of the technical dossier).

 

3,5,5-trimethylhexanoic acid

Information on development toxicity is available from a one-generation study according to OECD Guideline 415 (Exxon, 1998) with 3,5,5-trimethylhexanoic acid. In this one-generation range-finding study, the test substance was administered to rats in the diet in concentrations of 0.06, 0.12, 0.25 and 0.5% for at least ten weeks prior to mating, during the mating gestation and postpartum periods until weaning of the F1 offspring. The male P1 animals were sacrificed at the end of the mating period, the females and the offspring after weaning.
Reduced live birth index and survival indices were noted in the offspring of the 0.5% group. Offspring body weights of both sexes of the 0.25% and 0.5% groups were reduced compared with the controls during the postnatal period. A postnatal developmental retardation was obvious in the 0.5% dose group offspring, based on the delay of onset of eye opening in male offspring, pinna detachment in both sexes, retardation of preputial separation and vaginal patency. While treatment related, these delays were considered secondary to reduced offspring body weight.
The LOAEL for developmental effects was 0.25% (165-500 mg/kg bw/d for dams), the NOAEL 0.12% (79 -228 mg/kg bw/d for dams) (Exxon, 1998; key study, RL2).
There is no need for additional developmental toxicity studies.

 

Calcium 3,5,5 -trimethylhexanoate

Since no reproductive toxicity study is available for calcium 3,5,5-trimethylhexanoate, information on the individual constituents calcium and 3,5,5-trimethylhexanoic acid will be used for the hazard assessment and, when applicable, for the risk characterisation of calcium 3,5,5-trimethylhexanoate. For the purpose of hazard assessment of calcium 3,5,5-trimethylhexanoate, the point of departure for the most sensitive endpoint of each constituent will be used for the DNEL derivation.

 

 

Justification for selection of Effect on developmental toxicity: via oral route:

Information from read-across substances:

• human data for calcium: not reprotoxic (weight of evidence)


• animal data for 3,5,5-trimethylhexanoic acid: 

Justification for classification or non-classification

Calcium 3,5,5-trimethylhexanoate is not expected to show adverse effects on sexual function and fertility, since the two constituents calcium and 3,5,5-trimethylhexanoic acid have not shown effects in a range of test systems. Thus, calcium 3,5,5-trimethylhexanoate is not to be classified according to regulation (EC) 1272/2008 for reproductive toxicity: adverse effects on sexual function and fertility and for reproductive toxicity: effects on development.