Bis(pentane-2,4-dionato)calcium

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Adequacy of study:

supporting study

Reliability:

other: Expert statement is attached.

Rationale for reliability incl. deficiencies:

other: No studies are available on the toxicokinetics, metabolism and distribution of bis(pentane-2,4-dionato)calcium. Predictions were made based on physical-chemical properties and information from tox. studies and read across.

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Bis(pentane-2,4-dionato)calcium

EC Number:

243-001-3

EC Name:

Bis(pentane-2,4-dionato)calcium

Cas Number:

19372-44-2

Molecular formula:

C10H14CaO4

IUPAC Name:

calcium bis[(2Z)-4-oxopent-2-en-2-olate]

Applicant's summary and conclusion

Executive summary:

Basic Toxicokinetics for bis(pentane-2,4-dionato)calcium (CAS# 19372-44-2)

 

In order to fulfill the requirements for submission of a REACH dossier according to Annex IX of REACH Regulation (EC) No.1907/2006 (for substances >100 tonnes/year) and in absence of data on the toxicokinetics and dermal absorption, an assessment of toxicological behaviour is required.No studies are available on the toxicokinetics, metabolism and distribution of bis(pentane-2,4-dionato)calcium. Predictions were made based on physical-chemical properties and information from tox. studies and read across.

 

Below are some physical chemical properties of bis(pentane-2,4-dionato)calcium

 

Endpoint	bis(pentane-2,4-dionato)calcium
MW	238.294
WS	12.9 g/L
MP	Decomposes before melting: The decomposition starts at 205 °C.
Log Pow	-1.1
VP	At 25°C is well below 0.01 Pa or 0.1 μBar. (In the range of 1·10-12 - 1·10-6 Pa).
Skin irritation	Not irritating

 

There is no information on hydrolysis since the substance is readily biodegradable.

 

The available physico-chemical and toxicological information of the substance has been evaluated and used to assess the toxicological behaviour. The results of this analysis will address the question on how the chemical will react in the body.

The ECHA “Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance May 2008” document provides guidance, which physico-chemical properties commonly determine oral, inhalatory and dermal absorption, distribution, metabolism and elimination of substances(Link:http://echa.europa.eu/documents/10162/13632/information_requirements_r7c_en.pdf)

Dermal Absorption

Generally the smaller the molecule the more easily it may be taken up. Molecular weights below 500 are favorable for absorption. The molecular weight of this substance is238.294. The substance is soluble in water up to 12.9 g/L and the log Pow is moderate.

Therefore, the substance may be significantly absorbed via the skin based on the values above. The substance is not irritating to skin and increased absorption due to damaged skin is therefore not very likely. 

Inhalation Absorption

The vapor pressure of the substance was very low. However, the substance is available as a powder. Light microscopic examination revealed it is a very fine powder. The CoA that states 99% < 40 µm. 75.2% is < 10 µm and 47.9% is < 5 µm.

Based on the physico-chemical properties described above and the particle size the substance may be significantly absorbed via inhalation.

 

Oral Absorption

The LD50 for this substance is 1250 mg/kg bw indicating that the substance is absorbed via the oral route. Further information on oral absorption is not available for bis(pentane-2,4-dionato)calcium. Based on the physico-chemical properties described above of the substance significant absorption is expected.

 

Read across

 

Pentane-2,4-dione (CAS 123-54-6, EC 204-634-0).

From CSR:“No direct studies are available concerning the mode of action of the substance. 1,3 -Diketones unfold metal chelating properties in vivo which may lead to inhibition of the activity of metal containing enzymes like peroxidases or cytochrome P450. In an inhalation study conducted in male Fischer 344 rats it could be shown that 14C-labeled-2,4- pentanedione was readily absorbed. Nose-only exposure to 400 ppm 14C labeled-2,4-pentanedione resulted in a rapid increase in plasma radioactivity during the first 3 hours of exposure. A plateau was formed at the end of the 6 hour exposure period. Unmetabolized 14C-labeled-2,4-pentanedione was present throughout the whole of the exposure phase. Immediately post exposure, radioactivity was present in all tissues examined, but on a concentration basis (μg equivalents/g) there was no preferential accumulation of 14C in any tissue or organ. On a total organ basis, highest contents were in liver and kidneys. Unmetabolized 14C-labeled-2,4-pentanedione declined rapidly to undetectable concentrations by 12 hours. Elimination of 14C from plasma followed a biphasic pattern with a terminal half-life of 30.72 hours. Excretion over 48 hours of 14C was approximately equivalent between urine (37.6 %, mainly not identified metabolites) and expired 14CO2 (36.3 %), which the most part of the radioactivity was eliminated in the first 12 hours. Expired volatiles, feces, tissues and carcass accounted for 2.29, 2.78, 1.66 and 17.15 % of the total administered radioactivity dose 48 hours post dosing, respectively [modified from OECD SIDS Dossier]”

“Taking into consideration the measured octanol/water partition coefficient of 0.68 no potential for bioaccumulation/bioconcentration and geoaccumulation can be identified.”

 

Calcium.

Calcium levels in the body are regulated by homeostatic processes. These homeostatic processes are able to deal with moderate increases in calcium intake: either by storage in bone or by excretion via urine, faeces or sweat. Therefore, calcium and calcium carbonate are not toxic to humans but are essential elements to life and serious disorders, such as retarded skeletal growth may result from calcium deficiency. (For full details see: Chapter 11 from: FOA/WHO (2001) Human Vitamin and Mineral Requirements. Retrieved from:http://www.fao.org/docrep/004/Y2809E/y2809e00.htm#Content. Date last access Nov. 2012))

Conclusion

While toxicokinetic data is not available on bis(pentane-2,4-dionato)calcium, based on the properties of the substance and read across it is expected to be absorbed to a great extent and excreted. Bioaccumulation is not expected. Further information on distribution, metabolism or excretion is not available.