Diphosphoric acid, compd. with piperazine (1:1)

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics, other

Type of information:

other: expert statement

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented expert statement based on a series of physicochemical and toxicology studies

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

457-330-7

EC Name:

-

Cas Number:

66034-17-1

Molecular formula:

Hill formula: C4H10N2:H4O7P2 CAS formula: C4H10N2:H4O7P2

IUPAC Name:

(phosphonooxy)phosphonic acid; piperazine

Test material form:

solid: particulate/powder

Administration / exposure

Doses / concentrations

Remarks:

Doses / Concentrations:
.

Applicant's summary and conclusion

Conclusions:

Interpretation of results: no bioaccumulation potential based on study results Bioaccumulation is unlikely based on the good water solubility, low octanol/water partition coefficient and ionisation of the two constituents in aqueous environment.
.

Executive summary:

Physical-chemical properties

The substance T-1063 FM is a physical mixture of piperazine and pyrophosphate which is provided as powder. The molecular weight of T-1063 FM is 264 Da, the sum of 86 Da for piperazine and 178 Da for pyrophosphate. The substance T-1063 FM is soluble in water (12.24 g/l at 20°C), but not in fat (HB-307: < 1.5 mg/kg). The octanol/water partition coefficient (log P_ow) could not be determined for T-1063 FM because the substance ionises in water. However, based on the good water solubility and the very low fat solubility and the fact that both constituents of the substance T-1063 FM, i.e. piperazine and pyrophosphate, ionise in an aqueous environment the log P_owis expected to be < 3. The vapour pressure of T-1063 FM was determined to be below 6 x 10^-6Pa.

 Absorption by oral, dermal and inhalation route

The low molecular weights and the water solubility of the two constituents of T-1063 FM favour gastrointestinal absorption [ECHA 2014]. Systemic availability after oral dosing also can be deduced from the histopathological effects observed in the kidneys of female rats in the high dose group after 28 day repeated dosing.

The physical-chemical properties of T-1063 FM are considered also to favour (low) dermal absorption after topical administration [ECHA 2014].

Inhalation of any vapour from T-1063 FM is an unlikely route of human exposure, because the substance has a very low vapour pressure (< 6 x 10^-6Pa at 25°C) and decomposes without boiling at high temperatures. However, exposure of workers to inhalable particles of T-1063 FM is possible, because the substance is a very fine powder with most particles below 1.2 µm. Systemic availability of T-1063 FM after inhalation is very likely based on the physical-chemical properties.

Distribution, metabolism, excretion

All available study results gave no indication regarding the distribution, metabolic pathway or excretion of T-1063 FM. Based on the good water solubility T-1063 FM is expected to be distributed in the whole body whereas bioaccumulation in fat tissue is not to be expected due to the low log P_ow.

 Reference:          ECHA 2014, Chapter R.7c: Endpoint specific guidance