[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, sodium salt

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was well documented and meets generally accepted scientific principles, and conducted in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Objective of study:

other:

Principles of method if other than guideline:

This study investigated the effects of dosing via oral gavage (single and multiple doses),in the diet and orally to rats and mice. In addition the effect of co dosing with NaF was also investigated.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, sodium salt

EC Number:

244-742-5

EC Name:

[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, sodium salt

Cas Number:

22036-77-7

Molecular formula:

C6H20N2O12P4.xNa

IUPAC Name:

x sodium (8-x) hydrogen {ethane-1,2-diylbis[nitrilobis(methylene)]}tetrakis(phosphonate)

Details on test material:

Non labelled EDITEMPA ((Dequest 20419) - Lot nr 176-40-4) with chemical purity of 99%.
14C labelled EDITEMPA , with radiochemical purity ranging from 92-93%.. The 14C compound had a purity ranging from 96.4 - 99 %.

Radiolabelling:

yes

Test animals

Species:

other: Rat (Sprague Dawley) and mice (B6C3F1)

Strain:

other: Sprague Dawley rats and B6C3F1 mice

Sex:

male

Administration / exposure

Route of administration:

other: Dietary and by oral gavage

Vehicle:

unchanged (no vehicle)

Duration and frequency of treatment / exposure:

Single dose treatment by oral gavage: 20 male rats were orally treated with a single low dose (15 mg/kg) EDITEMPA, 20 male and 20 females were treated with the high dose (150 mg/kg), and 20 males received the high dose concurrently with NaF at a dose of 11.4 mg/kg. In addition 40 mice were orally treated with a single low dose (15 mg/kg) EDITEMPA or the other group with a single high dose (150 mg/kg), Multiple dosing by oral gavage:16 male rats were treated with 10 daily doses of 14C EDITEMPA at the low dose level (15 mg/kg (bw), 16 males and 16 females were treated at the high dose level (150 mg/kg) and 16 males received the high dose concurrently with sodium fluoride (NaF) at a dose of 11.4 mg/kg.

Multiple doses treatment: 20 male rats were orally treated with low dose (15 mg/kg) EDITEMPA, 20 male and 20 females were treated with the high dose (150 mg/kg), and 20 males received the high dose concurrently with NaF at a dose of 11.4 mg/kg. Four animals from each group sacrificed at 6, 24 and 96 hr and 14 and 28 days following dosing. The group of rats sacrificed at 96 hours were subjected to serial blood sampling at 1,2,4,8,24,48 and 96 hours following dosing. Rats sacrificed at 14 and 28 days were used to assess urinary and fecal excretion of radioactivity. Excreta were sampled at 8, 24,48,72,96 and 168 hours following dosing. At sacrifice tissues and organs were analysed for 14C content. 14 C levels were assessed in the bone and the pharmacokinetic behaviour of the test compound in bone was determined. In addition radioactivity in urine and faeces were analysed by HPLC to assess the metabolism of EDITEMPA.

Doses / concentrations

Remarks:

Doses / Concentrations:
15 mg/kg, 150 mg/kg

EDITEMPA was dissolved in NaOH with pH adjustement to reach pH 7.

No. of animals per sex per dose / concentration:

Males and females (depending on study)

Control animals:

no

Results and discussion

Preliminary studies:

Following single ORAL GAVAGE administration to rats only limited amount of radioactivity was detected in blood. At peak levels (8 -24 hour) only 0.02 to 0.03% of the dose was present in blood of male rats. In the female peal levels at 1 -4 hour ranged from 0.01 -0.02% of the dose. No changes in blood were noted for male rats treated concurrently with NaF and EDITEMPA. Most of the administered doses were eliminated in faeces during the first 48 hrs. Elimination of 14C in urine was limited, only 1% of the dose was excreted in urine in 24 hours. An additional 0.5% was excreted by the end of the collection period (168 hours). In rats treated simultaneously with NaF there and amounts of 14C were slightly higher, excretion in females was similar. Recovery in soft tissue and blood did not exceed 0.1% of the dose any any time following treatment. Recovery in bone was higher and ranged from 0.1 to 0.8% of the dose following the low dose and 0.2 to 0.5 % after the high dose. (Similar for females). Concurrent treatment with NaF resulted in slightly higher values. In rats receiving NaF, the AUC was slightly higher (177 micrograms/gram/day) Mice eliminated most of the dose in faeces at a higher rate than rats, most being eliminated by 24 hours. In urine 1.5 to 2% was excreted in 24 hours and an additional 0.4 to 1% during the remaining 168 hours. No difference in elimination rates were seen between the low and high dose mouse groups. Recovery of 14C in blood or tissues did not exceed 0.05% of the administered doses. In bone 0.2% of the dose was recovered after the low dose and 0.2 -0.5% after the high dose. AUC were 10 and 157 micrograms/g/day for low and high dose respectively. Following both doses the 14C levels in total mice bone were slightly higher than in rats. The AUC in mice bone were 9 and 140 micrograms/gram/day (versus 8 and 125 micrograms/gram/day for rats) after low and high dosing.

During MULTIPLE ORAL DOSING, the compound was eliminated primarily in faeces with limited amounts in urine (rats). Elimination in urine was slow and was limited to 1.2% of the low dose and 1.4% of the high dose during the 168 hour period. Excretion in the females was similar to males. Rats treated simultaneously with NaF showed the rate and amount of 14C excreted in urine to be slightly higher (3%). Only limited amounts of 14C were detected in blood following the 10 day treatment period. At peak levels, less than 0.1% of the last dose was recovered in blood. No apparent differences in treatment groups. 14C levels in tissue were low even at 24 hours and no significant changes in tissue recoveries were apparent in high dose males, females or with concurrent NaF treatment. However in all dose groups relatively high levels were retained in the bone marrow,; this was also seen following treatment in the single doses of the test compound. Recovery of 14C in bone was high (0.6-1.2% of last dose (low dose) and 1.3 - 2.8% after high dose. No apparent differences between males and females. But with males treated with NaF the 14C recovery in bone was twofold higher than in rats treated with the high dose alone. The disappearance of 14C from bone occurred at a slow rate t 1/2 ranged from 14 to 27 days. In comparison to single dose treatment, the uptake of 14C by bone was increased during multiple dosing. Following the low dose a six fold increase was seen in the total bone content, whereas in the high dose an eight fold increase was noted.
Mice eliminated most of administered dose in the faeces by 24 hours. Elimination in urine was limited to 1.3% and 2.5% after the low and high doses respectively. Adrenals and spleen showed some retention of 14C throughout the 28 day period following dosing. In bone 0.9 to 2.1% of the last dose was recovered following the low dose and 1.4-2.8% after the high dose.
In comparison to single dose treatment, the uptake of 14C by bone was increased during multiple dosing. Following the low dose a six fold increase was seen in the total bone content, whereas in the high dose an eight fold increase was noted. In rats receiving the high dose/NaF mixture, a 13 fold increase was demonstrated in the total bone content over those levels found following a single dose.

Applicant's summary and conclusion

Conclusions:

Changes occurring following SINGLE DOSING BY ORAL GAVAGE were limited to accumulation of EDITEMPA in the bone. C14 accumulation in blood and tissues was not apparent. No significant changes appeared to have occurred in rates of urinary or faecal elimination or in the extent of absorption of EDITEMPA. Concurrent administration of NaF appears to increase the absorption, uptake/retention of 14C by bone.
The MULTIPLE ORAL GAVAGE studies indicate limited absorption of EDITEMPA (1 -3% in rats) and (2 -4% in mice). Excretion of 14C was limited. Large proportions of absorbed radioactivity were recovered in the bone. Disappearance from the bone occurred at a slow rate with a t 1/2 of 15 -26 days. The trabecular bone had the highest 14C levels. Significant dose dependence or sex differences were not apparent. However concurrent dosing with NaF appears to increase absorption, uptake and/or retention of EDITEMPA. EDITEMPA does not appear to be metabolised greatly.