L-Aspartic acid, N,N'-1,2-ethanediylbis-, sodium salt (1:3)

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 to 7 May 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Objective of study:

absorption

distribution

excretion

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

Deviations:

yes

Remarks:

only one low dose used

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

416-530-4

EC Name:

-

Cas Number:

178949-82-1

Molecular formula:

C10H13N2Na3O8

IUPAC Name:

trisodium 2-({2-[(1-carboxy-2-carboxylatoethyl)amino]ethyl}amino)butanedioate

Details on test material:

- Name of test material (as cited in study report): radiolabelled-trisodium EDDS
- Substance type: technical product
- Physical state: clear liquid
- Radiochemical purity (if radiolabelling): 98.7%
- Specific activity (if radiolabelling): 16.1 uCi/mg
- Locations of the label (if radiolabelling): 14C on succinate groups
- Expiration date of radiochemical substance (if radiolabelling): 9 September 1993
- Stability under test conditions: no data
- Storage condition of test material: at about 4oC

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

other: Crl: (WI)BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Canada, St-Constant, Quebec
- Age at study initiation: 6-8 weeks
- Weight at study initiation: males: 191-303 g; females 173-253 g
- Fasting period before study: no data
- Housing: glass metabolism cages
- Individual metabolism cages: yes
- Diet (e.g. ad libitum): conventional, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 50 +/- 20
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 4 May 1993 To: 7 May 1993

Administration / exposure

Route of administration:

dermal

Vehicle:

water

Details on exposure:

TEST SITE
- Area of exposure: 7.6 cm2
- % coverage: no data
- Type of wrap if used: glass chamber applied with Permabond 102 adhesive
- Time intervals for shavings or clipplings: before dosing

REMOVAL OF TEST SUBSTANCE
- Washing (if done): test site washed at study termination at 72 h, and included with the rinsings from the dermal chamber for counting of radioactivity
- Time after start of exposure: 72 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.2 mL aqueous solution
- concentration (if solution): males, 4.14 mg/kg bw (66.7 uCi/kg bw); females, 5.12 mg/kg bw (84.0 uCi/kg bw )

VEHICLE
- Justification for use and choice of vehicle (if other than water): water
- Amount(s) applied: 0.2 mL

USE OF RESTRAINERS FOR PREVENTING INGESTION: no

Duration and frequency of treatment / exposure:

72 h

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

4.14 mg/kg bw/day (nominal)

Remarks:

Males, 4.14 mg/kg bw (66.7 uCi/kg bw)

Doses / concentrations 2

Dose / conc.:

5.12 mg/kg bw/day (nominal)

Remarks:

females, 5.12 mg/kg bw (84.0 uCi/kg bw )

No. of animals per sex per dose / concentration:

5/sex test group
1 male acted as a control

Control animals:

yes, concurrent vehicle

Positive control reference chemical:

no

Details on study design:

- Dose selection rationale: selected to provide sufficient material to determine the distribution, elimination and mass balance of radioactivity
- Rationale for animal assignment (if not random): random

Details on dosing and sampling:

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine, faeces, blood, plasma, cage washes, expired air, adipose tissue, brain, bone marrow, femur bone, gonads, heart, GI (combined stomach, large and small intestine), GI contents, kidneys, liver, lungs, muscle (right leg adductor), pancreas, spleen, carcass, skin from test site and three adjacent sites.

- Time and frequency of sampling: urine, faeces and cage washes were collected at 24, 48 and 72 h; expired air was trapped in potassium hydroxide and collected at 12, 24, 36, 48 and 72 h. Tissues and organs were sampled for radioactivity at study termination (72 h).

Statistics:

Bartlett's test and t-tests were used to determine any gender differences in the recovery of radioactivity. A in-transformation on the percent of dose was used to correct the non homogeneity of the variances when appropriate. For the skin test site, adjacent skin and dermal cell rinse a one-way ANOVA was used to compare the gender effect. The parameters tested were: radioactivity recovered in the tissues, urine, faeces, expired air, skin dose site, adjacent skin, dermal cell rinse and total recovered radioactivity.

Results and discussion

Preliminary studies:

none

Main ADME results

Main ADME results 1

Type:

absorption

Results:

After 72 h, 11.1% of applied dose was absorbed in males; 5% absorbed in females

Main ADME results 2

Type:

distribution

Results:

the combined mean blood and tissue (including carcass) recovery was 2.34% in males and 1.45% in females

Main ADME results 3

Type:

excretion

Results:

about 9% of the applied dose was excreted in males and about 4% in females during 72 h exposure

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Only about 11% of the applied dose was absorbed in males and 5% in females during the 72 h exposure period.

The total recovery of radioactivity was 59.1% in males and 62.8% in females. This mainly represented unabsorbed material found at the skin treatment site (about 40% of applied dose) and dermal chamber washings (about 10%).

Details on distribution in tissues:

Low amounts of radioactivity were detected in the organs and tissues examined, ranging from 0% to up to 1.2% in the male carcass. See table 1 for details.

Details on excretion:

Less than 9% of applied dose recovered in the excreta (urine, faeces, cage wash and expired air). See tables 1 and 2 for details.

Metabolite characterisation studies

Metabolites identified:

not measured

Any other information on results incl. tables

Table 1. Total recovery (mass balance) of radioactivity after dermal exposure of rats

Sample	Males (% of dose)	Females (% of dose)
Skin test site	38.5 ± 9.38	43.9 ± 11.4
Skin adjacent site	0.908 ± 0.829	0.916 ± 1.117
Dermal cell rinse	8.60 ± 3.36	12.8 ± 7.42
Urine	2.26 ± 1.63	0.521 ± 0.578
Faeces	4.90 ± 3.79	2.06 ± 2.69
Expired air	0.643 ± 0.413	0.340 ± 0.186
Cage wash	0.954 ± 0.879	0.805 ± 0.893
Blood	0.003 ± 0.006	0.000 ± 0.000
Liver	0.025 ± 0.021	0.023 ± 0.022
Kidneys	0.012 ± 0.012	0.004 ± 0.003
Heart	0.000 ± 0.000	0.001 ± 0.002
Lungs	0.000 ± 0.000	0.007 ± 0.010
Pancreas	0.002 ± 0.002	0.002 ± 0.001
Spleen	0.000 ± 0.000	0.004 ± 0.005
Brain	0.000 ± 0.000	0.000 ± 0.000
Testes/ovaries	0.000 ± 0.001	0.001 ± 0.002
Muscle	0.014 ± 0.031	0.000 ± 0.000
Epididymal fat	0.014 ± 0.018	0.121 ± 0.156
Bone marrow	0.000 ± 0.000	0.000 ± 0.000
Bone femur	0.000 ± 0.000	0.001 ± 0.002
GI tract	0.173 ± 0.297	0.184 ± 0.233
GI contents	0.896 ± 1.38	0.314 ± 0.261
Carcass	1.20 ± 0.914	0.794 ± 0.738
Total	59.1 ± 8.03	62.8 ± 18.6

Table 2. Mean cumulative recovery of radioactivity in excreta after dermal exposure

Time (h)	Males (% of dose)					Females (% of dose)
	Urine	Faeces	Expired air	Cage wash	Total	Urine	Faeces	Expired air	Cage wash	Total
0-12	a	a	0.086 ± 0.014	a	0.086 ± 0.014	a	a	0.087 ± 0.035	a	0.087 ± 0.035
0-24	1.51 ± 1.59	0.884 ± 1.18	0.145 ± 0.05	0.492 ± 0.627	3.03 ± 3.36	0.355 ± 0.26	0.168 ± 0.212	0.111 ± 0.043	0.032 ± 0.049	0.577 ± 0.438
0-36	1.51 ± 1.59	0.884 ± 1.18	0.251 ± 0.116	0.492 ± 0.627	3.14 ± 3.34	0.355 ± 0.26	0.168 ± 0.212	0.162 ± 0.079	0.032 ± 0.049	0.628 ± 0.470
0.45	1.74 ± 1.59	2.44 ± 1.79	0.437 ± 0.244	0.730 ± 0.722	5.35 ± 3.15	0.349 ± 0.322	0.998 ± 1.63	0.226 ± 0.152	0.627 ± 0.692	2.20 ± 2.66
0-72	2.26 ± 1.63	4.90 ± 3.79	0.643 ± 0.413	0.954 ± 0.879	8.76 ± 4.87	0.521 ± 0.578	2.06 ± 2.69	0.340 ± 0.186	0.805 ± 0.893	3.72 ± 4.28

a, no sample collected

Applicant's summary and conclusion

Conclusions:

In a GLP study, similar to OECD Guideline 417, only about 11% of the applied dermal dose of radiolabelled-trisodium EDDS was considered absorbed in males and 5% in females following a 72-h exposure period. Less than 9% was recovered in the excreta (urine, faeces, cage wash and expired air). Low amounts of radioactivity were detected in the organs and tissues examined, ranging from 0% to up to 1.2% in the male carcass.

Executive summary:

In a GLP study conducted according to a protocol similar to OECD Guideline 417, the absorption, distribution and elimination of 14C-trisodium EDDS was determined in male and female Wistar rats.

The radiolabelled test substance was applied (in water) at 4-5 mg/kg bw in a glass chamber to the shaved skin of five rats of each sex for 72 h. Urine, faeces, cage washings and expired air were collected at intervals throughout the study period and the radioactive content was measured. At study termination, levels of radioactivity were determined in adipose tissue, brain, bone marrow, femur bone, gonads, heart, gastrointestinal tract, gastrointestinal contents, kidneys, liver, lungs, muscle, pancreas, spleen, carcass, skin from the treatment site and adjacent sites.

The total recovery of radioactivity from all sources was 59.1% in males and 62.8% in females. This mainly represented unabsorbed material found at the skin treatment site (about 40%) and in the dermal chamber washings (about 10%). Only about 11% of the applied dose was considered absorbed in males and 5% in females during the 72-h exposure period, with less than 9% recovered in the excreta (urine, faeces, cage wash and expired air). Low amounts of radioactivity were detected in the organs and tissues examined, ranging from 0% to up to 1.2% in the male carcass.