Tetrasodium N,N-bis(carboxylatomethyl)-L-glutamate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2008 - December 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to standard protocol and under GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tetrasodium N,N-bis(carboxylatomethyl)-L-glutamate

EC Number:

257-573-7

EC Name:

Tetrasodium N,N-bis(carboxylatomethyl)-L-glutamate

Cas Number:

51981-21-6

Molecular formula:

C9H9NO8Na4

IUPAC Name:

tetrasodium 2-[bis(carboxylatomethyl)amino]pentanedioate

Details on test material:

- Name of test material (as cited in study report): GLDA
- Molecular formula (if other than submission substance): C9H13NO8.4Na
- Molecular weight (if other than submission substance): 351.13
- Physical state: White powder
- Analytical purity: See 'Confidential details on test material'
- Composition of test material, percentage of components: See 'Confidential details on test material'
- Purity test date: January 16, 2008
- Lot/batch No.: CFC-8593 (see CoA in the report attached)
- Expiration date of the lot/batch: 16 January 2010
- Storage condition of test material: Ambient temperature (15-25°C)
- Other:
Stable for 2 years at ambient temperature if stored well closed
Solubility: in water at least 60wt%, low in propylene glycol/ethanol/acetone, very low in corn oil and olive oil
pH: 11-12 at 1% (w/w)
Hygroscopy: high
Particle size range: 1-400 µm
Vapour pressure: extremely low (due to evaporation of attached water)
- Analytical purity / Composition of test material, percentage of components: Assay as GLDA-Na4 90.0±1.0%
- Purity test date: January 16, 2008

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: 7 weeks old (received at age of 6 weeks)
- Weight at study initiation: 233.6 g (average weight males), 165.3 g (average weight females)
- Fasting period before study: not applicable
- Housing: 5 males or 5 females per cage, except during exposure: housed individually in holders
- Diet (e.g. ad libitum): ad lib, except during exposure
- Water (e.g. ad libitum): ad lib, except during exposure
- Acclimation period: 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): generally within 40-70%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12-hour light, 12-hour dark cycle


IN-LIFE DATES: From: December 4, 2008 To: December 18, 2008

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: water

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only inhalation chamber, a modification of the chamber manufactured by ADG Developments Ltd., Codicote, UK
- Exposure chamber volume: ca. 60 litres
- Method of holding animals in test chamber: individually, in plastic animal holders
- Source and rate of air: dry compressed air, 20.0 normal Litres/minute (corresponding to 22.2 L/min at current T and pressure)
- Method of conditioning air: dry compressed air
- System of generating particulates/aerosols: to generate the test atmosphere, a solution of 50 wt% GLDA in water was passed via a peristaltic pump (Minipulse, Gilson, Villiers le Bel, France) to a compressed air driven atomizer (type 970/S, Schlick GmbH, Coburg, Germany); the air flow was measured using a mass stream meter (Bronkhorst Hi Tec, Ruurlo, The Netherlands).
- Method of particle size determination: Two particle size distribution measurements were performed (one before and one during exposure using the same settings). A 10-stage cascade impactor was used (Andersen, Atlanta, USA). The Mass Median Aerodynamic Diameter (MMAD) and geometric standard deviation (gsd) were calculated.
- Treatment of exhaust air: From the bottom of the unit the test atmosphere was led to an exhaust where it was filtered.
- Temperature, humidity, pressure in air chamber: The temperature and the relative humidity of the test atmosphere were recorded eight times during exposure at regular intervals (about twice per hour) using a CAN transmitter (G.Lufft Mess- und Regeltechnik GmbH, 70719 Fellbach, Germany). By securing a positive pressure in the central column and a slightly negative pressure in the outer cylinder, which encloses the entire animal holder, air leaks from nose to thorax rather than from thorax to nose and dilution of test atmosphere at the nose of the animals is prevented.

TEST ATMOSPHERE
- Brief description of analytical method used: The actual concentration (by weight) of the non-volatile particles present in the test atmosphere was determined approximately once each hour by means of gravimetric analysis. Representative test atmosphere samples were obtained by passing approximately 5 L test atmosphere at 5 L/min through fibre glass filters (Schleicher and Schuell, GF10, Ø 47 mm). The nominal concentration was determined by dividing the total amount of test material used (by weighing) by the total volume of air passed through the exposure unit.
- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle (if applicable): water
- Concentration of test material in vehicle (if applicable): 50 wt% GLDA in water
- Justification of choice of vehicle: based on good solubility in water
- Lot/batch no. (if required): no
- Purity: not applicable


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: During preliminary experiments, it was established that beyond a concentration of 4.3 g/m3, the particle size increased rapidly and the generation efficiency decreased. Therefore, 4.3 g/m3 was considered the technically highest attainable concentration, taking into account a respirable particle size, viz. a particle size distribution at 1-4 microns MMAD.
- MMAD (Mass Median Aerodynamic Diameter) / GSD (Geometric st. dev.):
at December 3: MMAD = 2.8 µm and GSD = 2.7
at December 4 (during exposure): MMAD = 2.8 µm and GSD = 2.7

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Target concentration: 5 g/m3.
Actual concentration reached: 4.2 g/m3.
The actual concentration (by weight) was determined approximately once each hour by means of gravimetric analysis. Time weighed average concentration.

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The rats were visually inspected just before exposure, for reactions to treatment during the exposure,
shortly after exposure, and at least once daily during the observation period.
Body weights of the animals were recorded just before exposure (day 0), on day 7, and on day 14 prior to necropsy.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, gross pathological changes

Statistics:

Not required.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 4.2 mg/L air (analytical)

Exp. duration:

4 h

Remarks on result:

other: limit test

Mortality:

None of the animals died during the study.

Clinical signs:

other: - During exposure: Although observation of the rats was limited during exposure due to the stay in restraining tubes, breathing at a decreased rate (graded as slight) was seen in all animals at all observation time points. - After exposure: Shortly after

Body weight:

Body weight gain during the observation period was as expected for animals of this age and strain.

Gross pathology:

No macroscopic abnormalities were observed at necropsy.

Any other information on results incl. tables

The nominal concentration of GLDA-Na4, calculated from the test material flow and the air flow was 33.3 g/m3 (66.6 g/m3 solution of 50 wt% GLDA-Na4), indicating a generation efficiency of 13%.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

Migrated information

Conclusions:

The acute inhalation LC50 of GLDA-Na4 was determined to be greater than 4.2 mg/L in males and females; this was the technically highest attainable concentration. As no mortality occurred at this concentration, no classification is needed according to OECD-GHS.

Executive summary:

GLDA-Na4 was evaluated for its acute inhalation toxicity potential in rats. The study was performed in accordance with OECD Guideline 403 (Acute Inhalation Toxicity). The study was designed and performed according to Good Laboratory Practice Standards. Five males and five females were exposed for four hours to an aerosol generated from the test material at a target concentration of 5 g/m3. A concentration of ca. 4.3 g/m3 was considered the technically highest attainable concentration, taking into account a respirable particle size (MMAD between 1 and 4 micron). The actual concentration of the test compound turned out to be 4.2 g/m3; the MMAD was 2.8 micron and gsd was 2.7. There was no mortality during the study. Clinical signs included slightly decreased breathing rate during exposure and a soiled fur of the head, neck, back, and/or abdomen shortly after exposure, which were no longer evident on Day 2. Sniffing was noticed in 4 animals shortly after exposure, in 7 animals on day 1 and in 1 animal on day 2. A discharge from the eyes was seen in a single animal on day 1. No other abnormalities were observed in the 14-day observation period. Body weight gain was as expected for animals of this age and strain and no macroscopic abnormalities were found.

The acute (4 -h) inhalation LC₅₀ of GLDA-Na4 was determined to be greater than 4.2 mg/L in males and females. This was the technically highest attainable concentration. As no mortality occurred at this concentration, no classification is needed according to OECD-GHS.