Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data taken from EU risk assessment/SIDS; Guideline study

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
SIDS Initial Assessment Report For SIAM 15
Author:
OECD
Year:
2003
Bibliographic source:
SIDS Dossier Sodium Bicarbonate, Final July 2003
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OTS 798.1150 (Acute inhalation toxicity)
Deviations:
no
GLP compliance:
yes
Remarks:
Product Safety Labs, New Jersey, USA
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): sodium bicarbonate
- Analytical purity: > 99.5%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hilltop Lab Animals, Scottdale, PA.
- Age at study initiation: the report states that the rats were young adults, but the exact age is not given
- Weight at study initiation: 224 - 239 g (males), 219 - 226 g (females)

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
not specified
Vehicle:
other: no data
Details on inhalation exposure:
TEST ATMOSPHERE
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): in two samplings of two minutes duration 2.9 +/- 1.77 µm and 2.7 +/- 2.04 µm, respectively.

PREPARATION OF PARTICLE:
The test substance was ground for 24 hours in a ball mill prior to aerosolisation. Thereafter it was sieved through a 425 micron screen to separate it from the grinding medium and any other large particles which remained.
Analytical verification of test atmosphere concentrations:
yes
Remarks:
by gravimetric calculation
Duration of exposure:
4.5 h
Concentrations:
4.74 +/- 1.03 mg/l
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: body weight was measured prior to exposure and on days 1, 7 and 14. Animals were observed before exposure commenced, every 15 min during the first exposure hour, and every 15 min thereafter through exposure termination.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4.74 mg/L air
Exp. duration:
4.5 h
Mortality:
There was no mortality
Clinical signs:
During the first hour of exposure, reduced movement and hunched posture were noted for most animals. At exposure termination test substance was observed on the fur of two animals, while the same was observed in all the remaining rats on the one or two after exposure termination.
Ocular and/or nasal discharge was observed in 6/10 rats within one day after exposure. 6/10 rats were active and health the from day 2 after exposure, and the remaining animals likewise from day 3.
Body weight:
All the animals gained body weight during the observation period (body weight males at 14 days: 311 - 341 g; body weight females at 14 days: 254 - 267 g).
Gross pathology:
The general findings at gross necropsy were unremarkable. One male and one female had moderately red lung tissue, while one male had slightly red lung tissue.

Applicant's summary and conclusion