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Administrative data

Endpoint:
immunotoxicity
Remarks:
subacute
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets general scientific principles, acceptable for assessment.

Data source

Reference
Reference Type:
publication
Title:
In vivo and in vitro effects of sodium azide on mouse complement
Author:
Johnson K.W. et al.
Year:
1984
Bibliographic source:
PMID: 6719470, Tox. Appl. Pharmacol. 73:559-63.

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
1. 1-day acute study
2. 6-day time course after single exposure
3. 11-day subacute study
GLP compliance:
no
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium azide
EC Number:
247-852-1
EC Name:
Sodium azide
Cas Number:
26628-22-8
Molecular formula:
N3Na
IUPAC Name:
sodium azide
Specific details on test material used for the study:
- Name of test material (as cited in study report): Sodium azide, NaN3
- Substance type: no data
- Physical state: no data
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Litton (Frederick, MD, US)
- Age at study initiation: 5-6 weeks
- Weight at study initiation: 17-20 grams
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum):ad libitum
- Acclimation period: 1 week quarantine

Administration / exposure

Route of administration:
other: 1- and 6-day study: intravenous; 11-day study: intraperitoneal
Vehicle:
physiological saline
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Sodium azide was prepared weekly in physiol. saline (0.15 M NaCl).
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
1-day, single injection
single injection with 6-day follow up
11-day, daily injections
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0.2, 2.0, 20 mg/kg bw
Basis:
nominal conc.
1-day study
Remarks:
Doses / Concentrations:
20 mg/kg bw
Basis:
nominal conc.
single injection with 6-day follow up
Remarks:
Doses / Concentrations:
10, 15, 20 mg/kg bw
Basis:
nominal conc.
11-day study
No. of animals per sex per dose:
1-day, single injection and 6-day follow up: 6 animals (female) per group
11-day, daily injections: 8 animals (female) per group
Control animals:
yes, concurrent vehicle

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
not examined
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Gross pathological findings:
not examined
Details on results:
As seen in Table 1, the effect of sodium azide on B6C3F1 complement haemolytic activity was limited.
The CH50 values (the amount of compartment lysing 50% of sensitized erythrocytes under standard conditions) for Sodium azide-treated animals in the 1-day acute study were neither dose related nor significantly different from saline controls.
Animals exposed to 20 mg/kg Sodium azide in the 6-day time course experiment displayed no significant changes in CH50 values. Of 36 treated animals, 3 died shortly after dosing during the 6-day study.
In the 11-day study, animals exposed to 10 mg/kg Sodium azide exhibited significantly higher CH50 values. However, this effect was not considered biologically significant due to low control values and the lack of a dose-dependent relationship. Lethality also occurred among animals in the 11-day study. Two mice in the 15-mg/kg group and all animals in the 20-mg/kg group died of Sodium azide-induced respiratory paralysis.

Specific immunotoxic examinations

Cell viabilities:
not examined
Humoral immunity examinations:
not examined
Specific cell-mediated immunity:
not examined
Non-specific cell-mediated immunity:
not examined
Other functional activity assays:
no effects observed

Effect levels

open allclose all
Dose descriptor:
NOAEL
Remarks:
acute study (1-day)
Effect level:
<= 20 mg/kg bw (total dose)
Sex:
female
Basis for effect level:
other: other functional activity assays (mouse complement mediated lysis of IgM sensitized rabbit erythrocytes)
Dose descriptor:
LOAEL
Remarks:
subacute study (11-day)
Effect level:
15 mg/kg bw (total dose)
Sex:
female
Basis for effect level:
other: Mortality

Any other information on results incl. tables

Table 1: The effect of sodium azide on B6C3F1 mouse complement levels following in vivo exposure

Experiment

Route

N

Exposure group

CH50 valuea

1-day, single injection

i.v.

6

Vehicle (NaCl)

107 ± 11.5

0.2 mg/kg

144 ± 20.6

2.0 mg/kg

98 ± 2.5

20 mg/kg

114 ± 11.2

6-day time course after single dose (20 mg/kg)

i.v.

6

Vehicle

106 ± 6.6

Day 1

136 ± 9.5

Day 2

112 ± 9.6b

Day 3

102 ± 7.0

Day 4

124 ± 15.9c

Day 6

117 ± 4.5

11-day, daily injection

i.p.

8

Vehicle

79 ± 2.0

10 mg/kg

101 ± 7.5d

15 mg/kg

89 ± 9.9e

20 mg/kg

---f

aThe CH5O value reflects functional complement levels.

bOne animal died (within 24 hr of dosing).

cTwo animals died (within 24 hr of dosing).

dValue differed significantly from control (p < 0.05).

eTwo animals died by Day 11.

fAll animals died by Day 4.

 

Applicant's summary and conclusion

Conclusions:
Sodium azide does not affect mouse complement levels in vivo.
Executive summary:

A microtiter hemolytic assay was utilized to determine Sodium azide modulation of B6C3F1 and C3H mouse serum complement levels in vivo and in vitro. Functional complement was expressed in CH50 units per milliliter. Experiments were performed to determine the in vitro effect of Sodium azide on complement mediated lysis of IgM sensitized rabbit erythrocytes.

Concentrations of 5, 10, 20, 30, 40, 60, and 80 mM Sodium azide were added to microtiter wells containing Tris buffer, IgM sensitized rabbit erythrocytes, and serum complement from naïve female C3H mice. Although NaCl and KCl controls had an inhibitory effect, Sodium azide demonstrated a significant dose-dependent inhibition of complement-mediated lysis.

In the three in vivo experiments, female B6C3FI mice were exposed to Sodium azide and physiological saline (vehicle control). Complement hemolytic ability was evaluated after a 1-day, single iv injection of 0.2, 2.0, and 20.0 mg/kg Sodium azide; at Days 1, 2, 3, 4, and 6 of a 6-day time course study after ip administration of 20 mg/kg Sodium azide; and at the end of an 11-day study involving daily injections of 10, 15, and 20 mg/kg Sodium azide given ip.

No significant changes in complement-mediated hemolysis were observed in the in vivo experiments. These studies indicate that Sodium azide does not affect mouse complement levels in vivo.