Calcium nitrite

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12-15 December 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Good quality study, conducted to GLP. The test material was a 34% solution of hydrated calcium nitrite.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Version / remarks:

29.12.92

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Calcium nitrite

EC Number:

237-424-2

EC Name:

Calcium nitrite

Cas Number:

13780-06-8

Molecular formula:

Ca.2HNO2

IUPAC Name:

calcium nitrite

Constituent 2

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Froxfield (UK) Ltd., Petersfield, Hampshire, England
- Age at study initiation: 11-14 weeks
- Weight at study initiation: 2.4-3.2 kg
- Housing: house individually in metal cages with perforated floors
- Diet (e.g. ad libitum): SDS Stanrab (P) standard laboratory rabbit diet ad libitum
- Water (e.g. ad libitum): drinking water ad libitum
- Acclimation period: "all animals were acclimatised to the experimental environment", but no details on the acclimation period given

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19
- Humidity (%): 30-70
- Air changes (per hr): 19
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: No data

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL [equivalent to about 0.17 mL as calcium nitrite]
- Concentration (if solution): the test material was applied as supplied (34% aqueous solution of calcium nitrite)

Duration of treatment / exposure:

4 hours

Observation period:

72 hours after exposure

Number of animals:

Three males

Details on study design:

TEST SITE
- Area of exposure: 25 mm x 25 mm from the dorso-lumbar region of each rabbit
- % coverage: no data
- Type of wrap if used: The gauze pad was covered by an elastic adhesive dressing

REMOVAL OF TEST SUBSTANCE
- Washing (if done): warm water (30-40°C) (the treated area was subsequently blotted dry)
- Time after start of exposure: 4 hours (upon removal of dressing and gauze pad)

OBSERVATION TIME POINTS
(indicate if minutes, hours or days): On the day of treatment (approximately 60 minutes after removal of the dressings) and on the subsequent three days (equivalent to 24, 48 and 72 hours after exposure)

SCORING SYSTEM:
Local dermal irritation was assessed using the following system:
Erythema and eschar formation: No erythema (0); slight erythema (1); well-defined erythema (2); moderate to severe erythema (3); severe erythema (beet redness) to slight eschar formation (injuries in depth) preventing erythema reading (4).
Oedema formation: No oedema (0); very slight oedema (barely perceptible) (1); slight oedema (edges of area well-defined by definite raising) (2); moderate oedema (raised approximately 1 mm) (3); severe oedema (raised by more than 1 mm and extending beyond the exposure area) (4).

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: No evidence of erythema was seen at the 24, 48 and 72-hour time points.

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: No evidence of oedema was seen at the 24, 48 and 72-hour time points.

Remarks on result:

no indication of irritation

Results 3

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

8

Reversibility:

other: No evidence of irritation was seen at the 24, 48 and 72-hour time points.

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Transient very slight erythema was observed in one animal 60 minutes after removal of the dressing (no evidence of irritation was apparent at the subsequent observation time points). No dermal response was seen in the remaining two animals.

Other effects:

- Other adverse local effects: no data
- Other adverse systemic effects: No signs of ill health or toxicity were reported.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In a guideline study, to GLP, calcium nitrite (hydrate) (0.5 mL) was applied (4-hr, semi-occluded) to the clipped skin of three male rabbits. Transient very slight irritation was reported in a single animal at the 1 hr observation point. No other irritation was reported.

Executive summary:

In an EU Method B.4 study, the skin irritant potential of calcium nitrite (hydrate) was assessed in three male New Zealand White rabbits. The test material (DCI) was available as a 34% aqueous solution of calcium nitrite. A 0.5 mL semi-occlusive application of the test material was made to the clipped skin for 4 hours. Following removal of the dressing, the treated sites were washed and subsequently assessed for evidence of erythema (and eschar) formation and oedema formation after approximately 1 hour, and again 24, 48 and 72 hours later.

 

One rabbit displayed transient very slight erythema one hour after removal of the dressing, though no evidence of irritation was apparent at the subsequent observation time points. No dermal response was seen in the remaining two animals. The overall irritation score was 0 (out of 8). No clinical signs of toxicity were reported.

 

Based on the results of this study, no classification for skin irritation is required under EU CLP criteria (EC 1272/2008).