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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 1991-02-19 to 1991-03-19
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
The study contains some relevant methodological deficiencies. When comparing the method used with the OECD 404 test guideline, the size of the exposed area was too small (2.5 cm2 instead of 6 cm2), and no scoring was done at 48 hours after patch removal. It should be noted that the study represents a worst-case approach as the animals were exposed for 24 hours (instead of 4 hours) using an occlusive dressing (instead of semi-occlusive). Additionally, next to intact skin, also abraded skin was exposed.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991
Reference Type:
publication
Title:
Unnamed
Year:
1990
Reference Type:
review article or handbook
Title:
Sax's Dangerous Properties of Industrial Materials
Author:
Lewis
Year:
1995
Bibliographic source:
9th ed., Van Nostrand Reinhold, New York, page 3416, ref. JACTDZ 12, 629, 93

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: 16 CFR 1500.41
Deviations:
no
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
no scoring at 48 h after patch removal; 24 h of exposure instead of 4 h; occlusive wrap instead of semi-occlusive; also abraded skin exposed; no 14-d observation period; exposed skin site is small (2.5 cm2 instead of ca. 6 cm2)
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Yttrium trinitrate
EC Number:
233-802-6
EC Name:
Yttrium trinitrate
Cas Number:
10361-93-0
Molecular formula:
N3O9Y
IUPAC Name:
yttrium trinitrate
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Yttrium nitrate
- Substance type: Off-white crystalline/powdered solid
- Physical state: Solid
- Further information on test material confidential.

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Davidson's Mill Farm, S. Brunswick, NJ, USA
- Age at study initiation: no data
- Weight at study initiation: no data
- Housing: Individually in suspended stainless steel caging with mesh floors.
- Diet (e.g. ad libitum): Pelleted Purina Rabbit Chow ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days of rest period

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.9-23.9°C
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data

Test system

Type of coverage:
occlusive
Preparation of test site:
other: one intact and one abraded site
Vehicle:
unchanged (no vehicle)
Controls:
no
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g/site
Duration of treatment / exposure:
24 hours
Observation period:
The test sites were evaluated 24 and 72 hours after initial exposure.
Number of animals:
6 (4 males, 2 females)
Details on study design:
TEST SITE
- Area of exposure: Two test application sites, each approximately 2.5 cm².
- % coverage: 10% of the body surface (dorsal and ventral surfaces from scapular to pelvic area).
- Type of wrap if used: Adhesive-backed gauze patches and the entire trunk of each rabbit were then wrapped with an elastic cloth to aid in maintaining test-patch position and to minimise evaporation. Neck collars were placed on each rabbit and the rabbits were returned to their individual cages.

REMOVAL OF TEST SUBSTANCE
The neck collars and patches were removed after 24 hours of exposure at which time the test sites were gently wiped clean of any residual test material. Skin sites were evaluated at approximately 24 and 72 hours after initial exposure.

SCORING SYSTEM: Scoring system of 16 CFR 1500.41 (Erythema and eschar formation, edema formation); Draize

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
other: 24 h and 72 h
Score:
3.6
Max. score:
8
Reversibility:
not fully reversible within: 72 hours
Remarks on result:
other: both intact and abraded skin taken into account
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
2.25
Max. score:
4
Reversibility:
not fully reversible within:
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 3 (intact) / 72h: 2 (abraded), 1 (intact)
Irritation parameter:
erythema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
2.25
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 3 (intact) / 72h: 2 (abraded), 1 (intact)
Irritation parameter:
erythema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
1.75
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks:
fully reversible within 72 h in intact skin
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 2 (intact) / 72h: 2 (abraded), 0 (intact)
Irritation parameter:
erythema score
Basis:
animal #4
Time point:
24/48/72 h
Score:
2
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 2 (intact) / 72h: 2 (abraded), 1 (intact)
Irritation parameter:
erythema score
Basis:
animal #5
Time point:
24/48/72 h
Score:
2
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 3 (intact) / 72h: 1 (abraded), 1 (intact)
Irritation parameter:
erythema score
Basis:
animal #6
Time point:
24/48/72 h
Score:
2.5
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 3 (intact) / 72h: 2 (abraded), 2 (intact)
Irritation parameter:
edema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
1.5
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 2 (abraded), 2 (intact) / 72h: 1 (abraded), 1 (intact)
Irritation parameter:
edema score
Basis:
animal #2
Time point:
24/48/72 h
Score:
2
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 3 (intact) / 72h: 1 (abraded), 1 (intact)
Irritation parameter:
edema score
Basis:
animal #3
Time point:
24/48/72 h
Score:
1
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks:
fully reversible within 72 in intact skin
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 2 (abraded), 1 (intact) / 72h: 1 (abraded), 0 (intact)
Irritation parameter:
edema score
Basis:
animal #4
Time point:
24/48/72 h
Score:
1.5
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks:
fully reversible within 72 h in intact skin
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 3 (abraded), 2 (intact) / 72h: 1 (abraded), 0 (intact)
Irritation parameter:
edema score
Basis:
animal #5
Time point:
24/48/72 h
Score:
1.25
Max. score:
4
Reversibility:
fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 2 (abraded), 3 (intact) / 72h: 0 (abraded), 0 (intact)
Irritation parameter:
edema score
Basis:
animal #6
Time point:
24/48/72 h
Score:
1.5
Max. score:
4
Reversibility:
not fully reversible within: 72 h
Remarks on result:
other: mean for intact and abraded skin
Remarks:
24h: 2 (abraded), 2 (intact) / 72h: 1 (abraded), 1 (intact)
Irritant / corrosive response data:
At 24 hours post-dosing, the intact and abraded sites of all rabbits had well-defined to severe erythema, and very slight to moderate edema. A small area of blanching at the dose site was observed in 2 animals (1 abraded, 1 intact skin).
By 72 hours, most abraded sites had well-defined erythema and very slight edema. Most intact sites had decreased to very slight erythema, while edema remained in only three rabbits. A small area of blanching at the dose site was observed in 1 animal (intact skin).
Other effects:
In two animals a small area of blanching at dose site is observed.
All animals were active and healthy. There were no signs of gross toxicity, adverse pharmacologic effects or abnormal behaviour. At 24 hours post-dose most treated sites had moderate erythema and edema. By 72 hours the incidence and severity of irritation had decreased. Erythema at most abraded sites was well defined; at most intact sites it was considered barely perceptible.

Applicant's summary and conclusion

Interpretation of results:
not classified
Conclusions:
Based on the scoring system used, yttrium trinitrate is classified as moderately irritating when applied as a powder. Based on the criteria of the CLP Regulation, the substance should not be classified as irritating to the skin, assuming that the readings at 24 h after patch removal would be equal or less severe than the readings immediately after patch removal, and assuming that the readings at 72 h after patch removal would be equally or less severe than the readings at 48 h after patch removal. Furthermore it can be reasonably assumed that the skin effects would be reversible within 14 days.