Ashes (residues), rice husk

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Apr 2010 - 23 Apr 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Before application, animals no. 2 and 3 showed slight redness around the application site, but not at the site where patch was applied. The redness could be due to shaving. This deviation did not influence the quality or integrity of the present study, as

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Landesinstitut für Arbeitsschutz und Produktsicherheit, Munich, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Ashes (residues), rice husk

EC Number:

275-735-5

EC Name:

Ashes (residues), rice husk

Cas Number:

71630-92-7

Molecular formula:

SiO2

IUPAC Name:

silanedione

Details on test material:

- Name of test material (as cited in study report): Rice husk ashes
- Physical state: crystalline black powder
- Analytical purity: >80%
- Storage condition of test material: room temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, D-97633 Sulzfeld
- Age at study initiation: approximately 11 weeks
- Weight at study initiation: > 2 kg
- Housing: ABS - plastic rabbit cages, floor 4200 cm2
- Diet (e.g. ad libitum): autoclaved hay and Altromin 2123 maintenance diet for rabbits (lot no. 0748), rich in erude fibre; ad libitum
- Water (e.g. ad libitum): tap water (drinking water, municipal residue control, microbiol. controlled periodically); ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

other: The untreated right side served as control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g

VEHICLE
- Amount(s) applied (volume or weight with unit): Not stated. The test item was applied first to a gauze patch at a single dose. To ensure good skin contact, it was moistened with aqua ad injectionem.

Duration of treatment / exposure:

4 h

Observation period:

Animals no. 1, 2 and 3 were observed for 3, 9 and 6 days, respectively, after the patch removal.

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: ca. 6 cm² on the left side of the dorsal area.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): At the end of the exposure period, the residual test item was removed by using tap water.
- Time after start of exposure: 4 h

SCORING SYSTEM: Draize scores

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: mean over 24, 48, 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: mean over 24, 48, 72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 9 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: mean over 24, 48, 72 h

Score:

1.34

Max. score:

4

Reversibility:

fully reversible within: 6 days

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: mean over 24, 48, 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: mean over 24, 48, 72 h

Score:

0.34

Max. score:

4

Reversibility:

fully reversible within: 72 h

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: mean over 24, 48, 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

The test item showed irritant but reversible effects on the intact skin of 2 female rabbits (strain NZW) after a contact time of 4 hours (Tables 1 and 2).
Before application, animals no. 2 and 3 showed slight redness around the application site, but not at the site where patch was applied.
From days 2-8 in animal no. 2, and from days 3-5 in animal no. 3, both the test site as well as the control site showed redness, which was more in the beginning and thereafter reduced.

Other effects:

Neither mortalities nor significant clinical signs of toxicity were observed.

Any other information on results incl. tables

Table 1. Dermal irritation evaluation.  

 

		Hours after patch removal
Animal number	Application site	1 h		24 h		48 h		72 h
		Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema
1	Test site control	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0
2	Test site control	0 0	0 0	0 0	0 0	2 2	1 1	4* 4*	0 0
3	Test site control	0 0	0 0	0 0	0 0	0 0	0 0	4* 4*	0 0

 

* Redness and eschar was seen also outside the application area, and on the control side also. It was considered a late reaction probably due to shaving.

 

		Days after patch removal
Animal number	Application site	4 d		5 d		6 d		7 d
		Erythema	Edema	Erythema	Edema	Erythema	Edema	Erythema	Edema
1	Test site control	- -	- -	- -	- -	- -	- -	- -	- -
2	Test site control	4^# 4^#	0 0	2^# 2^#	0 0	1^# 1^#	0 0	1^# 1^#	0 0
3	Test site control	4^# 4^#	0 0	1^# 1^#	0 0	0^# 0^#	0 0	- -	- -

 

^#slight scales present on both the treated and control site.

  

		Days after patch removal
Animal number	Application site	8 d		9 d
		Erythema	Edema	Erythema	Edema
1	Test site control	- -	- -	- -	- -
2	Test site control	1^# 1^#	0 0	0 0	0 0
3	Test site control	- -	- -	- -	- -

 

^#slight scales present on both the treated and control site.

Table 2. Individual data

 

Individual systemic and local findings
Time after patchremoval	Animal number 1			Animal number 2			Animal number 3
	systemicfindings	specific local findings	comments	systemicfindings	spectfic local findings	comments	systemicfindings	specific local findings	comments
1 h	nsf	nsf	-	nsf	nsf	-	nsf	nsf	-
24 h	nsf	nsf	-	nsf	nsf	-	nsf	nsf	-
48 h	nsf	nsf	-	nsf	nsf	-	nsf	nsf	-
72 h	nsf	nsf	-	nsf	eschar	-	nsf	eschar	-
4 days	-	-	-	nsf	slight desquamation	-	nsf	slight desqua‑ mation	-
5 days	-	-	-	nsf	slight desquamation	-	nsf	slight desqua‑ mation	-
6 days	-	-	-	nsf	slight desquamation	-	nsf	slight desqua‑ mation	-
7 days	-	-	-	nsf	slight desquamation	-	-	-	-
8 days	-	-	-	nsf	slight desquamation	-	-	-	-
9 days	-	-	-	nsf	nsf	-	-	-	-

 

nsf = no specific findings

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the present study, single dermal application of the test item Rice husk ash to rabbits at a dose of 0.5 g showed irritant effects in 2 out of 3 animals which were fully reversible within 9 days in animal no. 2 and within 6 days in animal no. 3.
Neither mortalities nor significant clinical signs of toxicity were observed.
In conformity with the EC criteria for classification and labelling requirements for dangerous substances and preparations according to Annex VI of Commission Directive 2001/59/EC and Annex I of Regulation (EC) 1272/2008, the test item Rice husk ash does not have to be classified and has no obligatory labelling requirement for skin irritation.