Bentonite, acid-leached

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 19 April 2005 and 29 April 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed to GLP and internationally accepted guideline

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Bentonite, acid-leached

EC Number:

274-324-8

EC Name:

Bentonite, acid-leached

Cas Number:

70131-50-9

Molecular formula:

unspecified for this UVCB substance

IUPAC Name:

Bentonite, acid-leached

Details on test material:

- Name of test material (as cited in study report): Acid-activated bentonite
- Physical state: pale beige powder
- Lot/batch No.: TONSIL EX 0096
- Storage condition of test material: room temperature in the dark

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: David Percival Ltd, Moston, Sandbach, Cheshire, UK
- Age at study initiation: 12 - 20 weeks
- Weight at study initiation: 2.0 - 3.5 kg
- Housing: Individually housed in suspended cages
- Diet: Free access to dertified rabbit diet (code 5322)
- Water: Free access to mains drinking water
- Acclimation period: At least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C):17 to 23
- Humidity (%): 30 - 70
- Air changes (per hr): At least 15
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

no

Amount / concentration applied:

0.5 g moistened with 0.5 mL of distilled water

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: Back of the rabbit
- Type of wrap if used: 2.5 cm x 2.5 cm cotton gauze patch secured in position with a strip of surgical adhesive tape


REMOVAL OF TEST SUBSTANCE
- Washing: Any residual test material was removed by gentle swabbing with cotton wool soaked in distilled water
- Time after start of exposure: 4 hours


SCORING SYSTEM: Draize classification scheme

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal 1

Time point:

other: 24, 48, 72 h

Score:

0

Results 2

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal 2

Time point:

other: 24, 48, 72 h

Score:

0

Results 3

Irritation parameter:

erythema score

Basis:

mean

Remarks:

animal 3

Time point:

other: 24, 48, 72 h

Score:

0

Results 4

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal 1

Time point:

other: 24, 48, 72 h

Score:

0

Results 5

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal 2

Time point:

other: 24, 48, 72 h

Score:

0

Results 6

Irritation parameter:

edema score

Basis:

mean

Remarks:

animal 3

Time point:

other: 24, 42, 72 h

Score:

0

Irritant / corrosive response data:

A single 4 hour, semi-occluded application of the test material to the intact skin of three rabbits produced no evidence of skin irritation. 3 minute and 1 hour semi-occluded applications of test material to the intact skin of one rabbit produced no evidence of skin irritation.

Any other information on results incl. tables

Table 1: pH of test material

Preparation	pH measurement
10% w/w aqueous preparation of test material	approximately 3.8

 

Table 2: Individual skin reactions following four hour exposure

Skin reaction	Observation time	Individual scores – rabbit number and sex			Total
		126 male	117 male	118 male
Erythema/Eschar formation	1 h 24 h 48 h 72 h	0 0 0 0	0 0 0 0	0 0 0 0	( 0 ) 0 ( 0 ) 0
Oedema formation	1 h 24 h 48 h 72 h	0 0 0 0	0 0 0 0	0 0 0 0	( 0 ) 0 ( 0 ) 0
Sum of 24 and 72 hour readings (S): 0
Primary irritation index (S/6): 0/6
Classification: NON-IRRITANT

( ) = Total values not used for calculation of primary irritation index

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test substance is not considered to be irritating to skin according to CLP Regulation (EC) no. 1272/2008