Mullite

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-01-05 - 2010-01-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-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 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

The relative humidity in the animal room was between approximately 21 - 65 % for few hours, due to maintenance. This deviation to the study plan, however, does not affect the validity of the study.

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Mullite

EC Number:

215-113-2

EC Name:

Mullite

Cas Number:

1302-93-8

Molecular formula:

Al6O13Si2

IUPAC Name:

Mullite; Al6O13Si2

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

5, 10, 25 %

No. of animals per dose:

4

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: test item 5 %: 1.31 test item 10 %: 0.75 test item 25 %: 1.09

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: DPM per lymph node: test item 5 %: 703.8 test item 10 %: 405.4 test item 25 %: 586.8

Any other information on results incl. tables

1.1         Calculation and Results of Individual Data

Vehicle: acetone:olive oil (4+1)

Test item concentration % (w/v)	Group	Measurement DPM	Calculation			Result
			DPM-BG^a)	number of lymph nodes	DPM per lymph node^b^)	S.I.
---	BG I	36	---	---	---	---
---	BG II	37	---	---	---	---
---	1	4350	4314	8	539.2
5	2	5667	5631	8	703.8	1.31
10	3	3280	3244	8	405.4	0.75
25	4	4731	4695	8	586.8	1.09

BG =  Background (1 ml 5% trichloroacetic acid) in duplicate

1    =  Control Group

2-4=  Test Group

S.I. =  Stimulation Index

^a)   =  The mean value was taken from the figures BG I and BG II

^b)    =  Since the lymph nodes of the animals of a dose group were pooled, DPM/node was determined by dividing the measured value by the number of lymph nodes pooled

The EC3 value could not be calculated, since all S.I.´s are below 3.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test item White Fused Mullite was not a skin sensitiser under the described conditions.

Executive summary:

In order to study a possible contact allergenic potential of White Fused Mullite, three groups each of four female mice were treated daily with the test item at concentrations of 5, 10, and 25% (w/v) in acetone:olive oil (4+1) by topical application to the dorsum of each ear lobe (left and right) for three consecutive days. A control group of four mice was treated with the vehicle (acetone:olive oil (4+1)) only. Five days after the first topical application the mice were injected intravenously into a tail vein with radio-labelled thymidine (³H-methyl thymidine). Approximately five hours after intravenous injection, the mice were sacrificed, the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of³H-methyl thymidine measured in ab-scintillation counter.

All treated animals survived the scheduled study period and no signs of toxicity were observed.

A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentration resulted in 3-fold or greater increase in incorporation of³HTdR compared with concurrent controls, as indicated by the Stimulation Index (S.I.). The estimated concentration of test item required to produce a S.I. of 3 is referred to as the EC3 value.

In this study Stimulation Indices of 1.31, 0.75, and 1.09 were determined with the test item at concentrations of 5, 10, and 25% in acetone:olive oil (4+1). The EC3 value could not be calculated, since none of the tested concentrations induced an S.I. greater than 3

The test item White Fused Mullite was not a skin sensitiser under the described conditions.