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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
The study was performed between 01 June 2010 and 24 June 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed according to GLP and internationally accepted guideline. Reliability reduced for read across

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Sponsor's identification: soda-ash flux calcined kieselguhr
Description : white powder
Lot number : 211184
Date received : 10 February 2010
Expiry date : 31 December 2013
Storage conditions: room temperature in the dark

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Ltd, Bicester, Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 to 23 g
- Housing: Individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes
- Diet: 2014 Tekland Global Rodent diet ad libitum
- Water: ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature: 19 to 25°C
- Humidity: 30 - 70 %
- Air changes: Approximately 15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

Study design: in vivo (LLNA)

Vehicle:
propylene glycol
Concentration:
Groups of four mice were treated with the test material at concentrations of 10%, 5% or 2.5% w/w in propylene glycol
No. of animals per dose:
4 mice per dose
Details on study design:
PRELIMINARY SCREENING TEST:
Using available information regarding the systemic toxicity/irritancy potential of the test material, a preliminary screening test was performed using one mouse. The mouse was treated by daily application of 25 µl of the test material at a concentration of 10% w/w in propylene glycol, to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The mouse was observed twice daily on Days 1, 2 and 3 and once daily on Days 4, 5 and 6. Any signs of toxicity or excessive local irritation noted during this period were recorded. The bodyweight was recorded on Day 1 (prior to dosing) and on Day 6

MAIN STUDY:
Groups of four mice were treated with the test material at concentrations of 10%, 5% or 2.5% w/w in propylene glycol. The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25 µl of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test material formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.
A further group of four mice received the vehicle alone in the same manner.

3H-Methyl Thymidine Administration
Five days following the first topical application of the test material or vehicle (Day 6) all mice were injected via the tail vein with 250 µl of phosphate buffered saline (PBS) containing 3H methyl thymidine (3HTdR: 80 µCi/ml, specific activity 2.0 Ci/mmol, ARC UK Ltd) giving a total of 20 µCi to each mouse






Positive control substance(s):
other: Phenylacetaldehyde (90%)

Results and discussion

Positive control results:
A group of five animals was treated with 50 µl (25 µl per ear) of Phenylacetaldehyde (90%) as a solution in propylene glycol at a concentration of 2.5% v/v. A further control group of five animals was treated with propylene glycol alone

The Stimulation Index expressed as the mean radioactive incorporation for the treatment group divided by the mean radioactive incorporation of the vehicle control group was 18.43.

Phenylacetaldehyde (90%) was considered to be a sensitiser under the conditions of the test

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Remarks on result:
other: 2.5 %w/w; SI = 1.13 5 %w/w; SI = 0.97 10 %w/w; SI = 0.99
Key result
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: The radioactive disintegrations per minute per lymph node are given in table 2.

Any other information on results incl. tables

Table 1: Clinical Observations, Bodyweight and Mortality Data – Preliminary Screening Test

Concentration (%w/w) in
propylene glycol

Animal Number

Bodyweight (g)

Day

1

2

3

4

5

6

Day 1

Day 6

Pre-Dose

Post Dose

Pre-Dose

Post Dose

Pre-Dose

Post Dose

10

S-1

19

20

0

0

0

0

0

0

0

0

0

0=      No signs of systemic toxicity

Table 2: Disintegrations per Minute, Disintegrations per Minute/Node and Stimulation Index

Concentration
(%w/w) in
propylene glycol

dpm

dpm/Nodea

Stimulation Indexb

Result

Vehicle

6210.33

776.29

na

na

2.5

7020.81

877.60

1.13

Negative

5

6047.51

755.94

0.97

Negative

10

6135.29

766.91

0.99

Negative

dpm=  Disintegrations per minute

a=      Disintegrations per minute/node obtained by dividing the disintegrations per minute value by 8 (total number of lymph nodes)

b=      Stimulation Index of 3.0 or greater indicates a positive result

na =    Not applicable

Table 3: Individual Clinical Observations and Mortality Data

Concentration
(% w/w) in
propylene glycol

Animal Number

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Pre-Dose

Post Dose

Pre-Dose

Post Dose

Pre-Dose

Post Dose

Vehicle

1-1

0

0

0

0

0

0

0

0

0

1-2

0

0

0

0

0

0

0

0

0

1-3

0

0

0

0

0

0

0

0

0

1-4

0

0

0

0

0

0

0

0

0

2.5

2-1

0

0

0

0

0

0

0

0

0

2-2

0

0

0

0

0

0

0

0

0

2-3

0

0

0

0

0

0

0

0

0

2-4

0

0

0

0

0

0

0

0

0

5

3-1

0

0

0

0

0

0

0

0

0

3-2

0

0

0

0

0

0

0

0

0

3-3

0

0

0

0

0

0

0

0

0

3-4

0

0

0

0

0

0

0

0

0

10

4-1

0

0

0

0

0

0

0

0

0

4-2

0

0

0

0

0

0

0

0

0

4-3

0

0

0

0

0

0

0

0

0

4-4

0

0

0

0

0

0

0

0

0


0=      No signs of systemic toxicity

Table 4: Individual Bodyweights and Bodyweight Changes

Concentration
(% w/w) in
propylene glycol

Animal Number

Bodyweight (g)

Bodyweight Change (g)

Day 1

Day 6

Vehicle

1-1

20

20

0

1-2

20

21

1

1-3

17

17

0

1-4

18

17

-1

2.5

2-1

18

17

-1

2-2

19

19

0

2-3

19

19

0

2-4

19

19

0

5

3-1

20

20

0

3-2

20

19

-1

3-3

18

18

0

3-4

20

20

0

10

4-1

17

17

0

4-2

21

20

-1

4-3

18

18

0

4-4

20

20

0

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Kieselguhr soda ash flux calcined is not classified as a skin sensitiser in accordance with CLP Regulation (EC) no. 1272/2008