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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed accordingly to the OECD Guideline No. 429 and in compliance with the GLP. Moreover, the information on the test substance is available.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Remarks:
There were no major deviations from the protocol.
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Aluminium ammonium bis (sulphate)

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/CaOlaHsd
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan UK Limited, Bicester
- Age at study initiation: no data
- Weight at study initiation: from 17 to 20 g on the day before dosing commenced.
- Housing: group housed during acclimatisation and individually housed from Day –1 in cages that conformed to the 'Code of Practice for the Housing and Care of Animals Used in Scientific Procedures' (Home Office, London, 1989).
- Diet (e.g. ad libitum): ad libitum, SQC(E) Rat and Mouse Maintenance Diet No 1, from Special Diets Services Ltd, Witham, UK
- Water (e.g. ad libitum): ad libitum, via cage-mounted water bottles.
- Acclimation period: 8 to 15 days
- Other: Nulliparous, non-pregnant females

ENVIRONMENTAL CONDITIONS
- Temperature (°C): from 20 to 24°C
- Humidity (%): from 45 to 65%
- Air changes (per hr): 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light (the rooms were illuminated by fluorescent strip-lights).

IN-LIFE DATES: no data

Study design: in vivo (LLNA)

Vehicle:
propylene glycol
Concentration:
10, 25 and 50 % w/v in propylene glycol
No. of animals per dose:
4 females/dose. See table 7.4.1/1
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: no data
- Irritation: no data
- Lymph node proliferation response: no data

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
Healthy animals were arbitrarily allocated to the study groups on the day prior to commencement of treatment.

- Name of test method: LLNA
The scintillation counter printed data including the DPM value (disintegrations per minute during a ten minute period). The DPM value was transformed into a DLM value (disintegrations per minute per lymph node) by dividing by the number of sites yielding lymph nodes. The DLM value for each test group was divided by the DLM for the control group to provide the Stimulation Index (SI) value for each test group

- Criteria used to consider a positive response:

The test result is not valid for those groups producing an SI value of 3.0 or more when the sites of application have shown excessive irritation and for those groups that have shown indications of systemic toxicosis.
The test article is regarded as a sensitiser when the maximum value of the SI is 3.0 or above.
The test article is classified as a non sensitiser when the maximum value of the SI is less than 3.0. (This result is unchanged by observations of irritation at sites of application of the test formulation).


TREATMENT PREPARATION AND ADMINISTRATION:
Each mouse was manually restrained with both auditory pinnae left free. The outer aspect of both pinnae of each mouse was treated by direct application of the appropriate test or control formulation (25 µL/ear) dispensed from an automatic micro pipette.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
mercaptobenzothiazole (CAS No 149-30-4)
Statistics:
Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

Results and discussion

Positive control results:
The sensitivity and reliability of the test system are checked at least every six months. Preferred substances are α hexylcinnamaldehyde (CAS Number 101 86 0) and mercaptobenzothiazole (CAS Number 149 30 4).

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: 0.8, 1.5 and 1.1 for 10, 25 and 50 % w/v respectively The threshold level to be considered is 3.0. All test substance concentrations tested were under this threshold.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: See table 7.4.1/3

Any other information on results incl. tables

Table 7.4.1/3 : Scintillation counts and stimulation indices

 

Sample identity

Number of sites yielding lymph nodes

Disintegrations per minute*

(DPM)

Disintegrations per minute per node (DLM)

Stimulation Index (SI)

Scintillation fluid with
5% w/v trichloroacetic acid

--

52

--

--

Vehicle control (propylene glycol))

8

162

20

--

Aluminium ammonium bis (sulphate), 10% w/v

8

125

16

0.8

Aluminium ammonium bis (sulphate), 25% w/v

8

242

30

1.5

Aluminium ammonium bis (sulphate), 50% w/v

8

170

21

1.1

* All scintillation counts corrected for the blank

SI =        Test group DLM value     

               Control group DLM value

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Under the test conditions, Aluminium ammonium bis(sulphate) showed no sensitisation potential and is not classified as a skin sensitiser according to the criteria of the Annex VI to the CLP Regulation and to the Directive 67/548/EEC.
Executive summary:

In a Local Lymph Node Assay (LLNA), Aluminium ammonium bis (sulfate) was tested for skin sensitisation on female CBA mices, according to OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay) and in compliance with the principles of Good Laboratory Practices.

Following a preliminary screening test using a 50% w/v suspension considered as suitable, the Aluminium ammonium bis (sulphate) was administered topically at 10, 25 and 50% in propylene glycol once daily on 3 consecutive days (days 1, 2 and 3). The vehicle alone was used as a negative control. Positive controls for the LLNA test are performed every six months in the laboratory.

On Day 6 a 20 μCi dose of tritiated3H-methyl thymidine was injected intravenously into each mouse. Five hours later the auricular lymph nodes were recovered from each animal and suspensions of the cellular components of the lymph nodes were processed through a scintillation counter.

Treated mice were observed twice daily on Days 1 to 5 and once on Day 6 for clinical signs of reaction to treatment or for irritation or other changes at the sites of application of the test article. Mice were weighed on Day ‑1 (the day before dosing) and on Day 6 prior to intravenous administration of3HTdR.

There were no clinical signs indicative of a systemic effect of treatment among mice treated with the vehicle or with 10, 25 or 50% w/v formulations of Aluminium ammonium bis (sulphate). The vehicle and the test formulation application sites remained free of irritation. There was no indication of a treatment related effect on body weight.

Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls.

The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0, and all test substance concentrations tested are under this threshold.

The Local Lymph Node Assay demonstrated that Aluminium ammonium bis (sulphate) does not have the potential to cause skin sensitisation.

Aluminium ammonium bis (sulphate) did not meet the criteria for classification as a sensitiser according to the criteria of the Annex VI to the CLP Regulation and to the Directive 67/548/EEC.