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Description of key information

A skin sensitisation study was performed in the guinea pig according to the Magnusson-Kligman method, using a maximisation method with Freund's complete adjuvant to evaluate the sensitisation potential of cadmium telluride (Török-Bathó, CiToxLAB Hungary 2012).

No signs of contact sensitisation were detected in guinea pigs previously exposed to the test item during the experiments.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The metals industry has historical data to indicate that metals can induce false positives/negatives in LLNA studies; this is confirmed from experiences in test labs.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: LAB-ÁLL Bt. Budapest, 1174 Hunyadi u. 7
- Age at study initiation: Young adult, 8 weeks
- Weight at study initiation: 344 – 386 g
- Housing: Animals were housed in macrolon cages, size III., with 2 or 3 animals/cage (42 x 42 x 19 cm)
- Diet ad libitum: PURINA Base – Lap gr. diet for rabbits produced by AGRIBRANDS Europe Hungary PLC, H-5300 Karcag, Madarasi road, Hungary
- Water ad libitum: Animals received tap water from municipal supply as for human consumption, containing 50 mg/100 ml ascorbic acid,
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.7 – 25.3 °C
- Humidity (%): 30 – 70 %
- Air changes (per hr): 15-20 air exchange/hour
- Photoperiod (hrs dark / hrs light): 12 hours daily from 6 a.m. to 6 p.m. (artificial light)

Route:
intradermal
Vehicle:
other: aqueous 1 % (w/v) Methylcellulose solution
Concentration / amount:
0.1 % (w/v) CdTe in 1% methylcellulose
Route:
epicutaneous, occlusive
Vehicle:
other: Methylcellulose
Concentration / amount:
100% (w/v) CdTe in 1% methylcellulose




Day(s)/duration:
48h
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: aqueous 1 % (w/v) Methylcellulose solution
Concentration / amount:
100% (w/v) CdTe in 1% methylcellulose
Day(s)/duration:
24h
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
test groups: 10
control group: 5
Details on study design:
RANGE FINDING TESTS:
*) For the intra-dermal treatment: the following formulations were applied:
-0.10 mL of the test item in 1 % methylcellulose at the 5, 1, 0.1 and 0.01 % (w/v) concentrations,
-0.10 mL of test item in 5, 1, 0.1 and 0.01 % (w/v) concentrations, formulated in a 1:1 (v/v) mixture of Freund's Adjuvant (FCA) and physiological saline (the test item was suspended in mixture of FCA and saline at concentrations of 10, 2, 0.2 and 0.02 % (w/v) and diluted with 1 % methylcellulose to the necessary concentrations).

It was found that 5 and 1 % (w/v) concentrations formulated with FCA and saline mixture are inapplicable due to the physical nature of the mixtures, therefore the 5 and 1 % (w/v) concentrations in 1 % methylcellulose were not tested during the preliminary test, since it will not be technically applicable for the main test.

*)For the dermal application: approximately 0.2 mL of the formulated test item in 1 % methylcellulose was applied at concentrations of 100, 75, 50 and 25 % (w/v) onto the clipped and shaved skin of the animals over an area of 4-6 cm2.


MAIN STUDY (cfr any other information on materials and methods)
A. INDUCTION EXPOSURE
a) intra-dermal induction exposure:
b) dermal induction exposure:
B. CHALLENGE EXPOSURE


Positive control substance(s):
not required
Remarks:
The sensitivity and reliability of the experimental procedure is assessed twice a year by use of items which are known to have moderate skin sensitisation properties (eg 2-mercaptobenzothiazole. 2-mercaptobenzothiazole was classified as skin sensitizer.
Positive control results:
The sensitivity and reliability of the experimental procedure is assessed twice a year by use of items which are known to have moderate skin sensitisation properties such as 2-mercaptobenzothiazole.
Challenge with test item 2-Mercaptobenzothiazole resulted in a positive response in test animals sensitised previously. The net response values at the 24 and 48 hours observations represented an incidence rate of 50 % and 40 % and the net score values of 0.70 and 0.40 respectively. In the control animals no visible changes were found either at the 24 and 48 hours examinations or following challenge with the test item. The dermal scores represented discrete erythema developed on the skin of sensitised guinea pigs.
On the basis of these results , the test item 2-mercaptobenzothiazole was classified as skin sensitizer.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100% (w/v) CdTe in 1% methylcellulose
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No overt sign of an adverse clinical response to treatment with the test item during the course of the study
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100% (w/v) CdTe in 1% methylcellulose . No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No overt sign of an adverse clinical response to treatment with the test item during the course of the study.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100% (w/v) CdTe in 1% methylcellulose
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No overt sign of an adverse clinical response to treatment with the test item during the course of the study
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 100% (w/v) CdTe in 1% methylcellulose . No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No overt sign of an adverse clinical response to treatment with the test item during the course of the study.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
100% (w/v) CdTe in 1% methylcellulose
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No overt sign of an adverse clinical response to treatment with the test item during the course of the study
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100% (w/v) CdTe in 1% methylcellulose . No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No overt sign of an adverse clinical response to treatment with the test item during the course of the study.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100% (w/v) CdTe in 1% methylcellulose
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No overt sign of an adverse clinical response to treatment with the test item during the course of the study
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 100% (w/v) CdTe in 1% methylcellulose . No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No overt sign of an adverse clinical response to treatment with the test item during the course of the study.
Group:
positive control
Remarks on result:
not measured/tested

Main Study

A group of 10 animals was treated with the test item during the induction phase of the study. Injections were given intra-dermally with and without FCA (sensitisation phase I) and one week later the test item was applied dermally on the same site (sensitisation phase II). The animals were challenged by dermal exposure two weeks laterwith the test item at a concentration of 100 % (w/v) in 1 % methylcellulose.

 

Five control guinea pigs were simultaneously exposed to 1 % methylcellulose during the sensitisation phase I (intra-dermal treatment; with and without FCA). During the sensitisation phase II (dermal treatment) thecontrol animals were treated with1 % methylcellulose and theywere treated with the test item at a concentration of 100 % (w/v) in1 % methylcellulose only on the challenge day.

 

Skin Effects after the Challenge Exposure

 

Test group

 

After the challenge with the test item at a concentration of 100 % (w/v) in 1 % methylcellulose, no positive response was observed in the treated animals. The mean of the scores was 0.00 according to the 24 and 48-hours results. The right shaved flank area of all animals was treated with a test item concentration of 50 (w/v) % in 1 % methylcelluloseas a safeguardand no reaction was noted.

 

Control group

 

After the challenge with the test itemat a concentration of 100 % (w/v) in 1 % methylcellulose no visible changes were found at the 24 and 48 hours examinations. The right shaved flank area of control animals was treated with a test item concentration of 50 (w/v) % in 1 % methylcelluloseas a safeguard and no reaction was noted.

 

Clinical Observations

 

There were no overt signs of an adverse clinical response to treatment with the test item during the course of the study.

 

Mortality

 

There were no moribund or dead animals during the study.


 

Body Weight

  

The individual body weights of the guinea pigs were measured at the beginning and at the end of experiment. There were no notable differences between the test animal group and the control group.

 

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of the present assay the test item Cadmium telluride (CdTe) (Batch No.: 138683) was shown to have no sensitisation potential and classified as a non-sensitizer, according to current EU-regulations.

Executive summary:

A skin sensitisation study was performed in the guinea pig according to the Magnusson-Kligman method, using a maximisation method with Freund's complete adjuvant to evaluate the sensitisation potential of test itemCadmium telluride (CdTe).

Ten test animals were subjected to sensitisation procedures in a two-stage process, i.e. an intra-dermal treatment and a topical application. The test item was used at a concentration of 0.1 % (w/v) in 1 % methylcellulose for intra-dermal injections and at a concentration of 100 % (w/v) test item suspension in 1 % aqueous methylcellulose for dermal sensitisation treatment.Two weeks after the last induction exposure, a challenge dose (at a concentration of100 % (w/v) test item suspension in 1 % methylcellulose) was administeredon the left flank of animal.The right flank area of animals was treated with 50 % dilution with 1 % methylcellulose of the maximum dermal challenge dose as a safeguard dose.Challenge was performed by dermal application of the test item. Five control guinea pigs were simultaneously exposed to 1 % methylcellulose during the sensitisation phase I (intra-dermal treatment). During the sensitisation phase II (dermal treatment) the control animals were treated with1 % methylcellulose and they were treated with the test item at a concentration of 100 % (w/v) and 50 % (w/v) in1 % methylcellulose only during the challenge (phase III).

 Incidence Rate:

 No signs of contact sensitisation were detected in guinea pigs previously exposed to the test item during the experiments.

 Intensity of Sensitisation Response:

 In the control and treated animals the mean of the scores was 0.00 according to the 24 and 48-hour results.

 In conclusion, under the conditions of the present assay the test itemCadmium telluride (CdTe)(Batch No.: 138683)was shown to have no sensitisation potential and classified as a non-sensitizer, according to current EU-regulations.

 

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based upon skin sensitization data and according to Regulation (EC) No 1272/2008, cadmium telluride does not require classification as a sensitizer.