Germanium

Endpoint summary

Description of key information

Germanium was shown to have no sensitisation potential in the guinea pig according to the Magnusson-Kligman method, using a maximisation method with Freund's complete adjuvant

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

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: LAB-ÁLL Bt. Budapest, 1174 Hunyadi u. 7
- Age at study initiation: Young adult, ~ 7 weeks old
- Weight at study initiation: 356 – 387 g
- Housing: Animals were housed in macrolon cages size IV, with 5 animals/cage to allow socialization
- Diet ad libitum: Cunigra Diet for Rabbits (produced by Bonafarm-Bábolna Takarmány Ltd., Hungary)
- Water ad libitum: Animals received tap water from municipal supply as for human consumption, containing 50 mg/100 ml ascorbic acid,
- Acclimation period: 20 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17.6 - 23.4 °C
- Humidity (%): 28 - 80%
- Air changes (per hr): 15-20 air exchange/hour
- Photoperiod (hrs dark / hrs light): 12 hours daily, from 6.00 a.m. to 6.00 p.m.

Route:

intradermal

Vehicle:

other: Methylcellulose

Concentration / amount:

5 % (w/v) Ge in 1% methylcellulose

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, occlusive

Vehicle:

other: methylcellulose

Concentration / amount:

75 % (w/v) Ge in 1% methylcellulose

Day(s)/duration:

48

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: Methylcellulose

Concentration / amount:

75 % (w/v) Ge 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:
A series of test item concentrations was tested to identify the primary irritation following intradermal injection and dermal application: 1, 2.5 and 5% (w/v) concentrations were used for intradermal injection and 10, 25, 50, 75% (w/v) for dermal application. Local effects were examined and scored 1, 24, 48 and 72 hours after the treatment or after patch removal. Skin effects were scored for erythema and oedema, any other observations of changes to the skin was recorded.

During the trial formulation the test item in the form as it was supplied by the Sponsor proved to be not suitable for intradermal treatments. (The test item blocked the needle of the syringe.) Because of this, the test item was ground with a ball mill and this ground form was used for the intradermal treatments in the preliminary study and in the main study.

*)For the intradermal application, 0.1 mL per concentration was injected intradermally into the hair free skin of the animals. Two concentrations were injected on the right side and another two concentrations on the left side of the animals. The highest concentration (5%) was also tested in a 1:1 mixture (v/v) of Freund's Complete Adjuvant and physiological saline solution. Each concentration was injected in duplicate. Two animals were used per concentration. The highest concentration (5%) caused no more than mild-to-moderate erythema (score 0 or 1) during the observation period, therefore this concentration can be used in the main study.

*) For the dermal application, the volume of the concentrations was 0.5 mL. A closed patch exposure was performed by means of an occlusive bandage using similar treatment procedures as for the main study. The time of exposure for the dermal application was 48 hours. One concentration was used on the right side and another concentration on the left side of animals. Two animals per concentrations were used. It was found that all the dermal treatments at the tested concentrations produced no reaction on the skin of guinea pigs. The concentration used for the challenge exposure should be the highest non-irritant dose; therefore 75% test item formulated in 1% methyl cellulose was decided to be used for the challenge treatment.


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 reference item 2-Mercaptobenzothiazole resulted in a positive response in test animals previously sensitised. The net response values at the 24 and 48 hours observations represented an incidence rate of 90% and 80% and net score values of 0.90 and 0.80 respectively. In the control animals no visible changes were found either at the 24 or 48 hours examinations following challenge with the reference item.
The dermal scores represented discrete erythema (score 1) developed on the skin of sensitised guinea pigs.
On the basis of the results of the reliability check study, the reference item 2-Mercaptobenzothiazole was classified as a skin sensitizer. This demonstrated that the experimental procedure and the test system were appropriate.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

75% (w/v) Ge in 1% methylcellulose

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No signs of systemic or local toxicity were observed in any animal

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

75% (w/v) Ge in 1% methylcellulose

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

No signs of systemic or local toxicity were observed in any animal

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

75% (w/v) Ge in 1% methylcellulose

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No signs of systemic or local toxicity were observed in any animal

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

75% (w/v) Ge in 1% methylcellulose

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

No signs of systemic or local toxicity were observed in any animal

Remarks on result:

no indication of skin sensitisation

Group:

positive control

Remarks on result:

not measured/tested

Remarks:

Not required: 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.

Ten test animals were subjected to sensitisation procedures in a two-stage process, i.e. an intradermal treatment and a topical application. The test item was used at a concentration of 5% (w/v) for intradermal injections and at a concentration of 75% (w/v) for dermal sensitisation treatment. Two weeks after the last induction exposure, a challenge dose at a concentration of 75% (w/v) was administered on the left side of animals. The right side of animals was treated with 50% dilution of the maximum dermal challenge dose as a safeguard dose (37.5% (w/v)). Challenge was performed by dermal application of the test item.

Five control guinea pigs were simultaneously exposed to vehicle only during the sensitisation phase I (intradermal treatment) and during the sensitisation phase II (dermal treatment). Control animals were treated with the test item at concentrations of 75% (w/v) and 37.5% (w/v) only during the challenge.

1% methyl cellulose was used as a vehicle for each formulation during the study.

 

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 safeguard and no reaction was noted.

 

Control group

 

After the challenge with the test item at a concentration of 100 % (w/v) in1 % 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 % methylcellulose as a safeguardand no reaction was noted.

 

Body weight

There were no notable differences between the test animal group and the control group.

Clinical Observations and mortality

No signs of systemic or local toxicity were observed in any animal.. No mortality was observed during the study.

 

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the present assay the test item GERMANIUM 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 and Kligman method, using a maximisation method with Freund's Complete Adjuvant to evaluate the sensitisation potential of test item. The study was performed according to OECD Guideline No. 406 (adopted in 1992) and in compliance with GLP guidelines.

 

Based on the results of a preliminary test, ten test animals were subjected to sensitisation procedures in a two-stage process, named induction phase: i.e. an intradermal treatment and a 48-hour topical application (dermal treatment under an occlusive dressing). The test item was used at a concentration of 5% (w/v) for intradermal injections and at a concentration of 75% (w/v) for topical sensitisation treatment. Five control guinea pigs were simultaneously exposed to vehicle only during the sensitisation phase.

 

Two weeks after the last induction exposure, a challenge dose at a concentration of 75% (w/v) was administered on the left side of all animals. The right side of the animals was treated with 50% dilution of the maximum dermal challenge dose as a safeguard dose (37.5% (w/v)). Challenge was performed by dermal application of the test item. Skin reactions were measured 24 and 48 hours after patch removal.

 

Results

 

No signs of systemic or local toxicity were observed in any animal.

 

Incidence rate:

 

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

 

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 item GERMANIUM 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 germanium skin sensitization data and according to Regulation (EC) No 1272/2008, germanium does not require classification as a sensitizer.