Magnesium

Endpoint summary

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Materials and methods well described; results presented adequately in text, tables and figures. A second observation (72 hours after beginning of the challenge) was not performed.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

see "rationale for reliability"

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

yes

Remarks:

see "rationale for reliability"

Principles of method if other than guideline:

The test animals are initially exposed to the test substance by intradermal injection (day 0) and topical induction (day 7). Following a rest period of 14 days (induction period), during which an immune response may develop, the animals are exposed to a challenge dose. The extent and degree of skin reaction to the challenge exposure (patch removal after 24h) in the test animals is compared with that demonstrated by control animals which undergo sham treatment during induction and receive the challenge exposure (48h after beginning of the challenge).

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann, Borchen, Germany
- Weight at study initiation: 400-550g
- Housing: in pairs in clean plastic cages (55 x 32.8 x 19 cm^3) on standard bedding
- Diet: ad libitum, standard pellets
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature: 20 +/- 3°C
- Humidity: humidity of 30-70%
- Photoperiod: 2 hours dark/light cycle
No further details are given.

Route:

intradermal and epicutaneous

Vehicle:

other: see "concentration"

Concentration / amount:

100%
All test items were tested both in a dissolved and in a solid state parallel to positive and negative control substances. Therefore, the magnesium alloys were dissolved by boiling in 2 mol/L HCl solution and buffered with 1 mol/L NaOH solution at pH 5.5. The supernatants were microfiltrated and the ion metal content was confirmed by ICP-AES.

Route:

epicutaneous, semiocclusive

Vehicle:

other: see "concentration"

Concentration / amount:

100%
All test items were tested both in a dissolved and in a solid state parallel to positive and negative control substances. Therefore, the magnesium alloys were dissolved by boiling in 2 mol/L HCl solution and buffered with 1 mol/L NaOH solution at pH 5.5. The supernatants were microfiltrated and the ion metal content was confirmed by ICP-AES.

No. of animals per dose:

20 animals for each test substance; 10 with the solid material and 10 with the dissolved material. 15 animals in the negative control group and 15 animals in the positive control group.

Details on study design:

An intradermal test and an epicutaneous patch test were performed. The skin reaction was interpreted by a qualitative grading of three independent observers immediately and 24 hours after patch removal. For grading of the skin reaction, the erythema classification according to Magnusson-Klingman test was used. A skin reaction graded greater than zero was defined as erythema.

The test site was clipped for intradermal injection. For topical application, the hair was clipped and closely shaved. Cellulose filters (2 x 4cm^2 and 2 x 2cm^2) were used as patches. Applied test patches were covered with overlapping pieces of impermeable plastic tape and fixed with 25cm long strips of elastic tape bandage which was secured by twp pieces of tape.

Cutaneous biopsies were harvested 24 hours after patch removal and analysed for histomorphological criteria. Epidermis and dermis were included in cell counting and histomorphological analysis.

Challenge controls:

Negative control: sodium-lauryl-sulfate
Preliminary test performed with all test items with one animal each; non irritant concentration were determined

Positive control substance(s):

yes

Remarks:

hydroxy-cinnamon-aldehyde

Positive control results:

All guinea pigs exposed to the standard allergen showed persisting erythema for more than 24 hours after patch removal. One animal died during the challenge phase for reasons not related to the test and one skin biopsy was lost because of technical problems. The histological analysis showed in 12 (92.3%) of the remaining 13 biopsies all four criteria of allergy such as spongiosis, oedema, and diffuse as well as perivascular mononuclear infiltrates. The positive control biopsies contained a mean of 52.7 basophile cells/400 leukocyte cells. Furthermore, in biopsies of the positive control group, a significant higher number of basophile cells was found compared to the negative control group and all tested substances (p=0.001, ANOVA).

Reading:

1st reading

Hours after challenge:

24

Group:

other: AZ91

Dose level:

dissolved test substance

No. with + reactions:

3

Total no. in group:

10

Clinical observations:

mild skin reactions after 24 hours

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: AZ91. Dose level: dissolved test substance. No with. + reactions: 3.0. Total no. in groups: 10.0. Clinical observations: mild skin reactions after 24 hours.

Reading:

1st reading

Hours after challenge:

0

Group:

other: AZ31

Dose level:

dissolved test substance

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

mild clinical skin response immediately after patch removal; 24h after the patch was removed, all erythema had faded.

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 0.0. Group: other: AZ31. Dose level: dissolved test substance. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: mild clinical skin response immediately after patch removal; 24h after the patch was removed, all erythema had faded..

Reading:

2nd reading

Hours after challenge:

24

Group:

other: AZ31

Dose level:

dissolved test substance

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 24.0. Group: other: AZ31. Dose level: dissolved test substance. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

No. with + reactions:

15

Total no. in group:

15

Clinical observations:

persisting erythema

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. No with. + reactions: 15.0. Total no. in groups: 15.0. Clinical observations: persisting erythema.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

No. with + reactions:

0

Total no. in group:

15

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 15.0.

Reading:

1st reading

Hours after challenge:

24

Group:

other: WE43 and LAE442

Dose level:

dissolved test substance

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

remarks: 10 per test substance (in total 20 animals)

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 24.0. Group: other: WE43 and LAE442. Dose level: dissolved test substance. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: remarks: 10 per test substance (in total 20 animals).

Test results for all substances used as received.

Between 90% (AZ31) and 100% (AZ91) of the tested skin areas displayed erythema immediately after patch removal. However, after 24 hours the erythema remained in 20% of the AZ91 group and 11% of the LAE442. To identify allergic erythema after 24 hours, dermal biopsies were taken. All biopsies exhibited significantly (p=0.001) less histomorphological criteria of allergenicity compared to the positive control group. In all biopsies no significant differences were found for basophile cells compared to the negative control. In the LAE442 group of the solid test substances, one animal died unrelated to the study conditions. Animals treated with AZ91and LAE442 which still had an erythema 24 hours after patch removal, showed no criteria of allergenicity in histomorphological analysis. No correlation was found between the cell count of eosinophiles and the concentration of aluminium in the test solutions (p>0.05).

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The tested magnesium alloys (with a total magnesium content between 89.2 – 96.8%) provide no sensitising potential compared to the control groups.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A guinea pig maximisation test according to OECD 406 conducted with some magnesium alloys with a minimum Mg concentration of 89% (w/w) is considered to be reliable with restrictions The results showed that magnesium does not produce any signs of sensitising potential.

Migrated from Short description of key information:
Skin sensitisation: not sensitising (OECD 406)

Justification for selection of skin sensitisation endpoint:
Reliable study with different magnesium alloys

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Based on long-term experience in handling magnesium metal, the essentiality of magnesium and lack of a skin sensitisation potential, respiratory sensitisation is not expected to be relevant for magnesium metal according to Regulation (EC) 1272/2008 and subsequent adaptations.

Justification for classification or non-classification

Sensitisation:

The reference Witte (2007) is considered as the key study on skin sensitisation and will be used for classification. With some magnesium alloys with a minimum Mg concentration of 89% (w/w) a sensitisation study according to OECD 406 (GPMT) Magnusson and Kligman was performed which indicated that magnesium does not produce any signs of sensitising potential. Therefore, no classification and labelling according to regulation (EC) 1272/2008 and subsequent regulations is required.