Magnesium chloride

Endpoint summary

Description of key information

Skin sensitisation study has been conducted with magnesium chloride hexahydrate. The result can be extrapolated to magnesium chloride anhydrous.

There was no evidence of sensitisation in the MgCl2 group at the challenge and the percentage of animals sensitised was 0 %.

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

Study period:

January 2010 till March 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

17 July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A LLNA test was ordered in first intention and preliminary experiments for the LLNA was carried out. However, these preliminary experimenst for the LLNA with Magnesium Chloride revealed that there is no suitable vehicle for this test. Therefore, the LLNA was cancelled and it was decided to perform the Guinea Pig Maximization test instead.
The test has been ordered in September 2009 and the protocol of the guinea pig maximisation test was completed on 12 March 2010. The LLNA 429 was not formally adopted by the OECD until 22 July 2010. Also, according to the OECD guideline 429, there are limitation to LLNA 429 including false negatives for certain metals.

Specific details on test material used for the study:

- Name of test material (as cited in study report): Magnesium chloride hexahydrate
- Physical state: Colourless; Solid, crystals
- Stability after opening: Instable after repeated contact to air
- Storage condition of test material: At room temperature, in a tightly closed package.
- pH: 5.5 - 7.0 (5% solution at 20 °C)
- Solvent: Water
No further information on the test material was stated.

Species:

guinea pig

Strain:

Hartley

Sex:

female

Details on test animals and environmental conditions:

Species/strain: Healthy Crl: HA - Guinea pigs (Full-Barrier). Source: Charles River, 97633 Sulzfeld, Germany
Sex: female (non-pregnant, nulliparous)
Age at the beginning of the study: approximately 5 weeks old
Body weight at the beginning of the study: 354 - 408 g
The animals were derived from a controlled full-barrier maintained breeding system (SPF).
A health inspection was performed to ensure the good state of health of the animals.

Housing and Feeding Conditions: semi barrier in an air-conditioned room, temperature: 22 (+/- 3)°C, relative humidity: 55 (+/- 10)%, artificial light, sequence being 12 hours light, 12 hours dark, air change: at least 10 x / hour, free access to to autoclaved hay and to Altromin 3122 maintenance diet, rich in crude fibre, free access to tap water, the animals were kept in groups in Terluran - cages on Altromin saw fibre bedding, adequate acclimatisation period (at least five days).

Route:

intradermal

Vehicle:

physiological saline

Remarks:

physiological saline 0.9% NaCl and vaseline

Concentration / amount:

A concentration of 5% for the intradermal induction (0.5 g of the test item was suspended ad 10 mL of vehicle to gain a 5% solution (w/w)).

Route:

epicutaneous, occlusive

Vehicle:

other: vaseline

Concentration / amount:

A concentration of 50% for the dermal induction (3 g of the test item was suspended in vehicle ad 6 g to gain a 50% suspension (w/w)).

Route:

epicutaneous, occlusive

Vehicle:

other: vaseline

Concentration / amount:

A concentration of 50% for the challenge application (5 g of the test item was suspended in 5 g of vehicle to gain a 50% suspension (w/w)).

No. of animals per dose:

10

Details on study design:

Induction: First Stage, Intradermal Injection. Three pairs of intradermal injections of 0.1 mL volume were given in the shoulder region which was cleared of hair by clipping so that one of each pair lies on each side of the midline.
Test group Day 0:
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl
Injection 2: a 5% concentration of the test item in physiological saline 0.9% NaCl
Injection 3: a 5% concentration of the test item formulated in a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl

Control group Day0:
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl
Injection 2: 100% physiological saline 0.9% NaCl
Injection 3: 50% physiological saline 0.9% NaCl in a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl

Injections 1 and 2 were given close to each other and nearest to the head, while injection 3 is given toward the caudal part of the test area.

Induction: Second Stage, Topical Application
Test and control group: Day 6: approximately twenty-four hours before the topical application the test area was painted with 0.5 mL of 10% sodium lauryl sulphate in vaseline after close clipping, in order to create a local irritation.
Test group Day 7: the test item was suspended in vaseline at a concentration of 50%. A patch was fully loaded with 0.5 g of the prepared test item, applied to the test area and held in contact by an occlusive dressing for 48 hours.

Challenge: Topical Application
The flanks of treated animals were cleared of hair by close-clipping.
Test and control group: Day 20: the test item was suspended in vaseline at a concentration of 50%. A patch, loaded with 0.5 g of the prepared test item was applied to the left flank of the animals. The patches were held in contact by an occlusive dressing for 24 hours. The application area was not rinsed with water.

Observation Period
Approximately 21 hours after removing the patch, the challenge area was cleared of hair by the use of a depilatory cream. Approximately 24 and 48 hours after removing the patch the skin reaction was observed and recorded according to the grades shown below. Additionally all animals were observed for signs of toxicity at least once daily during the test period.

Challenge controls:

Number of animals in the negative control group: 5

Induction: First Stage, Intradermal Injection
Day 0
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline 0.9% NaCl
Injection 2: 100% physiological saline 0.9% NaCl
Injection 3: a 50% (v/v) formulation of NaCl 0.9% in a 1:1 (v/v) mixture FCA/physiological saline 0.9% NaCl
Injections 1 and 2 were given close to each other and nearest to the head, while injection 3 is given toward the caudal part of the test area.

Induction: Second Stage, Topical Application
Day 6: approximately twenty-four hours before the topical application the test area was painted with 0.5 mL of 10% sodium lauryl sulphate in vaseline after close clipping, in order to create a local irritation.
Day 7 : a patch was fully loaded with 0.5 g of the vaseline and applied to the test area and held in contact by an occlusive dressing for 48 hours.

Challenge: Topical Application
The flanks ofcontrol animals were cleared of hair by close-clipping.
Day 20: a patch loaded with 0.5 mL of the vehicle was applied to the right flank. The patches were held in contact by an occlusive dressing for 24 hours. The application area was not rinsed with water.

Positive control substance(s):

yes

Remarks:

Positive-control substance: mercaptobenzothiazole, purity 98%. Concentrations: 2% induction I phase in cottonseed oil, 25% induction II phase in vaseline, 15% challenge in vaseline.

Positive control results:

The sensitisation rate after application of the positive-control substance mercaptobenzothiazole (15% in vaseline) was 100%, confirming the reliability of the test system.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No effect

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No effect.

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No effect

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No effect.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

50%

No. with + reactions:

1

Total no. in group:

5

Clinical observations:

Erythema grade 1 was observed after 24 hours in one animal.

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 50%. No with. + reactions: 1.0. Total no. in groups: 5.0. Clinical observations: Erythema grade 1 was observed after 24 hours in one animal..

Reading:

1st reading

Hours after challenge:

48

Group:

negative control

Dose level:

50%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

No effect

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No effect.

Reading:

1st reading

Group:

positive control

Dose level:

15%

No. with + reactions:

10

Total no. in group:

10

The animals of the test group showed no reduced weight gain compared to historical data.

All animals of both groups survived throughout the test period.

There are signs of irritation during the induction

Intradermal Induction I (24 hours reading):

- Injection site 1: erythema grade 2 in 5/5 control and 10/10 test animals, oedema grade 2 in 4/5 control and 10/10 test animals, oedema grade 1 in 1/5 control animals

- Injection site 2: erythema grade 1 in 9/10 test animal, eschar in 8/10 test animals

- Injection site 3: erythema grade 2 in 1/5 control and 1/10 test animals, erythema grade 1 in 1/5 control and 9/10 test animals, oedema grade 2 in 1/5 control and 1/10 test animals, oedema grade 1 in 1/5 control and 2/10 test animals eschar in 1/5 control and 6/10 test animals

Intradermal Induction I (48 hours reading):

- Injection site 1: erythema grade 2 in 1/5 control and 3/10 test animals, erythema grade 1 in 4/5 control and 7/10 test animals, oedema grade 2 in 1/5 control and 3/10 test animals, oedema grade 1 in 4/5 control and 7/10 test animals, necrosis (Ø 0.4 cm) in 1/10 test animals eschar in 1/5 control and 1/10 test animals

- Injection site 2: erythema grade 1 in 4/5 test animals

- Injection site 3: erythema grade 1 in 2/5 control and 9/10 test animals, oedema grade 1 in 1/5 control and 1/10 test animals

Dermal Induction II (48 hours exposure, occlusive):

- Immediately after removing the patch: Desquamation in 1/5 control animals, erythema grade 1 in 2/10 test animals

24 hours after removing the patch: Eschar in 5/5 control and 10/10 test animals, erythema grade 1 in 1/10 test animals, desquamation in 1/10 test animals

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, there was no evidence of sensitisation in the test item group at the challenge and the percentage of animals sensitised was 0%.

Executive summary:

The test for sensitisation was performed on the guinea pig according OECD Guidelines No. 406.

The following concentrations were determined by a preliminary test:

- intradermal induction: 5% of the test item, vehicle: physiological saline 0.9% NaCl

- Dermal induction: 50% of the test item, vehicle: vaseline

- Challenge exposure (the highest non-irritating dose): 50% of the test item, vehicle: vaseline.

During the induction slight signs of irritation were observed. These findings confirmed the validity of the study.

After the challenge exposure: no erythema was observed in any of the test animals at any time. Erythema grade 1 was observed after 24 hours in one animal of the control group. No oedema was observed in any animal at any time.

There was no evidence of sensitisation at the challenge and the percentage of animals sensitised was 0%.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There is only one study available for MgCl2: Ahuja V., 2010 (reliability 1). This key study was performed on the guinea pig (OECD 406). The following concentrations were determined by a preliminary test:

• Intradermal induction: 5% of the test item, vehicle: physiological saline 0.9% NaCl
• Dermal induction: 50% of the test item, vehicle: vaseline
• Challenge exposure (the highest non-irritating dose): 50% of the test item, vehicle: vaseline.

After the challenge exposure, no erythema was observed in any of the test animals at any time and no oedema was observed in any animal at any time. There was no evidence of sensitisation at the challenge and the percentage of animals sensitised was 0%.

Justification for classification or non-classification

On the basis of study result, the MgCl2 was not classified for skin sensitisation under the CLP regulation 1272/2008.