Zinc methacrylate

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

Study period:

20 August - 21 September 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP study conducted in compliance with OECD Guideline 406 with minor deviation: temperature in the animal room was slightly outside the range

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

temperature in the animal room was slightly outside the range

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Guinea pig maximisation test result is available

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, L’Arbresle, France.
- Age at study initiation: 5 weeks
- Weight at study initiation: 227-277 g
- Housing: Animals were housed in groups of 2 (in case of odd number, the last animal was housed individually) in polycarbonate containers.
- Diet: Food (SDS, FD1 guinea pig breeding and maintenance diet), ad libitum
- Water: Drinking water (tap water from public distribution system), ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19-25 °C
- Humidity: 30-70 %
- Air changes: Approximately 10-15 changes/h
- Photoperiod: 12 h dark / 12 h light

Concentration / amount:

Preliminary test:
- Determination by intradermal injection of the Maximal Non Necrotizing Concentration (MNNC): 0.25, 0.5, 1, 2.5, 5 and 10 % in olive oil; due to necrosis observed at all concentrations, the same animals received on both sides of the spine, a volume of 0.1 mL of the test item, at 3 concentrations: diluted at 0.05, 0.1 and 0.2 % in olive oil.
- Determination by topical application of the Pre-Maximal Non Irritant Concentration (Pre-MNIC): 10, 20, 35 and 60 % in liquid paraffin.
- Determination by topical application of the Maximal Non Irritant Concentration (MNIC): 5, 10, 20 and 35 % in liquid paraffin.

Main test:
Induction phase:
First Intradermal (ID) Induction:
Group 1 (Negative control):
2 ID: Freund’s Complete Adjuvant diluted at 50 % in olive oil.
2 ID: olive oil
2 ID: a mixture with equal volumes of: Freund’s Complete Adjuvant at 50 % and olive oil
Group 2 (Treated):
2 ID: Freund’s Complete Adjuvant diluted at 50 % in olive oil,
2 ID: test item at 0.2 % in olive oil,
2 ID: a test mixture in equal volumes of: Freund’s Complete Adjuvant at 50 % and the test item at 0.4 % in olive oil.

Second Topical Induction occlusive:
Group 1 (Negative control): 0.5 mL of liquid paraffin.
Group 2 (treated): 0.5 mL of the test item at 60 % in liquid paraffin.

Concentration / amount:

Challenge phase:
- Group 1 (Negative control) and Group 2 (Treated): 1 sample cup containing the test item at 10 % (MNIC) and 1 sample cup containing the vehicle (liquid paraffin).

No. of animals per dose:

Preliminary test:
- Determination by intradermal injection of the Maximal Non Necrotizing Concentration (MNNC): 2 animals
- Determination by topical application of the Pre-Maximal Non Irritant Concentration (Pre-MNIC): 2 animals
- Determination by topical application of the Maximal Non Irritant Concentration (MNIC): 3 animals

Main test:
- Group 1 (negative control): 5 females
- Group 2 (treated): 10 females

Details on study design:

PRELIMINARY TEST:
- Determination by intradermal injection of the Maximal Non Necrotizing Concentration (MNNC): Two animals received on both sides of the spine, a volume of 0.1 mL of the test item, at 0.25, 0.5, 1, 2.5, 5 and 10 % in olive oil and cutaneous reactions were recorded 24 h after the injections; due to necrosis observed at all concentrations, the same animals received 0.1 mL of the test item at concentrations of 0.05, 0.1 and 0.2 % in olive oil. Cutaneous reactions were conducted 24 h after the injection.
- Determination by topical application of the Pre-Maximal Non Irritant Concentration (Pre-MNIC): Test item was applied on the shorn skin of dorso-lumbar zone of two guinea pigs with occlusive dressing for 24 h at concentrations of 10, 20, 35 and 60 % in liquid paraffin. Cutaneous reactions were recorded 24 h after removal of the dressing and rinsed with liquid paraffin.
- Determination by topical application of the Maximal Non Irritant Concentration (MNIC): Three guinea pigs were treated according to the same treatment as animals from Group 1 (negative control) for the induction phase (i.e. olive oil and liquid paraffin). During the challenge phase, the animals were treated with the test item placed onto the selected treatment sites and covered with an occlusive dressing for a period of 24 h at the concentrations of 5, 10, 20 and 35 % in liquid paraffin. Cutaneous reactions were recorded 24 and 48 hours after removal of the occlusive dressing.

MAIN STUDY
A. INDUCTION EXPOSURE: INTRADERMAL
- No. of exposures: One
- Exposure period: 7 days
- Test groups: On Day 0, three pairs of intradermal injections (ID) of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil (2 ID), test item at 0.2 % in olive oil (2 ID) and a test mixture in equal volumes of Freund’s Complete Adjuvant at 50 % and the test item at 0.4 % in olive oil (2 ID) were performed on the either side of the spine in the scapular region.
- Control group: On Day 0, three pairs of intradermal injections (ID) of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil (2 ID), olive oil (2 ID) and a mixture with equal volumes of Freund’s Complete Adjuvant at 50 % and olive oil (2 ID) were performed on the either side of the spine in the scapular region.
- Site: Scapular region
- Duration: Days 0-6

B. INDUCTION EXPOSURE: TOPICAL
- No. of exposures: One
- Exposure period: 48 h
- Test groups: Topical application of 0.5 mL of the test item at 60 % in liquid paraffin under occlusive dressing for 48 h was performed on the injection sites of each animal.
- Control group: Topical application of 0.5 mL of liquid paraffin under occlusive dressing for 48 h was performed on the injection sites of each animal.
- Site: Scapular region
- Frequency of applications: Single application
- Duration: Days 7-20

C. CHALLENGE EXPOSURE: TOPICAL
- No. of exposures: One
- Day(s) of challenge: Day 20
- Exposure period: 24 h
- Test groups: Topical application of 1 sample cup containing the test item at 10% (MNIC) on either side of the spine, under occlusive dressing for 24 h.
- Control group: Topical application of 1 sample cup containing the vehicle (liquid paraffin) on either side of the spine, under occlusive dressing for 24 h.
- Site: Shorn dorso-lumbar zone
- Evaluation (h after challenge): 24, 48 and 72 h

OTHER:
- Animals were observed for mortality and weighed individually on the day of beginning (Day 0) and end of the study (Day 23).

Challenge controls:

Topical application of 1 sample cup containing the vehicle (liquid paraffin) on either side of the spine on Day 20 under occlusive dressing for 24 h.

Positive control substance(s):

yes

Remarks:

α-Hexylcinnamaldehyde (Study no. SMK-2011-002, SMK-2011-003 and SMK-2012-001)

Positive control results:

α-Hexylcinnamaldehyde induced positive skin sensitization reactions in guinea pigs.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 %

No. with + reactions:

5

Total no. in group:

10

Clinical observations:

none

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 %

No. with + reactions:

5

Total no. in group:

10

Clinical observations:

none

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

72

Group:

test chemical

Dose level:

10 %

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

None

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

Liquid paraffin

No. with + reactions:

2

Total no. in group:

5

Clinical observations:

None

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

negative control

Dose level:

Liquid paraffin

No. with + reactions:

1

Total no. in group:

5

Clinical observations:

None

Key result

Reading:

1st reading

Group:

positive control

Dose level:

Not specified

Remarks on result:

positive indication of skin sensitisation

Remarks:

Details not specified

Table 7.4.1/1: Results of skin sensitization – challenge phase

 

Groups	Reading time (h)	Concentrations (%)	Scores				% of positive responses ≥1	% of animal sensitized#
Negative Control Group	24	10	3	1	1	0	40	NA
	48	10	4	1	0	0	20
	72	10	5	0	0	0	0
Treated Group	24	10	1	3	1	5	90	50
	48	10	0	5	2	3	100	50
	72	10	3	7	0	0	70	70

 

Grading scales:

Erythema

0: No visible modification

1: Slight or patches of erythema

2: Moderate confluent erythema

3: Internal erythema and swelling

Oedema

0: No visible modification

1: Slight oedema

2: Moderate oedema

3: important oedema  

 

# A comparison of the intensities and persistence of reactions at the test item challenge sites in the test and control animals permits identification

of sensitisation reactions.

Others:

- No mortality was observed during the study.

- No abnormality was recorded in the body weight gain of treated and control groups.

Interpretation of results:

other: Category 1B (indication of skin sensitising potential) based on EU CLP criteria

Conclusions:

Under these test conditions, Zinc dimethacrylate is classified as “Category 1B” skin sensitiser according to the CLP Regulation (EC) N° (1272-2008).

Executive summary:

In a Magnusson & Kligman maximisation study (GPMT) performed according to OECD Guideline 406 and in compliance with GLP, groups of 10 Dunkin-Hartley female guinea pigs were induced with three pairs of intradermal injections of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil (2 ID), test item at 0.2 % in olive oil (2 ID) and a test mixture in equal volumes of Freund’s Complete Adjuvant at 50 % and the test item at 0.4 % in olive oil on Day 0 on three different sites on either side of the spine in the scapular region. Control group of 5 females was intradermally induced with three pairs of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil, olive oil and a mixture with equal volumes of Freund’s Complete Adjuvant at 50 % and olive oil. After one week the same area was topically induced with 0.5 mL of the test item at 60 % in liquid paraffin under occlusive dressing for 48 h, whereas control group was applied with 0.5 mL of liquid paraffin under occlusive dressing for 48 h. After 2 weeks of rest period, a challenge application of vehicle and test item at 10 % was applied on either side of the spine on the dorso-lumbar region. The test concentrations for the main study were determined from a preliminary toxicity study. No mortality was observed during the study. No abnormality was recorded in the body weight gain of treated and control groups. In the treatment group (treatment dose of 10%), a more severe reaction was observed in the treated site than in the control site (treated with liquid paraffin only) in 90% (9/10), 100% (10/10) and 70% (7/10) of the animals, 24, 48 and 72 hours respectively after the challenge phase. In the control group, a more severe reaction was observed in the treated site than in the control site (treated with liquid paraffin only) in 40% (2/5) and 20% (1/5) of the animals, 24 and 48 hours respectively after the challenge phase. As irritation was noted in the control group animals, only reactions in the test group animals that exceeded the most severe reactions seen in the control group animals were attributed to skin sensitization. Therefore, a sensitization reaction was noted in 50% (5/10), 50% (5/10) and 70% (7/10) of the animals from the treated group with the test item at 10%. Historical data on positive control (α-Hexylcinnamaldehyde) exhibited evidence of sensitization indicating the validity of the study. Under these test conditions, Zinc dimethacrylate is considered as skin sensitiser (Colas, 2012).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In a Magnusson & Kligman maximisation study (GPMT) performed according to OECD Guideline 406 and in compliance with GLP, groups of 10 Dunkin-Hartley female guinea pigs were induced with three pairs of intradermal injections of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil (2 ID), test item at 0.2 % in olive oil (2 ID) and a test mixture in equal volumes of Freund’s Complete Adjuvant at 50 % and the test item at 0.4 % in olive oil on Day 0 on three different sites on either side of the spine in the scapular region. Control group of 5 females was intradermally induced with three pairs of 0.1 mL of Freund’s Complete Adjuvant diluted at 50 % in olive oil, olive oil and a mixture with equal volumes of Freund’s Complete Adjuvant at 50 % and olive oil. After one week the same area was topically induced with 0.5 mL of the test item at 60 % in liquid paraffin under occlusive dressing for 48 h, whereas control group was applied with 0.5 mL of liquid paraffin under occlusive dressing for 48 h. After 2 weeks of rest period, a challenge application of vehicle and test item at 10 % was applied on either side of the spine on the dorso-lumbar region. The test concentrations for the main study were determined from a preliminary toxicity study.No mortality was observed during the study. No abnormality was recorded in the body weight gain of treated and control groups. In the treatment group (treatment dose of 10%), a more severe reaction was observed in the treated site than in the control site (treated with liquid paraffin only) in 90% (9/10), 100% (10/10) and 70% (7/10) of the animals, 24, 48 and 72 hours respectively after the challenge phase. In the control group, a more severe reaction was observed in the treated site than in the control site (treated with liquid paraffin only) in 40% (2/5) and 20% (1/5) of the animals, 24 and 48 hours respectively after the challenge phase. As irritation was noted in the control group animals, only reactions in the test group animals that exceeded the most severe reactions seen in the control group animals were attributed to skin sensitization. Therefore, a sensitization reaction was noted in 50% (5/10), 50% (5/10) and 70% (7/10) of the animals from the treated group with the test item at 10%. Historical data on positive control (α-Hexylcinnamaldehyde) exhibited evidence of sensitization indicating the validity of the study.Under these test conditions, Zinc dimethacrylate is considered as skin sensitiser (Colas, 2012).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the in vivo skin sensitisation study, the registered substance warrants classification as “Skin sensitization - Category 1B” (H317: May cause an allergic skin reaction) according to the EU CLP Regulation (EC) 1272/2008.