Registration Dossier

Administrative data

Description of key information

No data gaps were identified. The available data are adequate for risk assessment and classification and labelling purposes.

Two studies for skin sensitisation are available:

Guinea Pig Maximisation Test with N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamide containing no formaldehyde:

The skin sensitisation potential of the test item N-(3(5)-Methyl-1H-pyrazol-l-yl-methyl)- acetamid (P 70/05)was investigated in the Guinea-Pig Maximisation Test with the Dunkin Hartley albino strain, whose sensitivity to Benzocaine had been demonstrated, according to OECD Guideline 406 (Skin Sensitisation). N-(3(5)-MethyMH-pyrazol-l-yl-methyl)- acetamid (P 70/05) has not to be classified as skin sensitiser according to the results of this sensitisation study.

Guinea Pig Maximisation Test with N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamide containing formaldehyde:

The potential of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid to produce skin sensitisation reactions in guinea pigs was determined in a test model according to the MAGNUSSON and KLIGMAN method and OECD guideline 406.

N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid had no skin sensitizising properties.

Justification for selection of skin sensitisation endpoint:

Only one study available. The key study is GLP-compliant and has Klimisch score 1.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-09-17 - 2013-02-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The GPMT was regarded as reliable method. Since no LLNA study was available, it was justified not to perform a new study with experimental animals .
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
Species / Strain Guinea pig / Dunkin-Hartley

Breeder Charles River Laboratories,
Research Models and Services,
Germany GmbH
Stolzenseeweg 32 – 36
88353 Kißlegg
Germany

Selection of species According to international recommendations

Number of animals 15

Sex Male

Age
(at start of administration) 37 days

Body weight
(at start of administration) 330 - 384 g
(excluding positive control group)
Positive control group: 316 – 370 g

Identification of animals By cage label and coloured marks

Adaptation period At least 5 days

The animals were kept in pairs in MAKROLON cages (MZK 80/25) at a room tempera-ture of 22°C ± 3°C (maximum range) and a relative humidity of 55% ± 15% (maximum range).
Route:
intradermal and epicutaneous
Vehicle:
other: Aqua ad iniectabilia (stages 1, 2 and 3)
Concentration / amount:
Induction: intracutaneous: 10% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
Induction: topical: 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
Challenge: topical: 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
Route:
epicutaneous, occlusive
Vehicle:
other: Aqua ad iniectabilia (stages 1, 2 and 3)
Concentration / amount:
Induction: intracutaneous: 10% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
Induction: topical: 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
Challenge: topical: 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia
No. of animals per dose:
Tehicle control: 5 animals
Treatment group: 10
Details on study design:
Stage 1 (induction)
Day 0
Three pairs of intradermal injections of 0.1 mL were given in the shoulder region which was cleared of hair so that one of each pair lay on each side of midline.
(1) Freund's complete adjuvant (FCA)
(diluted 1 : 1 with 0.9% NaCl )

(2) the test item (N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid) (10%)

(3) the test item in a 1+1 mixture (v/v) FCA/physiological saline

In injection 3, the final concentration of the test item was equal to that in injection 2.
Injections (1) and (2) were given close to each other and nearest the head, while (3) was given towards the caudal part of the test area.

Day 6
As a 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia was non-irritating to the non-depilated skin of the test animals in the preliminary experiment, the fur was shaved from the application area and the exposed skin was coated with 0.5 mL sodium laurylsulfate 10% in vaseline in order to induce a local irritation.

Stage 2 (induction)
Day 7
7 days after the intracutaneous injection, the shoulder region of the same animals was shaved again and treated topically with test item (75% concentration) using the patch-test technique (exposure time: 48 hours). The patch was removed after 48 hours. No cleaning of the skin was necessary.

Stage 3 (challenge)
Day 21
Two weeks after the topical application (corresponds to a monitoring period of 21 days) the flanks of the same animals were shaved and depilated for a further topical application with test item (75% concentration) using the patch-test technique. The filter paper containing the test item was applied to the left flank, the filter paper with the vehicle to the right flank of the animal (exposure time: 24 hours). 21 hours after the filter paper had been removed the treated skin was cleaned and fur removed, if necessary.
Positive control substance(s):
yes
Remarks:
α-hexyl cinnamic aldehyde
Positive control results:
Animals of the same strain treated with -hexyl cinnamic aldehyde in sesame oil exhibited a sensitising reaction in all animals in form of a moderate and confluent erythema (grade 2).
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
10% (intracutaneous), 75% (topical)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no effects
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 10% (intracutaneous), 75% (topical). No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no effects.
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
10% (intracutaneous), 75% (topical)
No. with + reactions:
0
Total no. in group:
0
Clinical observations:
no effects
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 10% (intracutaneous), 75% (topical). No with. + reactions: 0.0. Total no. in groups: 0.0. Clinical observations: no effects.
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no effects
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no effects.
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no effects
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: 0. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no effects.
Reading:
1st reading
Hours after challenge:
48
Group:
positive control
Dose level:
10 % (intracutaneous), undiluted (topical), 0.01 % challenge
No. with + reactions:
20
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 10 % (intracutaneous), undiluted (topical), 0.01 % challenge. No with. + reactions: 20.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
72
Group:
positive control
Dose level:
10 % (intracutaneous), undiluted (topical), 0.01 % challenge
No. with + reactions:
20
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: positive control. Dose level: 10 % (intracutaneous), undiluted (topical), 0.01 % challenge. No with. + reactions: 20.0. Total no. in groups: 20.0.
Interpretation of results:
GHS criteria not met
Conclusions:
Under the test conditions, N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid revealed no sensitising properties in guinea pigs in a test model according to MAGNUSSON and KLIGMAN and OECD guideline 406.
Executive summary:

The purpose of this study was to determine the potential of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid to produce skin sensitisation reactions in guinea pigs in a test model according to the MAGNUSSON and KLIGMAN method and OECD guideline 406.

A 10% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia chosen for the 1st (intracutaneous) induction stage did not reveal any skin reactions.

2 mL of a 75% suspension N-((3(5)-Methyl-1H-pyrazol-1-yl)­methyl)­acetamid/animal chosen for the 2nd (topical) induction stage were not irritating to the shaved skin in the preliminary experiment.

Hence, in the main study the skin was coated with sodium laurylsulfate on the day before stage 2 induction in order to induce a local irritation. This treatment resulted in a discrete or patchy erythema in all test group animals 48 and 72 hours after start of exposure.

A 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia was the maximum concentration that could be prepared in order to produce a homogeneous test item-vehicle preparation. No higher suitable concentration could be prepared.

The challenge with 2 mL of a 75% suspension of N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid in aqua ad iniectabilia/animal revealed no skin irritation in any animal and, thus, the test item had no sensitising properties.

The vehicle control revealed no skin reactions.

Animals of the same strain treated witha-hexyl cinnamic aldehyde in sesame oil exhibited a sensitising reaction in all animals in form of a moderate and confluent erythema (grade 2).

The body weight gain of the animals treated with N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid was within the range of the vehicle control during the experiment.

Behaviour remained unchanged during the course of the study.

Therefore N-((3(5)-Methyl-1H-pyrazol-1-yl)methyl)acetamid had no skin sensitizising properties.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2007-05-02 - 2007-06-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to an internationally accepted guideline. All study parameters are based on the specific guideline.
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The GPMT was regarded as reliable method. Since no LLNA study was available, it was justified not to perform a new study with experimental animals .
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
Water: tap water, ad libitum (municipal supply), Makrolon® bottles, changed daily
Environment: air conditioned:
temperature: 20.5 - 25 °C
relative humidity: 40 - 70 %, with risings on 80 % from time to time
These risings did not negatively influence the general state of well-being and behaviour of the animals. Lighting: artificial light was set to give a cycle of 12 hours light and 12 hours dark
Light from 6.30 a.m. until 6.30 p.m.
Route:
other: Intracutaneous Injection
Vehicle:
other: vaseline
Concentration / amount:
Induction by Intracutaneous Injection:
Injection 1 : mixture of Aqua pro injectione and FCA (1:1, v/v)
Injection 2: 5 % (w/v) solution of the test item in AI
Injection 3: 5 % (w/v) mixture of the test item with AI and emulsifying with FCA in a proportion of 1:1 (v/v)

Challenge by Epicutaneous Administration:
One strip of gauze patch (2x4 cm) was loaded with 0.5 g of the 25 % (w/w) mixture of the test item with vaseline. One patch each was then applied to the right flank of all animals. Other strips of gauze patch were loaded with 0,5 g of vaseline and applied to the left flank of all animals.
Route:
epicutaneous, occlusive
Vehicle:
other: vaseline
Concentration / amount:
Induction by Intracutaneous Injection:
Injection 1 : mixture of Aqua pro injectione and FCA (1:1, v/v)
Injection 2: 5 % (w/v) solution of the test item in AI
Injection 3: 5 % (w/v) mixture of the test item with AI and emulsifying with FCA in a proportion of 1:1 (v/v)

Challenge by Epicutaneous Administration:
One strip of gauze patch (2x4 cm) was loaded with 0.5 g of the 25 % (w/w) mixture of the test item with vaseline. One patch each was then applied to the right flank of all animals. Other strips of gauze patch were loaded with 0,5 g of vaseline and applied to the left flank of all animals.
No. of animals per dose:
5 animals for the control group and 10 animals for the dose group
Details on study design:
Preparation of the Animals
The animals were assigned to treatment groups (5 animals for the control group and 10 animals for the dose group) according to random numbers after the acclimatisation period and weighed one day prior to first administration. After allocation to groups each animal was uniquely identified by ear notches.
The hair was removed from an area (approximately 2x4 cm) overlying the scapulae by clipping and shaving 24 hours prior to test item administration avoiding skin abrasion.

Induction by Intracutaneous Injection
Three pairs of intracutaneous injections of 0.1 ml volume were given to each animal in the shoulder region so that one of each pair lay on each side of the midline in cranial to caudal sequence.
Dose group:
Injection 1 : mixture of Aqua pro injectione and FCA (1:1, v/v) Injection 2: 5 % (w/v) solution of the test item in AI
Injection 3: 5 % (w/v) mixture of the test item with AI and emulsifying with FCA in a proportion of 1:1 (v/v)
Control group:
Injection 1 : mixture of Aqua pro injectione and FCA (1:1, v/v) Injection 2: AI
Injection 3: not necessary as the chosen vehicle is AI

Day 6: Preparation of Skin Area for Induction by Epicutaneous Administration
Because the test item was non-irritating after epicutaneous administration during the pilot study, a mild inflammatory response was induced by pretreatment of the skin with 10% sodium lauryl sulphate (Carl Roth GmbH, batch 38420362) in vaseline 24 hours before patch administration. The clearing of hair was carried out therefore on day 5.

Day 7: Induction by Epicutaneous Administration
Dose group:
One layer of filter paper (2x4 cm) was loaded with 0,5 g of the 25 % (w/w) mixture of the test item with vaseline. One patch each was then placed on the skin of both sides of the body.
Control group:
One layer of filter paper (2x4 cm) was loaded with 0.5 g of vaseline. One patch each was then placed on the skin of both sides of the body.
In both groups the papers were covered with film and held in contact with the skin by occlusive dressing.
After 48 hours the patches were removed and the administration areas were cleaned with corn oil.

Day 20: Preparation of Skin Area for Challenge
Both right and left flanks of all animals were cleared of hair approximately 5 x 5 cm 24 hours prior to test item administration avoiding skin abrasion.

Day 21: Challenge by Epicutaneous Administration
Dose and control group:
One strip of gauze patch (2x4 cm) was loaded with 0.5 g of the 25 % (w/w) mixture of the test item with vaseline. One patch each was then applied to the right flank of all animals. Other strips of gauze patch were loaded with 0,5 g of vaseline and applied to the left flank of all animals.
All patches were covered with film and held in contact with the skin by occlusive dressing. After 24 hours the patches were removed and the administration areas were cleaned with corn oil.

Days 23 and 24: Assessment of Challenge Reaction
The administration areas were cleared of hair again without altering the existing response or the integrity of the epidermis approximately 21 hours after patch removal. At 24 and 48 hours after patch removal (48 and 72 hours after start of challenge) the skin reaction was observed and recorded according to the MAGNUS S ON and KLIGMAN grading scale under section 5.3.
Positive control substance(s):
yes
Remarks:
Benzocaine
Positive control results:
The epicutaneous administration of the 10 % suspension of Benzocaine in Paraffinum liquidum caused an erythema (grade 1 and 2) in 8 of 10 animals of the dose group on day 23 and in 6 of 10 animals also on day 24.
The same administration to the control animals did not cause any irritation signs.
The administration of Paraffinum liquidum to the left flank did not cause any irritation signs
in all animals.
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
25 % (w/w) mixture of the test item with vaseline
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25 % (w/w) mixture of the test item with vaseline . No with. + reactions: 0.0. Total no. in groups: 10.0.
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
25 % (w/w) mixture of the test item with vaseline
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 25 % (w/w) mixture of the test item with vaseline . No with. + reactions: 0.0. Total no. in groups: 10.0.
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
positive control
Dose level:
10%
No. with + reactions:
8
Total no. in group:
10
Clinical observations:
no
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
positive control
Dose level:
10%
No. with + reactions:
6
Total no. in group:
10
Clinical observations:
no

Number of animals with skin sensitisation reaction after administration of

N-(3(5)-Methyl-1H-pyrazol-l-yl-methyl)-acetamid (P 70/05)

(left flank: control; right flank: test item)

Test group

Time after challenge

48 hours (Day 23)

72 hours (Day 24)

Left flank

Right flank

Left flank

Right flank

Animals with skin sensitisation reaction / used animals

Control group

0/5

0/5

0/5

0/5

Dose group

0/10

0/10

0/10

0/10


Interpretation of results:
GHS criteria not met
Conclusions:
N-(3(5)-Methyl-1H-pyrazol-l-yl-methyl)- acetamid (P 70/05) has not to be classified as skin sensitiser according to the results of this sensitisation study.
Executive summary:

The skin sensitisation potential of the test item N-(3(5)-Methyl-1H-pyrazol-l-yl-methyl)- acetamid (P 70/05)was investigated in the Guinea-Pig Maximisation Test with the Dunkin Hartley albino strain, whose sensitivity to Benzocaine had been demonstrated, according to OECD Guideline 406 (Skin Sensitisation).

The choice of doses for the main experiment based on the results of the pilot study.

None of the animals died or showed clinical signs during the course of investigation.

The body weights and the body weight gain were not affected by the treatment.

The intracutaneous injection of the 5 % (w/v) solution of the test item in Aqua pro injectione did not induce any skin reaction. In combination with sensitisation potentiating FCA erythema (grade 1-2) and oedema were observed.

The epicutaneous administration of the 25 % (w/w) mixture of the test item with vaseline did not cause any irritation signs in the course of the induction period.

The challenge using the 25 % (w/w) mixture of the test item with vaseline did not cause any irritation signs in the animals of the dose group.

The skin-fold thickness was not affected by the administration of the test item.

N-(3(5)-MethyMH-pyrazol-l-yl-methyl)- acetamid (P 70/05) has not to be classified as skin sensitiser according to the results of this sensitisation study.

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

According to the CLP Regulation (EU GHS Regulation (EC) No 1272/2008) classification and labelling is not required for skin sensitisation of N-(3(5)-Methyl-1 H-pyrazol-1 -yl-methyl)-acetamid, based on reliable data from an in-vivo study according to OECD 406.