N-[3-(dimethylamino)propyl]stearamide

Endpoint summary

Description of key information

Guinea pig maximisation test: not sensitising (OECD guideline 406; GLP); Induction: intradermal; Challenge: topical

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:

2008-09-09 to 2008-10-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A valid GPMT conducted according to guideline is available, which is reliable without restrictions and adequate for classification and labelling purposes. Potency estimation is not mandatory when existing guideline and GLP conforming data are available, which were conducted before the new annex of the REACH Regulation entered into force. Moreover, no indication for skin sensitisation was observed in this study, thus, no dose response information is needed. For this reason and for reasons of animal welfare no additional LLNA was conducted.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Species/strain: Hsd Poe: DH - guinea pigs (Full-Barrier)
- Source: Harlan Winkelmann GmbH, D.33178 Borchen
- Age at study initiation:
- Weight at study initiation: 300 - 361 g
- Housing: in groups in Terluran - cages on Altromin saw fiber bedding
- Diet (e.g. ad libitum): Altromin 3122 maintenance diet for guinea pigs, ad libitum
- Water (e.g. ad libitum): tap water (drinking water, municipal residue control, microbioI. controlled periodically), ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 °C
- Humidity (%): 55 +/- 10 %
- Air changes (per hr): at least 10 x /hour
- Photoperiod (hrs dark / hrs light): Artificial light, sequence being 12 hours light, 12 hours dark

Route:

intradermal and epicutaneous

Vehicle:

paraffin oil

Concentration / amount:

Intradermal induction: 2.5 % of the test item, in paraffinum perliquidum
Dermal induction: 1 % of the test item, in paraffinum perliquidum
Challenge: 2 % of the test item, in paraffinum perliquidum

Route:

epicutaneous, occlusive

Vehicle:

paraffin oil

Concentration / amount:

Intradermal induction: 2.5 % of the test item, in paraffinum perliquidum
Dermal induction: 1 % of the test item, in paraffinum perliquidum
Challenge: 2 % of the test item, in paraffinum perliquidum

No. of animals per dose:

Number of animals in the test group: 10
Number of animals in the negative control group: 5
Number of animals in the dose range finding study: 13

Details on study design:

RANGE FINDING TESTS:
Three animals were treated intradermally with a concentration of 2.5, 1.0, 0.5 % of the test item and the control vehicle (vehicle: paraffinum
perliquidum). Ten animals were treated topically with concentrations of 10, 5, 4, 3, 2.5, 2.0, 1, 1.5, 0.5, 0.1 % of the test item and the control
vehicle for 24 or 48 hours.


MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal (day 0)
- No. of exposures: 3 pairs of intradermal injections of 0.1 mL
Test group:
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline
Injection 2: a 2.5 % concentration of the test item 1:1 paraffinum perliquidum
Injection 3: a 2.5 % concentration of the test item formulated in a 1:1 mixture (v/v) FCA/physiological saline
Control group:
Injection 1: a 1:1 mixture (v/v) FCA/physiological saline
Injection 2: 100 % paraffinum perliquidum
Injection 3: a 50 % (v/v) formulation of paraffinum perliquidum in a 1:1 (v/v) mixture FCAIphysiological saline

Topical Application (day 7)
Test Group:
The test item was suspended in paraffinum perliquidum at a concentration of 1 %. A patch was fully loaded with 0.5 mL of the prepared test item,
applied to the test area and held in contact by an occlusive dressing for 48 hours.
Control Group:
A patch was fully loaded with 0.5 mL of the vehicle paraffinum perliquidum and applied to the test area and held in contact by an occlusive
dressing for 48 hours.

B. CHALLENGE EXPOSURE (day 20)
Test and Control Group:
The test item was suspended in paraffinum perliquidum at a concentration of 2 %. A patch, loaded with 0.5 mL of the prepared test item was applied
paraffinum perliquidum to the left flank of the animals and a patch loaded with 0.5 mL of the vehicle to the right flank (intraspecific control),
respectively. The patches were held in contact by an occlusive dressing for 24 hours.

The skin reaction was observed and recorded 24, 48 and 72 hours after patch removal.


OTHER:
Preparation of test item solution, example for a 1% solution:

1 g of the test item was weighed in a beaker and 99 g paraffinum perliquidum was added. A magnetic stirrer was put in the beaker and it was heated up to between 65°C and 75°C under agitation (approx. 400 rpm) on a heating plate. As soon as the test item was completely melted it was removed from the heating plate. A cloudy dispersion developed at room temperature.

Challenge controls:

The test item was suspended in paraffinum perliquidum at a concentration of 2 %. A patch, loaded with 0.5 mL of the prepared test item was applied paraffinum perliquidum to the left flank of the animals and a patch loaded with 0.5 mL of the vehicle to the right flank (intraspecific control), respectively. The patches were held in contact by an occlusive dressing for 24 hours.

Positive control substance(s):

yes

Remarks:

Mercaptobenzothiazole, Purity > 98%. The recent reliability check was performed in April/May 2008, (BSL Project ID 081342).

Positive control results:

The Sensitisation rate after application of the positive control substance Mercaptobenzothiazole (15 % in Vaseline) was 70 %, confirming the
reliability of the test system.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

2 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 2 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2 % . No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

2 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 2 % . No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

2 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

no

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 2 %. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no.

Skin reaction after induction exposure:

 

Intradermal Induction (24hours reading):

Injection site 1:      Erythema grade 1 in all control- and 7/10 test animals

Injection site 2:  Erythema grade 1in 6/10 test animals; eschar in 2/10 test animals; necrosis in 5/10 test animals

Injection site 3:  No signs of irritation were recorded for the control animals.

                                 Erythema grade 1 in 1/5 control animals and in 7/10 test animals

                                 Eschar in 2/10 test animals

                                 Necrosis in 2/10 test animals

Intradermal Induction (48 hours reading):

Injection site1:    Erythema grade 1in 7/10 test animals

Injection site2:    Erythema grade 1in 5/10 test animals

                                  Eschar in 3/10 test animals

                                  Necrosis in 5/10 test animals

                                  Oedema grade1in 1/10 test animals

Injection site 3:   Erythema grade 1 in 6/1 0 test animals

                                  Eschar in 3/10 test animals

                                  Necrosis in 2/10 test animals.

                                  Oedema grade 1 in 1/10 test animals

                                  No signs of irritation were recorded for the control animals.

 

 

Dermal Induction (48 hours exposure, occlusive):

Immediately after removing the patch:     Erythema grade 1 in 4/10 test animals

                                                                       Erythema grade 2 in 6/10 test animals

                                                                       Oedema grade 1 in 8/10 test animals

                                                                       All animals showed necrosis.

24 hours after removing the patch:           Erythema grade 1 in 8/10 test animals

                                                                       Erythema grade 2 in 2/10 test animals

                                                                       Oedema grade 1 in 8/10 test animals

                                                                       All animals showed necrosis.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: other: CLP, EU GHS (Regulation (EC) No 1272/2008)

Conclusions:

In this study, Stearic acid 3-(dimethylaminopropyl)amide (a.i. > 99 %), is not a dermal sensitiser.

Executive summary:

In a dermal sensitisation study according to OECD TG 406, 1992) with Stearic acid 3-(dimethylaminopropyl)amide (a.i. > 99 %) in paraffinum perliquidum, young adult Dunkin-Hartley guinea pigs were tested using the Maximization test method. Positive control substance was mercaptobenzothiazole with a sensitisation rate of 70 %.

 

Mild to moderate skin reactions and necrosis were observed after intradermal induction (2.5 %) and dermal induction (1 %) in the test substance animals. After challenge exposure (2 %) no skin reactions were observed in test or control animals at any observation time. Therefore the sensitisation rate was 0 %.

 

For the challenge concentration, which is the highest non-irritant dose, 2 % of the test item was used. The higher challenge concentration compared to the dermal induction concentration can be explained by the different exposure times, i.e. 48 hours for the dermal induction and 24 hours for the challenge.

 

In this study, Stearic acid 3-(dimethylaminopropyl)amide (a.i. > 99 %), is not a dermal sensitiser.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a dermal sensitisation study according to OECD TG 406, 1992) with Stearic acid 3-(dimethylaminopropyl)amide (a.i. > 99%) in paraffinum perliquidum, young adult Dunkin-Hartley guinea pigs were tested using the Maximization test method. Positive control substance was mercaptobenzothiazole with a sensitisation rate of 70%.

Mild to moderate skin reactions and necrosis were observed after intradermal induction (2.5%) and dermal induction (1%) in the test substance animals. After challenge exposure (2%) no skin reactions were observed in test or control animals at any observation time. Therefore the sensitisation rate was 0%.

For the challenge concentration, which is the highest non-irritant dose, 2% of the test item was used. The higher challenge concentration compared to the dermal induction concentration can be explained by the different exposure times, i.e. 48 hours for the dermal induction and 24 hours for the challenge.

In this study, Stearic acid 3-(dimethylaminopropyl)amide (a.i. > 99%), is not a dermal sensitiser.

 

This finding is supported by TOPKAT statistical model:

All validation criteria have been met by the assessment of the query. The performance of the submodel in the vicinity of the query is unknown. Therefore the Skin Sensitization NEG vs. SENS assessment as producing a negative response in the assay for the query structure is considered acceptable. Based on the prediction results obtained by means of TOPKAT statistical models system, the substance Stearic acid 3-(dimethylaminopropyl) amide is not a sensitiser. Computed probability was 0.0.

According to the Guidance on information requirements and chemical safety assessment, Chapter R.7a: “a probability of 0.7 or more indicates a strong sensitizer and a probability below 0.30 indicates a weak or moderate sensitizer. Probability values between 0.30 and 0.70 are referred to as indeterminate”.

 

There is no information available for respiratory sensitisation. Therefore, there is a data gap in this respect. However, the data gap cannot be fulfilled with experimental data, since there is no internationally accepted animal model for respiratory sensitisation. In case human data for respiratory sensitisation emerges, this will be taken into account. For skin sensitisation, there is no reason to believe that results obtained in guinea pigs would not be applicable to humans.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on relevant, reliable and adequate data, Stearic acid 3-(dimethylaminopropyl)amide does not have to be classified and labelled according to the CLP Regultion (EC) No 1272/2008 and Directive 67/548/EEC with respect to skin sensitisation.