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Diss Factsheets

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from review article or handbook

Data source

Reference
Reference Type:
publication
Title:
Final report of the safety assessment of niacinamide and niacin.
Author:
Cosmetic Ingredients Review (CIR)
Year:
2005
Bibliographic source:
International Journal of Toxicology 24 (Suppl 5): 1-31 2005

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Skin sensitization study of Niacinamide (CAS no: 98-92-0) was conducted in 10 guinea pigs to determine its sensitization potential.
GLP compliance:
not specified
Type of study:
not specified
Justification for non-LLNA method:
No Data Available

Test material

Constituent 1
Reference substance name:
Niacinamide
IUPAC Name:
Niacinamide
Constituent 2
Chemical structure
Reference substance name:
Nicotinamide
EC Number:
202-713-4
EC Name:
Nicotinamide
Cas Number:
98-92-0
Molecular formula:
C6H6N2O
IUPAC Name:
nicotinamide
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Niacinamide
- Molecular formula: C6H6N2O
- Molecular weight: 122.1264 g/mol
- Substance type: Organic
- Physical state:Solid (powder)
-Smiles: c1cc(cnc1)C(=O)N
- InChI: 1S/C6H6N2O/c7-6(9)5-2-1-3-8-4-5/h1-4H,(H2,7,9)
Specific details on test material used for the study:
- Name of test material (as cited in study report): Niacinamide
- Molecular formula: C6H6N2O
- Molecular weight: 122.1264 g/mol
- Substance type: Organic
- Physical state:Solid (powder)
-Smiles: c1cc(cnc1)C(=O)N
- InChI: 1S/C6H6N2O/c7-6(9)5-2-1-3-8-4-5/h1-4H,(H2,7,9)

In vivo test system

Test animals

Species:
guinea pig
Strain:
not specified
Sex:
not specified
Details on test animals and environmental conditions:
not specified

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal
Vehicle:
not specified
Concentration / amount:
Induction concentration: 0.1 mL at 2.5 X 5% (ICC i.e.,12.5%)
Day(s)/duration:
14 days
Adequacy of induction:
not specified
Challengeopen allclose all
No.:
#1
Route:
intradermal and epicutaneous
Vehicle:
not specified
Concentration / amount:
(A1)Challenge concentration: 0.1 mL at 5% (ICC) and 20% (ACC): 10 guinea pigs
Day(s)/duration:
24 hours
Adequacy of challenge:
not specified
No.:
#2
Route:
intradermal and epicutaneous
Vehicle:
not specified
Concentration / amount:
(B1)Rechallenge concentration: 0.1 mL at 5% (ICC) and 20% (ACC)
Adequacy of challenge:
not specified
No.:
#3
Route:
intradermal and epicutaneous
Vehicle:
not specified
Concentration / amount:
(B2) Confirmatory challenge : 0.1 mL at 5% (ICC) and 20% (ACC)
Adequacy of challenge:
not specified
No. of animals per dose:
18 guinea pigs
8: preliminary skin irritation test
10: skin sensitization test
Details on study design:
MAIN STUDY
INDUCTION EXPOSURE: Intradermal
- No. of exposures:4
- Exposure period: No Data Available
- Test groups:10 guinea pigs
- Control group: No Data Available
- Site: 4 sites, 2 auxillary and 2 inguinal lymph nodes
- Frequency of applications:1
- Duration: No Data Available
- Concentrations: 0.1 mL at 2.5 X 5% (ICC)

(A1).CHALLENGE EXPOSURE: Intradermal and Epicutaneous
- No. of exposures:1
- Day(s) of challenge: Fourteen days later, challenge test was performed
- Exposure period:24 hours
- Test groups:10guinea pigs
- Control group: No Data Available
- Site: onto the shaved flank in a small circular area
- Concentrations: 0.1 mL at 5% (ICC) and 20% (ACC).
- Evaluation (hr after challenge):24 hours

(B1). RECHALLENGE EXPOSURE
- No. of exposures:1
- Day(s) of challenge: 2 weeks Later, rechalleange test was performed.
- Exposure period: No Data Available
- Test groups:10 animal
- Control group: 4 animal (same sex)
- Site: Intradermally and topically on opposite flanks
- Concentrations: 0.1 mL at 5% (ICC) and 20% (ACC).
- Evaluation (hr after challenge): No Data Available

(B2) Confirmatory challenge:
- No. of exposures:1
- Day(s) of challenge: 1 weeks Later, test was Confirmatory challenge performed.
- Exposure period: No Data Available
- Test groups:10 animal
- Control group: 4 animal (same sex)
- Site: Intradermally and topically on opposite flanks
- Concentrations: 0.1 mL at 5% (ICC) and 20% (ACC).
- Evaluation (hr after challenge): No Data Available
Challenge controls:
4 animal (same sex):Rechallenge Test and Confirmatory challenge

Study design: in vivo (LLNA)

Statistics:

Each injection reaction was given a total score based on size (2 largest diameters), erythema and oedema. Individual reactions were considered positive when their total score was significantly greater than the average total score for control reactions. Application reactions were scored on a 0 to +++ scale.and individual reactions were considered positive if they were + or greater and there were no erythema reactions in controls.Reactions were examined under a constant and artificial day light.

Results and discussion

In vivo (non-LLNA)

Results
Reading:
1st reading
Hours after challenge:
168
Group:
test chemical
Dose level:
0.1 mL at 5% (ICC) and 20% (ACC).
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Negative skin effects were observed in treated animals.
Remarks on result:
no indication of skin sensitisation

In vivo (LLNA)

Cellular proliferation data / Observations:
Negative skin effects were observed in treated animals.

Applicant's summary and conclusion

Interpretation of results:
other: not sensitizing
Conclusions:
The test material Niacinamide (CAS no: 98-92-0) was considered to be not sensitizing on skin of guinea pigs.
Executive summary:

Skin sensitization study of Niacinamide (CAS no: 98-92-0) was conducted in guinea pigs to determine its sensitization potential.

 

The preliminary irritation tests were performed in 8 guinea pigs to determine concentrations suitable for sensitization test [injection challenge concentration (ICC) and application challenge concentration(ACC)]. The concentration giving slight but perceptible irritation with no oedema was selected as the injection challenge concentration (ICC) and the highest concentration which caused no irritation was selected as the application challenge concentration ( ACC).

 

As a result of the preliminary studies, the concentration selected for skin sensitization test were 5% forICC and 20% for ACC.

 

During the induction phase,the total dose was administered on one occasion as 4 intradermal injections, each 2.5 times the ICC (2.5X5%). Fourteen days later each animal was challenged intradermally in one flank and topically in the other with 0.1 ml aliquots of test substance at the respective ICC and ACC (5%and 20% respectively). Twenty-four hours later the reactions were observed.Reactions were examined under a constant and artificial day light.

 

In the absence of sensitization reactions at first challenge the induction and challenge procedures were repeated, andapparent sensitization reactions confirmed 7 days later by a second and confirmatory challenge with controls included.

 

At 24 hours after the first challenge(A1)and at the second(B1)and confirmatory challenge(B2)with 5% and 20% niacinamide none of the rabbits showed positive results. Thus, it can be concluded that theNiacinamide(CAS No: -98-92-0)was considered to be not sensitizing onguinea pigs.