Carbamic acid, (2-hydroxypropyl)-, compd. with 1-amino-2-propanol (1:1)

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

- modified LLNA (IMDS): Measurement of cell counts instead of radioactive labeling. In addition, measurements of ear swelling and ear weights were done to discriminate the irritating potential from the sensitizing potential of the test substance.

Principles of method if other than guideline:

Modified LLNA (IMDS; Integrated Model for the Differentiation of Skin Reactions). Modifications are authorised in the OECD TG 429 and in the Note for Guidance SWP/2145/00 of the CPMP (2001). Information on validation of IMDS and scientific justification is given in: Vohr HW et al., Arch. Toxicol., 73, 501-509 (2000); Ehling G et al., Toxicology 212, 60-68 and 69-79 (2005).

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

(2-hydroxypropyl)carbamic acid; 1-aminopropan-2-ol

EC Number:

605-539-0

Cas Number:

169115-74-6

Molecular formula:

C7 H18 N2 O4

IUPAC Name:

(2-hydroxypropyl)carbamic acid; 1-aminopropan-2-ol

Details on test material:

- Composition of test material, percentage of components: approximately 50% active compound in ethylene glycol

In vivo test system

Test animals

Species:

mouse

Strain:

NMRI

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan nederland, AD Horst, Netherland
- Strain: HsdWin:NMRI
- Age at study initiation: 8 weeks
- Weight at study initiation: 26 - 32 g
- Housing: individual
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 6 days

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Remarks:

Highest concentration without vehicle. The stability of the test item in the vehicle was analytically verified for up to 4 days.

Concentration:

0, 10, 30, 100 %

No. of animals per dose:

6

Details on study design:

TREATMENT PREPARATION AND ADMINISTRATION:
The test item in the formulation and the vehicle (A/OO) were applied epicutaneously onto the dorsal part of both ears of the animals. This  treatment was repeated on three consecutive days (d1, d2 and d3). The volume administered was 25 µl/ear. The used concentrations were based on the experiences with the test system and the toxic properties of the test substance.
The animals were anaesthetized by inhalation of carbon dioxide and sacrificed one day after the last application (d4). The appropriate organs were then removed. Lymphatic organs (the auricular lymph nodes) were transferred into physiological saline (PBS).
Investigations:
- weight of draining lymph nodes (given as weight index compared to vehicle controls)
- cell counts in draining lymph nodes (given as cell count index compared to vehicle controls)
Stimulation indices were calculated by dividing the absolute weight or number of cell counts of the substance treated lymph nodes by the vehicle treated ones.
- ear swelling (given in 0.01 mm and as index)
- ear weight (given in mg/8 mm diameter punch and as index)
- body weights

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

When it was statistically reasonable, the values from treated groups were compared with those from the control group by a one-way analysis of variance (ANOVA) when the variances are considered homogeneous according to a homogeneity testing like Cochran's test. Alternatively, if the variances are considered to be heterogenous (p<=0.05), a non-parametric Kruskal-Wallis test has been used (Kruskal-Wallis ANOVA) at significance levels of 5% . Two sided multiple test procedures were done according to Dunnett or Bonferroni-Holm, respectively. Outlying values in the LN weights were eliminated at a probability level of 99% by Nalimov's method. In addition, for the LLNA/IMDS the smallest significant differentes in the means were calculated by Scheffels method, which according to Sachs can be used for both equal and unequal sample sizes.

Results and discussion

Positive control results:

Alpha hexyl cinnamic aldehyde, used as positive control in a concentration of 30% in dimethylformamide, showed a clear sensitising potential in the local lymph node assay (IMDS).

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

Weight index of draining lymph nodes: slightly increased in the low dose group (10%), however within the normal range of variance for this parameter Cell count index in draining lymph nodes: 'positive level' of 1.4 has not been reached or exceeded in any dose group. Ear swelling: 'positive level' of 2x10E-2 mm increase (i.e. 10% of control level) has not been reached or exceeded in any dose group Ear weight: 'positive level' has not been reached or exceeded in any dose group

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: modified LLNA; measurement of cell counts instead of radioactive labeling

Any other information on results incl. tables

Compared to vehicle-treated animals, none of the parameters measured in the substance treated groups, i.e. cell counts and weights of the draining lymph nodes, ear weights and ear swelling, reached or exceeded the "positive levels" defined for this assay. These results show that there is no indication for a skin sensitizing effect after administration of a concentration up to and including 100 % test item in this test system.

In conclusion, these results show that the test item has no sensitizing potential in mice after dermal application of up to and including a 100 % concentration. No indication for a non-specific (irritant) activation was detected, too. Therefore, the concentration of 100 % turned out to be the NOEL for the parameters investigated in this study with respect to skin sensitization.

These results are verified by the comparison with the results of the positive control group (Alpha Hexyl Cinnamic Aldehyde).

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Executive summary:

Carbamic acid, (2-hydroxypropyl)-, compound with 1-amino-2-propanol (1:1) in ethylene glycol was investigated in the modified Local Lymph Node Assay (LLNA) on female mice, performed according to OECD TG 429, in concentrations of 0% (vehicle control), 10% and 30% in dimethylformamide and 100%. Body weights were not affected by treatment. Compared to vehicle-treated animals none of the investigated parameters (weight and cell count in draining lymph nodes, ear swelling and ear weight) reached or exceeded the positive levels defined for this assay. These results are verified by comparision with results of the positive control group treated with alpha hexyl cinnamic aldehyde (30% in dimethylformamide).

In conclusion, the test item showed no skin sensitizing potential in mice after dermal application of up to and including a 100% concentration. No indication for a non-specific (irritant) activation was detected too. Therefore, the concentration of 100% turned out to be the NOAEL for the parameters investigated in this study with respect to skin sensitization.