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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

There are two studies available on skin sensitisation. Both studies were used as part of a weight of evidence approach for the assessment of the skin sensitisation potential of 2-(dimethylamino) -2-methylpropan-1-ol (DMAMP). The first skin sensitisation study was conducted similar to OECD 406 (Parekh, 1982). The Buehler´s procedure was used to test the sensitisation potential of DMAMP via the topical route. During the induction period (initial 10 applications), the animals in the test group and in the positive control group showed mild skin reactions. When challenged with 0.25% of DMAMP, 2 of 10 animals in the test group showed skin reactions at the 48 h reading and 7 of 10 animals in the negative control group at 24 h as well as at 48 h after challenge exposure ended. A solution of 0.5% of DMAMP also caused skin reactions in more animals of the negative control group (6/ 10) than of the test group (1/10) at the 24 h scoring. At the second reading, repeatedly more animals of the negative control group (7/10) than of the test group (4/10) showed skin reactions. Taking into account that more animals of the negative control group of DMAMP than of the test group showed skin reactions at challenge, it is not possible to judge the skin sensitisation potential of DMAMP based on this study. However, the challenge with a 0.3% dinitrochlorobenzene (DNCB) solution, the positive control gave a valid response. At the first reading, 7 of 10 animals and at the second reading, 8 of 10 animals showed a clear sensitizing response. The challenge with 0.03% DNCB showed a decreased sensitising response: at 24 h (4/10 animals) and 48 hours (6/10 animals).

In general, the pH value of the DMAMP solution used in this study is not sated, however from skin irritation studies (Parekh, 1982) it is known that the pH of a 72% solution of DMAMP was 12.5. Due to the alkaline pH value of DMAMP and its skin corrosive potential, it is likely that the skin reactions observed could be attributed to irritation rather than sensitisation. Therefore, the skin sensitisation potential of DMAMP cannot be judged solely based on this study.

In the second study, the skin sensitisation potential of DMAMP was tested after intradermal injections (Parekh, 1982). During the induction phase, some of the animals in the test group showed skin reactions, but none of the animals in the negative control group. The animals in the positive control group showed mild to moderate skin reactions. When challenged with 0.01% of DMAMP, 1 of 10 animals in the test group showed skin reactions at 24 h and 2 of 10 animals in the negative control group, but none of the animals at the 48 h scoring. A solution of 0.1% of DMAMP did not lead to skin reactions in the test group and in the negative control group. At challenge with 0.03% dinitrochlorobenzene (DNCB) solution, the positive control gave a weak positive response (at 24 h: 4/10 animals and at 48 h: 5/10 animals). In the negative control group for DNCB, 2 of 10 animals showed skin reactions at the 24 h scoring. At the second scoring, no control animals were affected.

In conclusion, the study has some inconsistencies and deficiencies: At the 24 h scoring, only 1/10 animals in the test group (0.01% DMAMP) showed a skin reaction, but 2/10 animals in the negative control of DMAMP (0.01%) gave a positive response. Based on the alkaline pH of DMAMP and regarding that more animals of the negative control group of DMAMP than of the test group showed skin reactions at challenge, it is not possible to distinguish between a skin reaction caused by irritation or a skin reaction due to sensitization. The fact that one animal in the test group and 2 animals in the negative control group were affected at the first scoring but none animal at the second scoring could be attributed to skin irritation triggered by the application route (intradermal injections). Moreover, the lower concentration of 0.01% DMAMP led to skin reactions whereas a 0.1% solution of DMAMP did not affect the animals´ skin. DNCB (0.03%) caused skin reactions in only 4/10 animals at the first scoring and in 5/10 animals at the second scoring, indicating a weak positive response of the positive control substance. In the negative control group for DNCB, 2/10 animals showed skin reactions at the 24 h scoring. The reliability of the study is also devaluated by the fact that only 10 animals were used in the treatment groups. Taking into account all relevant data, it is not possible to judge the skin sensitisation potential of DMAMP based only on this study.

There are no further animal or human data available on the skin sensitising potential of DMAMP.

The modelling of potential metabolites via the OECD QSAR toolbox v.2.0 (2010) did not predict relevant metabolites of DMAMP. Based on the chemical structure of DMAMP, no metabolism is expected. Moreover, there is no evidence of chemically reactive properties of DMAMP under in-vitro test conditions. This is confirmed by studies on genetic toxicity in-vitro (Ames test, gene mutation in mammalian cells in-vitro, chromosome aberration in-vitro) which were all negative. By calculating the likelihood of interactions of DMAMP with skin proteins, no structural alerts were found (DR. KNOELL CONSULT, 2012). Therefore, no interactions of DMAMP with skin proteins are expected.

With respect to both skin sensitization studies there was no clear sensitising response using the Buehler´s procedure or the intradermal route. Due to the alkaline pH value of DMAMP and its skin corrosive properties, it is likely that the skin reactions observed could be attributed to irritation rather than sensitisation. But solely on the basis of the skin sensitisation studies, evaluation of the skin sensitisation potential of DMAMP is not possible. However, taking into consideration that all data generated via QSAR modelling did not predict relevant metabolites or interactions of DMAMP with skin proteins, there is no evidence for a skin sensitising potential of DMAMP. Therefore, it can be assumed that DMAMP is not a skin sensitiser.

Migrated from Short description of key information:

Based on the available studies and QSAR modelling of DMAMP, it can be assumed that DMAMP possesses no skin sensitisation potential.

Justification for selection of skin sensitisation endpoint:

There are two studies available on skin sensitisation. Both studies and QSAR modelling were used as part of a weight of evidence approach for the assessment of the skin sensitisation potential of the test substance.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

No data available.

Migrated from Short description of key information:

No data available.

Justification for classification or non-classification

Based on the weight of evidence of all available information on DMAMP, the available data on skin sensitisation do not meet the criteria for classification to Regulation (EC) 1272/2008 or Directive 67/548/EEC.