DL-2-aminopropan-1-ol

Endpoint summary

Description of key information

The substance was evaluated in three studies:

- a reduced LLNA, which cannot be used for classification (only one tested concentration and formation of scars may bias results and exclude the derivation of an EC3)

- a DPRA which was negative;

- a Keratinosens assay which was also negative.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

study performed before guideline was adopted

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 luciferase KeratinoSens™ test method)

Version / remarks:

study run before adoption of guideline

GLP compliance:

no

Remarks:

Close to GLP: Report signed by lead scientist, study director and technical reviewer, and includes all information and raw data.

Type of study:

ARE-Nrf2 luciferase KeratinoSens™ test method

Details of test system:

Keratinoses transgenic cell line [442D]

Details on the study design:

12 test concentrations from 0.98 to 2000 µM

Vehicle / solvent control:

DMSO

Positive control:

cinnamic aldehyde [442D]

Positive control results:

Keratinocytes exposed to CA exhibited dose dependent increase in luciferase activity on for each of the three replicates conducted on different days. The average EC1.5 (12.84 μM), maximum luciferase induction (4.39 fold) and cytotoxicity for CA were within the assay acceptable range. Similarly, average background variability for the three replicates was less than 9%, which was within the assay acceptance range. Based on these observations, all three replicates of the assay were considered acceptable.

Key result

Group:

test chemical

Parameter:

EC 1.5 [442D]

Remarks:

not determined: <1.5-fold luciferase induction at all test concentrations

Cell viability:

>90% at all test concentrations

Remarks on result:

no indication of skin sensitisation

Outcome of the prediction model:

negative [in vitro/in chemico]

Other effects / acceptance of results:

CA (positive control) was considered positive when the luciferase induction by CA was
statistically significant (by t-test) and above the threshold of 1.5 fold induction in at least
one dose level and cell viability at that dose was greater than 70%.

Maximum luciferase induction (Imax) and EC1.5 (test material concentration at which
luciferase induction is greater than 1.5 fold) was calculated for CA. The assay was
considered acceptable only if at least one of the two following criteria were fulfilled:
• Average luciferase induction in the three replicates for CA at 64 μM between 2 and 8.
• The EC1.5 was between 7.5 μM and 30 μM.

The average variability in the 6 solvent control wells of each of the three parallel test plates was calculated. The assay was considered acceptable only when the variability was below 20%.

Interpretation of results:

GHS criteria not met

Executive summary:

DL-Alaninol was evaluated for skin sensitization potential using the KeratinoSensTM assay. The assay uses a human keratinocyte cell line (HaCaT) in which activation of the Nrf2-ARE pathway is quantified via a luciferase reporter gene assay to assess chemical reactivity which is equated to sensitization potential. The test chemical was tested at twelve concentrations ranging from 1 to 2000 μM. A test chemical is considered positive for reactivity and sensitization potential when it induces luciferase activity greater than 1.5 fold with less than 30% cytotoxicity when compared to the solvent control.
In all independent replicates, the positive control compound, cinnamic aldehyde, was positive demonstrating appropriate assay conduct.

DL-alaninol was negative for reactivity in the KeratinoSensTM assay and is considered to lack skin sensitization potential.

Reference 2

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation Assays addressing the Adverse Outcome Pathway key event on covalent binding to proteins)

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Details of test system:

cysteine peptide, (Ac-RFAACAA-COOH)

lysine peptide (Ac-RFAAKAACOOH)

Details on the study design:

The Direct Peptide Reactivity Assay was used to assess the skin sensitization potential of the test article. Synthetic peptides containing cysteine or lysine were reacted with each test article for 24 ± 2 hours. After the incubation period, the extent of peptide depletion was analyzed using High Performance Liquid Chromatography (HPLC) coupled with ultra-violet (UV) spectrometric detection.

Vehicle / solvent:

acetonitrile

Positive control:

cinnamic aldehyde

Positive control results:

Mean Peptide Depletion (%): 71.41 for Cysteine, 62.87 for Lysine

Key result

Group:

test chemical

Parameter:

lysine depletion

Value:

3.39 %

At concentration:

100 mM

Positive controls validity:

valid

Key result

Group:

test chemical

Parameter:

cysteine depletion

Value:

3.71 %

At concentration:

100 mM

Positive controls validity:

valid

Outcome of the prediction model:

no or minimal reactivity [in chemico]

Other effects / acceptance of results:

The assay was accepted as the following criteria were met:

1) Each standard curve must have an r2 > 0.990 => criterion met
mean peptide concentration of reference controls A and C = 0.50 ± 0.05 mM => criterion met
peak area CV for reference controls B and C must be < 15% => criterion met

2) percent peptide depletion for cysteine peptide with positive control > 60.8% => criterion met
and SD for replicates < 14.9 => criterion met
percent peptide depletion for lysine peptide with positive control: 40.2 to 69% => criterion met
and SD for replicates < 11.6 => criterion met

3) SD of test substance replicates < 14.9% for cysteine depletion => criterion met
SD of test substance replicates <11.6% for lysine depletion => criterion met

Interpretation of results:

GHS criteria not met

Executive summary:

The test article, d,l-2-amino-1-propanol, was evaluated for skin sensitization potential using the Direct Peptide Reactivity Assay (DPRA) in 1 definitive trial.

The % peptide depletion was 3.71% (Cysteine) and 3.39% (Lysine). Based on these results, d,l-2-amino-1-propanol was predicted to be a non-sensitizer.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Justification for classification or non-classification

The substance is considered non-sensitizing based on results of two in vitro/in chemico studies. The third study, a reduced LLNA method, cannot be used for classification.