Chlorbutanol

Skin sensitisation

Administrative data

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

Version / remarks:

Due to a HPLC error causing a delayed start of the sequence, the calibration sam-ples had to be moved from the beginning to the end of the analysis sequence to ensure measurement of the peptide samples in a timely manner. The deviation was assessed and signed by the study director on 30. Jan. 2018.

Deviations:

yes

Remarks:

see remarks

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Cas Number:

6001-64-5

Molecular formula:

C4H7Cl3O H2O

IUPAC Name:

1,1,1-trichloro-2-methyl-2-propanol hemihydrate

Test material form:

solid: crystalline

Details on test material:

transparent and crystalline solid at ambient temperature

In vitro test system

Details on the study design:

The direct peptide reactivity assay (DPRA) is an in chemico assay to quantify the reactivity of the test item towards cysteine and lysine containing peptides. This reactivity is related to the skin sensitisation potential. This study was performed in order to estimate the skin sensitisation potential of Chlorobutanol Hemihydrate using a peptide model. To quantify the sensitisation potential, the depletion of the cysteine and lysine containing peptides caused by known amounts of the test item was measured using HPLC. The assay was used for supporting the discrimination between skin sensitizers (i.e. UN GHS Category 1) and non-sensitizers in accordance with the UN GHS. A categorization in the sub-categories 1 A and 1 B is not possible.

Results and discussion

In vitro / in chemico

Results

Results 1

Run / experiment:

other: Cysteine

Parameter:

other: Cys-peptide depletion [%]

Value:

2.77

Vehicle controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Results 2

Run / experiment:

other: Lysine

Parameter:

other: Lys-Peptide depletion [%]

Value:

1.75

Vehicle controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Results 3

Key result

Run / experiment:

other: mean (Cysteine and Lysine)

Parameter:

other: Mean peptide depletion [%]

Value:

2.26

Vehicle controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Table: Calculated peptide depletion values for the Lys-Peptide

Sample name	Depletion [%]
	Single	Mean	Standard Deviation
Positive control Rep. 1	28.07	34.12	8.69
Positive control Rep. 2	30.21
Positive control Rep. 3	44.08
Test item Rep. 1	0.00	1.75	3.04
Test item Rep. 2	0.00
Test item Rep. 3	5.26

 

Table: Calculated peptide depletion values for the Cys-Peptide

Sample name	Depletion [%]
	Single	Mean	Standard Deviation
Positive control Rep. 1	83.72	84.28	0.75
Positive control Rep. 2	85.13
Positive control Rep. 3	83.99
Test item Rep. 1	0.00	2.77	2.43
Test item Rep. 2	3.75
Test item Rep. 3	4.54

 

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

All acceptance criteria were fulfilled, therefore the test was considered valid. The DPRA prediction for the test item Chlorobutanol Hemihydrate was negative with reactivity class minimal according to the Cysteine 1:10/Lysine 1:50 prediction model.
No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Executive summary:

The study was performed in order to evaluate the reactivity of the test item Chlorobutanol Hemihydrate towards cysteine (Cys-) and lysine (Lys-) containing peptides. A 100 mM test item in acetonitrile was incubated 24 ± 2 h at 25 °C together with cysteine and lysine peptides, respectively, and the peptide concentration after the incubation was measured using HPLC-UV.

Three replicates were prepared using 1:10 and 1:50 molar ratio of the test item with the Cys- and Lys-peptide, respectively. Triplicate samples of the solvent without test item were incubated and measured in parallel. The peptide depletion values after incubation are: 

Cys-peptide depletion [%]	Lys-Peptide depletion [%]	Mean peptide depletion [%]
2.77	1.75	2.26

 According to the cysteine 1:10/lysine 1:50 prediction model, the DPRA predicition is “negative” with minimal reactivity.