N-hexane

Endpoint summary

Description of key information

Based on available data (Local Lymph Node Assay (OECD TG 429)), n-hexane is not considered to be a skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because there was no GLP statement provided, and limited data on methods were reported, but the study seemed to be well-conducted.

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

no

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

not specified

Sex:

not specified

Vehicle:

acetone/olive oil (4:1 v/v)

Statistics:

Results were given in terms of the EC3 value, the concentration of the substance which is expected to cause a 3-fold increase in proliferative activity. EC3 values were determined based on results of previous LLNA tests for the test substance.

Key result

Parameter:

EC3

Test group / Remarks:

Test substance (100%)

Remarks on result:

other: EC3 > 100%

Parameter:

SI

Test group / Remarks:

Test Concentration 1

Remarks on result:

not measured/tested

Remarks:

Results of previous LLNA experiments were used to calculate the EC3 value

Parameter:

SI

Test group / Remarks:

Test Concentration 2

Remarks on result:

not measured/tested

Remarks:

Results of previous LLNA experiments were used to calculate the EC3 value

Parameter:

SI

Test group / Remarks:

Test Concentration 3

Remarks on result:

not measured/tested

Remarks:

Results of previous LLNA experiments were used to calculate the EC3 value

Interpretation of results:

not sensitising

Conclusions:

Concentrations of up to 100% of test substance are not expected to be sensitizing.

Executive summary:

This study was done to determine the concentration of hexane that would be expected to cause sensitization in humans. Results of previous LLNA experiments were used to calculate the EC3 value, the concentration at which the test substance would produce a 3 -fold increase in the proliferative activity of lymph nodes in the LLNA test. The 3 -fold increase is considered a positive response for sensitization in the LLNA test. The EC3 value for hexane was determined to be > 100% concentration. The test substance is therefore not sensitizing.

Reference 2

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin sensitisation study does not need to be conducted because adequate data from an in vivo skin sensitisation study are available

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation data is available for n-hexane.

 

n-hexane

In a key sensitisation study (Basketter et al., 2000), a local lymph node assay (LLNA) was done to determine the concentration of hexane that would be expected to cause sensitisation in humans. Results of previous LLNA experiments were used to calculate the EC3 value, the concentration at which the test substance would produce a 3 -fold increase in the proliferative activity of lymph nodes in the LLNA test. The 3 -fold increase is considered a positive response for sensitization in the LLNA test. The EC3 value for hexane was determined to be > 100% concentration. The test substance is therefore not sensitising.

 

Results of previous LLNA tests on various tests substances were used to validate a new QSAR model for predicting the skin sensitisation potential of chemicals (Fedorowicz et al., 2004). The model predicted that hexane is not sensitising, which is in accordance with previous LLNA studies of hexane which have shown it is not sensitising.

 

Human Data

n-hexane

A study (Kligman, 1966) examined the skin sensitisation potential of hexane. 1.0 ml of test substance was placed on the extremities of 25 male volunteers, and covered occlusively. The induction patches were left in place for 48 hrs. After a 24 hr interval, the exposure was repeated for another 48 hrs. This was done for a total of 5 exposures. A challenge exposure was then done using a 25% concentration of test substance. The challenge exposure was 48 hrs. No irritation was seen in any of the test subjects. The test substance is not sensitising.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available (further information necessary)

Additional information:

There are no reports of respiratory sensitisation from n-hexane in laboratory animals or in humans. However, the skin sensitisation study found no indication of skin sensitisation in the local lymph node assay.  With these observations, it is presumed that n-hexane will not be a respiratory sensitising agent.

Justification for classification or non-classification

Based on available data, n-hexane does not meet the criteria for classification as a skin or respiratory sensitiser under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).