Cyclohexanone oxime

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study according to guideline, limited documentation

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan (Horst, The Netherlands) or Scanbur (Sollentuna, Sveden)
- Age at study initiation: 8 weeks

Vehicle:

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

Concentration:

0, 0.1, 1, 5, 10 or 20%

No. of animals per dose:

3-4

Details on study design:

- Quantitative criteria used to consider a positive response: EC3 < 0.1 extreme; >=0.1-<1: strong; >=1-<10 moderate;>=10-100: weak

TREATMENT PREPARATION AND ADMINISTRATION:
Mice received 25 μL of the test compound dissolved in vehicle on the dorsum of the ears daily for three consecutive days. Control animals were treated in the same way with vehicle. Mice were injected intravenously five days after the first treatment with 20 μCi of [3H]thymidine in 250 μL of phosphate-buffered saline. Five hours later, draining auricular lymph nodes were excised and pooled for each group. A single cell suspension of lymph node cells was prepared. The thymidine incorporation was measured by scintillation counting.
Results are expressed as mean dpm/lymph node for each experimental group and as stimulation index (SI), that is, test group/control group ratio.

Positive control substance(s):

not specified

Statistics:

EC3 values (concentration required to induce a stimulation index (SI) of 3) were calculated with linear interpolation

Positive control results:

Other test substances produced SI up to 11.3 can therefore be considered as valid positive controls

Parameter:

SI

Remarks on result:

other: Conc. SI [% w/v) Control: - 0.1: 0.96 1: 0.90 5: 0.77 10: 1.17 20 0.84

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Conc. dpm [% w/v) Control: 1081 0.1: 1036 1: 978 5: 828 10: 1260 20 906

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study the test substance was not sensitising

Executive summary:

Female mice (3-4 per dose group) received the test item on the dorsum of the ears daily for three consecutive days in concentrations of 0, 0.1, 1, 5, 10 or 20% in acetone/olive oil (4:1) vehicle. Five days later the animals were injected i.v. with 20 µCi 3H-thymidine in 250 µL phosphate buffered saline. The auricular lymph nodes were excised 5 h later and pooled from each group. The prepared cell suspension (one per dose group) was measured by scintillation counting. Dpm/lymph nodes were determined and the stimulation index (SI) compared to controls as well as the effect concentration producing a 3 -fold increase in SI (EC3) were calculated. The test substance produced SI between 0.77 and 1.17, resulting in an EC3 > 20%. According to the evaluation score of the authors they described the test item as weak sensitiser. Based on the guideline scoring scheme (SI >=3: positive) it is not considered to be a sensitiser. No data are given for a positive control, but other test substances produced SI up to 11.3, what is considered to be a positive response, indicating the validity of the test.

Therefore under the conditions of this study the test substance was not sensitising

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There is one LLNA assay available to assess the sensitising properties of CHO (guideline study, RL2). The test substance produced SI between 0.77 and 1.17, resulting in an EC3 > 20%. According to the evaluation score of the authors they described the test item as weak sensitiser. Based on the guideline scoring scheme (SI >=3: positive) it is not considered to be a sensitiser.

Migrated from Short description of key information:
A reliable local lymph node assay (LLNA) according to guideline revealed cyclohexanone oxime (CHO) as not sensitising.

Justification for selection of skin sensitisation endpoint:
only reliable study available (Klimisch 2)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the findings of a guideline study CHO has not to be classified for sensitisation according to Regulation (EC) No 1272/2008 and Council Directive 67/548/EEC.