Cyclopentanone

Endpoint summary

Description of key information

Two studies were available on cylopentanone and had the reliability 2 according to Klimisch rating. One of them was selected as key study

(Nunziata A, 1999

Cyclopentanone was not sensitizing for skin in maximization tests on guinea pig.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The test substance purity was known. The screening protocol was well described even if GLP were not validated.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

only 5 animals were used in the treatment group

Principles of method if other than guideline:

Method: other: screening protocol similar to OECD guide-line 406 "skin sensitisation"

GLP compliance:

no

Remarks:

screening test

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

In vivo test was made in 1999 before the in vitro test strategies.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

- Source: Harlan Nossan S.r.l., Italy
No more data

Route:

intradermal and epicutaneous

Vehicle:

polyethylene glycol

Concentration / amount:

Induction: 5% in PEG 200 (injection) and 100% (topical)
Challenge: 100 % (first challenge), 20 % in PEG 200 (second challenge)

Route:

epicutaneous, open

Vehicle:

polyethylene glycol

Concentration / amount:

Induction: 5% in PEG 200 (injection) and 100% (topical)
Challenge: 100 % (first challenge), 20 % in PEG 200 (second challenge)

No. of animals per dose:

5

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- type of epicutaneous induction: data not available
- SLS application: yes (concentration unknown)
- Exposure period: day 1 (intradermal) and day 8 (epicutaneous)
- Test groups: In an attempt to induce sensitisation, test animals were intradermally injected with an emulsion of Freund's complete adjuvant and the test substance in both the selected vehicle and an emulsion of Freund's complete adjuvant. One week later this was boosted by topical application of the test substance over the injection sites which had been pre-treated with sodium lauryl sulphate to promote an irritant reaction.
- Control group: animals were treated in the same manner but the selected vehicle was used in place of the test substance.
- Site: data not available
- Frequency of applications: on days 1 and 8
- Duration: 8 days
- Concentrations: 5% in PEG 200 (injection) and 100% (topical)

- Rest period: 2 weeks (after the second stage of induction)

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: 2 and 3 weeks after the second stage of induction
- Exposure period: data not available
- Test groups: both the vehicle and the test substance
- Control group: both the vehicle and the test substance
- Site: data not available
- Concentrations: 100 % (first challenge), 20 % in PEG 200 (second challenge)
- Evaluation: 24 and 48 h after challenge

Challenge controls:

no data

Positive control substance(s):

no

Group:

test chemical

Remarks on result:

other: The test substance did not elicite a sensitisation response in the Guinea  pig, there was no evidence of reaction at challenge following a period of   induction exposure to cyclopentanone.

Group:

positive control

Remarks on result:

not measured/tested

Group:

negative control

Remarks on result:

no indication of skin sensitisation

Table 1: Results

1st CHALLENGE			2nd CHALLENGE
Control Group			Control Group
Animal	Reaction at challenge		Animal	Reaction at challenge
Number	24 Hours	48 Hours	Number	24 Hours	48 Hours
423	0	0	423	0	0
425	0	0	425	0	0
427	1	0c	427	0	0
Test Group			Test Group
Animal	Reaction at challenge		Animal	Reaction at challenge
Number	24 Hours	48 Hours	Number	24 Hours	48 Hours
429	0	0	429	0	0
431	1	1	431	0	0
433	0	0	433	0	0
435	1	0c	435	0	0
437	1	1	437	0	0
c = Yellow colouration of skin

The test substance did not elicite a sensitisation response in the Guinea  pig, there was no evidence of reaction at challenge following a period of  

induction exposure to cyclopentanone.

Interpretation of results:

GHS criteria not met

Conclusions:

The test substance did not elicite a sensitisation response in the Guinea  pig, there was no evidence of reaction at challenge following a period of  
induction exposure to cyclopentanone.

Executive summary:

In a dermal sensitization study (Nunziata A, 1999) with cyclopentanone (99.8% purity) in PEG 200, Dunkin-Hartley guinea pigs (5 in the test group, 3 in the control group) were tested using the method of maximization.
In an attempt to induce sensitisation, test animals were intradermally injected with an emulsion of Freund's complete adjuvant and the test substance in both the selected vehicle and an emulsion of  Freund's complete adjuvant. One week later this was boosted by topical application of the test substance over the injection sites which had been pre-treated with sodium lauryl sulphate to promote an irritant reaction. Control group animals were treated in the same manner but the selected vehicle was used in place of the test substance. Two weeks after the second induction stage, all animals were challenged by topical application of both the vehicle and the test substance. Irritation to the test substance was noted and challenge was repeated 1 week later using the test substance at a lower concentration.
The results indicate that the test substance does not elicit a sensitisation response in the guinea pig, there being no evidence of reaction at challenge following a period of induction exposure to the substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Two studies were available and had the reliability 2 according to Klimisch rating. One of them was selected as key study, and the other one as supporting study. In these studies Cyclopentanone was not sensitizing in maximization tests on guinea pig.

The summary of the key study is the following: In a dermal sensitization study (Nunziata A, 1999) with cyclopentanone (99.8% purity) in PEG 200, Dunkin-Hartley guinea pigs (5 in the test group,3 in the control group) were tested using the method of maximization. In an attempt to induce sensitisation, test animals were intradermally injected with an emulsion of Freund's complete adjuvant and the test substance in both the selected vehicle and an emulsion of Freund's complete adjuvant. One week later this was boosted by topical application of the test substance over the injection sites which had been pre-treated with sodium lauryl sulphate to promote an irritant reaction. Control group animals were treated in the same manner but the selected vehicle was used in place of the test substance. Two weeks after the second induction stage, all animals were challenged by topical application of both the vehicle and the test substance. Irritation to the test substance was noted and challenge was repeated 1 week later using the test substance at a lower concentration.

The results indicate that the test substance does not elicit a sensitisation response in the guinea pig, there being no evidence of reaction at challenge following a period of induction exposure to the substance.

Based on these two studies with reliability 2, Cyclopentanone was not classified as skin sensitizer.

Migrated from Short description of key information:
Cyclopentanone is not sensitizing in maximization tests.

Justification for classification or non-classification

Based on two maximisation tests, cyclopentanone is not considered as a skin sensitizer.