6-methylhept-5-en-2-one

Endpoint summary

Description of key information

Skin sensitisation (non-guideline study OET): not sensitizing

Skin sensitisation (non-guideline study Modified Draize ): not sensitizing

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The results were taken from a review which discusses the Freund's Complete Adjuvant Test and the Open Epicutaneous Test. Data for about 300 fragrance raw materials were presented in tabular form.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Open epicutaneous test:
1. Pretest: establishing the primary irritating threshold concentration of the test substance
2. Main study:induction phase: a 3-week period of daily open applications of the test material usually to the same skin site (21 applications)challenge phase: induced and control animals are tested on day 21 and day 35 by topical application of the test substance if sensitisation has occurred

GLP compliance:

no

Remarks:

pre GLP

Type of study:

open epicutaneous test

Justification for non-LLNA method:

Existing OET of good quality that was generated before 11 October 2016.

Species:

guinea pig

Strain:

not specified

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 300 - 450g
- Diet: ad libitum
- Water: ad libitum

Route:

epicutaneous, open

Vehicle:

other: not specified for methyl heptenone

Concentration / amount:

Pretest: 1; 3; 10; 30; 100 %; not specified for methyl heptenoneInduction: 0.3; 1; 3; 10; 30; 100%; not specified for methyl heptenone

Day(s)/duration:

20 days

Route:

epicutaneous, open

Vehicle:

other: not specified for methyl heptenone

Concentration / amount:

Challenge: min. irritating concentration and three 3-fold serial dilutions (3% for methyl heptenone)

Day(s)/duration:

2 exposures, on days 21 and 35. The reactions are read after 24,48 and/or 72h

No. of animals per dose:

Pretest: 6-8 animals; Main study: 6-8 animals per dose in the main study; control: 10 animals

Details on study design:

Threshold irritation concentration:
- No. of exposures: 1
- Exposure period: 24 hours
- Control group: vehicle or negative control
- Site: clipped flank

MAIN STUDY

A. INDUCTION EXPOSURE
- No. of exposures: 21
- Control group: no pretreatment or vehicle (not specified for methyl heptenone)
- Site: clipped flank- Duration: 3 weeks
- Frequency of applications: daily

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: 21, 35
- Site: clipped flank
- Evaluation (hr after challenge): 24, 48, 72

Challenge controls:

4 dilutions containing the minimal-irritant and maximal-non irritant concentration in non-pretreated or 21-day vehicle pretreated animals (no further data given)

Positive control substance(s):

not specified

Reading:

other: all readings

Hours after challenge:

24

Group:

test chemical

Dose level:

3%

No. with + reactions:

0

Total no. in group:

8

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Reading:

other: all readings

Group:

negative control

Dose level:

0

Total no. in group:

10

Clinical observations:

none specified

Remarks on result:

other: control result not specified

Group:

positive control

Remarks on result:

not measured/tested

methyl heptenone was negative in the OET in guinea pigs.  

Interpretation of results:

other: not classified

Remarks:

based on CLP criteria

Conclusions:

Under the conditions of this study, the substance was not found to be sensitising. Based on this result, Methylheptenone does not need to be classified as skin sensitiser in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Executive summary:

Male and female guinea pigs, weighing 300-450g, were used in experimental groups of at least 6 guinea pigs for every concentration group. For controls 10 animals were used. Methylheptenone is applied epicutaneously, uncovered, undiluted and at concentrations of 30, 10, 3 and 1% or lower in a suitable vehicle. Constant volumes of each concentration were applied with a pipette or syringe on standard sites of the clipped flank of each animal. 1 day before starting the induction procedure, the threshold irritating concentration of methylheptenone was estimated on the guinea pigs subsequently used for the experimental group. A single application of 0.025 ml of each test concentration (e.g, 100,30,10 and 3%) was simultaneously performed on one of the sites measuring 2 cm2 of the flank skin previously clipped and marked with a circular stamp. Reactions were read 24 h after the application of the test material.

 

On day 1application of 0.1 ml of methylheptenone is performed to an site measuring 8 cm2 on the clipped flank skin of the guinea pigs. The applications were repeated daily for 3 weeks or done 5 times weekly during 4 weeks, usually on the same skin sites. The application sites were left uncovered and the reactions, if continuous daily applications were performed, were read 24 h after each application, or at the end of each week.

 

To determine whether or not contact sensitization was induced, all groups of guinea pigs previously treated for 21 days as described above, as well as 10 untreated, or only pretreated with the vehicle, controls were tested on days 21 and 35 on the contralateral flank with methylheptenone at the minimal irritating and some lower primary nonirritating concentrations. These tests were performed by applying with a pipette 0.025 ml of each concentration to skin sites measuring 2 cm2. The reactions were read after 24,48 and/or 72h. Methyl heptenone was negative in this OET in guinea pigs.  Based on this result, Methylheptenone does not need to be classified as skin sensitiser in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The results were taken from a publication which reports modified Draize procedure. Data for 23 natural and 46 synthetic perfume ingredients were presented in tabular form.

Qualifier:

no guideline followed

Principles of method if other than guideline:

For each test material preliminary irritation tests were done in guinea pigs to determine concentrations suitable for sensitization testing. Guinea pigs were then treated by intradermal injection to induce sensitization and challenged 2 weeks later by both intradermal injection and topical application. When there was no evidence of sensitization the induction and challenge procedures were repeated.
The method is modified from Draize. In the Draize test sensitization is induced by 10 intradermal injections of test material at the ICC given over a 3 week period, whereas in this modified method the equivalent total dose was administered on one occasion as 4 intradermal injections, each 2.5 times the injection challenge concentration.

GLP compliance:

no

Remarks:

pre-GLP

Type of study:

Draize test

Justification for non-LLNA method:

Existing Modified Draize test of good quality that was generated before 11 October 2016.

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Random samples from commercial batches
- Testing: samples passed quality control checks for odour and, in some cases, gas liquid chromatography to identify major components.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: aliquots were made of a range of concentrations of tests material in a suitable solvent
- Final preparation of a solid: injection challenge concentration (ICC) 0,1%, application challenge concentration (ACC) 20%

Species:

guinea pig

Strain:

Hartley

Remarks:

Inbred Hartley strain albino guinea pigs

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Bred in own colony.
- Females: not specified
- Weight at study initiation: approx. 350 g
- Housing: wire mesh cages in pairs of the same sex
- Diet (e.g. ad libitum): pelleted guinea pig diet, cabbage, hay ad libitum
- Water (e.g. ad libitum): ad libitum

Route:

intradermal

Vehicle:

not specified

Concentration / amount:

2.5 times the ICC 0,1%: 0.25% Methylheptenone
injected intradermally at 4 sites

Day(s)/duration:

14 days

Adequacy of induction:

other: The concentration giving slight but perceptible irritation with no oedema was selected as the injection challenge concentration (ICC).

Route:

intradermal and epicutaneous

Vehicle:

not specified

Concentration / amount:

0.1 ml aliquots of test substance
Intradermal 0,1% Methylheptenone
Epicutaneous 20% Methylheptenone

Day(s)/duration:

examination at 24 hours

No. of animals per dose:

10

Details on study design:

RANGE FINDING TESTS:
Four animals of the same sex and weighing about 450 g were each injected intradermally on the shaved flanks with 0.1 ml aliquots of a range of concentrations of tests material in a suitable solvent. The reactions were examined for size (two largest diameters), erythema and oedema 24 h later and the concentration giving slight but perceptible irri-tation with no oedema was selected as the injection challenge concentration (ICC). Topical application. Aliquots (0.1 ml) of a range of concentrations of test substance in a suitable solvent were applied in small circular areas to the shaved flanks of 4 guinea pigs of the same sex and weighing about 450 g. The reactions were examined for erythema 24 h later and the highest concentration which caused no irritation was selected as the application challenge concentration (ACC).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: one occasion as 4 intradermal injections
- Exposure period: 1 occasion, after which 14 days of induction time before challenge
- Site: 4 sites which overlie the 2 auxillary and 2 inguinal lymph nodes
- Frequency of applications: 1 occasion
- Concentrations: 2.5 times the ICC = 0.25% methylheptenone

B. CHALLENGE EXPOSURE
- No. of exposures: 2 exposures intradermally and epicutaneous, if no sensitisation occures a follow up induction and challenge incl. control substance was performed
- Day(s) of challenge: challenge 1 at Day 14. If positive after 1st challenge: rechallenge 2 at day 21. If negative after 1st challenge: re-induction on day 21, challenge on day 35 and rechallenge on day 42.
- Site: both flanks (one flank intradermal other topical)
- Concentrations: injection challenge concentration 0.1%, application challenge concentration 20%
- Evaluation (hr after challenge): 24h

SCORING: Reactions were examined under a Philips colour-matching unit with 3 Philips 40 W Actinic Blue 05 fluorescent tubes and 3 Philips 40 W White 35 fluorescent tubes. Each injection reaction was given a total score based on size (2 largest diameters), erythema and oedema. Individual reactions were considered positive when their total score was significantly greater than the average total score for control reactions. Application reactions were scored on a 0 to +++ scale and individual reactions were considered positive if (a) they were + or greater and (b) there were no erythema reactions in controls.

Challenge controls:

At each challenge with controls, 4 previously untreated animals of the same sex and similar weight to the test animals were treated intradermally and topically on opposite flanks with 0.1 ml aliquots of test substance at the ICC and ACC respectively.

Positive control substance(s):

no

Reading:

other: all readings

Hours after challenge:

24

Group:

test chemical

Dose level:

ICC (0.1%) and ACC (20%)

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Group:

positive control

Remarks on result:

not measured/tested

Group:

negative control

Dose level:

0

Remarks on result:

not measured/tested

Interpretation of results:

other: not classified

Remarks:

based on CLP criteria

Conclusions:

Under the conditions of this study, the substance was not found to be sensitising. Based on this result, Methylheptenone does not need to be classified as skin sensitiser in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Executive summary:

A modified Draize procedure was used to test methylheptenone for its potential to induce allergic contact dermatitis in guinea pigs. Preliminary irritation tests were done in guinea pigs to determine concentrations suitable for sensitization testing. Four animals of the same sex and weighing about 450 g were each injected intradermally on the shaved flanks. The reactions were examined for size (two largest diameters), erythema and oedema 24 h later and the concentration giving slight but perceptible irritation with no oedema was selected as the injection challenge concentration (ICC 0.1% methylheptenone). Furthermore, Aliquots (0.1 ml) of a range of concentrations of test substance in a suitable solvent were applied in small circular areas to the shaved flanks of 4 guinea pigs of the same sex and weighing about 450 g. The reactions were examined for erythema 24 h later and the highest concentration which caused no irritation was selected as the application challenge concentration (ACC 20% methylheptenone).

 Guinea pigs were then treated by 4 intradermal injections on 4 sites which overlie the 2 auxillary and 2 inguinal lymph node. The concentration used was 0.25% methylheptenone to induce sensitization and the animals were challenged 2 weeks later by both intradermal injection and topical application (injection challenge concentration 0.1%, application challenge concentration 20% methylheptenone). When there was no evidence of sensitization the induction and challenge procedures were repeated. Methylheptenone did not induce sensitization in this modified Draize testing procedure, and was therefore considered a non-sensitizer. Based on this result, Methylheptenone does not need to be classified as skin sensitiser in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Two in vivo studies are available which examined the skin sensitisation potential of methylheptenone. In the study by Klecak et al. 1985, the Freund's Complete Adjuvant Test and the Open Epicutaneous Test were performed. Data for about 300 fragrance raw materials were presented in tabular form, methylheptenone was found non-sensitising. Furthermore, in the study by Sharp et al. 1978 a modified Draize procedure was reported in which data for 23 natural and 46 synthetic perfume ingredients were presented in tabular form, here methylheptenone was also found non-sensitising.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the WoE presented by the available data, methylheptenone does not need to be classified for skin sensitisation in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).