Ethanone, 1-(4-methoxyphenyl)-2-[(3-methoxyphenyl)thio]-

Specific investigations: other studies

Administrative data

Endpoint:

specific investigations: other studies

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jun to Oct 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: EEC / OECD guideline, GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: Method B42 of Commission Directive 2004/73/EC

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD Guidelines for Testing of chemicals, method 429 (adopted 24 April 2002

GLP compliance:

yes

Type of method:

in vivo

Endpoint addressed:

skin sensitisation

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

469-300-0

EC Name:

-

Cas Number:

63675-73-0

Molecular formula:

Hill Empirical Formula: C16H16O3S CAS Empirical Formula: C16H16O3S

IUPAC Name:

1-(4-methoxyphenyl)-2-[(3-methoxyphenyl)sulfanyl]ethan-1-one

Test material form:

solid: particulate/powder

Details on test material:

Lot no: 151105Purity - 101.39%

Test animals

Species:

mouse

Strain:

other: CBA/CaCrl

Sex:

female

Details on test animals or test system and environmental conditions:

Nulliparous, non-pregnant female mice of the CBA/CaCrl strain were obtained from Charles River (UK) Ltd, Margate. All animals were given a clinical inspection for ill health on arrival and a sample was weighed.A preliminary screening test was performed with one mouse. The mouse was treated by daily application of 25 µL of the test article at the maximum suitable concentration (50% w/v in DMF) to the dorsal surface of each ear for three consecutive days (Days I, 2 and 3). The mouse was observed daily for five days from the initiation of treatment. Any signs of toxicity or irritation during this period were recorded. The body weight was recorded on Day -1. The animal was killed by exposure to a rising concentration or carbon dioxide at the end of the observation period.

Administration / exposure

Route of administration:

dermal

Vehicle:

other: Dimethylformamide

Details on exposure:

The outer aspect of both pinnae of each mouse was treated by direct application of the appropriate test or control formulnt1on (0 025 mJJpinna) dispensed from an automatic micropipette.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

3 days

Frequency of treatment:

once per day

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

10 other: % w/v

Doses / concentrations 2

Dose / conc.:

25 other: % w/v

Doses / concentrations 3

Dose / conc.:

50 other: %w/v

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

A preliminary screening test was performed with one mouse. The mouse was treated by daily application of 25 µL of the test article at the maximum suitable concentration (50% w/v in DMF) to the dorsal surface of each ear for three consecutive days (Days I, 2 and 3). The mouse was observed daily for five days from the initiation of treatment. Any signs of toxicity or irritation during this period were recorded. The body weight was recorded on Day -1. The animal was killed by exposure to a rising concentration or carbon dioxide at the end of the observation period.Groups or five female mice were assigned to study according to table 1 below. . Doses were selected from the concentration series 100%, 50%, 25%, 10%, 5%, 2.5%, 1.0%, 0.5% etc. Three consecutive concentrations were selected on the basis of the preliminary screening test so that the highest concentration maximised exposure whilst avoiding systemic toxicity and excessive local irritation. Mice were arbitrarily selected from the delivery boxes and allocated to the appropriate number of cages. The condition of the animals was assessed daily throughout the acclimatisation period or 22 days. A second inspection was performed prior to study commencement 10 ensure the animals were suitable for the study. Overtly healthy animals were arbitrarily allocated to the study groups on the day prior 10 commencement or treatment. A unique number inscribed onto the tail with indelible ink on the day prior to dosing individually identified the mice. A colour-coded card on each cage gave information including study number, animal number and sex.

Examinations

Examinations:

Treated mice were observed twice daily on Days 1 to 5 and once on Day 6 for clinical signs of reaction to treatment or for irritation or other changes at the sites of application of the test article.Auricular lymph nodes were removed on day 6, five hours after injecting a 20uCi dose of tritiated 3H-methyl thymidine intravenously into each mouse. The pairs of nodes from each animal were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/v trichloroacetic acid and processed through a scintillation counter.

Positive control:

25% alpha-Hexylcinnamaldehyde

Results and discussion

Details on results:

In the preliminary screening test, the animal survived and no signs of systemic toxicity or excessive irritation were noted. Based on this information the dose levels selected for the main test were 10%, 25% and 50% w/v in DMF.In the main test, all animals survived treatment with the test article.There were no clinical signs indicative of a systemic effect of treatment among mice treated with the vehicle or with 10, 25 or 50% w/v formulations of the test article. The vehicle control and test formulation application sites remained free of irritation. White residue to the tips of the ears was noted in animals dosed with the test article at a concentration of 50% w/v in DMF. This was noted on all days except Day 2.Wet fur around the ears was noted in the positive control animals on Day I. Greasy fur around the head and redness of the ears was noted from Day 2 to Day 4 with greasy fur around the head and neck on Days 5 and 6.There was no indication of a treatment-related effect on body weight.Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation counts obtained from the test groups relative to the corresponding mean scintillation count obtained from controls. see table 2 below.The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

Any other information on results incl. tables

Table 2

	Concentration of test article in applied formulation (%w/v)
	10%	25%	50%
Stimulation Index	0.73	0.54	0.37

Applicant's summary and conclusion

Conclusions:

The Local Lymph Node Assay demonstrated that the test anicle does not have the potential to cause skin sensitisation.The test article did not meet the criteria for classification as a sensitiser according to EU labelling regulations Commission Directive 2001/59/EC. No symbol and risk phrase are required.

Executive summary:

This study was conducted toassess the potential of the test article of the test article, to cause skin sensitisation in the mouse.Following a preliminary screening test using a 50%w/v formulation, the test article was prepared for administration at 10, 25 and 50 w/v in dimethylformamide. Groups of five female CBAICa mice were subjected to topical applications of vehicle or of one of the test formulations to the outer aspect of the auditory pinnae once daily on Days 1, 2 and 3. On Day6 a 20µCi dose of tritiated 3H·methylthymidine was injected intravenously into each mouse. Five hours later the auricular lymph nodes were recovered from each animal. The pairs of nodes from each animal were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/v trichloroacetic acid and processed through  a scintillation counter.

 

Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation counts obtained from the test groups relative to the corresponding mean scintillation count obtained from controls The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0. The simulation index for test was measure to be 0.73 for 10% concentration (%w/v), 0.54 for 25% and 0.37 for 50%

The  Local  Lymph Node Assay demonstrated that the test article does not have the potential to cause skin sensitisation.

The test article did not meet the criteria for classification as a sensitiser according to EU labelling regulations Commission Directive 2001/59/EC.No symbol and risk phrase are required.