Lactofen

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Principles of method if other than guideline:

The modified Local Lymph Node Assay (IMDS) was performed on 24 female NMRI mice of the strain Crl:NMRI BR (6 animals/test item group and 6 control animals) to determine if there is any specific (sensitizing) or non-specific (irritant) stimulating potential of the test item Lactofen.

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

(2-ethoxy-1-methyl-2-oxoethyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate

EC Number:

616-466-9

Cas Number:

77501-63-4

Molecular formula:

C19H15ClF3NO7

IUPAC Name:

(2-ethoxy-1-methyl-2-oxoethyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate

Test material form:

other: liquid

Details on test material:

Test item: Lactofen
CAS No.: 77501-63-4
Chemical name: (2-ethoxy-1-methyl-2-oxoethyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate
Content: 95.54%
Empirical formula: C19H15ClF3NO7
Molecular mass: 461.8 g/mol
Physical state: liquid (at arrival)
Appearance: brown
Storage: room temperature

In vivo test system

Test animals

Species:

mouse

Strain:

NMRI

Sex:

female

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

Group 1 Vehicle (A/OO = acetone/olive oil)
Group 2 2 % Lactofen (in A/OO)
Group 3 10 % Lactofen (in A/OO)
Group 4 50 % Lactofen (in A/OO)
Group 5 3, 10, 30 % Alpha Hexyl Cinnamic Aldehyde (in A/OO)

No. of animals per dose:

6 animals/test item group and 6 control animals

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

A modified Local Lymph Node Assay (IMDS) was carried out in mice. The modifications refer to the measurement of cell proliferation by cell counting instead of radioactive labeling. In addition, the acute inflammatory skin reaction is determined to discriminate specific from non-specific activation of immune competent cells in the draining lymph nodes, as also recommend in the update of OECD TG 429. Direct LLNA (NMRI mice, female, 6 animals/group) Dose [%] Weight index Cell count index (index of mean +/-SD in %) 0 1.00 +/- 13.85 1.00 +/- 22.34 2 0.88 +/- 24.90 1.06 +/- 25.06 10 1.18 +/- 21.42 1.07 +/- 24.80 50 0.99 +/- 16.42 1.04 +/- 21.30 Ear swelling (NMRI mice, female, 6 animals/group, in 0.01 mm) Dose [%] day 1 day4 Index day4 (mean +/- SD in %) 0 17.50 +/- 2.98 17.50 +/- 2.98 1.00 2 17.67 +/- 3.69 17.50 +/- 4.56 1.00 10 17.83 +/- 2.18 17.92 +/- 5.03 1.02 50 17.92 +/- 2.87 18.67 +/- 5.75 1.07 Ear weight (NMRI mice, female, 6 animals/group, in mg per 8 mm diameter punch) Dose [%] day4 Index day4 (mean +/- SD in %) 0 11.20 +/- 6.51 1.00 2 11.53 +/- 8.58 1.03 10 11.51 +/- 6.84 1.03 50 11.65 +/- 7.85 1.04 Group 1 Vehicle (A/OO = acetone/olive oil) Group 2 2 % Lactofen (in A/OO) Group 3 10 % Lactofen (in A/OO) Group 4 50 % Lactofen (in A/OO) Group 5 3, 10, 30 % Alpha Hexyl Cinnamic Aldehyde (in A/OO)

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: not applicable

Any other information on results incl. tables

Stimulation indices (weight and cell counts; ear swelling and ear weight)

Based on results obtained in validation studies and general experiences with this test system groups of mice were treated with vehicle, 2 %, 10% or 50% Lactofen in acetone/olive oil (A/OO).

The NMRI mice did not show an increase in the stimulation indices for cell counts or for weights of the draining lymph nodes after application of the test item Lactofen.

The "positive level", which is 1.4 for the cell count index, was never reached or exceeded in any dose group.

The "positive level" of ear swelling, which is 2xl0E-2 mm increase, i.e. about 10% of the control values, has not been reached or exceeded in any dose group.

A slight significant increase compared to vehicle treated animals regarding ear swelling was detected in the high dose group. However, this change was in the range of normal variance for this parameter and did not exceed the cut-off level (cf. above). No increase in the ear weights were observed in any dose group.

It has to be clarified that the "positive levels" mentioned above are exclusively defined for the NMRI outbred mice used for this study. Such positive limits have to be calculated for each strain of mice individually.

Body weights

The body weights of the animals were not affected by any treatment.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Executive summary:

The modified Local Lymph Node Assay (lMDS) was performed on 24 female NMRI mice of the strain Hsd Win:NMRI (6 animals/ test item group and 6 control animals) to determine if there is any specific (sensitizing) or non-specific (irritating) stimulating potential

of the test item Lactofen.

The study was conducted according to OECD Guideline No. 429, No. 406, EC Guideline 96/54/EC (22nd Adaptation of Guideline 67/548/EEC)/Health Effects Test Guideline, OPPTS 870.2600 (EPA) with the following test item concentrations: 0 (vehicle control), 2, 10 and 50%.

The test item was formulated in Acetone/Olive Oil (4: 1) (A/OO) to yield a solution.

Compared to vehicle treated animals none of the parameter measured, i.e. cell counts and weights of the draining lymph nodes, ear weights and ear swelling reached or exceeded the "positive levels" defined for this assay. These results show that there is no indication

for a skin sensitizing effect after administration of a concentration of up to 50% Lactofen in this test system.

A slight significant increase compared to vehicle treated animals regarding ear swelling was detected in the high dose group. No increase was determined for the ear weights in any dose group.

In conclusion, these results show that the test item (Lactofen) was negative in mice after dermal application of up to and including a 50% concentration. No indication for a non-specific (irritating) activation was detected, too. Therefore, the concentration of 50% turned out to be the NOEL for the parameters investigated in this study with respect to skin sensitization.