1H-Benz[e]indolium, 1,1,2,3-tetramethyl-, 4-methylbenzenesulfonate (1:1)

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test accoding to GLP and the study procedures described in this report were based on the most recent OECD and EC guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

1,1,2,3-tetramethyl-1H-benzo[e]indol-3-ium 4-methylbenzene-1-sulfonate

Cas Number:

141914-99-0

Molecular formula:

C23H25NO3S

IUPAC Name:

1,1,2,3-tetramethyl-1H-benzo[e]indol-3-ium 4-methylbenzene-1-sulfonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Identification: V173520
Appearance: White powder (determined by WIL Research Europe)
Batch: AN
Purity/Composition: Not indicated
Test substance storage: At room temperature
Stable under storage conditions until: 20 April 2017 (expiry date)

Chemical name (IUPAC), synonym or trade name: 1,1,2,2-tetramethyl-1H-Benz(e)indolium 4- methylbenzenesulfonate
CAS Number: 141914-99-0
Molecular formula: C23H25NO3S
Molecular weight: 395.53
pH (1% in water, indicative range) : 4.1 – 4.03 (determined by WIL Research Europe B.V. )
Solubility in vehicle: N,N-Dimethylformamide: +- 10%
Stability in vehicle: N,N-Dimethylformamide: Unknown

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Species: Mouse, CBA/J strain, inbred, SPF-Quality.
Recognized by the international guidelines as the recommended test system (e.g. OECD, EC, EPA).
Source: Janvier, Le Genest-Saint-Isle, France
Number of animals: 20 females (nulliparous and non-pregnant), five females per group (main study only).
Age and body weight: Young adult animals (approx. 10 weeks old) were selected. Body weight variation was within +/- 20% of the sex mean.
Identification: Tail mark with marker pen.
Health inspection: At least prior to dosing. It was ensured that the animals were healthy and that the ears were intact and free from any abnormality.

Animal husbandry

Conditions
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, at least 10 air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.

Accommodation
Animals were group housed in labeled Makrolon cages (MIII type; height 18 cm) containing sterilised sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany). Paper (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) and shelters (disposable paper corner home, MCORN 404, Datesand Ltd, USA) were supplied as cage-enrichment. The acclimatization period was at least 5 days before the start of treatment under laboratory conditions. On Day 6, the animals were group housed in Makrolon MII type cages with a sheet of paper instead of sawdust and cage enrichment.

Diet
Free access to pelleted rodent diet (SM R/M-Z from SSNIFFS pezialdiäten GmbH, Soest, Germany).

Water
Free access to tap water.

Diet, water, bedding and cage enrichment evaluations for contaminants and/or nutrients were performed according to facility standard procedures. There were no findings that could interfere with the study.

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

The vehicle was selected on the basis of maximizing the solubility using the test substance data provided by the Sponsor and trial preparation results performed at WIL Research Europe. The vehicle was chosen from the vehicles specified in the test guideline: Acetone/Olive oil (4:1 v/v), N,N-dimethylformamide, methylethylketone, propylene glycol and dimethylsulfoxide.
The test substance preparations (w/w) were prepared within 4 hours prior to each dosing. No adjustment was made for specific gravity of the vehicle. Homogeneity was obtained to visually acceptable levels.

No. of animals per dose:

5

Details on study design:

Three groups of five animals were treated with one test substance concentration per group. The highest test substance concentration was selected from the pre-screen test.
One group of five animals was treated with vehicle.

Induction - Days 1, 2 and 3
The dorsal surface of both ears was topically treated (25 μL/ear) with the test substance, at approximately the same time on each day. The concentrations were stirred with a magnetic stirrer immediately prior to dosing.
The control animals were treated in the same way as the experimental animals, except that the vehicle was administered instead of the test substance.

Excision of the nodes - Day 6
Each animal was injected via the tail vein with 0.25 mL of sterile phosphate buffered saline (PBS) (Merck, Darmstadt, Germany) containing 20 μCi of 3H-methyl thymidine (PerkinElmer Life and Analytical Sciences, Boston, MA, US).
After five hours, all animals were killed by intraperitoneal injection (0.2 mL/animal) of Euthasol® 20% (AST Farma BV, Oudewater, The Netherlands). The draining (auricular) lymph node of each ear was excised. The relative size of the nodes (as compared to normal) was estimated by visual examination and abnormalities of the nodes and surrounding area were recorded. The nodes were pooled for each animal in approximately 3 mL PBS.

Results and discussion

Positive control results:

The results of a reliability test with three concentrations of Hexylcinnamaldehyde (CAS No. 101-86-0) in Acetone/Olive oil (4:1 v/v), performed not more than 6 months previously and using the same materials, animal supplier, animal strain and essential procedures are summarized in APPENDIX 2 of this report. For both scientific and animal welfare reasons, no concurrent positive control group was included in the study.
An extensive data base is available with reliability checks performed each half year during at least the recent 9 years showing reproducible and consistent positive results.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: The SI values calculated for the substance concentrations 10, 25 and 50% were 11.7, 15.7 and 18.1, respectively.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 6177, 8264 and 9560 DPM, respectively. The mean DPM/animal value for the vehicle control group was 527 DPM.

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

According to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments), V173520 should be classified as skin sensitizer (Category 1) and labeled as H317: May cause an allergic skin reaction.