2-benzoylbenzoic acid

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Dec 2018 to 29 Jan 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

2017

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-benzoylbenzoic acid

EC Number:

201-612-2

EC Name:

2-benzoylbenzoic acid

Cas Number:

85-52-9

Molecular formula:

C14H10O3

IUPAC Name:

2-benzoylbenzoic acid

Specific details on test material used for the study:

Appearance: Off-white powder
Purity/Composition: 98.8%
Test item storage: At room temperature

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Species: Rat
Strain: Crl: WI(Han)
Condition: Outbred, SPF-Quality
Source: Charles River Deutschland, Sulzfeld, Germany
Number of Animals: 3 females (nulliparous and non-pregnant).
Age at the Initiation of Dosing: Young adult animals (approximately 11 weeks old) were selected.
Weight at the Initiation of Dosing: 192 to 211 g.

 
Justification for Test System and Number of Animals:
The Wistar Han rat was chosen as the animal model for this study as recognized by international guidelines as a recommended test system. The test method and number of animals were based on the test guidelines.
The study plan was reviewed and agreed by the Animal Welfare Body of Charles River Laboratories Den Bosch B.V. within the framework of Appendix 1 of project license AVD2360020172866 approved by the Central Authority for Scientific Procedures on Animals (CCD) as required by the Dutch Act on Animal Experimentation (December 2014).

Animal Identification:
At study assignment, each animal was identified using a tail mark with indelible ink.

Environmental Acclimation:
The animals were allowed to acclimate to the Test Facility toxicology accommodation for at least 5 days before the commencement of dosing.

Selection, Assignment, Replacement, and Disposition of Animals:
Animals were assigned to the study at the discretion of the coordinating biotechnician according to body weights, with all animals within ± 20% of the sex mean. Animals in poor health or at extremes of body weight range were not assigned to the study.
Before the initiation of dosing, a health inspection was performed and any assigned animal considered unsuitable for use in the study were replaced by alternate animals obtained from the same shipment and maintained under the same environmental conditions.
The disposition of all animals was documented in the study records.

Husbandry:
Housing:
On arrival, animals were group housed (up to 5 animals of the same sex together) in polycarbonate cages (Makrolon MIV type; height 18 cm.) and following assignment to the study, animals were individually housed in polycarbonate cages (Makrolon MIII type; height 18 cm.) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) equipped with water bottles. The room in which the animals were kept were documented in the study records.
Animals were separated during designated procedures/activities. Each cage was clearly labeled.

Environmental Conditions:
Target temperatures of 18 to 24°C with a relative target humidity of 40 to 70% were maintained. The actual daily mean temperature during the study period was 20 to 21°C with an actual daily mean relative humidity of 36 to 53% (see deviations in Appendix 3). A 12 hour light/12 hour dark cycle was maintained. Ten or greater air changes per hour with 100% fresh air (no air recirculation) were maintained in the animal rooms.
 
Food:
Pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany) was provided ad libitum throughout the study, except during designated procedures.
The feed was analyzed by the supplier for nutritional components and environmental contaminants. Results of the analysis were provided by the supplier and are on file at the Test Facility.
It is considered that there were no known contaminants in the feed that would interfere with the objectives of the study.

Water:
Municipal tap-water was freely available to each animal via water bottles.
Periodic analysis of the water was performed, and results of these analyses are on file at the Test Facility.
It is considered that there were no known contaminants in the water that would interfere with the objectives of the study.

Animal Enrichment:
For psychological/environmental enrichment, animals were provided with paper (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom), except when interrupted by study procedures/activities.

Veterinary Care:
Veterinary care was available throughout the course of the study; however, no examinations or treatments were required.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

A single dose of test item was administered to the appropriate animals by dermal application on Day 1. One day before dosing, an area of approximately 5x7 cm on the back of the animals was clipped. The test item was applied in an area of approximately 10% of the total body surface, i.e. approximately 18 cm² for females. The test item was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D), successively covered with Coban elastic bandage. A piece of Micropore tape was additionally used for fixation of the bandages in females only. The application period was 24 hours, after which the dressing was removed and the skin cleaned of residual test item using water.

The dose volume for each animal was based on the body weight measurement prior to dosing. A dose volume of 10 mL/kg body weight will be used for each dose.

The dosing formulations were stirred continuously during dose administration.

Duration of exposure:

24 hours

Doses:

2000 mg/kg

No. of animals per sex per dose:

2

Control animals:

no

Details on study design:

In-life Procedures, Observations, and Measurements:
Mortality/Moribundity Checks:
Throughout the study, animals were observed for general health/mortality and moribundity twice daily, in the morning and at the end of the working day. Animals were not removed from cage during observation, unless necessary for identification or confirmation of possible findings.

Clinical Observations:
Postdose Observations:
Postdose observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter. The observation period was 14 days.
All the animals were examined for reaction to dosing. The onset, intensity and duration of these signs was recorded (if appropriate), particular attention being paid to the animals during and for the first hour after dosing.

Body Weights:
Animals were weighed individually on Day 1 (predose), 8 and 15.

Irritation:
The skin reactions were assessed approximately 24, 48 and 72 hours after the removal of the dressing and test item. Adjacent areas of untreated skin of each animal served as controls.
The following numerical scoring system was used in the scoring of skin reactions:

Erythema and eschar formation:
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beef redness) * 4
*. Where signs of necrosis or corrosion (injuries in depth) prevent erythema scoring, the maximum grade for erythema (= 4) is given.

Oedema formation:
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimeter) 3
Severe oedema (raised more than 1 millimeter and extending beyond the area of exposure) 4

Terminal Procedures:
All animals were sacrificed by oxygen/carbon dioxide procedure at the end of the observation period. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded.

Results and discussion

Preliminary study:

See Appendix 1 for detailed results

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

>= 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred

Clinical signs:

other: Chromodacryorrhoea (nose) was noted in two animals on Day 1.

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Other findings:

Irritation:
No erythema or edema of the treated skin was noted for any of the animals at any time point. In one animal scabs on the left flank were noted from Day 13 onwards.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The dermal LD50 value of 2-Benzoylbenzoic acid in Wistar Han rats was established to exceed 2000 mg/kg body weight.

Based on these results, 2-Benzoylbenzoic acid does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2017) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Executive summary:

The objective of this study was to determine the potential toxicity of 2-Benzoylbenzoic acid, when given by a single dermal dose.

The study was carried out based on the guideline described in:

•       OECD No. 402 (2017) "Acute Dermal Toxicity".

Initially, 2-Benzoylbenzoic acid was administered to a single female Wistar Han rat by a single dermal application at 2000 mg/kg body weight for 24 hours in a range finder study.  Based on the results, the main study was performed by dosing two females at 2000 mg/kg.  All animals were subjected to daily observations and weekly determination of body weight.  Macroscopic examination was performed on the day of death or after terminal sacrifice (Day 15).

No mortality occurred.

Chromodacryorrhoea (nose) was noted in two animals on Day 1.

No erythema or edema of the treated skin was noted for any of the animals at any time point.  In one animal scabs on the left flank were noted from Day 13 onwards.

The body weight gain shown by the animals during the observation period was within the range expected for rats used in this type of study.

No abnormalities were found at macroscopic post mortem examination of the animals.

The dermal LD₅₀ value of 2-Benzoylbenzoic acid in Wistar Han rats was established to exceed 2000 mg/kg body weight.  

Based on these results, 2-Benzoylbenzoic acid does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2017) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).