Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08 August 2017 to 22 August 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
See "Any other information" for details
Qualifier:
according to guideline
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Version / remarks:
Commission Regulation (EC) No 440/2008 of 30 May 2008, B.3.Tris
Deviations:
yes
Remarks:
See "Any other information" for details
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1200 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
See "Any other information" for details
GLP compliance:
yes (incl. QA statement)
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
6,6'-di-tert-butyl-2,2'-thiodi-p-cresol
EC Number:
202-009-7
EC Name:
6,6'-di-tert-butyl-2,2'-thiodi-p-cresol
Cas Number:
90-66-4
Molecular formula:
C22H30O2S
IUPAC Name:
6,6'-di-tert-butyl-2,2'-thiodi-p-cresol
Test material form:
solid: particulate/powder
Details on test material:
Name: 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol
Other name: LOWINOX® TBP-6
CAS number: 90-66-4
Batch/Lot Number: C036K0111
Description: White powder
Purity*: 99.8%
Expiry date: 29 March 2018
Storage condition: Controlled room temperature (15-25 ºC, below 70 RH%)
Safety precautions: Routine safety precautions (gloves, goggles, face mask, lab coat) for unknown materials were applied to assure personnel health and safety.
Specific details on test material used for the study:
No further details specified in the study report.

Test animals

Species:
rat
Strain:
Wistar
Remarks:
Crl:WI
Sex:
male/female
Details on test animals or test system and environmental conditions:
Species and strain: Crl:WI Wistar rats
Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld, Germany.
Hygienic level at arrival: SPF
Hygienic level during the study: Standard housing conditions
Number of animals: 5 animals/sex
Sex: Male and female, female rats were nulliparous and non-pregnant
Age of animals at dosing: Young adult rats
Body weight at treatment: Between 221 g and 255 g
Acclimatisation period: 5 days

Husbandry
Animal health: Only healthy animals were used for the test. The health status was certified by the staff Veterinarian.
Number of animal room: 242/6
Housing: Individual caging
Cage type: Type II. polypropylene/polycarbonate
Bedding and nesting: “Lignocel 3/4-S Hygienic Animal Bedding” and “Arbocel crinklets natural” nest building material produced by J. Rettenmaier & Söhne GmbH + Co.KG (D-73494 Rosenberg, Germany) was available to animals during the study.
Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 21.1 – 28.2 °C
Relative humidity: 32 – 74 %
Ventilation: 15-20 air exchanges/hour
Enrichment: Rodents were housed with deep wood sawdust bedding to allow digging and other normal rodent activities.
The temperature and relative humidity were recorded twice daily during the acclimatisation period and throughout the study.

Food and Water Supply
Animals received ssniff® SM R/M "Autoclavable complete diet for rats and mice – breeding and maintenance" produced by ssniff Spezialdiäten GmbH, D-59494 Soest, Germany (batch number: 262 21592, expiry date: 31 January 2018), ad libitum, and tap water from the municipal supply, as for human consumption from a 500 mL bottle, ad libitum. The food is considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
Water quality control analysis is performed once every three months and microbiological assessment is performed monthly, by Veszprém County Institute of State Public Health and Medical Officer Service (ÁNTSZ, H-8201 Veszprém, József A. u. 36., Hungary).

Animal Identification
Animals were individually identified using numbers written on the tail with an indelible marker pen. The numbers were given on the basis of CiToxLAB Hungary Ltd.' s Master File, for each animal allocated to the treatment groups. The cages were identified by cards, with information about study code, sex, dose group, cage number and individual animal numbers.

Administration / exposure

Type of coverage:
semiocclusive
Vehicle:
water
Details on dermal exposure:
Formulation
The test item was administered as a single dose. Sufficient water was used to dampen the test material to ensure good contact with the skin.

Procedure
The back of each animal was shaved (approximately 10% area of the total body surface) approximately 24 hours prior to treatment. The test item was applied as a single dose to the shaved skin and remained in contact with the skin for the 24-hour exposure period. The test material was dampened with sufficient water before application to ensure good contact with the skin. Sterile gauze pads were placed on the skin of rats to cover the test item. These gauze pads were kept in contact with the skin using a patch with adhesive hypoallergenic plaster. The entire trunk of the animal was then wrapped with semi occlusive plastic wrap for 24 hours.
At the end of the exposure period, the area of skin treated with the test item was washed with water of body temperature.
Duration of exposure:
24 hours.
Doses:
A single dermal application was made.
No. of animals per sex per dose:
10 (5 males/5 females)
Control animals:
no
Details on study design:
Clinical Observations
Clinical observations were performed on the day of treatment at 1 and 5 hours after application of the test item and once each day for 14 days thereafter. Observations included the skin and fur, eyes and mucous membranes, the respiratory, circulatory, autonomic and central nervous system, somatomotor activity and behaviour pattern.
Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Skin Irritation:
Adverse skin reactions at the site of application were recorded daily following the removal of the dressing.

Body Weight Measurement
The body weights were recorded on Day 0 (before test item administration) and on Days 7 and 14 just before necropsy.

NECROPSY
Macroscopic examination was performed on all animals. The animals were sacrificed by exsanguination under pentobarbital anaesthesia (Release, 300 mg/mL pentobarbital sodium; Lot number: 106075, Expiry date: 31 July 2018, Produced by: Wirtschaftsgenossenschaft deutscher Tierärzte eG, Germany). After examination of the external appearance, the cranial, thoracic and the abdominal cavities were opened and the organs and the tissues were observed. Macroscopic abnormalities were recorded.
Statistics:
Not specified.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at the dose level of 2000 mg/kg bw.
Clinical signs:
There were no systemic clinical signs noted in any animal throughout the study.
Body weight:
Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.
Gross pathology:
There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.
Other findings:
No local dermal signs were observed after treatment with the test item during the 14 days observation period.

Any other information on results incl. tables

CLINICAL OBSERVATIONS

DOSE LEVEL: 2000 mg/kg bw

 

SEX: MALE

Cage No.

Animal No.

Observations

Observation days

Frequency

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

1h

5h

1

357

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

2

358

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

3

359

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

4

360

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

5

361

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

 

DOSE LEVEL: 2000 mg/kg bw

 

SEX: FEMALE

Cage No.

Animal No.

Observations

Observations days

Frequency

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

1h

5h

6

362

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

7

363

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

8

364

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

9

365

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

10

366

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

16/16

Remarks:             + = present

                         h = hour (s)          Treatment day = Day 0

                          Frequency of observation = number of occurrence of observations / total number of observations

 

BODY WEIGHT DATA

DOSE LEVEL: 2000 mg/kg bw

 

 

 

SEX: MALE

Cage No.

Animal No.

Body weight (g)

Body Weight Gain (g)

Days

0

7

14

0-7

7-14

0-14

1

357

233

297

349

64

52

116

2

358

243

285

319

42

34

76

3

359

247

309

366

62

57

119

4

360

229

288

358

59

70

129

5

361

222

289

247

67

58

125

Mean:

234.8

293.6

347.8

58.8

54.25

113.0

Standard deviation:

10.2

9.7

17.8

9.8

13.1

21.3

 

DOSE LEVEL: 2000 mg/kg bw

 

 

 

SEX: FEMALE

Cage No.

Animal No.

Body weight (g)

Body Weight Gain (g)

Days

0

7

14

0-7

7-14

0-14

6

362

225

264

279

39

15

54

7

363

242

261

276

19

15

34

8

364

255

317

338

62

21

83

9

365

221

240

251

19

11

30

10

366

232

252

257

20

5

25

Mean:

235.0

266.8

280.2

31.8

143.4

45.2

Standard deviation:

13.7

29.6

34.5

18.9

5.9

23.8

 

NECROPSY FINDINGS

DOSE LEVEL: 2000 mg/kg bw

 

 

SEX: MALE

Cage No.

Animal No.

Necropsy Date/ Necropsy Day

External Observations

Internal Observations

Organ/ Tissue

1

357

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

2

358

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

3

359

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

4

360

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

5

361

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

 

DOSE LEVEL: 2000 mg/kg bw

 

 

SEX: FEMALE

Cage No.

Animal No.

Necropsy Date/ Necropsy Day

External Observations

Internal Observations

Organ/ Tissue

6

362

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

7

363

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

8

364

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

9

365

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

10

366

22 August 2017

Day 14

No external observations

No internal observations

Not applicable

 

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the conditions of this study, the acute dermal median lethal dose (LD50 value) of the test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was found to be above 2000 mg/kg bw in male and female Crl:WI rats.
According to the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute dermal exposure.
Executive summary:

An acute dermal toxicity study was performed with test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol in Crl:WI rats, in compliance with OECD Guideline No. 402.

 

A limit test was carried out at 2000 mg/kg body weight (bw) in both sexes (5 rats/sex). The test item was applied as a single dermal 24-hour exposure followed by a 14-day observation period.

 

Clinical observations were performed on all animals at 1 and 5 hours after dosing and daily for 14 days thereafter. Body weight was measured prior to dosing on Day 0 and on Days 7 and 14. Gross macroscopic examination was performed on all animals at the end of the 2-week observation period (Day 14).

 

RESULTS

Mortality

6,6’-di-tert-butyl-2,2’-thiodi-p-cresol did not cause mortality at the dose level of 2000 mg/kg bw.

 

Clinical Observations

There were no systemic clinical signs noted in any animal throughout the study.

 

Local dermal signs

No local dermal signs were observed after treatment with the test item during the 14 days observation period.

 

Body weight and body weight gain

Body weight gains of 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol treated animals during the study showed no indication of a test item-related effect.

 

Macroscopic Findings

There was no evidence of the macroscopic observations at a dose level of 2000 mg/kg bw.

 

CONCLUSIONS

Under the conditions of this study, the acute dermal median lethal dose (LD50 value) of the test item 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol was found to be above 2000 mg/kg bw in male and female Crl:WI rats.

 

According to the GHS criteria, 6,6’-di-tert-butyl-2,2’-thiodi-p-cresol can be ranked as "Category 5 or Unclassified" for acute dermal exposure.

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