Registration Dossier

Administrative data

Description of key information

Acute toxicity: oral

LD50 value of α,α’-Dichloro-p-xylene was found to be above 2000 mg/kg bw in female Crl:WI Wistar rats.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
14 November 2017 - 30 November 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Version / remarks:
OECD Guidelines for Testing of Chemicals (No. 423, Acute Oral Toxicity – Acute Toxic Class Method. Adopted: 17 December 2001)
Deviations:
yes
Remarks:
See "Any other information" for details
Qualifier:
according to
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Version / remarks:
Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris
Deviations:
yes
Remarks:
See "Any other information" for details
Qualifier:
according to
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
Version / remarks:
EPA Health Effects Test Guidelines (OPPTS 870.1100), United States, EPA 712-C-98-190 (1998)
Deviations:
yes
Remarks:
See "Any other information" for details
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes
Specific details on test material used for the study:
No further details specified in the study report.
Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals 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: 6 animals, 3 animals/group
Sex: Female, nulliparous and non-pregnant
Age of animals at dosing: Young healthy adult rats, 12 weeks old
Body weight at treatment: 239 - 261 g
Acclimatisation period: 33 or 35 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: 522/3
Housing: 3 animals/cage
Cage type: Type II. polypropylene/polycarbonate
Bedding: Lignocel 3/4-S Hygienic Animal Bedding produced by J. Rettenmaier & Söhne GmbH + CO.KG (D-73494 Rosenberg, Germany) was available to animals during the study.
A copy of the Certificate of Analysis is retained in the archive at Citoxlab Hungary Ltd.
Nesting: Arbocel crinklets natural produced by J. Rettenmaier & Söhne GmbH + CO.KG (D-73494 Rosenberg, Germany) was available to animals during the study.
A copy of the Certificate of Analysis is retained in the archive at Citoxlab Hungary Ltd.
Lighting period: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 20.5 – 25.5 °C
Relative humidity: 32 – 91 %
Ventilation: 15-20 air exchanges/hour
Enrichment: Animals were housed by group to allow social interaction and 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 Attila u. 36., Hungary). The quality control results are retained in the archives at Citoxlab Hungary Ltd.

Animal Identification
Animals were individually identified using numbers written on the tail with an indelible 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.
Route of administration:
oral: gavage
Vehicle:
other:
Remarks:
% Methyl cellulose aqueous solution + 1% w/v Polysorbate 80.
Details on oral exposure:
The initial dose level was selected by the Study Director to be that which is most likely to produce mortality in some of the dosed animals. Based on the available toxicological information received from the Sponsor, 2000 mg/kg bw was selected to be the starting dose.
Initially, three female animals were treated with 2000 mg/kg bw of the test item. No mortality was observed, therefore further 3 animals were treated at the dose level of 2000 mg/kg bw. As no mortality was observed in this second dose group, further testing was not required according to the test guidelines (OECD 423, Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris).
Doses:
2000 mg/kg
No. of animals per sex per dose:
6 female rats, 3 per group
Control animals:
no
Details on study design:
A single oral gavage administration was followed by a 14-day observation period. On the night before treatment, the animals were fasted. The food but not water was withheld during an overnight period. Animals were weighed before treatment. The test item was administered by oral gavage in the morning. The food was returned 3 hours after the treatment.
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
α,α’-Dichloro-p-xylene did not cause mortality at a dose level of 2000 mg/kg bw in any animal.
Clinical signs:
At a dose level of 2000 mg/kg bw, the following test item related symptoms were observed from Day 3 up to Day 10: hunched back (5 out of 6 animals) and piloerection (4 out of 6 animals). From Day 11 all animals were symptom-free until the end of the 14-day observation period.
Body weight:
Slight or moderate decrease was detected in body weight between Day 0 and Day 7 in 5 out of 6 animals, which was considered to be related to the test item. Body weights were within the range commonly recorded for this strain and age between Day 7 and Day 14.
Gross pathology:
α,α’-Dichloro-p-xylene caused thickness of the non-glandular region of the stomach in 5 out of 6 animals. The other experimental animal showed no macroscopic changes at necropsy.

CLINICAL OBSERVATIONS

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0                                                                                          SEX: FEMALE

Cage No.

Animal Number

Observations

Observations days

Frequency

0

1

2

3

4

5

6

7

8

9

10

11-14

30’

1h

2h

3h

4h

6h

1

1249

Symptom Free

+

+

+

+

+

+

+

+

+

+

-

-

-

-

+

+

+

16/20

Hunched back

-

-

-

-

-

-

-

-

-

-

+

+

+

+

-

-

-

4/20

Piloerection

-

-

-

-

-

-

-

-

-

-

-

+

+

-

-

-

-

2/20

1250

Symptom Free

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

20/20

1251

Symptom Free

+

+

+

+

+

+

+

+

+

+

-

-

-

-

+

+

+

16/20

Hunched back

-

-

-

-

-

-

-

-

-

-

+

+

+

+

-

-

-

4/20

2

1252

Symptom Free

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

+

12/20

Hunched back

-

-

-

-

-

-

-

-

+

+

+

+

+

+

+

+

-

8/20

Piloerection

-

-

-

-

-

-

-

-

+

+

+

-

-

-

-

-

-

3/20

1253

Symptom Free

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

+

12/20

Hunched back

-

-

-

-

-

-

-

-

+

+

+

+

+

+

+

+

-

8/20

Piloerection

-

-

-

-

-

-

-

-

+

+

+

-

-

-

-

-

-

3/20

1254

Symptom free

+

+

+

+

+

+

+

+

-

-

-

-

-

-

-

-

+

12/20

Hunched back

-

-

-

-

-

-

-

-

+

+

+

+

+

+

+

+

-

8/20

Piloerection

-

-

-

-

-

-

-

-

+

+

+

-

-

-

-

-

-

3/20

Remarks:         + = present                  - = absent

                       h = hour                       ‘ = minute

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

 

BODY WEIGHT DATA

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0                                                                   SEX: FEMALE

Cage No.

Animal Number

Body weight (g)

Days

Body Weight Gain (g)

-1

0

7

14

-1-0

0-7

7-14

-1-14

1

1249

274

259

234

280

-15

-25

46

6

1250

270

261

259

278

-9

-2

19

8

1251

269

254

239

267

-15

-15

28

-2

2

1252

250

239

229

253

-11

-10

24

3

1253

255

249

219

248

-6

-30

29

-7

1254

262

256

262

290

-6

6

28

28

Mean:

263.3

253.0

240.3

269.3

-10.3

-12.7

29.0

6.0

Standard deviation:

9.4

8.0

17.0

16.4

4.1

13.6

9.1

12.1

 

NECROPSY FINDINGS

DOSE LEVEL: 2000 mg/kg bw, Treatment on Day 0                                SEX: FEMALE

Cage No.

Animal Number

Necropsy Date/ Necropsy Day

External Observations

Internal Observations

Organ/Tissue

1

1249

28 November 2017

Day 14

No external observations recorded

No internal observations recorded

Not applicable

1250

28 November 2017

Day 14

No external observations recorded

Thickness, Non-glandular Region, Wall

Stomach

1251

28 November 2017

Day 14

No external observations recorded

Thickness, Non-glandular Region, Wall

Stomach

2

1252

30 November 2017

Day 14

No external observations recorded

Thickness, Non-glandular Region, Wall

Stomach

1253

30 November 2017

Day 14

No external observations recorded

Thickness, Non-glandular Region, Wall

Stomach

1254

30 November 2017

Day 14

No external observations recorded

Thickness, Non-glandular Region, Wall

Stomach

 

Interpretation of results:
Category 5 based on GHS criteria
Conclusions:
Under the conditions of this study, the acute oral LD50 value of the test item α,α’-Dichloro-p-xylene was found to be above 2000 mg/kg bw in female Crl:WI Wistar rats.
According the GHS criteria, classification of α,α’-Dichloro-p-xylene can be ranked as "Category 5" for acute oral exposure.
Executive summary:

SUMMARY

The single-dose oral toxicity study with α,α’-Dichloro-p-xylene was performed according to the acute toxic class method (OECD 423 and Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris) in Crl:WI Wistar female rats. Two groups of three female Crl:WI rats were treated with the test itemat a dose level of 2000 mg/kg body weight (bw) (Group 1 and Group 2). A single oral treatment was carried out by gavage for each animal after an overnight food withdrawal. Food was made available again 3 hours after the treatment. The test item was administered at the dose level of 2000 mg/kg bw. Initially, three females (Group 1) were treated at a dose level of 2000 mg/kg bw. As no mortality was observed, a confirmatory group (Group 2) was treated at the same dose level. No mortality was observed in the confirmatory group; therefore, no further testing was required according to OECD 423 and Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris. Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weight was measured on Days -1, 0, 7 and before necropsy (Day 14). All animals were subjected to a necropsy and a macroscopic examination.

RESULTS

Mortality

α,α’-Dichloro-p-xylene did not cause mortality at a dose level of 2000 mg/kg bw. Clinical Observations At a dose level of 2000 mg/kg bw, the following test item related symptoms were observed from Day 3 up to Day 10: hunched back (5 out of 6 animals) and piloerection (4 out of 6 animals). From Day 11 all animals were symptom-free until the end of the 14-day observation period.

Body Weight and Body Weight Gain

Slight or moderate decrease was detected in body weight between Day 0 and Day 7 in 5 out of 6 animals, which was considered to be related to the test item. Body weights were within the range commonly recorded for this strain and age between Day 7 and Day 14.

Macroscopic Findings

α,α’-Dichloro-p-xylene caused thickness of the non-glandular region of the stomach in 5 out of 6 animals. The other experimental animal showed no macroscopic changes at necropsy.

CONCLUSION

Under the conditions of this study, the acute oral LD50 value of the test item α,α’-Dichloro-p-xylene was found to be above 2000 mg/kg bw in female Crl:WI Wistar rats.

According the GHS criteria, classification of α,α’-Dichloro-p-xylene can be ranked as "Category 5" for acute oral exposure.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
2 000 mg/kg bw
Quality of whole database:
K1

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Acute toxicity: oral

The single-dose oral toxicity study with α,α’-Dichloro-p-xylene was performed according to the acute toxic class method in Crl:WI Wistar female rats. Two groups of three female Crl:WI rats were treated with the test item at a dose level of 2000 mg/kg body weight (bw) (Group 1 and Group 2). A single oral treatment was carried out by gavage for each animal after an overnight food withdrawal. Food was made available again 3 hours after the treatment. The test item was administered at the dose level of 2000 mg/kg bw. Initially, three females (Group 1) were treated at a dose level of 2000 mg/kg bw. As no mortality was observed, a confirmatory group (Group 2) was treated at the same dose level. No mortality was observed in the confirmatory group; therefore, no further testing was required according to OECD 423 and Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.tris. Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weight was measured on Days -1, 0, 7 and before necropsy (Day 14). All animals were subjected to a necropsy and a macroscopic examination.

RESULTS

Mortality

α,α’-Dichloro-p-xylene did not cause mortality at a dose level of 2000 mg/kg bw. Clinical Observations At a dose level of 2000 mg/kg bw, the following test item related symptoms were observed from Day 3 up to Day 10: hunched back (5 out of 6 animals) and piloerection (4 out of 6 animals). From Day 11 all animals were symptom-free until the end of the 14-day observation period.

Body Weight and Body Weight Gain

Slight or moderate decrease was detected in body weight between Day 0 and Day 7 in 5 out of 6 animals, which was considered to be related to the test item. Body weights were within the range commonly recorded for this strain and age between Day 7 and Day 14.

Macroscopic Findings

α,α’-Dichloro-p-xylene caused thickness of the non-glandular region of the stomach in 5 out of 6 animals. The other experimental animal showed no macroscopic changes at necropsy.

CONCLUSION

Under the conditions of this study, the acute oral LD50 value of the test item α,α’-Dichloro-p-xylene was found to be above 2000 mg/kg bw in female Crl:WI Wistar rats.

Justification for classification or non-classification

According the GHS criteria, classification of α,α’-Dichloro-p-xylene can be ranked as "Category 5" for acute oral exposure.