α,α'-dichloro-p-xylene

Endpoint summary

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

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

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

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. QA statement)

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 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: 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:

other: 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-da

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

Value:

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.