Bis(2,4-dichlorobenzoyl) peroxide

Endpoint summary

Description of key information

The acute oral toxicity of Bis(2,4-dichlorobenzoyl) peroxide, paste, 50% in silicone oil, was determined in rats. The test item was administered orally as a suspension in arachis oil BP. A group of 3 fasted females was treated with the test item at a dose level of 2000 mg/kg bodyweight. This was followed by a further group of 3 fasted females at the same dose level. Clinical signs and bodyweight development were monitored during the 14 day study. All animals were subjected to gross necropsy. There were no deaths or any clinical signs of systemic toxicity. All animals showed expected gains in bodyweight over the study period. No abnormalities were noted at necropsy. It was concluded that the acute oral median lethal dose (LD50) of the test item in the female Wistar strain rat was greater than 2000 mg/kg bodyweight, and does not meet the criteria for classification under GHS.

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:

Between 01 May 2012 and 31 May 2012

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

No analysis was carried out to determine the homogeneity, concentration or stability of the test item formulation. This exception is considered not to affect the purpose or integrity of the study.

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

Female Wistar (RccHan:WIST) strain rats were supplied by Harlan Laboratories UK Ltd., Oxon, UK. On receipt the animals were randomly allocated to cages. The animals were nulliparous and non-pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink marking on the tail and a number written on a cage card. At the start of the study the animals were eight to twelve weeks of age. The bodyweights fell within an interval of ±20% of the mean initial bodyweight of the first treated group.
The animals were housed in groups of three in suspended solid floor polypropylene cages furnished with woodflakes. With the exception of an overnight fast immediately before dosing and for approximately three to four hours after dosing, free access to mains drinking water and food (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK) was allowed throughout the study. The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that would reasonably be expected to affect the purpose or integrity of the study.
The temperature and relative humidity were set to achieve limits of 19 to 25°C and 30 to 70% respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe.

Doses:

2000 mg/kg

No. of animals per sex per dose:

3 female @2000 mg/kg
3 female @2000 mg/kg

Control animals:

no

Details on study design:

Using available information on the toxicity of the test item, 2000 mg/kg was chosen as the starting dose.
Groups of fasted animals were treated as follows:
Dose Level(mg/kg) Concentration(mg/ml) Dose Volume(ml/kg) Number of Rats (Female)
2000 200 10 3
2000 200 10 3
All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe. The volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing. Treatment of animals was sequential. Sufficient time was allowed between each group to confirm the survival of the previously dosed animals.
The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.
Individual bodyweights were recorded prior to dosing and seven and fourteen days after treatment.
At the end of the observation period the animals were killed by cervical dislocation. All animals were subjected to gross pathological examination. This consisted of an external examination and opening of the abdominal and thoracic cavities for examination of major organs. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 500 mg/kg bw

Based on:

test mat.

Mortality:

Individual mortality data are given in Table 1.
There were no deaths.

Clinical signs:

other: Individual clinical observations are given in Table 1. No signs of systemic toxicity were noted.

Gross pathology:

Individual necropsy findings are given in Table 3.
No abnormalities were noted at necropsy.

Evaluation of Data

Data evaluations included the relationship, if any, between the exposure of the animal to the test item and the incidence and severity of all abnormalities including behavioural and clinical observations, gross lesions, bodyweight changes, mortality and any other toxicological effects.

Using the mortality data obtained, an estimate of the acute oral median lethal dose (LD₅₀) of the test item was made.

The results were also evaluated according to the Regulation (EC) No 1272/2008, relating to the Classification, Labelling and Packaging of Dangerous Substances.

Table 1              Individual Clinical Observations and Mortality Data

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Dosing (Hours)				Effects Noted During Period After Dosing (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0= No signs of systemic toxicity

Table 2              Individual Bodyweights and Weekly Bodyweight Changes

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight Gain (g) During Week
		0	7	14	1	2
2000	1-0 Female	164	185	189	21	4
	1-1 Female	161	186	211	25	25
	1-2 Female	161	185	202	24	17
	2-0 Female	165	178	187	13	9
	2-1 Female	170	191	199	21	8
	2-2 Female	177	196	216	19	20

Table3              Individual Necropsy Findings

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
2000	1-0 Female	Killed Day 14	No abnormalities detected
	1-1 Female	Killed Day 14	No abnormalities detected
	1-2 Female	Killed Day 14	No abnormalities detected
	2-0 Female	Killed Day 14	No abnormalities detected
	2-1 Female	Killed Day 14	No abnormalities detected
	2-2 Female	Killed Day 14	No abnormalities detected

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral median lethal dose (LD50) of the test item in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight (Globally Harmonised Classification System - Unclassified).

Executive summary:

Introduction.The study was performed to assess the acute oral toxicity of the test item following a single oral administration in the Wistar strain rat. The method was designed to be compatible with the following:

OECD Guidelines for the Testing of Chemicals No. 423 " Acute Oral Toxicity - Acute Toxic Class Method (adopted 17 December 2001)

Method B1 tris Acute Toxicity (Oral) of Commission regulation (EC) No. 440/2008

Method. A group of three fasted females was treated with the test item at a dose level of 2000 mg/kg bodyweight. This was followed by a further group of three fasted females at the same dose level.

The test item was administered orally as asuspensioninarachis oil BP. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality. There were no deaths.

Clinical Observations. There were no signs of systemic toxicity.

Bodyweight. All animals showed expected gains in bodyweight over the study period.

Necropsy. No abnormalities were noted at necropsy.

Conclusion. The acute oral median lethal dose (LD₅₀) of the test item in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight (Globally Harmonised Classification System - Unclassified).

The test item does not meet the criteria for classification according to the Regulation (EC) No 1272/2008, relating to the Classification, Labelling and Packaging of Dangerous Substances.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

> 2 000 mg/kg bw

Quality of whole database:

A well-conducted, recent GLP study and rated reliable without restrictions.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: No guideline followed. Not a GLP study. Evaluation of clinical symptoms was not reported. The identity of the test material was not established.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Graded doses of the test material were applied to the skin of rabbits and observed for 14 days.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

Eight rabbits equally divided as to sex, weighing 2317 to 2831 gms were used. No other details were provided.

Type of coverage:

occlusive

Vehicle:

not specified

Details on dermal exposure:

The hair was clipped from the back of each rabbit. the skin was abraded for 1/2 of the rabbits in each group. The rabbits were divided into four groups of 2 rabbits (one male and one female) for each group (dose levels of 1000, 2000, 3000, and 4000 mg/kg). The test material was applied as received to the backs in appropriate doses. The site of application was covered with gauze bandaging and occluded with Saran wrap.

Duration of exposure:

14 days

Doses:

1000, 2000, 4000 and 8000 mg/kg

No. of animals per sex per dose:

one male and female per dose.

Control animals:

no

Details on study design:

No other details provided

Statistics:

None

Preliminary study:

The rabbits were observed for death at 24 hours and daily thereafter for a total of 14 days. It was concluded that the acute dermal toxicity (LD50) value in albino rabbits would be greater than 8000 mg/kg.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 8 000 mg/kg bw

Based on:

other:

Remarks on result:

other: Not clear as to how the dose formulations were calculated and prepared from the test item.

Mortality:

None.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute dermal toxicity (LD50) value in albino rabbits would be greater than 8000 mg/kg.

Executive summary:

There were no mortalities.

Although the study concluded that the LD50 value in rabbits was greater than 8000 mg/kg, due to the non-GLP nature of the experiment, and the lack of some details on the test item and some experimental conditions, the level of confidence in the conclusions is somewhat less reliable.

Reference 2

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

8 000 mg/kg bw

Quality of whole database:

Although a lower reliability rating (K4) was assigned, the LD50 was >8000 mg/kg, and well above the current limit dose.

Additional information

Due to its low vapor pressure, exposure to the test substance through inhalation is not expected. An acute dermal toxicity study in rabbits with a low reliability rating determined that the LD50 was well above the current limit dose. The most recent, well conducted acute oral toxicity (GLP) study data resulted in non-classification of the test material. Therefore, the registered substance was not acutely toxic to rats when tested by oral gavage route.

Justification for selection of acute toxicity – oral endpoint
A well-conducted, recent GLP study based on OECD 423.

Justification for selection of acute toxicity – inhalation endpoint
Due to its low vapor pressure ( < 0.009 Pa at 25 degrees C), exposure to the test material by inhalation is not expected.

Justification for selection of acute toxicity – dermal endpoint
This is the only study available.

Justification for classification or non-classification

Based on the results of the acute oral toxicity study and acute dermal toxicity discussion, the data are conclusive but not sufficient for classification.