Reaction mass of 2,4-dimethyl-6-phenyl-3,6-dihydro-2H-pyran and 2-methyl-4-methylene-6-phenyltetrahydro-2H-pyran and 4,6-dimethyl-2-phenyl-3,6-dihydro-2H-pyran

Endpoint summary

Description of key information

The acute oral toxicity of the test substance was assessed according to OECD Test Guideline 423 “Acute Oral Toxicity – Acute Toxic Class Method”.  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.

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:

The study was conducted between 17 January 2012 and 09 February 2012.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP 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)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

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 wood flakes. 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:

unchanged (no vehicle)

Doses:

2000 mg/kg

No. of animals per sex per dose:

Six females per dose. Treatment of animals was sequential. Sufficient time was allowed between each group to confirm the survival of the previously dosed animals.

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.

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 0.5 1, 2 and 4 hours after dosing and subsequently once daily for up to fourteen days.
Individual bodyweights were recorded prior to dosing and seven and fourteen days after treatment or at death.
At the end of the observation period the surviving 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:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

One animal was killed for humane reasons, one day after dosing, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence.

Clinical signs:

other: Signs of systemic toxicity noted were hunched posture, increased salivation, decreased respiratory rate, laboured or noisy respiration, ataxia, pilo-erection and lethargy. Hypothermia and chromodacryorrhea were confined to one animal. Surviving animals ap

Gross pathology:

Abnormalities noted at necropsy of the animal that was killed during the study were dark liver, dark kidneys and epithelial sloughing of the gastric mucosa. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

Individual clinical observations and mortality data

Dose level (mg/kg)	Animal No. & sex	Effects noted after dosing (hours)				Effects noted during period after dosing (days)
		0.5	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 female	HS	0	0	0	A	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-1 female	HSRn	S	S	0	A	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-2 female	HS	0	0	0	A	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-0 female	0	0	0	0	HAPHol ChRIRdX*
	2-1 female	0	0	0	0	HA	HARd	H	0	0	0	0	0	0	0	0	0	0	0
	2-2female	0	0	0	0	HALP	HARd	H	0	0	0	0	0	0	0	0	0	0	0

0 = No signs of systemic toxicity

H = Hunched posture

S = Increased salivation

Rd = Decreased respiratory rate

Rl = Laboured respiration

Rn = Noisy respiration

A = Ataxia

P = Piloerection

L = Lethargy

Ho = Hypothermia

Ch = Chromodacryorrhea

X* = Animal killed for humane reasons due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project licence.

 

Individual body weights and weekly body weight changes

Dose level (mg/kg)	Animal No. & sex	Bodyweight (g) at day			Bodyweight (g) at death	Bodyweight gain (g) during week
		0	7	14		1	2
2000	1-0 female	158	184	195		26	11
	1-1 female	159	195	207		36	12
	1-2 female	156	184	202		28	18
	2-0 female	163	-	-	153	-	-
	2-1 female	157	180	195		23	15
	2-2female	160	180	200		20	20

- = Animal dead

 

Individual necropsy findings

Dose level (mg/kg)	Animal No. & 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	Humanely killed Day 1	Liver: Dark Kidneys: Dark Gastric mucosa: Epithelial sloughing
	2-1 female	Killed Day 14	No abnormalities detected
	2-2female	Killed Day 14	No abnormalities detected

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

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.

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 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 undiluted. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality.

One animal was killed for humane reasons, one day after dosing, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence.

Clinical Observations.

Signs of systemic toxicity noted were hunched posture, increased salivation, decreased respiratory rate, laboured or noisy respiration, ataxia, pilo-erection and lethargy. Hypothermia and chromodacryorrhea were confined to one animal. Surviving animals appeared normal two or four days after dosing.

Bodyweight.

Surviving animals showed expected gains in bodyweight over the study period.

Necropsy.

Abnormalities noted at necropsy of the animal that was killed during the study were dark liver, dark kidneys and epithelial sloughing of the gastric mucosa. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

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.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

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

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 undiluted.

One animal was killed for humane reasons, one day after dosing, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence. Signs of systemic toxicity noted were hunched posture, increased salivation, decreased respiratory rate, laboured or noisy respiration, ataxia, pilo-erection and lethargy. Hypothermia and chromodacryorrhea were confined to one animal. Surviving animals appeared normal two or four days after dosing. Surviving animals showed expected gains in bodyweight over the study period. Abnormalities noted at necropsy of the animal that was killed during the study were dark liver, dark kidneys and epithelial sloughing of the gastric mucosa. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

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.

Justification for selection of acute toxicity – oral endpoint
The study was conducted on the target substance in vivo, in an appropriate test species and according to internationally recognised guidelines.

Justification for classification or non-classification

Acute toxicity is defined as the adverse effects occurring following a single administration of a substance, or multiple doses given within 24 hours by the oral or dermal routes, or an inhalation exposure of 4 hours.

Substances can be allocated to one of four toxicity categories based on acute toxicity by the oral, dermal or inhalation route according to the Globally Harmonized Classification System and Regulation (EC) No. 1272/2008, relating to the Classification, Labelling and Packaging of Substances and Mixtures. Acute toxicity values are expressed as approximate LD50 or LC50 (inhalation) values.

A test substance is classified according to one of these four toxicity categories when the acute LD50 value is ≤ 2000 mg/kg for exposure via the oral route.

The LD50 of the test substance was > 2000 mg/kg and is therefore not classified for acute oral toxicity.