Reaction Mass of 4-tert-butyl-2-hydroxycyclohexyl methacrylate and 5-tert-butyl-2-hydroxycyclohexyl methacrylate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 September - 17 November 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

other: solid dispersed in viscous liquid phase

Details on test material:

Test material name: T-butyl hydroxycyclohexyl methacrylate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test Animals:Body weight: M = 150.0 - 191.7 g, F = 140.6 - 167.6 gAge: 6-7 weeksNumber: 20 M and 20 F. Females were nulliparous and non-pregnant.Acclimatisation: 14 days prior to testingDiet: A commercially available standard 17 % rat/mouse pelleted diet was freely available at all times.Water: Drinking water (mains supply) was available at all times. Water was monitored for bacteria and coliforms. Neither the diet of drinking water was found to contain contaminants that could interfere with tthe study.Envirnonmental conditions:Temperature: 18-24 °CRH: 42-74.4 %Lighting: 12 h light/dark cyclesHousing: 56 x 37.5 x 17.5 cm rat boxes. Autoclaved woodshavings used as adsorbent material. Boxes changed twice weekly.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

T-butyl hydroxycyclohexyl methacrylate in corn oil was mixed well using a magnetic stirrer to ensure homogeneity. Solutions were administered by oral gavage at a dose volume of 1 mL/ 100 g body weight, using a graduated syringe and stainless stell cannula. Dilutions were administered within 20 mins of the solution preparation.

Doses:

A single oral dose was administered to each group of 5 rats at the following dose levels;Males: 2000, 5000, 10000 mg/kgFemales: 2000, 5000, 10000 mg/kgControl: Corn oil administered at a dose volume of 1.0 mL/100 g bodyweight.

No. of animals per sex per dose:

5 animals per sex/ dose

Control animals:

yes

Details on study design:

Four groups of 10 rats (5 male, 5 female) were selected, acclimatised and maintained as described above. On the day of dosing food was removed and the animals fasted for between 19-21 h. On the day of dosing t-butyl hydroxycyclohexyl methacrylate test solutions were prepared and administered in a single dose. For the high dose level, t-butyl hydroxycyclohexyl methacrylate was administered undiluted, the other two test solutions were diltutions prepared in corn oil.Each animal was observed for toxic responses to the administered dose. The observation periods were immediately post dosing, 20-40 mins, 1, 2, 3 and 4 hours post dosing. Animals were observed daily thereafter. In addition animals were checked for mortality at the start and end of each day, with the exception of weekends where animals were checked once, around noon.Bodyweight of animals was recorded on dosing day (Day 0), Day 7 and, for surviving animals, Day 14.Gross necropsy was carried out on all study animals with the following organs examined; brain, pineal gland, pituitary gland, thymus, lungs, heart, thyroids, trachea, oesophagus, stomach, small and large intestine, liver, spleen, pancreas, mesenteric lymph nodes, salivary glands, lymph nodes, kidneys, adrenals, urinary bladder, reproductive organs.On Day 14, all survivng animals were sacrificed by CO2 asphyxiation and gross necropsy carried out, as described above.

Statistics:

The LD50 could not be determined for each sex due to the low number of deaths in each group. The LD50 values were determined for both sexes in combination.LD50 was estimated by Probit Analysis.

Results and discussion

Preliminary study:

Preliminary test was conducted at 10000 mg TBE/kg bodyweight using 2 male and 2 female rats.1/2 male rats died on Day 1 of the prelim test. Decreased bodyweight was observed at Day 1 (-10 %).2/2 female rats died- one on Day 2, the second on Day 3.

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

7 080 mg/kg bw

Based on:

test mat.

95% CL:

>= 5 043 - <= 10 187

Mortality:

Males; 2000 mg/kg: 0/5 5000 mg/kg: 1/5 10000 mg/kg: 3/5 Females; 2000 mg/kg: 0/5 5000 mg/kg: 1/5 10000 mg/kg: 5/5

Clinical signs:

2000 mg/kg group;All male and female rats had an increased respiration rate on Day 0. This was not evident on Day 1. One female rat showed increased salivation shortly after dosing. This was not evident on Day 1. No abnormal signs were observed from Day 1 to Day 14.5000 mg/kgAn increase in respiration rate was observed in all rats immediately after dosing. This was not evident at Day 1. Four male and four female rats showed no clinical signs on Day 1 to Day 14. One male rat was clear of signs on Day 1 but showed anormal posture, abnormal grip/limb tone, decreased body tone and decreased abdominal tone on Day 2. The animal died on Day 2. One female rat showed decreased activity, decreased general reaction, abnormal posture, abnormal gait, abnormal righting reflex, decreased body tone and decreased abdominal tone on Day 1. This animal was found dead on Day 2.10000 mg/kg20 minutes post-dosing, 5 male rats showed decreased activity. In the case of 3 animals, this persisted until death (on Day 1 and Day 2). The 2 remaining male rats appeared normal on Day 1 and Day 2. All male rats showed increased respiration immediately post dosing. In one animal this dissapeared at 20 mins post dosing. The animal was found dead in its cage on the morning of Day 1. In the case of the other two decendents, this sign persisted until death. In the case of the two survivors, this sign has cleared by Day 2. An impaired righting reflex was observed in three male rats on Day 1. One of the animals was found dead on Day 2 while the other two rats became free of this sign on Day 2 and 3. Decreased activity was observed in all female rats and persisted until death (Day 2). All female rats showed increased respiration immediately after dosing and 20 mins post dosing. This sign was not observed at any other timepoints prior to death on Day 2. Abnormal limb position, abnormal gait, abnormal righting reflex and decreased bodytone was evident on Day 1 in all female rats.

Body weight:

All surviving rats showed an increase in bodyweight from Day 0 to Day 7 and from Day 7 to Day 14. The weight gain was considered satisfactory for this age and strain of rat during all exposures and the control.

Gross pathology:

Post-mortem examination showed that the stomachs of the animals in the higher dose group were compacted and an enlarged mass was present. The stomach appeared thin and almost transparent. In one male the lungs had a blotchy red appearance. Two female rats had perforation of the stomach wall. The wall itself was almost transparent. The pineal gland on the surface of the brain was slightly larger in one female rat.In the lower dose group all 5 male rats had slightly compacted stomachs. In one male rat, the stomach lining was almost transparent. One male had red-white discolouration of the lungs while two animals had pale lungs. Four female rats had slightly compacted stomachs. The external lining of the stomach was very thin in 2/5 females.

Any other information on results incl. tables

Table 1       Body weight details and time of death

Sex	Test Concetration (mg/kg bodyweight)	Bodyweight (Day 0) (g)	Bodyweight (Day 7) (g)	Bodyweight (Day 14) (g)	Change in Bodyweight (g)
M	Control	164.8	252.3	291.0	+126.2
M	Control	163.2	240.4	271.9	+108.7
M	Control	150.0	225.5	253.6	+103.6
M	Control	165.8	242.5	274.4	+108.6
M	Control	169.0	245.4	272.8	+103.8
Mean		162.6	241.2	272.7	+110.2
F	Control	167.6	205.1	228.1	+60.5
F	Control	163.4	208.8	246.7	+83.3
F	Control	145.9	183.6	206.9	+61.0
F	Control	151.0	188.1	215.8	+64.8
F	Control	149.0	190.4	223.0	+74.0
Mean		155.4	195.2	224.1	+68.7
M	2000	158.4	212.2	281.3	+122.9
M	2000	167.2	220.7	278.0	+110.8
M	2000	176.8	231.5	268.0	+91.2
M	2000	168.2	232.8	300.0	+131.8
M	2000	166.3	238.3	305.4	+139.1
Mean		167.4	189.3	286.5	+119.2
F	2000	140.6	183.6	213.0	+72.4
F	2000	142.6	172.3	198.8	+56.2
F	2000	141.4	174.0	202.2	+60.8
F	2000	144.8	192.0	220.6	+75.8
F	2000	141.2	182.5	213.8	+72.6
Mean		142.1	180.9	209.7	+67.6
M	5000	173.4	220.0	274.8	+101.4
M	5000	179.5	230.8	302.6	+123.1
M	5000	169.4	- (2)
M	5000	166.9	210.2	276.9	+110.0
M	5000	161.2	210.2	256.8	+95.6
Mean		170.1	215.6	277.8	+107.5
F	5000	159.2	206.5	239.8	+80.6
F	5000	145.6	- (2)
F	5000	148.9	196.3	225.2	+76.3
F	5000	153.1	194.7	226.0	+72.9
F	5000	161.2	194.6	227.9	+66.7
Mean		153.6	198.0	229.7	+74.1
M	10000	191.7	224.3	320.8	+129.1
M	10000	168.1	- (2)
M	10000	162.4	- (1)
M	10000	170.4	204.8	279.6	+109.2
M	10000	177.2	- (1)
Mean		174.0	214.6	300.2	+119.2
F	10000	146.4	- (2)
F	10000	167.1	- (2)
F	10000	143.9	- (2)
F	10000	157.1	- (2)
F	10000	152.1	- (2)
Mean		153.3	-

-: rat deceased before weight recored

number in paranthesis indicates day of death (Study Day)

Survivng rats were sacrificed on Day 14

Table 2       Summary of pharmaco-toxicological responses appearing in CD rats (Day 0)

Clinical sign	Incidence of animals showing signs (M/F)
	Control	2000 mg/kg	5000 mg/kg	10000 mg/kg
Activity	0 / 0	0 / 0	0 / 0	5 / 5
< General Reaction	0 / 0	0 / 0	0 / 0	1 / 1
> Respiration Rate	0 / 0	5 / 5	5 / 5	5 / 5
> Salivation	0 / 0	0 / 1	0 / 0	0 / 0

Table 3       Summary of pharmaco-toxicological responses appearing in CD rats (Day 1 -14)

Clinical sign	Incidence of animals showing signs (M/F)
	Control	2000 mg/kg	5000 mg/kg	10000 mg/kg
< General Reaction	0 / 0	0 / 0	0 / 1	3 / -
Abnormal Body Posture	0 / 0	0 / 0	1 / 1	0 / -
Righting-Reflex	0 / 0	0 / 0	0 / 1	3 / -
Grip/Limb Tone	0 / 0	0 / 0	1 / 0	0 / -
< Body Tone	0 / 0	0 / 0	1 / 1	0 / -
< Abdominal Tone	0 / 0	0 / 0	1 / 1	0 / -
< Activity	0 / 0	0 / 0	0 / 1	0 / -
Abnormal Gait	0 / 0	0 / 0	0 / 1	0 / -
> Respiration Rate	0 / 0	0 / 0	0 / 1	0 / -

Table 4       Summary of mortality

	Dose Rate (mg/kg bodyweight)
	Control	2000	5000	10000
No. of treated animals	5 / 5	5 / 5	5 / 5	5 / 5
No. of animal’s deaths (Day 0-14)	0 / 0	0 / 0	1 / 1	3 / 5
No. of animal’s euthenized (at Day 14)	5 / 5	5 / 5	4 / 4	2 / 0

Male / Female rat mortality

Table 5       Summary of gross necropsy findings

Abnormality	Number of animals showing abnormality (male / female)
	2000 mg/kg	5000 mg/kg	10000 mg/kg
Liver	0 / 0	0 / 2	0 / 5
Stomach	5 / 4	2 / 5	5 / 4
Small Intestine	0 / 0	1 / 1	0 / 4
Large Intestine	0 / 0	1 / 1	2 / 5
Reproductive Organs	0 / 0	0 / 0	1 / 0
Thymus/Lungs/Heart	3 / 0	1 / 0	2 / 3
Brain-Pituitary Gland/Pineal Gland/Skull	0 / 0	0 / 1	0 / 0

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information Criteria used for interpretation of results: other: Annex VI (EEC Directive 93/21/EEC)

Conclusions:

The LD50 (for male and female combined) was 7080 mg/kg (CL: 5043, 10187 mg/kg).

Executive summary:

The study was designed to provide information on the acute oral toxicity of t-butyl hydroxycyclohexyl methacrylate in the Sprague Dawley CD rat following a single dose in corn oil to three dose groups (2000, 5000 and 10000 mg/kg bodyweight) of ten rats (five male and five female per group).

For the high dose level, t-butyl hydroxycyclohexyl methacrylate was administered undiluted. For the low and intermediate dose levels, dilutions of t-butyl hydroxycyclohexyl methacrylate were prepared in corn oil. The dosing solutions were administered by oral gavage at a dose volume of 10 mL/kg bodyweight, using a graduated syringe and stainless steel dosing cannula, within one hour of the solution preparation. A single oral dose was administered to each rat. A control group containing five male and five female rats were dosed with corn oil.

There was a total of 10 deaths in the main test (3 in the range-finder). One male and two female rats died within 48 h of the 10000 mg/kg administration in the range-finding test. During the main test two male rats treated with 10000 mg/kg dose died on Day 1 of the study and a third on Day 2. Five female rats treated with 10000 mg/kg died on Day 2. One male and one female rat treated at 5000 mg/kg died on Day 2.

Shortly after dosing mild clinical signs were noted including; decreased activity, decreased general reactions, increased respiration and abnormal righting reflex. No clinical signs were noted in survivng rats post Day 2.

All surviving rats were killed and necropsied on Day 14. The stomachs appeared slightly compacted in the male rats treated at 10000 mg/kg.

The LD50 (for male and female combined) was 7080 mg/kg (CL: 5043, 10187 mg/kg).