1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)propane-1,3-dione

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March - July 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

: no neurobehavioral tests were made, no purity of the test item was reported, 4-week recovery period in the control and high-dose group

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)propane-1,3-dione

EC Number:

274-581-6

EC Name:

1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)propane-1,3-dione

Cas Number:

70356-09-1

Molecular formula:

C20H22O3

IUPAC Name:

1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione

Test material form:

solid

Details on test material:

- Name of test material : BMDBM
- Physical state: solid

Test animals

Species:

rat

Strain:

other: Füllinsdorf Albino-SPF

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Füllinsdorf
- Age at study initiation: 6 - 8 weeks
- Weight at study initiation: 158 - 190 g (males), 130 - 147 g (females)
- Housing: 2 animals per cage
- Diet: NAFAG No. 850, restricted (feeding study)
- Water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 45 - 65
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 1983-03-08 To: 1983-07-07

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet: The test article was sifted to remove clots and mixed with the rat diet. The mixtures were freshly prepared each week (2.5 kg diet + test article for each male dose group; 2 kg diet + test article for each female dose group).
- Mixing appropriate amounts with: NAFAG No. 850 (pulverized)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of mixtures for analysis were taken during week 2 and week 13.

Duration of treatment / exposure:

91 - 94 days
Half the animals of the control and of the high-dose group were observed for further 30 days without treatment.

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

Doses / concentrations 2

Dose / conc.:

200 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

Doses / concentrations 3

Dose / conc.:

450 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

No. of animals per sex per dose:

12 rats per sex per dose group

Control animals:

yes, plain diet

Details on study design:

- Rationale for animal assignment: random table
- Post-exposure recovery period: 30 days

Positive control:

No positive control substance was used.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: continuously

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION AND COMPOUND INTAKE: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: at week 13
- Dose groups that were examined: only high-dose group (1000 mg/kg bw/day)

HAEMATOLOGY: Yes
- Time schedule for collection of blood: during weeks 2, 6, and 14
- Anaesthetic used for blood collection: Yes (N2O)
- Animals fasted: No data
- How many animals: all
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: during weeks 2, 6, and 14
- Animals fasted: No data
- How many animals: all
- Parameters checked in table 1 were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: during week 5 and 13
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters checked in table 1 were examined.

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table 2)
HISTOPATHOLOGY: Yes (see table 2)

Statistics:

Results of haematology and blood chemistry:
Dunn test (Technometrics 1964, 6: 241-52):Multiple comparisons, control versus all treated groups. Error rate = 0.1.

Body weights:
Growth rate (Rao, Biometrics 1958, 14: 1-17)
Adjusted organ weights (Trieb et al., Toxicol. Appl. Pharmacol. 1976, 35: 531-42)
Jonckheere test (Biometrika 1954, 41: 133-45)
U-test (Siegel, Monoparametric statistics 1956)

Results and discussion

Results of examinations

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Clinical signs were loss of hair, excitation, and crusted eye. The symptoms were distributed among the test groups as summarised in table 3. With one exception all symptoms had a slight intensity. These symptoms are normally found in animals used fort his study.
They were not considered to be treatment-related.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Treatment-related deaths did not occur. Two female rats (450 mg/kg/day; 1000 mg/kg/day) died as a result of anaesthesia and taking of blood samples.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

The weight development of all groups took a normal course throughout the study with the exception of the male group treated with 450 mg/kg/day. In this group, 4 rats did not receive their diet as a result of a blockage of the feed containers for some days. In this study, there was no influence of the test article butyl methoxydibenzoylmethane (BMDBM) on the body weight development.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

The feed consumption of males and females treated with 200 mg/kg bw/day was slightly higher than that of the control animals whereas males and females treated with 450 and 1000 mg/kg bw/day consumed less feed than control animals. These observations can be correlated with the body weight development.
The compound intakes are listed in table 4 and were all slightly higher than the intended dose.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No findings were observed in eyes of control rats and rats treated with 1000 mg/kg bw/day.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

All mean values of haematologic parameters were within the normal limits for rats in this laboratory at weeks 2 and 6, but at week 14, the mean RBC and Hb values of females treated with 1000 mg/kg bw/day nearly lay at the lower limit and were clearly lower than the mean RBC and Hb values of the female control group. The trend referring to the RBC decrease in the female group treated with 1000 mg/kg bw/day already occurred at week 6.
The RBC decrease in females treated with 1000 mg/kg bw/day was considered to be related to treatment.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The mean values of parameters of clinical chemistry listed in table 6 minimally laid outside of the physiological range for rats in this laboratory. These findings were considered to be treatment-related but not systematizable.
A few particular values clearly jutted out from the physiological range (AST in 1 animal of the control group, GLDH in 1 animal of the low-dose and in 2 animals of the high-dose group). These observations were not considered to be of toxicological importance.

Endocrine findings:

not examined

Urinalysis findings:

no effects observed

Description (incidence and severity):

Urinalysis results were similar in treated and control groups.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

With the exception of liver weights, all organ weights laid within the physiological range for rats in this laboratory. Mean relative liver weights of male rats treated with 1000 mg/kg bw/day as well mean absolute and mean relative liver weights of female rats treated with 200 mg/kg bw/day approached the upper limit of normal (table 7). Mean absolute and mean relative liver weights of female rats treated with 450 and 1000 mg/kg bw/day laid above of the physiological range.
These observations can be correlated with the slight increase in size of hepatic parenchyma cells in female rats treated with 1000 mg/kg bw/day (the lower dose groups were not examined).
The described increase of liver weights were considered to be related to treatment.
After a treatment-free period of 4 weeks, liver weights of male and female rats formerly treated with 1000 mg/kg bw/day were comparable with liver weights of control rats.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Necropsy findings were sporadic and consisted of bladder concrement and renal and ovarian cysts.
These observations were accidental findings which were not considered to be related to treatment.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

The histopathological changes are summarized in table 8.
With the exception of the slight increase in size of hepatic parenchyma cells, all other changes were not considered to be of toxicological importance. The incidence, degree, and group distribution of these changes did not show any effect of the treatment with BMDBM on a cellular structure of the examined organs and tissues.

The oral administration of BMDBM when given for 13 weeks caused a slight reduction of red blood cells in female rats treated with 1000 mg/kg/day. The quantity of reticulocytes was normal and the bone marrow was unchanged. The reason for the erythrocytes reduction was not detected.
The absolute and relative liver weights were higher in male rats treated with 1000 mg/kg/day and in all female dose groups than those in the control groups. In addition, a hepatocellular hypertrophy appeared in female rats treated with 1000 mg/kg/day (the lower dose groups were not examined). These findings were signs of an intensification of hepatic function which was interpreted as a process of adaptation because the liver weights of high dosed males and females were normalized after a treatment-free period of 4 weeks.
In all probability, the petty shifts of concentration of plasma proteins have connection with the process of adaption.

Histopathological findings: neoplastic:

not examined

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

450 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

2

Key result

Dose descriptor:

LOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Significant incresed liver weights and reduced Hb and RBC in the females of the 1000 mg/kd bw/day dose group.

Target system / organ toxicity

Key result

Critical effects observed:

not specified

Any other information on results incl. tables

Table 3: Clinical observations made during the oral administration of butyl methoxydibenzoylmethane (BMDBM) to rats over 90 days.

Symptom	Control	BMDBM [mg/kg bw/day]
		200	450	1000
Loss of hair	1F	2F	-	2F
Exitation	-	1F	2M	1M
Crusted eye	-	-	1F	1M

F: female, M. male

 

Table 4: Compound intake during the oral administration of butyl methoxydibenzoylmethane (BMDBM) to rats over 90 days.

Intended dose [mg/kg bw/day]	Mean compound intake [mg/kg bw/day]
	Males	Females
0	0.00	0.00
200	204.27	202.64
450	459.34	247.73
1000	1019.32	1012.75

 

Table 5:Selected haematology findingsmade during the oral administration of butyl methoxydibenzoylmethane (BMDBM) to female rats over 90 days.

	Control	BMDBM [mg/kg bw/day]
		200	450	1000
Red blood cell count (Mio./µL)
Week 2	7.55 ± 0.30	7.29 ± 0.28	7.38 ± 0.39	7.38 ± 0.34
Week 6	8.28 ± 0.16	8.03 ± 0.34	7.96 ± 0.32	7.88 ± 0.17
Week 14	8.38 ± 0.10	8.29 ± 0.29	8.15 ± 0.30	7.77 ± 0.20
Hemoglobin (g/dL)
Week 2	15.7 ± 0.6	15.1 ± 0.8	15.2 ± 0.9	15.0 ± 0.6
Week 6	16.5 ± 0.4	15.7 ± 0.5	15.7 ± 0.3	15.6 ± 0.5
Week 14	16.0 ± 0.2	15.5 ± 0.6	15.4 ± 0.7	14.3 ± 0.2

 

Table 6: Selected clinical chemistry findingsmade during the oral administration of butyl methoxydibenzoylmethane (BMDBM) to rats over 90 days

Test group [mg/kg bw/day]	Sex	Parameter	Week	Change
1000	Males	Potassium	6	Increased
1000	Males	Albumin [%]	6	Increased
1000	Males	Albumin [g/L]	6	Increased
1000	Males	Albumin/globulin	6	Increased
1000	Females	Albumin [%]	6	Increased
450, 1000	Females	alpha-Globulin 3 [%]	6	Decreased
450, 1000	Females	alpha-Globulin 3 [g/L]	6	Decreased
1000	Females	Albumin/globulin	6	Increased
1000	Females	Albumin [%]	14	Increased
200, 450, 1000	Females	beta-Globulin 3 [%]	14	Decreased
200, 450, 1000	Females	beta-Globulin 3 [g/L]	14	Decreased
1000	Females	Albumin/globulin	14	Increased

 

Table 7: Absolute liver and liver-to-brain ratios of rats fed butyl methoxydibenzoylmethane (BMDBM) over 90 days

	Control	BMDBM [mg/kg bw/day]
		200	450	1000
Males
Absolute [g]	15.557 ± 2.153	16.198 ± 2.517	16.836 ± 1.820	17.263 ± 2.363
Relative [g/ 100g bw]	6.04 ± 0.73	6.40 ± 0.71	6.77 ± 0.50	7.46 ± 0.87 *
Males (4 weeks recovery)
Relative [g/ 100g bw]	6.17 ± 0.54			6.36 ± 0.43
Females
Absolute [g]	8.517 ± 0.847	10.312 ± 1.203	10.900 ± 0.723	11.101 ± 2.107
Relative [g/ 100g bw]	5.42 ± 0.45	6.60 ± 0.63^##	7.26 ± 0.47 **	8.59 ± 0.74 **
Females (4 weeks recovery)
Relative [g/ 100g bw]	5.73 ± 0.34			6.25 ± 0.60

* P<0.05 (Jonckheere test)

** P<0.01 (Jonckheere test)

^##P<0.01 (U-test)

 

Table 8: Number of animals with gross, non-neoplastic, or neoplastic lesions at end of dosing period.

SEX	males		females
DAILY DOSE (mg/kg bw/day)	0	1000	0	1000
NUMBER OF ANIMALS EXAMINED	6	6	6	6
Heart
Non-neoplastic lesion:
Myocardial necrosis, slight	1
Multifocal lympho-histiocytic infiltration of the interstice, minimal to slight	5	5	5	5
Small accumulation of inflammatory cells within of the ventricle, minimal	1		1
Small focus of cartilage, minimal	1	2
Neoplastic lesion:
Lung
Non-neoplastic lesion:
Small atelectatic region, minimal	1			1
Small focus of inflammatory cells in the interstice, minimal			1	1
Diffuse infiltration of inflammatory cells in the connective tissue, minimal				1
Trachea
Non-neoplastic lesion:
Desquamation of epithelial cells, minimal	1
Liver
Non-neoplastic lesion:
Lympho-histiocytic infiltration of portal tracts with altered bile ducts, minimal to moderate	3	6	6	6
Multifocal infiltration of the parenchyma by mainly lymphocytes and histiocytes, minimal to moderate	6	6	4	6
Focal necroses in the parenchyma, minimal to moderate	1	3	1	2
Increased fat content, minimal to slight	2
Slight increase in size of hepatic parenchyma cells				6
Pancreas
Non-neoplastic lesion:
Area with increase of connective tissue and loose infiltration by inflammatory cells and destruction of the exocrine parenchyma, minimal to moderate	1	2		1
Perivascular accumulation of lymphocytes, minimal			3
Kidney
Non-neoplastic lesion:
Subcapsular lympho-histiocytic infiltration, minimal		1
Perivascular lympho-histiocytic infiltration, minimal	1	1		3
Lympho-histiocytic infiltration with necrosis of epithelium of renal tubules, minimal	1	2	1
Nephrocalcinosis, minimal			3	3
Thyroid
Non-neoplastic lesion:
Desquamation of epithelial cells, minimal to moderate	6	4	4	4
Thyroid of recovery animals
Non-neoplastic lesion:
Desquamation of epithelial cells, minimal to slight	2	5	5	3
Adrenal gland
Non-neoplastic lesion:
Focal infiltration by mainly lymphocytes, minimal	1	2	1	3
Testis
Non-neoplastic lesion:
Damage of the germinal epithelium, moderate to severe		1
Bone
Non-neoplastic lesion:
Epiphyseal plate with an irregula region, minimal			1	1

 

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the NOAEL was considered to be 450 mg/kg bw/day. A significant increase in absolute and relative liver weight was observed in female rats at 450 and 1000 mg/kg bw/day and in male rats at 1000 mg/kg bw/day. Furthermore, a decrease in RBC and Hb was observed in female animals at 1000 mg/kg bw/day.

Executive summary:

The UV-A filter butyl methoxydibenzoylmethane (BMDBM) was administered as feed admix during 13 weeks. Four test groups each consisting of 12 rats per sex were formed. The animals received 0, 200, 450, and 1000 mg active ingredient per kg body weight per day. Mortality, general symptoms, and body weights were recorded. Haematology and clinical chemistry determinations were performed. All rats were autopsied. Organs and tissues of the control rats and rats treated with 1000 mg/kg bw/day were microscopically examined.

Deaths related to treatment did not occur throughout the test period. Two female rats died as a result of anaesthesia. Treatment-related clinical symptoms were not observed. The treatment with BMDBM did not have an effect on the weight development and feed consumption. The number of red blood cells was decreased in female rats treated with 1000 mg/kg bw/day. The results of the urinalysis were normal. No findings were observed in eyes of control rats and rats treated with 1000 mg/kg bw/day. No treatment-related necropsy findings were seen. The liver weights of male rats treated with 1000 mg/kg bw/day and of females treated with 200, 450, and 1000 mg/kg bw/day were higher than those of the control groups. The liver weight increase in the animals treated with 200 mg/kg bw/day could be attributed to their higher body weight compared to the control animals, but the effect in the higher dose groups must be considered as related to treatment. After a treatment-free period of 4 weeks, the high dosed male and female rats had a normal liver weight. With the exception of hepatic parenchyma cells which became hypertrophic in females treated with 1000 mg/kg bw/day, no histopathological changes were considered to be related to treatment.

Under the conditions of this study, the maximum oral dose level producing no toxic effect (NOAEL) was considered to be 450 mg/kg bw/day. The increase of liver weights as well the increase of hepatic parenchyma cells were interpreted as a process of liver adaption to treatment.