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

Endpoint summary

Description of key information

A sub-chronic oral toxicity study (90-day) revealed a NOAEL of 450 mg/kg bw/day, and a LOAEL of 1000 mg/kg bw/day. In one dermal repeated dose toxicity study (21 days) a NOAEL of 360 mg/kg bw/day (highest concentration tested) was obtained with the rabbit. Applying route to route extrapolation, by assuming that penetration of BMDBM through skin is equal to penetration through the intestinal wall, the same effect levels as for oral route shall apply for the dermal route of exposure.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

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

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

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

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

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

Dose / conc.:

200 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

Dose / conc.:

450 mg/kg bw/day (nominal)

Remarks:

Basis: nominal in diet

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.

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)

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

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

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.

Key result

Critical effects observed:

not specified

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

 

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.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

450 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

similar to OECD TG 408

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1979-11-08 - 1980-06-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

yes

Remarks:

: use of intact as well as abraded skin

GLP compliance:

no

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hacking & Churchill Ltd. Wyton, Huntingdon, Cambs., England
- Age at study initiation: 11 -14 weeks
- Weight at study initiation: 2.0 - 2.8 kg
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 20 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 °C
- Humidity (%): 45 ± 10 %
- Air changes (per hr): 19

IN-LIFE DATES: From: 1979-11-08 To:1979-11-30

Type of coverage:

occlusive

Vehicle:

other: Carbitol (diethylene glycol monoethyl ether)

Details on exposure:

TEST SITE
- Area of exposure: mid dorsal
- % coverage: approx. 10 % of body surface
- Type of wrap if used: occlusive bandage consisting of a gauze covered with Elastoplast elastic adhesive dressing backed with impervious Sleek plaster.
- Time intervals for shavings or clippings: Abrasion was carried out weekly and hair clipping was repeated daily.

REMOVAL OF TEST SUBSTANCE
- Washing: with warm tap water
- Time after start of exposure: 6 h

TEST MATERIAL
- Concentration: 30, 100, and 360 mg/kg bw/day
- Constant volume used: yes
- For solids, paste formed: yes

VEHICLE
- Justification for use and choice of vehicle (if other than water): Carbinol, due to the good solubility of the test item
- Amount(s) applied: 2 mL/kg bw/day
- Lot/batch no.: 19431787 and B711019

USE OF RESTRAINERS FOR PREVENTING INGESTION: yes

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

6 h per day

Frequency of treatment:

21 days

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

30 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

360 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 males and 10 females per dose group. Half of the animals were tested with intact the other half was tested with abraded skin.

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: tested up to the highest soluble concentration

Positive control:

No positive control used.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: daily, prior to application

BODY WEIGHT: Yes
- Time schedule for examinations: at the start of dosing and then twice weekly (days 1, 5, 8, 12, 15, 19, and 22)

FOOD CONSUMPTION:
- Food consumption for each animal determined: Yes

WATER CONSUMPTION: Yes
- Time schedule for examinations: only during week 3

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: prior to treatment and then during the 3rd week of treatment
- Anaesthetic used for blood collection: No
- Animals fasted: Yes
- How many animals: prior to treatment: all animals; during the 3rd week of treatment: 5 male and 5 female rabbits with abraded skin from each group
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: prior to treatment and then during the 3rd week of treatment
- Animals fasted: Yes
- How many animals: prior to treatment: all animals; during the 3rd week of treatment: 5 male and 5 female rabbits with abraded skin from each group
- Parameters checked in table 1 were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table)
HISTOPATHOLOGY: Yes (see table) / No / No data

Statistics:

Analysis of variance followed by Student's t-test was used to assess the significance of intergroup differences in clinical laboratory data.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No behavioural changes or signs of toxicosis were observed amongst surviving rabbits during the study period. Soft faeces and/or diarrhoea of a sporadic nature were observed in surviving rabbits from all groups, including the controls. This finding was considered to be incidental and not related to treatment with butyl methoxydibenzoylmethane (BMDBM).

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

(Tables 5a and b)
Sporadic slight erythema was observed in three negative control rabbits during week 3 of the study.
Slight dermal reactions were generally seen in all rabbits treated with Carbitol (vehicle control) during weeks 2 and 3 of the study and well-defined erythema was recorded in five rabbits of this group during week 3.
The severity of dermal reactions of rabbits receiving BMDBM was generally greater than the controls and increased in a dosage-related manner. Slight to well-defined dermal reactions were observed from Day 6 to the end of the treatment period in all rabbits treated with BMDBM 30 or 100 mg/kg/day, although well-defined reactions were more persistent in rabbits of Group 4 (BMDBM, 100 mg/kg/day). Well-defined to moderate dermal reactions were generally seen in all rabbits treated with BMDBM, 360 mg/kg/day during this period.
Dryness and sloughing of the epidermis was observed in the majority of rabbits treated with BMDBM and the incidence was seen to increase with dosage. This finding was also observed in only 3 rabbits treated with Carbitol (vehicle control) but was not observed in procedural control rabbits.
There were no apparent differences in the dermal reactions of rabbits with intact or abraded skin condition within each group.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Five rabbits died during the study period and one rabbit was sacrificed in extremis. The distribution of the animal mortality was not dependent on test item treatment and is tabulated in table 3.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

No treatment-related trends were apparent (Table 4). Bodyweight losses on day 19 in the majority of the control and treated rabbits with abraded skin were considered to be a result of overnight food deprivation prior to removal of blood samples on day 19.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No treatment-related trends were apparent.

Food efficiency:

not examined

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

no effects observed

Description (incidence and severity):

No treatment-related trends were apparent.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

There were no changes that were considered to be related to treatment with BMDBM.
Statistical analysis of values from the week 3 investigations revealed statistical significances in comparison to the controls. These differences were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

There were no apparent changes that were considered to be directly related to treatment with BMDBM.
Statistical analysis of values from the week 3 investigations revealed statistical significances in comparison to the controls. These differences were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No changes were seen that were considered to be related to treatment with BMDBM.
Group mean organ weights for some groups attained statistical significance in comparison with control values. These findings were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No changes were seen that were considered to be indicative of a treatment-related effect.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Skin: No abnormalities were seen in skin taken from procedural control group rabbits or from the untreated control sites on the animals in the treated groups. In treated skin samples from the vehicle control group and the treatment groups a minimal focal to moderate generalised increase in epidermal thickness was recorded. This was occasionally but in frequently associated with a minimal cutaneous inflammatory infiltration. No quantitative differences could be determined between animals with intact or abraded skin.
The severity of the epidermal change showed no dose-relationship in treated groups and this was considered to be similar to the severity if this change observed in the vehicle control group.
Liver: Pericholangitis characterised by occasional parenchymal or portal foci if mononuclear cell infiltration in a proportion of animals from each group. Hepatocyte necrosis in occasional rabbits.
Kidneys: Varying degrees of chronic interstitial nephritis and fibrosis in a large proportion of rabbits from both control and treatment groups. No significant differences in terms of severity are distinguishable that might be ascribed to the vehicle or the test compound.
Gastro-intestinal tract: Chronic inflammatory bowel lesions of the gastro-intestinal mucosa in a small number of rabbits at termination and in all decedents. These lesions were probably due to a localised infection and considered a contributing factor to death in the decedents in this study. This was considered to be unrelated to treatment.
Brain: Perivascular inflammatory cuffing and cerebral gliosis and granulomata in a proportion of rabbits from all groups. These lesions were probably indicative of an enzephalitozoon infestation.

Histopathological findings: neoplastic:

not examined

Key result

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

360 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Dose descriptor:

LOAEL

Remarks:

systemic

Effect level:

> 360 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: As the animals showed no systemic signs of toxicity with the highest concentration used, no LOAEL for systemic toxicity could be identified.

Remarks on result:

not determinable due to absence of adverse toxic effects

Dose descriptor:

LOAEL

Remarks:

local

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: In this concentration, distinct local effects (formation of erythema / edema) were visible after treatment.

Key result

Critical effects observed:

not specified

Table 3: Summarized mortalities after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to rabbits.

Group		Mortalities		Total per group	Mortality
		Males	Females
1	Negative control	0	2	2/20	10 %
2	Vehicle control	2	0	2/20	10 %
3	BMDBM 30 mg/kg bw/day	0	1	1/20	5 %
4	BMDBM 100 mg/kg bw/day	0	0	0/20	0 %
5	BMDBM 360 mg/kg bw/day	1	0	1/20	5 %

 

Table 4: Group mean bodyweights (g) of rabbits after repeated dermal application of BMDBM.

Group		Skin	Bodyweight [g] on day							Bodyweight change days 1 - 22	as % of controls
			0	5	8	12	15	19	22
Male
1	Negative control	Intact Abraded	2927 2968	2895 3026	2939 3068	3037 3177	3088 3262	3063 3171	3106 3270	179 302	- -
2	Vehicle control	Intact Abraded	2928 2962	2936 2980	2931 3023	2990 3162	3086 3203	2994 3134	3360 3286	432 324	241 107
3	BMDBM 30 mg/kg bw/day	Intact Abraded	2962 2947	2976 2992	3013 3046	3082 3127	3156 3201	3194 3056	3212 3216	250 269	140 89
4	BMDBM 100 mg/kg bw/day	Intact Abraded	2943 2938	2981 2935	3010 3012	3093 3100	3195 3171	3237 3130	3263 3213	320 275	179 91
5	BMDBM 360 mg/kg bw/day	Intact Abraded	2934 2942	2950 2926	2934 2981	3047 3077	3056 3157	3114 3109	3151 3252	217 310	121 103
Female
1	Negative control	Intact Abraded	2873 2854	2907 2781	2912 2910	2923 2984	2961 3085	3022 3030	3002 3080	129 226	- -
2	Vehicle control	Intact Abraded	2871 2871	2928 2910	3047 2903	3145 3028	3224 3093	3296 3105	3329 3184	458   313	355 138
3	BMDBM 30 mg/kg bw/day	Intact Abraded	2888 2866	2875 2860	2910 2897	2949 3004	3008 3120	3116 3049	3131 3189	243 323	188 143
4	BMDBM 100 mg/kg bw/day	Intact Abraded	2861 2861	2934 2917	2980 2948	3072 3007	3122 3082	3240 3114	3255 3114	394 253	305 112
5	BMDBM 360 mg/kg bw/day	Intact Abraded	2856 2785	2927 2858	2961 2908	3063 2988	3165 3084	3213 2971	3280 3128	424 343	329 152

 

Table 5a: Mean erythema (E) and oedema (O) scores after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to 5 male rabbits (intact skin).

Day	Negative control		Vehicle control		BMDBM [mg/kg bw/day]
					30		100		360
Erythema/Oedema:	E	O	E	O	E	O	E	O	E	O
1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
2	0.0	0.0	0.0	0.0	0.0	0.0	0.2	0.0	0.0	0.0
3	0.0	0.0	0.0	0.0	0.4	0.0	0.6	0.2	0.6	0.8
4	0.0	0.0	0.2	0.0	1.0	0.0	1.2	0.8	1.0	1.2
5	0.0	0.0	0.4	0.2	1.0	0.8	1.6	1.0	1.2	1.8
6	0.0	0.0	0.0	0.0	0.8	0.8	1.8	1.8	2.0	2.0
7	0.0	0.0	0.4	0.0	1.2	0.8	1.6	2.0	2.0	2.0
8	0.0	0.0	0.6	0.2	1.0	1.0	1.6	2.0	2.0	2.0
9	0.0	0.0	0.2	0.0	1.0	0.6	1.6	1.2	2.0	1.8
10^1	0.0	0.0	0.8	0.0	1.0	0.8	1.8	1.4	2.0	2.0
11	0.0	0.0	0.5	0.0	0.8	0.6	1.6	1.4	2.0	2.0
12	0.0	0.0	1.0	0.0	1.0	0.6	1.6	1.6	2.0	2.0
13	0.0	0.0	0.8	0.0	1.0	0.6	1.6	1.2	2.0	2.2
14	0.0	0.0	0.8	1.0	1.0	0.8	1.8	1.2	2.0	2.4
15	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.6	2.0	2.0
16	0.0	0.0	0.8	0.3	1.2	0.6	2.0	1.6	2.0	1.6
17	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.6	2.0	1.8
18	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.8	2.0	1.8
19	0.4	0.4	1.3	0.5	1.2	1.0	1.6	1.8	2.0	2.2
20	0.0	0.0	1.0	0.5	1.2	1.0	1.8	1.8	2.0	2.0
21	0.0	0.0	1.3	0.5	1.2	1.0	2.0	1.8	2.0	2.0
22^2	0.0	0.0	1.3	0.3	1.2	1.0	2.0	1.8	2.0	2.2
23	0.0	0.0	1.3	1.0	1.0	1.0	2.0	2.0	2.0	2.0

¹ 1 out of 5 animals was found dead in the negative control group

² 1 out of 5 animals was found dead in the negative control group

 

Table 5b: Mean erythema (E) and oedema (O) scores after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to 5 female rabbits (intact skin).

	Negative control		Vehicle control		BMDBM [mg/kg bw/day]
					30		100		360
Erythema/Oedema:	E	O	E	O	E	O	E	O	E	O
1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
2	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
3	0.0	0.0	0.2	0.0	0.6	0.0	0.6	0.2	0.4	0.0
4	0.0	0.0	0.4	0.0	0.6	0.0	0.8	0.4	1.4	0.8
5	0.0	0.0	0.8	0.4	1.4	1.4	1.2	1.4	2.0	1.8
6	0.0	0.0	0.4	0.0	1.2	1.0	1.8	1.6	2.2	2.0
7	0.0	0.0	0.4	0.2	1.0	1.2	1.6	1.8	2.2	2.0
8^1	0.0	0.0	0.2	0.0	1.0	1.3	1.4	1.8	2.0	2.0
9	0.0	0.0	0.0	0.0	1.0	0.3	1.6	1.2	2.0	1.8
10	0.0	0.0	0.0	0.0	1.0	0.8	1.6	1.4	2.0	2.0
11	0.0	0.0	0.8	0.4	1.0	0.5	1.8	1.4	2.0	2.0
12^2	0.0	0.0	0.8	0.4	1.0	1.0	2.0	1.6	2.0	2.0
13	0.0	0.0	0.8	0.2	1.0	0.8	2.0	1.4	2.0	2.2
14	0.0	0.0	0.8	0.2	1.0	1.0	2.0	1.8	2.0	2.4
15	0.0	0.0	0.8	0.2	1.5	1.0	2.0	1.6	2.2	2.2
16^3	0.0	0.0	0.8	0.4	1.3	0.3	2.0	1.0	1.8	2.0
17	0.0	0.0	0.8	0.6	1.3	0.5	2.0	1.0	2.0	2.0
18	0.0	0.0	0.8	0.6	1.5	0.8	2.0	1.2	2.0	2.0
19	0.0	0.0	1.0	0.8	1.0	1.0	1.6	1.2	2.0	2.0
20	0.0	0.0	1.0	1.0	1.0	1.0	1.8	1.4	2.0	2.2
21	0.0	0.0	1.2	0.8	1.0	1.0	2.0	1.6	2.0	2.6
22	0.0	0.0	1.0	0.8	1.0	1.0	1.8	1.8	2.0	2.2
23	0.0	0.0	1.0	0.0	1.0	1.0	2.0	2.0	2.0	2.3

¹ 1 out of 5 animals was found dead in the 30 mg/kg bw group

² 1 out of 5 animals was found dead in the negative control group

³ 1 out of 5 animals was found dead in the negative control group

Conclusions:

Repeated (21 days) dermal application of BMDBM (30, 100, and 360 mg/kg bw/day) to the intact or abraded skin of rabbits caused no deaths. Therefore, the NOAEL for systemic toxicity was set to the highest applied dose of 360 mg/kg bw/day. There was a dosage-related increase in the severity of dermal reactions of rabbits treated with BMDBM, including slight to moderate erythema and edema. The respective vehicle control exhibited only slight dermal reactions.

Executive summary:

BMDBM, a crystalline sun protection substance, was prepared freshly each day as 1.5, 5 and 18 % w/v solutions in Carbitol and applied to the skin of rabbits once daily at dosage levels of 30, 100 and 360 mg/kg bw/day, for an exposure period of six hours each day, for twenty-one consecutive days.

There was a dosage-related increase in the severity of dermal reactions of rabbits treated with BMDBM. Slight to well-defined dermal reactions were generally observed in rabbits treated with BMDBM 30 or 100 mg/kg bw/day, although well-defined reactions were more persistent in rabbits treated with BMDBM, 100 mg/kg bw/day. Well-defined to moderate dermal reactions were generally seen in rabbits treated with BMDBM, 360 mg/kg/day. Slight dermal reactions occurred in the vehicle control animals (Carbitol). Microscopic examination of the treated skin sites revealed an increased incidence of epidermal thickening in rabbits from the vehicle control and treatment groups when compared to the untreated control group. Five rabbits were found dead during the study and one rabbit was sacrificed. The death of these animals was not considered to be directly related to treatment. Histopathological examination revealed gastrointestinal infection to be a factor contributory to the death of each animal.

In all other aspects including general health, bodyweights, food consumption, water consumption, haematology, blood chemistry, organ weights macroscopic pathology, and microscopic pathology of tissues excluding skin, rabbits treated with BMDBM were similar to the procedural and vehicle controls. Therefore, the NOAEL, based on systemic effects, can be considered to be 360 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

360 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

similar to OECD TG 410

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1979-11-08 - 1980-06-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

yes

Remarks:

: use of intact as well as abraded skin

GLP compliance:

no

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hacking & Churchill Ltd. Wyton, Huntingdon, Cambs., England
- Age at study initiation: 11 -14 weeks
- Weight at study initiation: 2.0 - 2.8 kg
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 20 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 °C
- Humidity (%): 45 ± 10 %
- Air changes (per hr): 19

IN-LIFE DATES: From: 1979-11-08 To:1979-11-30

Type of coverage:

occlusive

Vehicle:

other: Carbitol (diethylene glycol monoethyl ether)

Details on exposure:

TEST SITE
- Area of exposure: mid dorsal
- % coverage: approx. 10 % of body surface
- Type of wrap if used: occlusive bandage consisting of a gauze covered with Elastoplast elastic adhesive dressing backed with impervious Sleek plaster.
- Time intervals for shavings or clippings: Abrasion was carried out weekly and hair clipping was repeated daily.

REMOVAL OF TEST SUBSTANCE
- Washing: with warm tap water
- Time after start of exposure: 6 h

TEST MATERIAL
- Concentration: 30, 100, and 360 mg/kg bw/day
- Constant volume used: yes
- For solids, paste formed: yes

VEHICLE
- Justification for use and choice of vehicle (if other than water): Carbinol, due to the good solubility of the test item
- Amount(s) applied: 2 mL/kg bw/day
- Lot/batch no.: 19431787 and B711019

USE OF RESTRAINERS FOR PREVENTING INGESTION: yes

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

6 h per day

Frequency of treatment:

21 days

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

30 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

360 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 males and 10 females per dose group. Half of the animals were tested with intact the other half was tested with abraded skin.

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: tested up to the highest soluble concentration

Positive control:

No positive control used.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: daily, prior to application

BODY WEIGHT: Yes
- Time schedule for examinations: at the start of dosing and then twice weekly (days 1, 5, 8, 12, 15, 19, and 22)

FOOD CONSUMPTION:
- Food consumption for each animal determined: Yes

WATER CONSUMPTION: Yes
- Time schedule for examinations: only during week 3

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: prior to treatment and then during the 3rd week of treatment
- Anaesthetic used for blood collection: No
- Animals fasted: Yes
- How many animals: prior to treatment: all animals; during the 3rd week of treatment: 5 male and 5 female rabbits with abraded skin from each group
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: prior to treatment and then during the 3rd week of treatment
- Animals fasted: Yes
- How many animals: prior to treatment: all animals; during the 3rd week of treatment: 5 male and 5 female rabbits with abraded skin from each group
- Parameters checked in table 1 were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table)
HISTOPATHOLOGY: Yes (see table) / No / No data

Statistics:

Analysis of variance followed by Student's t-test was used to assess the significance of intergroup differences in clinical laboratory data.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No behavioural changes or signs of toxicosis were observed amongst surviving rabbits during the study period. Soft faeces and/or diarrhoea of a sporadic nature were observed in surviving rabbits from all groups, including the controls. This finding was considered to be incidental and not related to treatment with butyl methoxydibenzoylmethane (BMDBM).

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

(Tables 5a and b)
Sporadic slight erythema was observed in three negative control rabbits during week 3 of the study.
Slight dermal reactions were generally seen in all rabbits treated with Carbitol (vehicle control) during weeks 2 and 3 of the study and well-defined erythema was recorded in five rabbits of this group during week 3.
The severity of dermal reactions of rabbits receiving BMDBM was generally greater than the controls and increased in a dosage-related manner. Slight to well-defined dermal reactions were observed from Day 6 to the end of the treatment period in all rabbits treated with BMDBM 30 or 100 mg/kg/day, although well-defined reactions were more persistent in rabbits of Group 4 (BMDBM, 100 mg/kg/day). Well-defined to moderate dermal reactions were generally seen in all rabbits treated with BMDBM, 360 mg/kg/day during this period.
Dryness and sloughing of the epidermis was observed in the majority of rabbits treated with BMDBM and the incidence was seen to increase with dosage. This finding was also observed in only 3 rabbits treated with Carbitol (vehicle control) but was not observed in procedural control rabbits.
There were no apparent differences in the dermal reactions of rabbits with intact or abraded skin condition within each group.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Five rabbits died during the study period and one rabbit was sacrificed in extremis. The distribution of the animal mortality was not dependent on test item treatment and is tabulated in table 3.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

No treatment-related trends were apparent (Table 4). Bodyweight losses on day 19 in the majority of the control and treated rabbits with abraded skin were considered to be a result of overnight food deprivation prior to removal of blood samples on day 19.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No treatment-related trends were apparent.

Food efficiency:

not examined

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

no effects observed

Description (incidence and severity):

No treatment-related trends were apparent.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

There were no changes that were considered to be related to treatment with BMDBM.
Statistical analysis of values from the week 3 investigations revealed statistical significances in comparison to the controls. These differences were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

There were no apparent changes that were considered to be directly related to treatment with BMDBM.
Statistical analysis of values from the week 3 investigations revealed statistical significances in comparison to the controls. These differences were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No changes were seen that were considered to be related to treatment with BMDBM.
Group mean organ weights for some groups attained statistical significance in comparison with control values. These findings were not considered to be of toxicological importance and variations in values for individual rabbits were considered to bias statistical analysis in these instances.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No changes were seen that were considered to be indicative of a treatment-related effect.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Skin: No abnormalities were seen in skin taken from procedural control group rabbits or from the untreated control sites on the animals in the treated groups. In treated skin samples from the vehicle control group and the treatment groups a minimal focal to moderate generalised increase in epidermal thickness was recorded. This was occasionally but in frequently associated with a minimal cutaneous inflammatory infiltration. No quantitative differences could be determined between animals with intact or abraded skin.
The severity of the epidermal change showed no dose-relationship in treated groups and this was considered to be similar to the severity if this change observed in the vehicle control group.
Liver: Pericholangitis characterised by occasional parenchymal or portal foci if mononuclear cell infiltration in a proportion of animals from each group. Hepatocyte necrosis in occasional rabbits.
Kidneys: Varying degrees of chronic interstitial nephritis and fibrosis in a large proportion of rabbits from both control and treatment groups. No significant differences in terms of severity are distinguishable that might be ascribed to the vehicle or the test compound.
Gastro-intestinal tract: Chronic inflammatory bowel lesions of the gastro-intestinal mucosa in a small number of rabbits at termination and in all decedents. These lesions were probably due to a localised infection and considered a contributing factor to death in the decedents in this study. This was considered to be unrelated to treatment.
Brain: Perivascular inflammatory cuffing and cerebral gliosis and granulomata in a proportion of rabbits from all groups. These lesions were probably indicative of an enzephalitozoon infestation.

Histopathological findings: neoplastic:

not examined

Key result

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

360 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Dose descriptor:

LOAEL

Remarks:

systemic

Effect level:

> 360 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: As the animals showed no systemic signs of toxicity with the highest concentration used, no LOAEL for systemic toxicity could be identified.

Remarks on result:

not determinable due to absence of adverse toxic effects

Dose descriptor:

LOAEL

Remarks:

local

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: In this concentration, distinct local effects (formation of erythema / edema) were visible after treatment.

Key result

Critical effects observed:

not specified

Table 3: Summarized mortalities after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to rabbits.

Group		Mortalities		Total per group	Mortality
		Males	Females
1	Negative control	0	2	2/20	10 %
2	Vehicle control	2	0	2/20	10 %
3	BMDBM 30 mg/kg bw/day	0	1	1/20	5 %
4	BMDBM 100 mg/kg bw/day	0	0	0/20	0 %
5	BMDBM 360 mg/kg bw/day	1	0	1/20	5 %

 

Table 4: Group mean bodyweights (g) of rabbits after repeated dermal application of BMDBM.

Group		Skin	Bodyweight [g] on day							Bodyweight change days 1 - 22	as % of controls
			0	5	8	12	15	19	22
Male
1	Negative control	Intact Abraded	2927 2968	2895 3026	2939 3068	3037 3177	3088 3262	3063 3171	3106 3270	179 302	- -
2	Vehicle control	Intact Abraded	2928 2962	2936 2980	2931 3023	2990 3162	3086 3203	2994 3134	3360 3286	432 324	241 107
3	BMDBM 30 mg/kg bw/day	Intact Abraded	2962 2947	2976 2992	3013 3046	3082 3127	3156 3201	3194 3056	3212 3216	250 269	140 89
4	BMDBM 100 mg/kg bw/day	Intact Abraded	2943 2938	2981 2935	3010 3012	3093 3100	3195 3171	3237 3130	3263 3213	320 275	179 91
5	BMDBM 360 mg/kg bw/day	Intact Abraded	2934 2942	2950 2926	2934 2981	3047 3077	3056 3157	3114 3109	3151 3252	217 310	121 103
Female
1	Negative control	Intact Abraded	2873 2854	2907 2781	2912 2910	2923 2984	2961 3085	3022 3030	3002 3080	129 226	- -
2	Vehicle control	Intact Abraded	2871 2871	2928 2910	3047 2903	3145 3028	3224 3093	3296 3105	3329 3184	458   313	355 138
3	BMDBM 30 mg/kg bw/day	Intact Abraded	2888 2866	2875 2860	2910 2897	2949 3004	3008 3120	3116 3049	3131 3189	243 323	188 143
4	BMDBM 100 mg/kg bw/day	Intact Abraded	2861 2861	2934 2917	2980 2948	3072 3007	3122 3082	3240 3114	3255 3114	394 253	305 112
5	BMDBM 360 mg/kg bw/day	Intact Abraded	2856 2785	2927 2858	2961 2908	3063 2988	3165 3084	3213 2971	3280 3128	424 343	329 152

 

Table 5a: Mean erythema (E) and oedema (O) scores after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to 5 male rabbits (intact skin).

Day	Negative control		Vehicle control		BMDBM [mg/kg bw/day]
					30		100		360
Erythema/Oedema:	E	O	E	O	E	O	E	O	E	O
1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
2	0.0	0.0	0.0	0.0	0.0	0.0	0.2	0.0	0.0	0.0
3	0.0	0.0	0.0	0.0	0.4	0.0	0.6	0.2	0.6	0.8
4	0.0	0.0	0.2	0.0	1.0	0.0	1.2	0.8	1.0	1.2
5	0.0	0.0	0.4	0.2	1.0	0.8	1.6	1.0	1.2	1.8
6	0.0	0.0	0.0	0.0	0.8	0.8	1.8	1.8	2.0	2.0
7	0.0	0.0	0.4	0.0	1.2	0.8	1.6	2.0	2.0	2.0
8	0.0	0.0	0.6	0.2	1.0	1.0	1.6	2.0	2.0	2.0
9	0.0	0.0	0.2	0.0	1.0	0.6	1.6	1.2	2.0	1.8
10^1	0.0	0.0	0.8	0.0	1.0	0.8	1.8	1.4	2.0	2.0
11	0.0	0.0	0.5	0.0	0.8	0.6	1.6	1.4	2.0	2.0
12	0.0	0.0	1.0	0.0	1.0	0.6	1.6	1.6	2.0	2.0
13	0.0	0.0	0.8	0.0	1.0	0.6	1.6	1.2	2.0	2.2
14	0.0	0.0	0.8	1.0	1.0	0.8	1.8	1.2	2.0	2.4
15	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.6	2.0	2.0
16	0.0	0.0	0.8	0.3	1.2	0.6	2.0	1.6	2.0	1.6
17	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.6	2.0	1.8
18	0.0	0.0	0.8	0.3	1.2	0.8	2.0	1.8	2.0	1.8
19	0.4	0.4	1.3	0.5	1.2	1.0	1.6	1.8	2.0	2.2
20	0.0	0.0	1.0	0.5	1.2	1.0	1.8	1.8	2.0	2.0
21	0.0	0.0	1.3	0.5	1.2	1.0	2.0	1.8	2.0	2.0
22^2	0.0	0.0	1.3	0.3	1.2	1.0	2.0	1.8	2.0	2.2
23	0.0	0.0	1.3	1.0	1.0	1.0	2.0	2.0	2.0	2.0

¹ 1 out of 5 animals was found dead in the negative control group

² 1 out of 5 animals was found dead in the negative control group

 

Table 5b: Mean erythema (E) and oedema (O) scores after repeated dermal application of butyl methoxydibenzoylmethane (BMDBM) to 5 female rabbits (intact skin).

	Negative control		Vehicle control		BMDBM [mg/kg bw/day]
					30		100		360
Erythema/Oedema:	E	O	E	O	E	O	E	O	E	O
1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
2	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
3	0.0	0.0	0.2	0.0	0.6	0.0	0.6	0.2	0.4	0.0
4	0.0	0.0	0.4	0.0	0.6	0.0	0.8	0.4	1.4	0.8
5	0.0	0.0	0.8	0.4	1.4	1.4	1.2	1.4	2.0	1.8
6	0.0	0.0	0.4	0.0	1.2	1.0	1.8	1.6	2.2	2.0
7	0.0	0.0	0.4	0.2	1.0	1.2	1.6	1.8	2.2	2.0
8^1	0.0	0.0	0.2	0.0	1.0	1.3	1.4	1.8	2.0	2.0
9	0.0	0.0	0.0	0.0	1.0	0.3	1.6	1.2	2.0	1.8
10	0.0	0.0	0.0	0.0	1.0	0.8	1.6	1.4	2.0	2.0
11	0.0	0.0	0.8	0.4	1.0	0.5	1.8	1.4	2.0	2.0
12^2	0.0	0.0	0.8	0.4	1.0	1.0	2.0	1.6	2.0	2.0
13	0.0	0.0	0.8	0.2	1.0	0.8	2.0	1.4	2.0	2.2
14	0.0	0.0	0.8	0.2	1.0	1.0	2.0	1.8	2.0	2.4
15	0.0	0.0	0.8	0.2	1.5	1.0	2.0	1.6	2.2	2.2
16^3	0.0	0.0	0.8	0.4	1.3	0.3	2.0	1.0	1.8	2.0
17	0.0	0.0	0.8	0.6	1.3	0.5	2.0	1.0	2.0	2.0
18	0.0	0.0	0.8	0.6	1.5	0.8	2.0	1.2	2.0	2.0
19	0.0	0.0	1.0	0.8	1.0	1.0	1.6	1.2	2.0	2.0
20	0.0	0.0	1.0	1.0	1.0	1.0	1.8	1.4	2.0	2.2
21	0.0	0.0	1.2	0.8	1.0	1.0	2.0	1.6	2.0	2.6
22	0.0	0.0	1.0	0.8	1.0	1.0	1.8	1.8	2.0	2.2
23	0.0	0.0	1.0	0.0	1.0	1.0	2.0	2.0	2.0	2.3

¹ 1 out of 5 animals was found dead in the 30 mg/kg bw group

² 1 out of 5 animals was found dead in the negative control group

³ 1 out of 5 animals was found dead in the negative control group

Conclusions:

Repeated (21 days) dermal application of BMDBM (30, 100, and 360 mg/kg bw/day) to the intact or abraded skin of rabbits caused no deaths. Therefore, the NOAEL for systemic toxicity was set to the highest applied dose of 360 mg/kg bw/day. There was a dosage-related increase in the severity of dermal reactions of rabbits treated with BMDBM, including slight to moderate erythema and edema. The respective vehicle control exhibited only slight dermal reactions.

Executive summary:

BMDBM, a crystalline sun protection substance, was prepared freshly each day as 1.5, 5 and 18 % w/v solutions in Carbitol and applied to the skin of rabbits once daily at dosage levels of 30, 100 and 360 mg/kg bw/day, for an exposure period of six hours each day, for twenty-one consecutive days.

There was a dosage-related increase in the severity of dermal reactions of rabbits treated with BMDBM. Slight to well-defined dermal reactions were generally observed in rabbits treated with BMDBM 30 or 100 mg/kg bw/day, although well-defined reactions were more persistent in rabbits treated with BMDBM, 100 mg/kg bw/day. Well-defined to moderate dermal reactions were generally seen in rabbits treated with BMDBM, 360 mg/kg/day. Slight dermal reactions occurred in the vehicle control animals (Carbitol). Microscopic examination of the treated skin sites revealed an increased incidence of epidermal thickening in rabbits from the vehicle control and treatment groups when compared to the untreated control group. Five rabbits were found dead during the study and one rabbit was sacrificed. The death of these animals was not considered to be directly related to treatment. Histopathological examination revealed gastrointestinal infection to be a factor contributory to the death of each animal.

In all other aspects including general health, bodyweights, food consumption, water consumption, haematology, blood chemistry, organ weights macroscopic pathology, and microscopic pathology of tissues excluding skin, rabbits treated with BMDBM were similar to the procedural and vehicle controls. Therefore, the NOAEL, based on systemic effects, can be considered to be 360 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

6.6 mg/cm²

Study duration:

subacute

Species:

rabbit

Quality of whole database:

Spiers and Candas, J Appl Physiol. 1984 Jan;56(1):240-3: Skin surface area (Ab) of rat in relation to mass m is Ab = 6.88m^0.736. 300 g average weight for rats was assumed.

Additional information

Oral

The substance 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.

Dermal

The substance was prepared freshly each day as 1.5, 5 and 18 % w/v solutions in Carbitol and applied to the skin of rabbits once daily at dosage levels of 30, 100 and 360 mg/kg bw/day, for an exposure period of six hours each day, for twenty-one consecutive days. There was a dosage-related increase in the severity of dermal reactions of rabbits treated with BMDBM. Slight to well-defined dermal reactions were generally observed in rabbits treated with BMDBM 30 or 100 mg/kg bw/day, although well-defined reactions were more persistent in rabbits treated with BMDBM, 100 mg/kg bw/day. Well-defined to moderate dermal reactions were generally seen in rabbits treated with BMDBM, 360 mg/kg/day. Slight dermal reactions occurred in the vehicle control animals (Carbitol). Microscopic examination of the treated skin sites revealed an increased incidence of epidermal thickening in rabbits from the vehicle control and treatment groups when compared to the untreated control group. Five rabbits were found dead during the study and one rabbit was sacrificed. The death of these animals was not considered to be directly related to treatment. Histopathological examination revealed gastrointestinal infection to be a factor contributory to the death of each animal.

In all other aspects including general health, bodyweights, food consumption, water consumption, haematology, blood chemistry, organ weights macroscopic pathology, and microscopic pathology of tissues excluding skin, rabbits treated with BMDBM were similar to the procedural and vehicle controls. Therefore, the NOAEL, based on systemic effects, can be considered to be 360 mg/kg bw/day.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. As a result the substance is not considered to be classified for repeated dose toxicity under Regulation (EC) No 1272/2008, as amended for the twelfth time in Regulation (EU) 2019/521.