Registration Dossier

Administrative data

Endpoint:
sub-chronic 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:
other: Comparable to guideline study with acceptable restrictions and without GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980
Report Date:
1980

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material : BMDBM
- Physical state: solid

Test animals

Species:
rabbit
Strain:
New Zealand White
Sex:
male/female
Details on test animals 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 (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): 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

Administration / exposure

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 dressingbacked with impervious Sleek plaster.
- Time intervals for shavings or clipplings: Abrasion was carried out weekly and hair clipping wwas repeated daily.

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

TEST MATERIAL
- Concentration (if solution): 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 (volume or weight with unit): 2 mL/kg bw/day
- Lot/batch no. (if required): 19431787 and B711019

USE OF RESTRAINERS FOR PREVENTING INGESTION: yes
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
6h per day
Frequency of treatment:
21 days
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 30, 100, and 360 mg/kg bw/day
Basis:
nominal per unit body weight
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.

Examinations

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.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Dermal irritation:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
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 was 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).
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.

DERMAL IRRITATION (Tables 5a and b)
Sporadic slight erythema were 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.

BODY WEIGHT AND WEIGHT GAIN
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
No treatment-related trends were apparent.

WATER CONSUMPTION
No treatment-related trends were apparent.

HAEMATOLOGY
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 CHEMISTRY
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.

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

HISTOPATHOLOGY
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.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
360 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Dose descriptor:
LOAEL
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.
Dose descriptor:
LOAEL
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.

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

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

101

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

222

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

81

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

122

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

163

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

 

Applicant's summary and conclusion

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, 100mg/kg bw/day. Well-defined to moderate dermal reactions were generally seen in rabbits treated with BMDBM, 360mg/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.