4,4'-bis(diethylamino)benzophenone

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 September 2017 - 10 November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The following functional groups are common across the target and source substance: aryl groups and carbonyl groups. It is the scientific hypothesis of this read-across justification that the presence of these functional groups dictates the toxicological potential of the target substance. The target and sources substances both pass Lipinski’s rule of five and are therefore considered to have the potential to be absorbed into the body via the oral route. The breakdown products within the body are likely to be similar, or the same, as shown in the table below.
Breakdown products:
Source substance - Benzophenone, Toluene, Hippuric acid or ortho-Cresol
Target substance - Benzophenone, Diethylamine (x2)

The target and source substance are expected to degrade in a similar way within the body and are expected to generate similar if not the same major metabolites. The molecular weight of the target and source substance are similar and are both below 500 daltons. The water solubility and partition coefficients of the target and source substances are comparable. Both the target and source substances pass Lipinski’s rule of five indicating that they may be orally absorbed and therefore are available within the body and may act in a similar toxic way.

2. SOURCE AND TARGET CHEMICAL
The source and target substances are composed of the same functional groups bound together in similar ways. The molecular weight of the target and source substances are similar and they are expected to be absorbed in the body in similar ways. The breakdown products of the substance are expected to be the same or very similar and are expected to have the same potential for acute toxicity.
The target and source substance contains very low levels of unidentified impurities. These impurities are considered not to affect the classification and labelling of the substance due to the very low levels at which they occur. No information on impurities present in the source test materials was available in the literature sources.
The impact of “impurities” is therefore considered not to affect the reliability of the read-across prediction.


3. ANALOGUE APPROACH JUSTIFICATION
Due to the similarities of the source and target substance with regards to physico-chemical properties, Lipinski’s rule of 5, and the fact that the target substance is expected to breakdown into structurally similar molecules in the body, the target substance is expected to behave in a substantially similar manner to the source substance. The target substance is therefore predicted NOAEL >1000 mg/kg bw/day in the OECD 422 study when conducted in the rat. By extension, the target substance is considered not to fulfil the criteria for target organ toxicity, repeat dose under the Classification, Labelling, and Packaging (CLP) regulation (1272/2008).

4. DATA MATRIX
See appended full justification document.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Dose descriptor:

NOAEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

gross pathology

haematology

mortality

organ weights and organ / body weight ratios

Critical effects observed:

no

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-phenylbenzophenone

EC Number:

218-345-2

EC Name:

4-phenylbenzophenone

Cas Number:

2128-93-0

Molecular formula:

C19H14O

IUPAC Name:

{[1,1'-biphenyl]-4-yl}(phenyl)methanone

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
Batch No.of test material: 20161118
- Expiration date of the lot/batch: 22 November 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature protected from light

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Crl: WI(Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: [yes/no] not specified - checking with lab.
- Age and weight at study initiation: males were 10 weeks old and weighed between 273 and 316 g and females were 13 weeks old and weighed between 202 and 248 g.
- Housing: On arrival and following the pre-test (females only) and pre-mating period, animals were group housed (up to 5 animals of the same sex and same dosing group together) in polycarbonate cages. During the mating phase, males and females were cohabitated on a 1:1 basis in Macrolon plastic cages. During the post-mating phase, males were housed in their home cage with a maximum of 5 males/cage. Females were individually housed in Macrolon plastic cages. During the lactation phase, females were housed in Macrolon plastic cages. Pups were housed with the dam.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 8 days prior to start of the pre-test period (females) or 10 days before the commencement of dosing (males).

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24°C
- Humidity (%): 40 to 70%
- Air changes (per hr): Ten or greater air changes per hour with 100% fresh air (no air recirculation)
- Photoperiod (hrs dark / hrs light): 12 hour light/12 hour dark cycle

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

propylene glycol

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis for concentration, homogeneity and stability were undertaken on duplicate samples.

Duration of treatment / exposure:

Once daily oral gavage 7 days a week for a minimum of 29 days.
Males were treated for 29 days (2 weeks prior to mating, during mating, and up to and including the day before scheduled necropsy).
Females that delivered were treated for 50 - 56 days (most females) or 64 days (one female of Group 3), (14 days prior to mating (with the objective to cover at least two complete estrous cycles), the variable time to conception, the duration of pregnancy and 13-15 days after delivery, up to and including the day before scheduled necropsy).
Females which failed to deliver or had a total litter loss were treated for 39-43 days (Group 4) or 41-54 days (Groups 2 and 3).

Frequency of treatment:

Once daily oral gavage 7 days a week for a minimum of 29 days.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

300 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes

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

WATER CONSUMPTION: Yes

HAEMATOLOGY: Yes
- Anaesthetic used for blood collection: Yes (identity) / No / Not specified
- Animals fasted: Yes / No / Not specified
- How many animals:
- Parameters checked in table [No.?] were examined.

CLINICAL CHEMISTRY: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Battery of functions tested: Hearing ability, Pupillary reflex, Static righting reflex, Fore- and hind-limb grip strength, Locomotor activity.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes

Statistics:

All pairwise comparisons were conducted using two sided tests and were reported at the 1% and 5% levels.
Descriptive statistics number, mean and standard deviation (or %CV or SE when deemed appropriate) were reported whenever possible.
The following pairwise comparisons were made:
Group 2 vs. Group 1
Group 3 vs. Group 1
Group 4 vs. Group 1

Parametric: Datasets with at least 3 groups (the designated control group and 2 other groups) were compared using Dunnett-test (many-to-one-t-test).
Non-Parametric: Datasets with at least 3 groups was compared using a Steel-test (many-to-one rank test). The motor activity data set was compared using an overall Kruskal-Wallis.
Incidence: An overall Fisher’s exact test was used to compare all groups at the 5% significance level. The above pairwise comparisons were conducted using Fisher’s exact test whenever the overall test is significant.

Results and discussion

Results of examinations

Clinical signs:

effects observed, non-treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Food consumption and compound intake (if feeding study):

no effects observed

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

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

In males at 1000 mg/kg bw, statistically significant differences were noted for alkaline phosphatase (ALP) activity (lower) and chloride (higher). These findings were not accompanied by adverse anatomic pathology alterations and the mean values for these parameters in 1000 mg/kg bw males remained within the historical control ranges . As such, these clinical pathology changes were regarded as non-adverse.

In lactating females, isolated statistically significant differences were noted for glucose (lower at 100 and 300 mg/kg bw) and sodium (higher at 300 mg/kg bw). These differences were considered to be unrelated to treatment as they showed no dose-related trend (glucose) and/or remained within normal limits.

Clinical chemistry values in females treated at 1000 mg/kg bw showed the following statistically significant differences from concurrent controls, all considered to be related to the difference in physiological status (percentage differences were not calculated due to the difference in physiological status). It cannot be determined if values in 1000 mg/kg bw females remained within the normal range, since no historical control data is available for females with implantation sites only. Query with lab.

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Gross pathological findings:

no effects observed

Description (incidence and severity):

Query with lab.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

> 1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

gross pathology

haematology

mortality

organ weights and organ / body weight ratios

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

In conclusion, based on the results of this combined 28-day repeated dose toxicity study with the reproduction/developmental toxicity screening test, the No Observed Adverse Effect Levels (NOAELs) of the substance was established to be at least 1000 mg/kg (highest dose employed).

Executive summary:

The potential toxic effects of the substance when given orally by gavage for a minimum of 28 days to Wistar Han rats and the potential to affect male and female reproductive performance such as gonadal function, mating behaviour, conception, parturition and early postnatal development was determined in a 28-day repeated dose toxicity study with the reproduction/developmental toxicity screening test according to OECD TG 422.The dose levels were 0, 100, 300 and 1000 mg/kg/day, based on the results of the dose range finder.No parental toxicity was observed up to the highest dose level tested (1000 mg/kg). In conclusion, based on the results of this study, the parental NOAEL was determined to be at least 1000 mg/kg, this being the highest dose employed in the study.