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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Remarks:
REPEATED DOSE 90-DAY ORAL TOXICITY STUDY
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
other: Status report
Title:
Unnamed
Year:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Version / remarks:
June 2018
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
rat
Strain:
Wistar
Details on species / strain selection:
CD® rats
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories Germany GmbH
Sandhofer Weg 7
97633 Sulzfeld
Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: Young adults; 8-10 weeks at 1st dosing*
- Weight at study initiation:
- Fasting period before study:
- Housing: The animals are kept singly in MAKROLON cages (type III plus) with a basal surface of approximately 39 cm x 23 cm and a height of approximately 18 cm
- Diet: ad libitum
- Water: ad libitum
- Acclimation period:

DETAILS OF FOOD AND WATER QUALITY:
Commercial diet ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany, the composition of the diet will be stated in the report) serves as food. This food is offered ad libitum. Food residue is removed and weighed.
Periodic analysis of the food for contaminants based on EPA/USA2 is conducted by LUFA-ITL3 (see section 9.1 Limitation for contaminants in the diet). Certificates of analysis of the composition and for contaminants are provided by the manufacturer and are QAU archived.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 3°C
- Humidity (%): 55% ± 10%
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 h each

IN-LIFE DATES: From: May 9, 2019 To: September 4, 2019

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Analytical verification of doses or concentrations:
yes
Duration of treatment / exposure:
Once daily for 90 days
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Remarks:
control
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
10
Control animals:
yes
yes, concurrent no treatment
Details on study design:
- Dose selection rationale: The dose levels for this study will be selected in agreement with the Sponsor based on the available toxiciological data of an OECD 422 study. The dose of 1000 mg/kg b.w. was considered to be a maximum tolerated dose.
- Rationale for animal assignment (if not random):
- Fasting period before blood sampling for clinical biochemistry:
- Rationale for selecting satellite groups:
- Post-exposure recovery period in satellite groups:
- Section schedule rationale (if not random):
- Other:

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: one daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once before the first exposure (to allow for within-subject comparisons) and once a week thereafter, detailed clinical observations will be made in all animals

BODY WEIGHT: Yes
- Time schedule for examinations: The weight of each rat will be recorded at the time of group allocation, daily from the day of commencement of treatment up to and including test week 6 for dose adjustment, thereafter weekly throughout the experimental period.

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: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes / No / Not specified
- Time schedule for examinations: Water consumption will be recorded weekly by weighing the water bottles when filled and the residues upon removal at the end of the test week. The residue will be discarded.

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Examinations will be performed on all animals before first dosing, at main study termination and at the end of the recovery period.


HAEMATOLOGY: Yes
- Time schedule for collection of blood:
At the end of test week 13 (before necropsy):All main study animals
At the end of the recovery period: All recovery animals
- Anaesthetic used for blood collection: Yes
- Animals fasted: Yes
- Parameters checked were examined.:
Differential blood count10 (relative)
Differential blood count (absolute)
Erythrocytes (RBC)
Leucocytes (WBC)
Haematocrit value
Haemoglobin content
Platelets
Reticulocytes
Mean corpuscular volume (MCV)
Mean corpuscular haemoglobin (MCH)
Mean corpuscular haemoglobin concentration (MCHC)
Prothrombin time (PT)
Activated partial thromboplastin time (aPTT)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Examinations will be performed on all animals before first dosing, at main study termination and at the end of the recovery period.
- Animals fasted: Yes
- Parameters were examined.:
Sodium
Potassium
Calcium
Chloride
Albumin
Total bilirubin
Total cholesterol
High density lipoprotein (HDL)
Low density lipoprotein (LDL)
Glucose
Total protein
Blood urea nitrogen (BUN)
Creatinine
Aspartate aminotransferase (ASAT/GOT)
Alanine amino-transferase (ALAT/GPT)
Alkaline phosphatase (aP)
Lactate dehydrogenase (LDH)

URINALYSIS: Yes
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine: Yes / No / Not specified
- Animals fasted: Yes / No / Not specified
- Parameters checked in table [No.?] were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations:
In test week 13 (before any blood sampling for laboratory examinations): All animals
At the end of the recovery period: All recovery animals
- Battery of functions tested: sensory activity / grip strength / motor activity /

IMMUNOLOGY: No


OTHER: Thyroid hormone (T3, T4, TSH) determination: In order to obtain approximately 2x150 μL serum for each endocrine endpoint (T3, T4, TSH), a sufficient volume of blood will be taken from the retrobulbar venous plexus under isoflurane anaesthesia from animals fasted overnight.
Sacrifice and pathology:
GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes
Statistics:
Toxicology and Pathology data will be captured, whenever possible, using the departmental computerized systems (Provantis®12 Integrated preclinical software, Instem LSS Ltd.). Raw data not fully compatible with the computerized systems will be maintained on paper according to appropriate SOPs.

Results and discussion

Results of examinations

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
Slight salivation starting up to 5 minutes p.a.
lasting 20 to 60 minutes was observed for 1 of
10 males treated with 300 mg Di-(iso)-pentyl
terephalate (DPT)/kg b.w./day on test days 59
and 60.
Slight to moderate salivation starting up to 5 minutes p.a. lasting 20 to 60 minutes was observed for 8 of 10 males and for 7 of 10 females treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day on 1 to 31 days starting on test day 55 (males) or 59 (females).
These changes are regarded to be test item-related, but not adverse.

A haemorrhagic left canthus was observed for
male no. 85 treated with 1000 mg Di-(iso)-pentyl
terephalate (DPT)/kg b.w./day on 19 test days
starting on test day 2.
This change is not regarded to be test item-related but to be related to the blood withdrawal.

Recovery period (restricted to groups 1 and 4)
No changes in behaviour, external appearance, or consistency of faeces were noted for the previously high-dosed male and female animals during the 28-day treatment-free recovery period.

Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
The body weight of the male animals treated with 1000 mg Di-(iso)-pentyl terephalate
(DPT)/kg b.w./day was slightly decreased by 5% to 9% starting on test day 22 compared to the
control animals (statistically significant at p ≤ 0.05 or 0.01 on test days 22, 29, 71, 78, 85 and 90).
The body weight of the female animals treated with 1000 mg Di-(iso)-pentyl terephalate
(DPT)/kg b.w./day was slightly decreased by 5% on test day 78 compared to the control animals
(statistically significant at p ≤ 0.05 on test day 78). The body weight gain and the body weight
at autopsy of the high dose animals were slightly reduced accordingly.
These changes were only slight (< 10% difference to control) and are considered not to be adverse.

Recovery period (restricted to groups 1 and 4)
The body weight of the male animals previously treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day was still reduced by 17% to 18% (statistically significant at p ≤ 0.05 on test days 97, 104, 111 and 118). The percentage difference in comparison to the control group during the recovery period was higher than that during the treatment period due to the comparably high or low body weight of the high dose group and the control group, respectively. This effect was mainly due to the animal constellation of the groups. Coincidentally, the control recovery animals were the heaviest while the high dose recovery animals were the lightest animals of the respective group.
The body weight at autopsy was reduced accordingly. However, the body weight gain of the previously high dosed males was above that of the control group indicating a trend towards recovery.
The body weight, the body weight gain and the body weight at autopsy of the female animals previously treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day were within the range of the control group.
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
effects observed, treatment-related
Description (incidence and severity):
The drinking water consumption of the male and female animals treated with 1000 mg Di-(iso)- pentyl terephalate (DPT)/kg b.w./day by oral
administration was slightly increased by up to 17% for the males and by up to 19% for the females starting in test week 2 (males) or 3
(females) compared to the control animals, evaluated by weekly quantitative assessment (statistically significant at p ≤ 0.05 or 0.01 in
test week 2 for the males and in test week 2 and 4 for the males and females).
This finding is considered to be test item-related but not adverse, and might be due to the irritating properties of the test item.

Recovery period (restricted to groups 1 and 4)
The drinking water consumption of the male animals previously treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day was still slightly increased by up to 13% during the recovery period (statistically significant at p ≤ 0.05 in test week 14). The drinking water consumption of the female animals previously treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day was within the range of the control group during the 28-day treatment-free recovery period.
Ophthalmological findings:
no effects observed
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Immunological findings:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
The macroscopic inspection at necropsy did not reveal any test item-related changes in the organs and tissues of the animals treated with 100, 300 or 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day by repeated oral administration after terminal sacrifice at the end of the treatment period.
Changes in the tissue enlargement, enlarged lymph node, dilated uterus partly filled
with clear liquid, hairless abdomen and forepaws.
These changes are not regarded to be test item-related but spontaneous.
Neuropathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Description (incidence and severity):
Thyroid hormone (T3, T4, TSH) levels:
No test item-related influence was observed on the thyroid hormone levels of T3, T4 and TSH of the male and female animals treated with 100, 300 or 1000 mg
(DPT)/kg b.w./day by oral administration for 90 days compared to the control animals at the end of the treatment period (test day 91) and at the end of the recovery period (test day 119). All data are within the limits of normal biological variability.

Effect levels

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
> 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
not determinable due to absence of adverse toxic effects
Dose descriptor:
NOEL
Effect level:
300 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
clinical signs
water consumption and compound intake
Dose descriptor:
NOEL
Effect level:
300 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
clinical signs
water consumption and compound intake

Target system / organ toxicity

Key result
Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
The no-observed-adverse-effect level (NOAEL) was 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day by oral administration for 90 days. The no-observed-effect level (NOEL) was 300 mg (iso)-pentyl terephthalate (DPT)/kg b.w./day by oral administration for 90 days.
Executive summary:

The aim of the study was to obtain information on the toxicity of DPT when given to rats by daily oral administration via gavage for 90 days and to assess the reversibility of any effects after a treatment-free recovery period.

The rats were treated with 100, 300 or 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day for 90 days.

None of the animals died or had to be sacrificed prematurely.

Slight salivation was observed for 1 of 10 males treated with 300 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day on test days 59 and 60. Slight to moderate salivation was observed for 8 of 10 males and for 7 of 10 females treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day on 1 to 31 days starting on test day 55 (males) or 59 (females).These slight changes are regarded to be test item-related, but not adverse.

The body weight of the male and female animals treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day was slightly decreased (<10%) during the treatment period compared to the control animals. The body weight gain and the body weight at autopsy were slightly reduced accordingly.These changes are considered not to be adverse.

The drinking water consumption of the male and female animals treated with 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day by oral administration was slightly increased compared to the control animals, evaluated by weekly quantitative assessment. This findingis considered to be test item-related but not adverse, andmight be due to the irritating properties of the test item.

No test item-related changes were observed during the detailed clinical observations, food consumption, for any of the parameters of the neurological screening, for any of the haematological, coagulation, and clinical chemistry parameters, the thyroid hormone levels, the eyes or optic region, the auditory acuity, at macroscopic inspection at necropsy, the organ weights,the oestrus cycle, the sperm viability and morphologyand at histopathological examination at any dose level.

At the end of the recovery period, the body weight and body weight at autopsy of the male animals were still reduceddue to the animal constellation of the groups.Body weight gain indicated a slight trend to recovery. The drinking water consumption of the male animals was still slightly increased during the recovery period. The body weight and the drinking water consumption of the female animals had normalized during the 28-day treatment-free recovery period. All other changes had subsided during or at the end of the 28-day treatment-free recovery period.

Based on the above results, the no-observed-adverse-effect level (NOAEL) was 1000 mg Di-(iso)-pentyl terephthalate (DPT)/kg b.w./day by oral administration for 90 days. The no-observed-effect level (NOEL) was 300 mg (iso)-pentyl terephthalate (DPT)/kg b.w./day by oral administration for 90 days.