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Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08.01.2007 to 13.06.2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD Guideline study no deviations GLP
Cross-reference
Reason / purpose for cross-reference:
reference to other study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)
GLP compliance:
yes (incl. QA statement)
Remarks:
notes: 1) DRF pre-study was a non-GLP; 2) two external laboratories not officially certified acc. to GLP: Principal Investigator 1, i.e. Biofocus GmbH for blood analysis - ISO 9001 certified; Principal Investigator 2, i.e.HISTO-PATH GmbH for histopatholog
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
470-680-5
EC Name:
-
Cas Number:
958872-63-4
Molecular formula:
C16H30O3
IUPAC Name:
1-[2-({1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl}oxy)propoxy]propan-2-ol; 1-{[1-({1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl}oxy)propan-2-yl]oxy}propan-2-ol; 2-[2-({1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl}oxy)propoxy]propan-1-ol; 2-{[1-({1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl}oxy)propan-2-yl]oxy}propan-1-ol
Details on test material:

- Name of test material (as cited in study report): Dipropyleneglycolisobornylether
- Substance type: mixture of isomers
- Physical state: clear liquid
- Analytical purity: 98.8%
- Lot/batch No.: V07 – 017 - 9
- Expiration date of the lot/batch: 01 March 2011
- Storage condition of test material: Room temperature (20°C ± 5°C)

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
Rattus norvegicus, strain: Wistar Unilever; Age at experimental starting date: 5-8 weeks; health status: SPF
Source: Harlan Winckelmann GmbH, 33178 Borchen, Germany;
Upon arrival at the test facility, the animals were visually checked for signs of ill health and abnormalities. All animals were accepted for this study.
Housing: Clean conventional housing: airing with approx. 10 air changes per hour, room climate 22 ± 3°C at 30-70% relative humidity,
artificial lighting 12 h light/12 h dark
Caging: Eight groups of five animals each in open makrolon cages type 2000P (TechniPlast)
Bedding: Lignocel hygienic animal bedding (J. Rettenmaier & Söhne , De-73494 Rosenberg)
Diet: Maintenance diet rat/mouse, pellets, No. 1324 (altromin, D-32791 Lage), ad lib. or other suitable diet
Water: Autoclaved community tap water, ad lib.
On the day of arrival, the animals were caged in groups of five according to the following stratification protocol: rats were weighed individually and grouped into weight categories, the main group consisting of animals weighing between 100 g and 120 g. These were placed consecutively into prepared cages. Rats weighing more than 120 g, but not more than 140 g, were caged similarly after the main weight group was placed. At the time point of stratification, no rat weighed less than 100 g or more than 120 g. The animals were transported into animal facility OP4 and were acclimatised to laboratory conditions for 8-9 days until the first day of application (day 1). All animals assigned to this study were housed in the same room throughout the entire study period.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:
1. Weigh the required amount of Dipropyleneglycolisobornylether into an appropriate vial on an analysis scale.
2. Add corn oil to the substance up to the required volume: for the high dose group, 2,5 g of the test item will be emulsified in corn oil to a final volume of 10 ml, corresponding to a dose of 1000 mg/kg bodyweight (BW)
3. Stir for at least 1 minute.
The test solution is intended for an application volume of 4 ml per kg BW. All preparation protocols for the test solution will be stored with the raw data.

DIET PREPARATION
- Rate of preparation of diet (frequency): daily. Freshly prepared before application
- Storage temperature of food:Room temperature


VEHICLE
- Justification for use and choice of vehicle (if other than water): Corn oil. As the test item’s solubility in water is poor, corn oil was be used as organic solvent. Corn oil is very well investigated as vehicle for toxicity studies, and it is explicitly recommended by the OECD 407 guideline.
- Concentration in vehicle: for the high dose group, 2,5 g of the test item will be emulsified in corn oil to a final volume of 10 ml, corresponding to a dose of 1000 mg/kg bodyweight (BW)

- Purity:100%
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
28 d; DRF pre-study: 14 d
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
DRF pre-study: 1000 - 2000 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
main study: 200 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
main study: 500 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
main study: 1000 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
DRF pre-study: 3
main study: 5
Control animals:
yes, concurrent vehicle
Details on study design:
A Dose-Range-Finding study previously performed by NewLab BioQuality GmbH (LAS306 DRF, 2007, non-GLP) produced no observable toxic effects at a dose level of 2000 mg/kg body mass in rats. On the base of the DRF-results, a limit test (LAS306) according to OECD 407, applying a single dose level of 2000 mg/kg BM, was performed. Since a NOAEL could not be defined from those data, the German BfR (Federal Office of Risc Assessment)
recommended a full study according to OECD 407 using three dose levels.

The first day of application was indicated as day 1. Three different solutions of Dipropyleneglycolisobornylether in corn oil were prepared as test items, the vehicle control consisted of pure corn oil. Depending to the experimental group, each animal received 4 ml/kg BM of one of these solutions daily. To the test item groups, this corresponds to a specific dose of 200, 500 and 1000 mg/kg body mass. The protocols for the preparation of test solutions were stored with the raw data.

Examinations

Observations and examinations performed and frequency:
The following parameters were observed and documented during the In-life period:
- Viability / fatalities: Daily
- General clinical signs / behaviour: Once workdays
- Detailed clinical signs: Once weekly (including once before beginning of application)
- Grip strength, limb placing test: Once before application and once during the last exposure week
- Body mass: Once weekly (including once before application start)
- Group Food consumption: Once weekly (including once before application start)
- Water consumption: Twice weekly
Sacrifice and pathology:
On day 29, approx. 600-1000 μl blood was taken from the retroorbital vein plexus of each animal immediately before sacrification. In order to avoid coagulation, 90 μl of each individual blood sample was mixed with 10 μl 10x HEPES-EDTA solution directly after bleeding. 30 μl of the remaining blood was used to directly determine the blood clotting time and potential, the rest of the blood was prepared as serum. Blood and serum samples were transferred to the Principal Investigator 1 to analyse parameters on hematology and serum biochemistry within 6 hours after bleeding. The original results of the analysis were returned to the hands of the study director at NewLab BioQuality GmbH.

The in-life phase was terminated on day 29. Animals were sacrificed by asphyxiation, therefore placing them into a CO2 atmosphere. After determination of the body mass, a full macroscopic examination was performed. All occuring lesions were noted. The weight of the organs was recorded.
Histological preparation was performed of the organs and tissues. The selected tissues were embedded in paraffin wax, sectioned, and stained with hemalaum and eosin. The stained sections were transferred to the principal investigator 2 for histopathological examination. The results were returned in a pathology expert report to the hands of the study director.
Statistics:
Grip strength and limb placing test:
results would be analysed statistically by the nonparametric Mann-Whitney U-Test.
All data was statistically analysed by t-student method.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
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):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Details on results:
No animal of the test item groups or the vehicle groups died in the in-life phase of this study. Abnormalities in the general clinical signs or the behaviour were not observed. No signs of illness (e.g. changes in skin, secretions), autonomic activity (e.g. lacrimation, piloerection), stereotypies or behavioural reactions (e.g. self-mutilation) in response to the treatment or otherwise were apparent. Body mass and food consuption remained unaltered in the test item groups. Water consumption was slightly raised dose dependently. Motor activity and reactivity to visual and proprioceptive stimuli were not altered by the administration of the test item. No differences in grip strength were observed in relation to the vehicle control group, and none of the animals showed significant differences to the vehicle group during the limb placing test. The most noticeable effects were the significantly lower level of glutamic-oxaloacetic transaminase (GOT) and of MCHC in males and females of the high dose and medium dose groups, in combination with the enlarged liver in male rats. A large number of medicinal agents with different chemical structures and therapeutic activities produce liver enlargement when given in high doses to species used in toxicity studies. GOT and MCHC often respond to liver stress. Findings of this nature are in favour of an adaptive response rather than a direct toxic effect of the test item. These findings, not present in the control animals, are considered to be related to the treatment with the test item. Although some additional significant changes were noticeable, overall none of the average data points were extremely out of range for rats of this strain and age. No other biochemical parameters and the blood cell counts showed significant differences among the groups.
The histomorphological examination of rat organs from a 28-day subchronic toxicity study by oral administration of the test item dipropyleneglycolisobornylether did not reveal morphological lesions considered to be related to the test item. The inflammatory lesions in different organs are considered to be coincidental findings or spontaneous organ changes and are therefore not test item related. No morphological differences were noted between the groups. The involution of the thymus in the rats of all groups corresponded in type, incidence and severity to the age of the animals. All the findings recorded in this study are commonly encountered in rats of this strain and age. Type, incidence, and severity of the lesions recorded were not increased in the treated animals as compared to the control animals.

Effect levels

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Sex:
male/female

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

A daily oral administration of the test item dipropyleneglycolisobornylether to Wistar rats at a dose level of 200, 500 and 1000 mg/kg body mass over a time period of 28 days resulted in only mild systemic and local effects in test animals treated with the high dose (1000 mg /kg).

Applicant's summary and conclusion

Conclusions:
A daily oral administration of the test item dipropyleneglycolisobornylether to Wistar rats at a dose level of 200, 500 and 1000 mg/kg body mass over a time period of 28 days resulted in only mild systemic and local effects in test animals treated with the high dose (1000 mg /kg).
Executive summary:
Aim of the study: The aim of this study was to assess data on the subchronic toxicity of the chemical substance Dipropyleneglycolisobornylether, emulsified in corn oil. The study was in accordance with OECD guideline 407. Experimental model: The test item Dipropyleneglycolisobornylether was administered daily by oral gavage to 5 male and 5 female Wistar rats each at dose levels of 200, 500 and 1000 mg/kg BW/day over a period of 28 days. Another 5 male and 5 female rats received the same total volume of corn oil as vehicle control. Of these solutions, 4 ml/kg BW was administered daily to each animal. Assessed parameters: During the in-life phase, viability, general and detailed clinical signs, food and water consumption, body mass, grip strength and reactivity to sensory stimuli (limb placing test) were recorded. At the end of the in-life phase, blood samples from all animals were collected to provide data on haematology and serum biochemistry. All animals were sacrificed immediately after bleeding and examined by gross necropsy. Weights of selected organs were recorded, and tissues and organs were preserved. All samples were processed for histopathological examination. The latter was conducted on samples from the high dose groups and the vehicle groups exclusively. Results: No animal of the test item groups or the vehicle groups died in the in-life phase of this study. Abnormalities in the general clinical signs or the behaviour were not observed. No signs of illness (e.g. changes in skin, secretions), autonomic activity (e.g. lacrimation, piloerection), stereotypies or behavioural reactions (e.g. self-mutilation) in response to the treatment or otherwise were apparent. Body mass and food consuption remained unaltered in the test item groups. Water consumption was slightly raised dose dependently. Motor activity and reactivity to visual and proprioceptive stimuli were not altered by the administration of the test item. No differences in grip strength were observed in relation to the vehicle control group, and none of the animals showed significant differences to the vehicle group during the limb placing test. The most noticeable effects were the significantly lower level of glutamic-oxaloacetic transaminase (GOT) and of MCHC in males and females of the high dose and medium dose groups, in combination with the enlarged liver in male rats. A large number of medicinal agents with different chemical structures and therapeutic activities produce liver enlargement when given in high doses to species used in toxicity studies. GOT and MCHC often respond to liver stress. Findings of this nature are in favour of an adaptive response rather than a direct toxic effect of the test item. These findings, not present in the control animals, are considered to be related to the treatment with the test item. Although some additional significant changes were noticeable, overall none of the average data points were extremely out of range for rats of this strain and age. No other biochemical parameters and the blood cell counts showed significant differences among the groups. The histomorphological examination of rat organs from a 28-day subchronic toxicity study by oral administration of the test item dipropyleneglycolisobornylether did not reveal morphological lesions considered to be related to the test item. The inflammatory lesions in different organs are considered to be coincidental findings or spontaneous organ changes and are therefore not test item related. No morphological differences were noted between the groups. The involution of the thymus in the rats of all groups corresponded in type, incidence and severity to the age of the animals. All the findings recorded in this study are commonly encountered in rats of this strain and age. Type, incidence, and severity of the lesions recorded were not increased in the treated animals as compared to the control animals. Conclusion: A daily oral administration of the test item dipropyleneglycolisobornylether to Wistar rats at a dose level of 200, 500 and 1000 mg/kg body mass over a time period of 28 days resulted in only mild systemic and local effects in test animals treated with the high dose (1000 mg /kg).