Tetrahydro-3-pentyl-2H-pyran-4-yl acetate

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Januari 2014 - November 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

Version / remarks:

(1981)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.28 (Sub-Chronic Dermal Toxicity Test: 90-Day Repeated Dermal Dose Study Using Rodent Species)

Version / remarks:

(2008)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF SE

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

63500-71-0; 65418-70-4 (trans); 65418-69-1 (cis)

IUPAC Name:

63500-71-0; 65418-70-4 (trans); 65418-69-1 (cis)

Constituent 2

Reference substance name:

Pyranol

IUPAC Name:

Pyranol

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Pyranol
- Physical state: liquid

Test animals

Species:

rat

Strain:

other: Crl:WI(HAN)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services GmbH, Sulzfeld, Germany
- Age at study initiation: 63 ± 1 days
- Weight at study initiation: Males: 245.0-275.6 g; Females: 170.4-206 g
- Fasting period before study: no
- Housing: individually in polysulfonate cages (motor activity measurements were conducted in polycarbonate cages)
- Use of restrainers for preventing ingestion (if dermal): yes, covered for at least 6 hours after application using a semiocclusive dressing, consisting of 4 layers of porous gauze dressing
- Diet: ad libitum; ground Kliba maintenance diet mouse/rat “GLP”, meal, supplied by Provimi Kliba SA, Kaiseraugst, Switzerland
- Water: ad libitum, water bottles
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): set at 20-24
- Humidity (%): set at 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 27 January 2014 To: 30 April 2014

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

corn oil

Details on exposure:

TEST SITE
- Area of exposure: 10% of the body surface
- Type of wrap if used: The skin was covered for at least 6 hours after application using a semiocclusive dressing, consisting of 4 layers of porous gauze dressing (Absorbent gauze EP supplied by Lohmann GmbH & Co. KG, Neuwied, Germany) and a stretch bandage (Fixomull® stretch [adhesive fleece] supplied by Beiersdorf AG, Hamburg, Germany).
- Time intervals for shavings or clipplings: The animals were reclipped at least once a week (depending on hair growth).

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the treated skin was washed with lukewarm water
- Time after start of exposure: After removal of the dressing.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): The application volume was 4 mL/kg bw, based upon the latest individual body weight determination.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of the test substance in corn oil at room temperature for a period of 8 days was demonstrated during the application period.
The test substance was completely miscible with corn oil and thus a solution. Therefore, the test-substance preparation was considered to be homogenous. Consequently further homogeneity analyses were not carried out.
Concentration control analyses of the test-substance preparations were performed in samples of all concentrations at the start of the application period.

Duration of treatment / exposure:

at least 6 hours daily

Frequency of treatment:

5 days per week (once daily)

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300 and 1000 mg/kg bw/day
Basis:
nominal per unit body weight

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: at the request of the sponsor.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily (working days), once daily (Satudays, Sundays and public holidays)

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once before beginning of the applicationperiod (day 0) and subsequently once a week

DERMAL IRRITATION: Yes
- Time schedule for examinations: once each workday (immediately before application)

BODY WEIGHT: Yes
- Time schedule for examinations: before the start of application period, on day 0 and thereafter at weekly intervals

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Food consumption was determined weekly as representative value over a period of 1 day and calculated as mean food consumption in grams per rat and day.

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: before administration and toward the end of the application period
- Dose groups that were examined: control and high dose (other dose groups will be examined only if there is a striking discrepancy between the highest dose group and the control group)

HAEMATOLOGY: Yes
- Time schedule for collection of blood: day 92 (males) and day 93 (females)
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes (fasting peroid of about 16 to 20 hours)
- Blood was taken from the retro-bulbar venous plexus.
- Parameters examined: according to guideline

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day 92 (males) and day 93 (females)
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes (fasting peroid of about 16 to 20 hours)
- Blood was taken from the retro-bulbar venous plexus
- Parameters examined: according to guideline

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: once towards the end of treatment
- Dose groups that were examined: all animals
- Battery of functions tested: (FOB) Home cage observation, open field observation, Sensory motor tests/ reflexes, Motor activity

Sacrifice and pathology:

All animals were sacrified by decapitation under isoflurane anesthesia.

GROSS PATHOLOGY: Yes
Anesthetized animals, adrenal glands, kidneys, liver, testes and thyroid glands were weighed.

HISTOPATHOLOGY: Yes
according to guidelines

Statistics:

Food consumption, body weight, body weight change: A comparison of each group with the control group was performed using DUNNETT's test (twosided) for the hypothesis of equal means.
Weight parameters: Non-parametric one-way analysis using KRUSKAL WALLIS test (two-sided). If the resulting p-value was equal or less than 0.05, a pairwise comparison of each dose group with the control group was performed using WILCOXON test (two-sided) for the equal medians.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

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):

not examined

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

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No animal died prematurely in the present study. Clinical examinations did not reveal treatment-related, adverse effects up to and including a dose level of
1000 mg/kg bw/day. Erythema, erosions and scales are considered related to treatment. Although these observations were not present untill the end of the study, the induction of skin erosion is considered adverse. The observation in the mid dose group (3 males) are questionable concerning substance-related adversity, as in this dose group erosion was observed in 3 males only (not in females), and in the control group 1 female showed erosion. In the high dose group erosion was observed in both males (5) and females (4), and considered as adverse effect.

BODY WEIGHT AND WEIGHT GAIN
No effects on body weight parameters which were of toxicological concern were observed in this study. Body weight change values were significantly increased in female animals of 1000 mg/kg bw/day on study day 14. The finding was assessed to be incidental and not related to treatment as no clear trend in body weight development occurred.

FOOD CONSUMPTION
No test substance-related effects on food consumption were obtained. All values were within the range typical for animals of this strain and age.

OPHTHALMOSCOPIC EXAMINATION
No test substance-related observations were noted. All findings were assessed as being incidental in nature since they occurred in individual animals only and did not show a dose-response relationship.

HAEMATOLOGY
No treatment-related changes among haematological parameters were observed.
In males of test group 300 mg/kg bw/day staticical significant decreases in the total values of white blood cells, neutrophiles, lymphocytes and monocytes were observed. These alterations were not dose-dependent and therefore they were regarded as incidental and not treatment-related.

CLINICAL CHEMISTRY
No treatment-related changes among clinical chemistry parameters were observed.
In females of the mid and high dose groups (300 mg/kg bw/day and 1000 mg/kg bw/day) glucose values were slightly but statistically significant decreased (4.99 and 4.72 mmol/L, respectively) compared to controls (5.36 mmol/L). Although the decreases in glucose were statistically significantly different to the control value and showed a dose-response relationship, these isolated findings were assessed as being fortuitous since similar increases were not observed in the males.

NEUROBEHAVIOUR
Deviations from "zero values" were obtained in several animals. However, as most findings were equally distributed between test-substance treated groups and controls, were without a dose-response relationship or occurred in single animals only, these observations were considered to have been incidental.

ORGAN WEIGHTS
All mean absolute and mean relative weight parameters did not show significant differences when compared to the control group.

GROSS PATHOLOGY
All findings occurred either individually or were biologically equally distributed over control and treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.

HISTOPATHOLOGY
All findings occurred either individually or were biologically equally distributed over control and treatment groups. They were considered to be incidental or spontaneous in origin and without any relation to treatment.

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:

other: no treatment-related, adverse effects were observed

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The administration of Pyranol by dermal application over a period of 3 months did not cause test substance-related adverse signs of systemic toxicity.
Therefore, under the conditions of the present study the no observed adverse effect level (NOAEL) was 1000 mg/kg bw/day in male and in female Wistar rats.
In addition, based on the observed skin erosion in high dose animals, the NOAEL for local dermal effects in this study is set at 300 mg/kg bw/day.

Executive summary:

Pyranol was applied by dermal application to groups of 10 male and 10 female Wistar rats at dose levels of 0 mg/kg bw/day (vehicle control), 100 mg/kg bw/day, 300 mg/kg bw/day and 1000 mg/kg bw/day over a period of 3 months (5 days per week).

Food consumption and body weights were determined weekly. The animals were examined for signs of toxicity or mortality at least once a day. In addition, the rats were daily examined for any clinically abnormal signs. The findings on the treated skin were obtained immediately before application once on each working day. Detailed clinical examinations in an open field were conducted prior to the start of the application period and weekly thereafter. Ophthalmological examinations were performed before the beginning and at the end of the application period. Beside this, a functional observational battery (FOB) as well as measurement of motor activity (MA) were carried out at the end of the application period. Clinicochemical and hematological examinations were performed towards the end of the application period. After the application period all rats were sacrificed and assessed by gross pathology. Organ weights were determined followed by histopathological examinations.

The administration of Pyranol by dermal application over a period of 3 months did not cause test substance-related adverse signs of systemic toxicity. Therefore, under the conditions of the present study the no observed adverse effect level (NOAEL) was 1000 mg/kg bw/day in male and in female Wistar rats.

In addition, based on the observed skin erosion in high dose animals, the NOAEL for local dermal effects in this study is set at 300 mg/kg bw/day.