Hydrocarbons, terpene processing by-products

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

14 weeks in 2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Recent study conducted by NTP similarly to OECD guideline 413 with deviations: food consumption, hematology, ophthalmological examination, some organ weights were not recorded.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

other: data available on NTP website

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

Deviations:

yes

Remarks:

food consumption, hematology, ophthalmological examination, some organ weights were not recorded

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Pin-2(3)-ene

EC Number:

201-291-9

EC Name:

Pin-2(3)-ene

Cas Number:

80-56-8

Molecular formula:

C10H16

IUPAC Name:

2,6,6-trimethylbicyclo[3.1.1]hept-2-ene

Details on test material:

- Purity ≥ 97%

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

After a 10- to 14-day quarantine period, animals are assigned at random to treatment groups.

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

not specified

Vehicle:

not specified

Remarks on MMAD:

MMAD / GSD: No data

Details on inhalation exposure:

No data

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data

Duration of treatment / exposure:

14 weeks; 6 hours per day

Frequency of treatment:

Five times per week, weekdays only

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
25 ppm
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
50 ppm
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
100 ppm
Basis:
nominal conc.

Doses / concentrations 4

Remarks:

Doses / Concentrations:
200 ppm
Basis:
nominal conc.

Doses / concentrations 5

Remarks:

Doses / Concentrations:
400 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

No

Positive control:

No

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes for moribundity and death
- Time schedule: twice daily, at least 6 hours apart (before 10:00 AM and after 2:00 PM)

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: on Day 1 of the test, after 7 days and at weekly intervals thereafter

FOOD CONSUMPTION: No

FOOD EFFICIENCY: No

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: No

CLINICAL CHEMISTRY: Yes

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

No data

Statistics:

Kaplan-Meier used for probability of survival. Statistical analyses used for possible dose-related effect on survival was Cox (Cox D.R. (1972) Regression models and life tables. J.R. Stat. Soc. B34: 187-220.) for testing two groups for equality; and Tarone’s (Tarone R.E. (1975) Tests for trend in life table analysis. Biometrika 62; 679-682) life table test for a dose-related trend.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry 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:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

MORTALITY
All mice survived until the terminal sacrifice.

CLINICAL EXAMINATION
There were no treatment-related clinical signs.

BODY WEIGHT AND WEIGHT GAIN
Body weight gain was comparable for all test animals when compared to controls.

CLINICAL CHEMISTRY
No data available.

ORGAN WEIGHTS
Absolute liver weights were increased for both sexes at the 400 ppm and relative and absolute liver weights were increased for both sexes at 200 ppm and 400 ppm. The 400 ppm male group showed decreased absolute and relative thymus weight. No gross or microscopic lesions were associated with these organ weight findings.

HISTOPATHOLOGY: NON-NEOPLASTIC
Histopathological examination of male and female mice exposed to atmospheres of ≥100 ppm of α-pinene revealed evidence of hyperplasia of the transitional epithelium of the urinary bladder. However, there was no evidence of histopathological changes to the clitoris, ovaries, uterus, epididymis, preputial gland, seminal vesicles, and testes any of the control or test groups of animals.

Effect levels

Dose descriptor:

NOAEL

Effect level:

50 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Presence of transitional cell hyperplasia of the urinary bladder at 100 ppm.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1 - Histopathological effects - Urinary bladder - Males

Dose Group	Urinary bladder - Transitional epithelium - Hyperplasia Number of animals
	Absent	Minimal	Mild	Moderate
Vehicle Control	10	0	0	0
25 ppm	10	0	0	0
50 ppm	10	0	0	0
100 ppm	3	6	1	0
200 ppm	0	0	10	0
400 ppm	0	0	5	5

Table 2 - Histopathological effects - Urinary bladder - Females

Dose Group	Urinary bladder - Transitional epithelium - Hyperplasia Number of animals
	Absent	Minimal	Mild	Moderate
Vehicle Control	10	0	0	0
25 ppm	10	0	0	0
50 ppm	10	0	0	0
100 ppm	4	6	0	0
200 ppm	0	4	6	0
400 ppm	0	0	8	2

Applicant's summary and conclusion

Conclusions:

The NOAEL in male and female rats is 50 ppm based on minimal to moderate hyperplasia observed in the transitional epithelium of the urinary bladder in animals treated at 100 to 400 ppm.

Executive summary:

In a 90-day inhalation study conducted by NTP similarly to OECD guideline 413, groups of 10 animals per dose and per sex were administered for 6 hours per day, 5 weekdays per week at 0, 25, 50, 100, 200 and 400 ppm for a total of 14 weeks. The animals were observed twice per day and weighed once per week. A complete histopathologic evaluation including treatment-related gross lesions was performed on all animals including early death animals. Treatment-related lesions (target organs) were identified and these organs and gross lesions were examined to a no-effect level.

Similar effects were observed in male and female mice from the same dose level (100 ppm): minimal to moderate hyperplasia observed in the transitional epithelium of the urinary bladder.

The NOAEL in male and female rats is 50 ppm based on minimal to moderate hyperplasia observed in the transitional epithelium of the urinary bladder in animals treated at 100 to 400 ppm.