(S)-p-mentha-1,8-diene

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

other information

Study period:

2000

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

Study performed similarly to OECD Guideline 403 with major deviations: exposure duration: 30 min instead of 4 hours; observation period: 30 min; bodyweights and necropsy not followed; no data on housing conditions. The number of groups tested and corresponding concentrations were not reported.

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:

publication

Title:

Unnamed

Year:

2000

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

exposure duration: 30 min instead of 4 hours; observation period: 30 min; bodyweights and necropsy not followed; no data on housing conditions

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(S)-p-mentha-1,8-diene

EC Number:

227-815-6

EC Name:

(S)-p-mentha-1,8-diene

Cas Number:

5989-54-8

Molecular formula:

C10H16

IUPAC Name:

4-isopropenyl-1-methylcyclohexene

Details on test material:

- Name of test material (as cited in study report): S-(-)-limonene
- Analytical purity: 97%
- Source: Fluka Chemie, Switzerland

Test animals

Species:

mouse

Strain:

Balb/c

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Bomholtgard, Denmark
- Weight at study initiation: 27.0 ± 2.0 g
- Housing: Housed in polypropylene cages with sawdust bedding (Lignocel S8, Brogarden, Denmark)
- Diet: Altromin Standard Diet no.1324, Brogarden, Denmark
- Water: Tap water, ad libitum
- Acclimation period: 10-15 min before initiating a 15 min baseline period in the exposure chamber

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

head only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Plethysmograph
- Exposure chamber volume: 2.3 L
- Method of holding animals in test chamber: Mice were placed in separate body plethysmographs and installed head-only into the exposure chamber.
- Source and rate of air: Room air, 17-25 L/min

TEST ATMOSPHERE
- Brief description of analytical method used: Concentrations of the test material were monitored by infrared spectroscopy (Miran 1A, Foxboro).

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Infrared spectroscopy (Miran 1A, Foxboro)

Duration of exposure:

30 min

Concentrations:

Measured concentrations: 316-2421 ppm (mL vapor/cm3 of air)

No. of animals per sex per dose:

Four naive mice

Control animals:

no

Details on study design:

- Duration of observation period following administration: 30 min
- Frequency of observations: Animals were observed for mortality, sensory irritation, airflow limitation and pulmonary irritation at 0-10, 11-20 and 21-30 min
- Concentrations, which cause a 50% decrease in respiratory rate (RD50) and the extrapolated threshold concentration (RD0) were determined.

Statistics:

- Trend over time (time-response relationship) was studied by two-way analysis of variance and regression analysis.
- Both parametric and nonparametric (Spearman's rank correlation) tests were used to evaluate exposure effects on tidal volume.
- Calculations were performed by use of the Minitab Statistical Software, Release 10.51 Xtra (Minitab Inc.). P values less than 0.05 were considered statistically significant.

Results and discussion

Preliminary study:

Not applicable

Effect levels

Effect levels 1

Key result

Sex:

male

Dose descriptor:

LC50

Effect level:

>= 2 421 ppm

Based on:

test mat.

Exp. duration:

30 min

Remarks on result:

other: equivalent to 1.68 mg/L/4 h exposure

Effect levels 2

Sex:

male

Dose descriptor:

other: RD50

Effect level:

1 715 ppm

Based on:

test mat.

95% CL:

>= 1 168 - <= 2 519

Exp. duration:

30 min

Remarks on result:

other: RD50 is concentration causing 50% of decrease of respiratory rate

Effect levels 3

Sex:

male

Dose descriptor:

other: RD0

Effect level:

199 ppm

Based on:

test mat.

95% CL:

>= 129 - <= 307

Exp. duration:

30 min

Remarks on result:

other: RD50 is concentration causing 50% of decrease of respiratory rate

Mortality:

One mouse died at 1788 and one at 2421 ppm S-(-)-limonene concentrations, after 2 and 4 min, respectively. There was no concentration or
time -dependent effect of death and none of the deaths is considered to be exposure related.

Clinical signs:

other: Sensory irritant: - Respiratory rate: Decreased in a dose-dependent manner; reached plateau within first 10 min and was stable during remaining period - Time of break: Increased in a dose-dependent manner

Body weight:

No data

Gross pathology:

No data

Other findings:

None

Any other information on results incl. tables

Following 30 minutes of exposure, LC50 in mouse was determined to be higher than the highest tested dose, i.e. 2421 ppm, because no treatment-related death was observed at any of the treatment doses. Based on the conversion factor , as 1 ppm corresponds to 5.56 mg/m3 for d-limonene. LC50 is determined to be greater than 8890.44 mg/m3 following 30 minutes of exposure and 1680 mg/m3 (1.68 mg/L) following 4 hours of exposure, based on Haber’s law (Cn x t = k), where n = 1.

Table 1: RD50 and RD0 values at different time periods

 

Period (min)	n^a	Range of concentration^b(ppm)	Slope^c(%/ log concentration)	RD50^d(ppm)	RD0^d(ppm)
0-10	26	316-2421	61.9 ± 6.3	1467 (902 -2387)	232 (125 -431)
11-20	26	316-2421	53.1 ± 4.0	1734 (1205 -2495)	202 (125 -326)
21-30	26	316-2421	46.3 ± 4.0	1918 (1274 -2887)	159 (90 -281)
0-30	26	316-2421	53.8 ± 3.1	1715 (1168-2519)	199 (129 -307)

^aNumber of mice used for construction of the regression line.

^bRange of concentration used for construction of the regression line.

^cThe ± is the SD value.

^dThe 95% confidence intervals are given in brackets.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

Under the test conditions, the acute inhalation LC50 (30 min) value was considered to be greater than 2421 ppm in male mice. LC50 (4 h) was calculated to be > 1.68 mg/L.

Executive summary:

In an acute inhalation toxicity study performed similarly to OECD Guideline 403, groups (4/dose) of male BALB/cA mice were exposed (head only) to vapors of S-(-)-limonene at concentration range of 316 -2421 ppm (measured) for 30 min. Animals were observed for mortality and signs of sensory irritation, airflow limitation and pulmonary irritation during the exposure period.  

 

One mouse died at 1788 and one at 2421 ppm S-(-)-limonene concentrations, after 2 and 4 min, respectively. There was no concentration or time -dependent effect of death and none of the deaths is considered to be exposure related.

A dose-dependent decrease in respiratory rate and increase in time of break indicated the sensory irritant effect of S-(-)-limonene.

The RD50 values at 0-10, 11-20, 21-30 or 0-30 min were estimated to be 1467 (902 -2387), 1734 (1205 -2495), 1918 (1274 -2887) or 1715 (1168 -2519), respectively.

 

Under the test conditions, as no death was considered to be treatment-related, the acute inhalation LC50 (30 min) value was estimated to be greater than 2421 ppm in male mice. LC50 (4 h) was calculated to be > 1.68 mg/L.