O-isopropyl ethylthiocarbamate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Propan-2-ol (Isopropyl alcohol) is both reagents used in the manufacture of IPETC/ O-isopropyl ethylthiocarbamate . Therefore, Propan-2-ol (Isopropyl alcohol) need to be considered in the assessment of IPETC/O-isopropyl ethylthiocarbamate .

Data source

Reference

Reference Type:

publication

Title:

Isopropanol: acute vapor inhalation neurotoxicity study in rats.

Author:

Gill MW, Burleigh-Flayer HD, Strother DE, Masten LW, McKee RH, Tyler TR, Gardiner TH.

Year:

1995

Bibliographic source:

J Appl Toxicol. 1995 Mar-Apr;15(2):77-84.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

6 hr exposure period instead of 4 hr, 14-day observation period was not clearly stated

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

O-isopropyl ethylthiocarbamate

EC Number:

205-517-7

EC Name:

O-isopropyl ethylthiocarbamate

Cas Number:

141-98-0

Molecular formula:

C6H13NOS

IUPAC Name:

N-ethyl(propan-2-yloxy)carbothioamide

Test material form:

liquid

Details on test material:

IPETC is prepared through reacting ethoxycarbonyl isothiocyanate/ Ethyl isothiocyanatoformate (CAS 16182-04-0) with propan-2-ol/ isopropyl alcohol (CAS Number 67-63-0) and Butan-1-ol/ butyl alcohol (CAS Number 71-36-3).

IPETC/O-isopropyl ethylthiocarbamate contains propan-2-ol (CAS number 67-63-0) and Butan-1-ol (CAS number 67-63-0) which are an integral part of the substance.
Propan-2-ol (CAS number 67-63-0) and Butan-1-ol (CAS number 67-63-0) are both reagents used in the manufacture of IPETC/O-isopropyl ethylthiocarbamate. Therefore, Propan-2-ol (CAS number 67-63-0) and Butan-1-ol (CAS number 67-63-0) need to be considered in the assessment of IPETC/O-isopropyl ethylthiocarbamate.

EC Name: propan-2-ol
CAS Number :67-63-0
EC Number:200-661-7
CAS Name: isopropyl alcohol

EC Name: Butan-1-ol
CAS Number : 71-36-3
EC Number: 200-751-6
CAS Name: butyl alcohol

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Spague-Dawley, Inc. (Indianapolis, IN)
- Age at study initiation: 9 to 11 weeks
- Housing: individually in stainless stell wire mesh cages
- Diet (e.g. ad libitum): Ground Purina Certified Rodent Chow ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: approximately one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 25
- Humidity (%): 40 to 70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: stainless steel chambers with glass doors and windows
- Exposure chamber volume: Four approximately 1330-liter and one approximately 900-liter
- Source and rate of air: filtered air at a flow rate of approximately 14 air changes per hour
- Temperature, humidity in air chamber: recorded approximately 12 times during each exposure

TEST ATMOSPHERE
- Brief description of analytical method used: flame ionization gas chromatographic (GC) technique
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 6 h

Concentrations:

500, 1500, 5000, 10000 ppm

No. of animals per sex per dose:

25 animals/sex/dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: twice daily, beginning on the day of after exposure and continuing until sacrifice
- Frequency of observations and weighing: body weights were recored prior to exposure and during each test session
- Necropsy of survivors performed: no

Statistics:

The data for continuous, parametric variables were intercompared for the dose and control groups by use of Levene’s test for homogeneity of variances,by analysis of variance, and by pooled variance t-tests. The t-tests were used, if the analysis of variance was significant (P
Intra-session motor activity data was analyzed using a repeated measures analysis with dose as grouping factor and session time as the within subject factor. Group comparisons at each reporting epoch were made (as described above) if significant dose effects or time by dose interactions were observed.
The epsilon-adjustment procedure (Greenhouse-Geisser correction) was used in repeated measures analysis of motor activity data.
Frequency data from FOB tests was evaluated using Fisher’s exact
probability test.

All statistical tests were performed using BMDPm Statistical Software (Dixon, 1985 or Dixon, 1988). The fiducial limit of 0.05 was used as the critical level of significance for all tests.

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

other: transient, concentration-related narcosis and/or central nervous system sedation

Effect level:

5 000 ppm

Based on:

test mat.

Exp. duration:

6 h

Effect levels 2

Sex:

male/female

Dose descriptor:

other: transient, concentration-related narcosis and/or central nervous system sedation

Effect level:

10 000 ppm

Based on:

test mat.

Exp. duration:

6 h

Effect levels 3

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 10 000 ppm

Based on:

test mat.

Exp. duration:

6 h

Remarks on result:

other: Concentrations of 10000 ppm is equal to 24.95 mg/m³ (molecular mass of 60.10 g/mol for Propan-2-ol)

Effect levels 4

Sex:

male

Dose descriptor:

other: NOEL

Effect level:

500 ppm

Based on:

test mat.

Exp. duration:

6 h

Remarks on result:

other: Based on minor decreases in motor activity in males at a concentration of 1500 ppm.The no-observed-effect level (NOEL) for this was 500 ppm isopropanol.

Effect levels 5

Sex:

male/female

Dose descriptor:

LC50

Effect level:

24.95 mg/m³ air

Based on:

test mat.

Exp. duration:

6 h

Remarks on result:

other: Concentrations of 10000 ppm is equal to 24.95 mg/m³ (molecular mass of 60.10 g/mol for Propan-2-ol)

Mortality:

none

Clinical signs:

other: In the 10000 ppm group, prostration, severe ataxia, decreased arousal, slowed or labored respiration, decreased neuromuscular tone, hypothermia, and loss of reflex function was observed 1 and 6 hours after exposure. Concentration-related decreases in mean

Body weight:

Body weight was measured at the time of behavioral testing so that any possible confounding effect that body weight might have on behavior could be assessed. Mean body weights for the five exposure groups were not statistically significantly different at any time during the study. Mean body weight tended to be lower for animals in the 10000 ppm exposure group assigned to FOB testing at the 6-hour and 24-hour post-exposure evaluations. This decrease is considered to reflect decreased food consumption during the time period when prostration and narcosis were observed.

Gross pathology:

none

Any other information on results incl. tables

Five groups of 25 Fischer 344 rats of each sex were exposed for 6 h to isopropanol vapor at 0, 500, 1500, 5000 or 10,000 ppm. Behavioral observations for 10 rats of each sex were made prior to and 1, 6, and 24 h after exposure. Motor activity was evaluated for 15 rats of each sex prior to and immediately following exposure. Exposure to isopropanol caused a spectrum of transient effects indicative of narcosis at 10,000 ppm and sedation at 5000 ppm. Prostration or severe ataxia, decreased arousal, slowed or labored respiration, decreased neuromuscular function, hypothermia and loss of reflex function were observed 1 and 6 h after exposure to 10,000 ppm isopropanol vapor. Similar, but less severe, alterations were observed in animals in the 5000 ppm exposure group 1 h after exposure. Exposure concentration-related decreases in motor activity were observed in males and females in the 5000 and 10,000 ppm groups and slight decreases in motor activity were observed in males in the 1500 ppm group. Animals in the 1500 and 5000 ppm exposure groups recovered from these motor activity effects within 5 h. Based on this study, exposure of male and female rats to isopropanol vapor produces transient, concentration-related narcosis and/or sedation at concentrations of 5000 and 10,000 ppm and minor decreases in motor activity in males at a concentration of 1500 ppm. The no-observed-effect level (NOEL) for this was 500 ppm isopropanol.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on this study, exposure of male and female rats to isopropanol the LC50 was > 10000 ppm.Concentrations of 10000 ppm is equal to 24.95 mg/m³ (molecular mass of 60.10 g/mol for Propan-2-ol)
Propan-2-ol (Isopropyl alcohol) is both reagents used in the manufacture of IPETC/O-isopropyl ethylthiocarbamate . Therefore, Propan-2-ol (Isopropyl alcohol) need to be considered in the assessment of IPETC/ O-isopropyl ethylthiocarbamate .

Executive summary:

Based on this study, exposure of male and female rats to isopropanol vapor produces transient, concentration-related narcosis and/or sedation at concentrations of 5000 and 10,000 ppm and minor decreases in motor activity in males at a concentration of 1500 ppm. The no-observed-effect level (NOEL) for this was 500 ppm isopropanol.