Methyl 3-mercaptopropionate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1983-04-14 to 1983-07-06

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study similar to OCED guideline 403 with limited details provided on the test substance, and details on some of the materials and methods were lacking.

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:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

Limited details provided on the test substance and details on some of the materials and methods were lacking.

Principles of method if other than guideline:

N/A

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl 3-mercaptopropionate

EC Number:

220-912-4

EC Name:

Methyl 3-mercaptopropionate

Cas Number:

2935-90-2

Molecular formula:

C4H8O2S

IUPAC Name:

methyl 3-sulfanylpropanoate

Details on test material:

- Name of test material (as cited in study report): methyl 3-mercaptopropionate
- Molecular formula (if other than submission substance): N/A
- Molecular weight (if other than submission substance): N/A
- Smiles notation (if other than submission substance): N/A
- InChl (if other than submission substance): N/A
- Structural formula attached as image file (if other than submission substance): N/A
- Substance type: active
- Physical state: liquid
- Stability under test conditions: N/A
- Storage condition of test material: N/A
- Other: N/A

Test animals

Species:

rat

Strain:

other: Sprague-Dawley descended

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: CD/ Charles River Laboratories, Inc.
- Age at study initiation: young adult
- Weight at study initiation: 200-350 grams
- Fasting period before study: N/A
- Housing: Individually housed in stainless-steel wire-mesh caging
- Diet: Purina Lab Chow # 5001, ad libitum except during exposure period
- Water (e.g. ad libitum): Tap water, ad libitum except during exposure period
- Acclimation period: at least 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (deg. C): 21-22 degrees C
- Humidity (%): 40 to 60%
- Air changes (per hr): N/A
- Photoperiod (hrs dark / hrs light): 12-hour light:dark cycle
-Oxygen concentration: range of 20-21%


IN-LIFE DATES: From: N/A To: N/A

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

not specified

Vehicle:

other: room air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 38-liter glass and stainless steel exposure chamber; the test chambers were situated in a laboratory exhaust hood with the chamber exhaust passed through a liquid scrubber as required. Depending on the physical characteristics of the test compound, the compound was generated as a vapor. In no case was the oxygen concentration to be allowed to fall below 19% within the chamber. Vapors were generated by use of a water-jacketed counter-flow column maintained at approximately 60 degrees C. The liquid test material was metered into the top of the column with air introduced through the bottom.
- Exposure chamber volume: 2400 L of air passing through the chamber during generation.
- Method of holding animals in test chamber: N/A
- Source and rate of air: The airflow during each exposure was monitored and maintained at 10 liters/minute. For control exposures and compound generation , filtered breathable air were supplied. Filtered, dried and rehumidified make-up air, where needed, were used in all test exposure chambers.
- Method of conditioning air: N/A
- System of generating particulates/aerosols: N/A
- Method of particle size determination: N/A
- Treatment of exhaust air: The vapors were exhausted from an alternate outlet at the column top and directed into the air input opening of the chamber.
- Temperature, humidity, pressure in air chamber: Target ranges were 23-24 degrees C and 50-70% relative humidity.


TEST ATMOSPHERE
- Brief description of analytical method used: Total hydrocarbon analysis (THC)
- Samples taken from breathing zone: N/A


VEHICLE
- Composition of vehicle: N/A
- Concentration of test material in vehicle: N/A
- Justification of choice of vehicle: N/A
- Lot/batch no. (if required): N/A
- Purity: N/A


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: N/A
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): N/A


CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: N/A

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Total hydrocarbon analysis

Duration of exposure:

4 h

Concentrations:

mean measured concentrations at 779.38, 476.00, 403.13, 360.63, and 265.50 ppm
nominal concentrations of 4.75, 2.21, 1.81, 1.63, 1.19 mg/L

No. of animals per sex per dose:

5/sex/dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: During exposure and twice daily (A.M. and P.M.) for 14 days thereafter, all surviving animals were observed for signs of toxicity, abnormal appearance, and unusual behavior. Body weights were recorded at study initiation, and on days 2, 3, 4, 7 and 14 post exposure.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, gross pathology

Statistics:

The nominal concentration was calculated by dividing the total weight of test material disseminated into the chamber atmosphere by the total volume (2400 L) of air passed through the chamber during generation.

Results and discussion

Preliminary study:

N/A

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

1.72 mg/L air

95% CL:

1.63 - 1.81

Exp. duration:

4 h

Remarks on result:

other: See table below in "Remarks on results including tables and figures" section.

Effect levels 2

Sex:

female

Dose descriptor:

LC50

Effect level:

1.91 mg/L air

95% CL:

1.71 - 2.11

Exp. duration:

4 h

Remarks on result:

other: See table below in "Remarks on results including tables and figures" section.

Effect levels 3

Sex:

male/female

Dose descriptor:

LC50

Effect level:

1.8 mg/L air

95% CL:

1.69 - 1.93

Exp. duration:

4 h

Remarks on result:

other: See table below in "Remarks on results including tables and figures" section.

Mortality:

All males in the 779.38 ppm exposure group died after 2 hours of exposure. Three females in the 779.38 ppm exposure group died after 2 hours of exposure, 1 female died at 3 hours of exposure and 1 female died at 4 hours of exposure.
In the 476 ppm exposure group, one male and one female died after 3 hours of exposure, 2 females and 4 males died at 4 hour of exposure, 1 female died one day post exposure.
In the 403.13 ppm exposure group, one female died at 3 hours of exposure, 4 male and one female died at 4 hours of exposure. One female died one day post exposure.
One male in the 360.63 ppm exposure group died after 4 hours of exposure.
All animals in the 265.50 ppm exposure group survived.

Clinical signs:

other: Clinical signs observed in most or all animals at the four highest exposure levels included: tremors, a languid appearance, convulsions, labored respiration and squinted eyes. In addition, salivation, nasal discharge, and death were observed at the three

Body weight:

No distinct exposure-related trends were apparent in the mean body weight data.

Gross pathology:

The only exposure-related trend apparent in the gross pathology data was the high incidence of abnormal findings in the lungs (failure to collapse at an incidence of 10/10, 8/10, and 5/10 in the three highest dose groups, respectively; bright or dark red area(s) on the surface at an incidence of 8/10, 4/10, and 5/10 in the three highest dose groups, respectively) in animals exposed to 779.38, 476.00 and 403.13 ppm. There was also a high incidence of abnormal liver findings (tan areas on the surface (9/10 at 779.38 ppm) and all lobes thickened (7/10 at 476.00; 10/10 at 779.38) in animals exposed to the two highest dose levels.

Other findings:

- Organ weights: N/A
- Histopathology: N/A
- Potential target organs: N/A
- Other observations: N/A

Any other information on results incl. tables

Nominal Conc. Tested (mg/L)	Mean Analytical Conc. +/- Stand Dev (ppm)	Mortality Ratio Males: Females (0/5:0/5)
4.75	779.38 +/- 146.52	5/5:5/5
2.21	476.00 +/- 77.21	5/5:4/5
1.81	403.13 +/- 92.35	4/5:3/5
1.63	360.63 +/- 45.70	1/5:0/5
1.19	265.50 +/- 36.38	0/5:0/5

 

Applicant's summary and conclusion

Interpretation of results:

Category 2 based on GHS criteria

Remarks:

Migrated information

Conclusions:

The acute inhalation LC50 of the test substance was determined to be 1.80 mg/L with 95% confidence limits of 1.69 to 1.93 mg/L in male and female rats under the conditions of this study.

Executive summary:

N/A