Registration Dossier

Administrative data

Endpoint:
specific investigations: other studies
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1983-07-11
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This study was classified as reliable with restrictions because it was an acceptable, well-documented study report which meets basic scientific principles.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1983

Materials and methods

Principles of method if other than guideline:
The guideline followed was not reported but the methods used are deemed appropriate as utilized in the report.
GLP compliance:
not specified
Type of method:
in vivo
Endpoint addressed:
respiratory irritation

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): ethyl mercaptan (ethanethiol)

Test animals

Species:
mouse
Strain:
other: outbred SPF mice (CD-1, COBS)
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: Young adults
- Weight at study initiation: 20-25 grams
- Housing: Stainless-steel wire-mesh cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.11
- Humidity (%): 40-60%
- Air changes (per hr): No data reported
- Photoperiod (hrs dark / hrs light): 12 hrs/ 12 hrs

Administration / exposure

Route of administration:
other: Inhalation, head only
Vehicle:
not specified
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
Exposure is one minute, followed by ten minutes in room air, followed by another one minute exposure.
Post exposure period:
The animals are observed in real time during the exposures and for at least five minutes or until recovery from exposure.
Doses / concentrations
Remarks:
Doses / Concentrations:
1.93 mg/L (56.75 ppm)
Basis:

No. of animals per sex per dose:
4
Control animals:
no

Results and discussion

Details on results:
No effects of exposure to ethyl mercaptan at 1.93 mg/L were observed.

Applicant's summary and conclusion

Conclusions:
Based on the results the authors concluded that the test material is not an irritant when 1.93 mg/L is inhaled by mice (Pence, 1983).
Executive summary:

In a respiratory irritation tract study (Pence, 1983), 4 male outbred SPF mice were exposed via head only inhalation to 1.93 milligram per liter (56.75 ppm) of ethanethiol for two periods of one minute exposures separated by a ten minute exposure to room air. Animals were then observed for five minutes or until the respiratory rate returned to pre-exposure rates.

 

The test material was applied as a vapor in a head only exposure chamber attached to a plethysmograph. Only three mice were exposed because one mouse was reported to have died prior to exposure. None of the three mice demonstrated changes in respiratory rate during either one minute exposures to 1.93 mg/L ethanethiol. Based on the results the authors concluded that the test material is not an irritant when 1.93 mg/L is inhaled by mice. Compound-induced corrosion was not reported. 

 

This study received a Klimisch score of 2 and was classified as reliable with restrictions because it was an acceptable, well-documented study report which meets basic scientific principles. This study was well conducted and reported. However, since the exposure period was only 1 minute, and was followed by a recovery period, the results will be considered to build a weight of evidence together with those from other acute and repeated-dose inhalation studies. Irritation effects are often considered to be concentration dependent, rather than duration dependent, therefore results from this study are considered to provide some relevant information.