Mercaptamine

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Mercaptamine

EC Number:

200-463-0

EC Name:

Mercaptamine

Cas Number:

60-23-1

Molecular formula:

C2H7NS

IUPAC Name:

mercaptamine

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Han

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 10-11 weeks old
- Weight at study initiation: 168 - 202g
- Fasting period before study:
- Housing: On arrival and following assignment to the study, animals were group housed (up to 3 animals of the same sex and same dosing group together) in polycarbonate cages (Makrolon MIV type; height 18 cm.) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) equipped with water bottles. The room(s) in which the animals were kept were documented in the study records.
Animals were separated during designated procedures/activities. Each cage was clearly labeled.

- Diet (e.g. ad libitum): ad libitum - Pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany)
- Water (e.g. ad libitum): ad libitum - Municipal tap-water was freely available to each animal via water bottles.
- Acclimation period: 5 days before dosing

ENVIRONMENTAL CONDITIONS
Target temperatures of 18 to 24°C with a relative target humidity of 40 to 70% were maintained. The actual daily mean temperature during the study period was 20 to 21°C with an actual daily mean relative humidity of 41 to 51%. A 12 hour light/12 hour dark cycle was maintained. Ten or greater air changes per hour with 100% fresh air (no air recirculation) were maintained in the animal rooms.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 2000 mg/kg

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: The oral route was selected as it is a possible route of human exposure during manufacture, handling or use of the test item. The dose levels were based on the OECD test guidelines and were selected from the series 5 (lowest dose level), 50, 300 and 2000 (highest dose level) mg/kg body weight. The starting dose level should be the one that is likely to produce mortality in at least some of the animals and was selected based on available toxicity data of the test item.

Doses:

300 and 2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

Mortality/Moribundity Checks
Throughout the study, animals were observed for general health/mortality and moribundity twice daily, in the morning and at the end of the working day. Animals were not removed from cage during observation, unless necessary for identification or confirmation of possible findings. These observations may include additional body weight measurements to check the health status of the animals. Animals showing pain, distress or discomfort, which was considered not transient in nature or is likely to become more severe, were sacrificed for humane reasons based on OECD guidance document on the recognition, assessment, and use of clinical signs as humane endpoints for experimental animals used in safety evaluation (ENV/JM/MONO/ 2000/7).

Clinical Observations
Postdose Observations
Postdose observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter. The observation period was 14 days.

All the animals were examined for reaction to dosing. The onset, intensity and duration of these signs was recorded (if appropriate). Signs were graded for severity and the maximum grade was predefined at 3 or 4. Grades were coded as slight (grade 1), moderate (grade 2), severe (grade 3) and very severe (grade 4). For certain signs, only its presence (grade 1) or absence (grade 0) was scored.

Body Weights
Animals were weighed individually on Day 1 (predose), 8 and 15. A fasted weight was recorded on the day of dosing.

Terminal Procedures
All moribund animals and animals surviving to the end of the observation period were sacrificed by oxygen/carbon dioxide procedure. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded.

Statistics:

not applicable

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50 cut-off

Effect level:

500 mg/kg bw

Based on:

test mat.

Mortality:

At 2000 mg/kg, two animals were found dead on Day 1 and one animal was killed in extremis on Day 1.
At 300 mg/kg, no mortality occurred.

Clinical signs:

At 2000 mg/kg, lethargy, flat posture, hunched posture, uncoordinated movements, piloerection, scabs on the right cheek, ptosis, quick breathing and/or clonic spasms were noted prior to death.

At 300 mg/kg, lethargy, hunched posture, uncoordinated movements and piloerection were noted between Days 1 and 3. Hunched posture and piloerection reoccurred for three animals on Days 8 and 9. In addition, lean appearance was noted for two animals on Days 8 and 9.

Body weight:

Three animals treated at 300 mg/kg showed body weight loss at Day 8, all animals gained weight on Day 15 compared to the starting weights, except for one animal which showed a slight body weight loss on Day 15 compared to the starting weight.

Gross pathology:

At macroscopic post mortem examination, abnormalities of the glandular mucosa of the stomach (dark red or black discoloration), jejunum (black discoloration) and duodenum (black discoloration) were found in the animals that died or were sacrificed for humane reasons during the study.

Enlarged axillary lymph nodes were noted for one surviving animal.

Macroscopic post mortem examination of the other surviving animals at termination did not reveal any abnormalities.

Any other information on results incl. tables

TABLE 1 MORTALITY DATA
TEST DAY HOURS AFTER TREATMENT	1 0	1 2	1 4	2	3	4	5	6	7	8	9	10	11	12	13	14	15
FEMALES 2000 MG/KG	-	1	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-
FEMALES 300 MG/KG	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
FEMALES 300 MG/KG	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The oral LD50 value of Mercaptamine in Wistar rats was established to be within the range of 300-2000 mg/kg body weight.

According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 500 mg/kg body weight