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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
Deviations:
no
Principles of method if other than guideline:
NA
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
Identity: 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH)
CAS No. : 80-51-3
EC No.: 201-286-1
Test facility Code No.: K-5450
Batch/Lot No.: 201512001
Appearance White fine powder
Purity: 99.5 - 100%
Storage conditions: Room temperature, Protected from light, Protected from moisture
Expiry date: 2016.12

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
Species Rat (Specific Pathogen Free)
Strain/Substrain Sprague-Dawley/Crl:CD (SD)
Number at receipt 20 (Male 10, Female 10)
Number on study start 12 (Male 6, Female 6)
Number on study end 12 (Male 6, Female 6)
Age range at receipt Approximately 8 weeks
Age range on study start Approximately 9 weeks (1st step) Approximately 10 weeks (2nd step) '
Body weight range Male: 312.4-337.2 g at the start of exposure (1st step) Male: 341.6-359.4 g at the start of exposure (2nd step) Female: 196.0-213.5 g at the start of exposure (1st step) Female: 204.1-217.6 g at the start of exposure (2nd step)

Supplier Orient Bio Inc. 322, Galmachi-ro, Jungwon-gu, Seongnam-si, Gyeonggi-do 13201, Republic of Korea Method of identification Color marking, Tail tattoo, Cage card
Acclimation period 5 days Pre-treatment period 2 days (1st step) 6 days (2nd step)
Replacement There was no replacement of the animals.

During pre-treatment period, 1 time of holder adaptation training was performed according to KIT SOP in order to decrease a stress that could be resulted from nose-only inhalation exposure

Housing and Animal Care:

Animal and exposure room No.
Animal room No.: F103, Exposure room No.: F102 (Inhalation toxicology building)

Housing
Animals were housed in groups of up to 3 animals in suspended, stainless-steel cage (255W×465L×200H mm) for the acclimation period, pre-treatment and exposure period.

Environment
The animal room environment was automatically controlled according to SOPs (target range: temperature 22 ± 3°C, relative humidity 30-70%, approximately 12 hours light cycle with 150-300 Lux, and ventilation 10-20 times/hour). Temperature and relative humidity were monitored continuously. Animal room and cage cleaning was performed according to KIT SOPs.

Identification for cage and animal room and exposure room
Cage card were attached to the cages. The animal room use record was displayed in the animal room and the exposure room use record use record was also displayed in the exposure room.

Food and Water
A standard rat and mouse pellet diet (Lab Diet® #5053, PMI Nutrition International, USA; irradiated by gamma-ray) was provided to the animals ad libitum. Microbial monitoring for diet was performed at test facility and a certificate of analysis for the diet was provided by the supplier. The animals have had ad libitum access to filtered, ultraviolet light-irradiated municipal tap water at all times. The drinking water was analyzed every 6 months for specified contaminants in the Gwangju Health & Environment Research Institute (149, Hwajeong-ro, Seo-gu, Gwangju, 61986, Republic of Korea). There were no known contaminants in the food or water at levels that would be expected to interfere with the results of the study and the data were maintained in the raw data.

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
not specified
Remark on MMAD/GSD:
Mass median aerodynamic diameters (MMADs) were 2.22 and 2.26 μm and geometric standard deviations (GSDs) were 2.02 and 1.92 for 1st step exposure, respectively.

Mass median aerodynamic diameters (MMADs) were 2.47 and 2.48 μm and geometric standard deviations (GSDs) were 2.00 and 2.03 for 2nd step exposure, respectively.
Details on inhalation exposure:
Exposure method of test item:
Test item was generated using dust generator [DF-3 Special, Sibata] and then supplied to the nose-only exposure inhalation experiment device [SIS-30BN, Sibata].

Chamber and conditions inside chamber:
Nose-only exposure inhalation experiment device [SIS-30BN, Sibata] Temperature was targeted to be maintained at 22 ± 3°C and relative humidity was targeted to be maintained in the range of 50 ± 20%. As well, oxygen concentration was targeted to be maintained above 19% and carbon dioxide concentration was targeted to be maintained below 1%.

Measurement and Monitoring of Exposure:
Nominal concentration: Total amount of test items used for generation of test item / Total volume of air supplied into chamber
Actual concentration: Exposure concentration of test item was measured 3 times by gravimetric analysis using microglass fiber filter during exposure, and then actual concentration (mass concentration) of exposed test item was assessed.

Environmental conditions of inhalation chamber:
Temperature, relative humidity, chamber airflow, chamber pressure, oxygen concentration and carbon dioxide concentration were monitored and recorded at least hourly during exposure.
Oxygen concentration was measured by multi-gas monitor [M40, ISC] and carbon dioxide concentration was measured by carbon dioxide meter [PGM-6208, RAE Systems].
Particle size distribution:
Particle size of the generated and exposed test item was measured 2 times during exposure by cascade impactor [Mini MOUDI 135-6S, MSP Corporation].
Mass median aerodynamic diameter (MMAD) with geometric standard deviation (GSD) was assessed based on measured values using Microsoft Excel® software (Microsoft Corporation, USA).

Method Verification (Inhalation Exposure Validation):
The chamber homogeneity on generated and exposed test item was performed during acclimation period.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
The rats were assigned to two groups (3 animals/sex/group) and were exposed nose-only to target concentrations of 1.00 mg/L (1st step exposure) or 5.00 mg/L (2nd step exposure) of 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH) for 4 hours.

Mean exposure concentration (actual concentration) of test item of 1st step and 2nd step were 1.06 ± 0.07 mg/L and 4.78 ± 0.30 mg/L for 4 hours, respectively
No. of animals per sex per dose:
3 animals per sex per dose
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: At receipt, at randomization, on day 1, 2, 5, 8 and 14 and at necropsy.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight and macrosopic findings

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
not determinable due to absence of adverse toxic effects
Mortality:
There were no unscheduled deaths in both sexes of 1st or 2nd step exposure group during the study period.
Clinical signs:
There were no test item-related clinical signs in both sexes of 1st or 2nd step exposure group during the study period
Body weight:
After acute inhalation exposure, body weights in both sexes of 1st and 2nd step exposure groups were transiently decreased on Day 2. Body weight gains in both sexes of 1st and 2nd step exposure groups were also transiently delayed on Day 2. But afterward, these were recovered.
Gross pathology:
There were no test item-related gross changes in both sexes of 1st or 2nd step exposure group
Other findings:
NA

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute inhalation toxicity of 4,4’Oxybis(benzenesulfonyl hydrazide) (OBSH) was evaluated in accordance to OECD 436 in both sexes of Sprague-Dawley rats. The rats were assigned to two groups (3 animals/sex/group) and were exposed nose-only to target concentrations of 1.00 mg/L (1st step exposure) or 5.00 mg/L (2nd step exposure). No effects were seen, thus the LC50 was > 5.00 mg/L (actual concentration 4.78 mg/L) and GHS criteria for classification was not meet.
Executive summary:

The acute inhalation toxicity of 4,4’Oxybis(benzenesulfonyl hydrazide) (OBSH) was evaluated in accordance to OECD 436 in both sexes of Sprague-Dawley rats. The rats were assigned to two groups (3 animals/sex/group) and were exposed nose-only to target concentrations of 1.00 mg/L (1st step exposure) or 5.00 mg/L (2nd step exposure) for 4 hours.

The mean exposure concentration (actual concentration) of OBSH for the 1st step and 2nd step were 1.06 ± 0.07 mg/L and 4.78 ± 0.30 mg/L for 4 hours, respectively. Mass median aerodynamic diameters (MMADs) were 2.22 and 2.26 μm and geometric standard deviations (GSDs) were 2.02 and 1.92 for 1st step exposure, respectively. Mass median aerodynamic diameters (MMADs) were 2.47 and 2.48 μm and geometric standard deviations (GSDs) were 2.00 and 2.03 for 2nd step exposure, respectively.  

No unscheduled death were seen as well as no clinical signs or gross changes. Transient body weight decreases were observed in males and females of 1st and 2nd exposure groups at Day 2 but it was recovered afterward.

In conclusion, no effects were seen, thus the LC50 was > 5.00 mg/L (actual concentration 4.78 mg/L) and GHS criteria for classification was not meet in this study.