4'-tert-butyl-2',6'-dimethyl-3',5'-dinitroacetophenone

Endpoint summary

Description of key information

Acute oral toxicity: LD50 (male/female): >5000 mg/kg bw (Equivalent or similar to 401)

Acute inhalation toxicity: LC50 (male/female): > 2.99 ± 0.120 mg/L (OECD 403/GLP)

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 18, 1978 - September 15, 1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: IFF; (CS) HRH-06-190; Off-white, crystalline powder

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, PA, USA
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Weight at study initiation: 150-200g
- Fasting period before study: 12 hours prior to dosing
- Housing: Individually in suspended, wire-bottomed, stainless steel cages
- Diet: Purina rat chow ad libitum
- Water: ad libitum
- Acclimation period: Minimum 7 days

ENVIRONMENTAL CONDITIONS
- Temperature: 23.3°C
- Humidity: 45-55%
- Photoperiod: artificial light cycle of 12 hours

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 0.8 ml/100 gm body weight, equivalent to 5000 mg/kg bw

Doses:

The 5 doses levels evaluated in the initial range-finding study (2 males/2 females) were not disclosed. The single dose level evaluated in the main study was 5000 mg/kg bw.

No. of animals per sex per dose:

2 rats/sex/dose in the initial range-finding study.
5 rats/sex/dose in the main study.

Control animals:

no

Details on study design:

-Duration of observation period following administration: 14 days
- Frequency of observations and weighing: animals were observed for pharmacotoxic signs at 1, 3, and 6 hours following intubation, and daily thereafter. Bodyweights were measured prior to dosing and 14.
- Necropsy of survivors performed: yes

Preliminary study:

An initial range-finding study evaluated 5 doses levels in 2 males and 2 females (doses were not disclosed). No deaths were reported in the range finding study.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Mortality:

No mortality was observed in male or female rats during the study.

Clinical signs:

other: All animals exhibited sedation and/or piloerection at 1 hour following intubation, and tremors, some sedation, and respiratory abnormalieies (depression and short, rapid respiration) at 3 and 6 hours following intubation. test animals showed no pharmacoto

Gross pathology:

A single animal had an enlarged spleen. Otherwise, no gross pathological organ changes were observed in any animals.

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute oral toxicity study in Sprague-Dawley rats, the LD 50 (male/female) was > 5000 mg/kg bw.

Executive summary:

In an acute oral toxicity study (55049), Sprague-Dawley rats (5/dose/sex) were given musk ketone in corn oil by gavage at doses of 5000 mg/kg bw and observed for 14 days.

LD50 (male/female): was >5000 mg/kg bw.

No mortality was observed in male or female rats during the study. All animals exhibited sedation and/or piloerection at 1 hour following intubation, and tremors, some sedation, and respiratory abnormalities (depression and short, rapid respiration) at 3 and 6 hours following intubation. Test animals showed no toxic signs on day 1, and continued to remain normal during the remainder of the 14-day observation period. Body weights at days 0 and 14 were within a normal range for both male and female animals. A single animal had an enlarged spleen; otherwise, no gross pathological organ changes were observed in any animals.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Quality of whole database:

There is one key study available. The quality of the database is medium.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 October 2017 to 05 december 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

traditional method

Limit test:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: PuyangOuya Chemical Technology Co., Ltd.; 2017073046
- Expiration date of the lot/batch: 31/Dec/2018
- Purity test date: 99.87% (w/w)

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The test item was aerosolized non-diluted and in its solid form utilized in the quantity of 110.85 g. The test item was ground and sieved (100# mesh sieve) in order to decrease the particle-size and to increase its respirability.

Species:

rat

Strain:

other: Wistar Hannover

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: ANILAB – Animais de laboratório Criação e Comércio Ltda., batches: 037/17 and 038/17
- Age at study initiation: 10 and 11 weeks of age on the day of exposure
- Weight at study initiation: 206 – 334g
- Housing: Polypropylene cages (41x34x19 cm) with autoclaved wood shavings and stainless steel mesh lids containing five rats of the same sex per cage were used in the experimental phase.
- Diet: Pelleted and autoclaved commercial diet for rats (Comercial name: Presence; Batch: 41EX170062037; Validity date: 24/Jan/2018) were available ad libitum.
- Water: The animals had free access to filtered water throughout the test, provided by SEMAE (Serviço Municipal de Água e Esgoto) in plastic bottles with capacity of 1000 mL.
- Acclimation period: 17 days (males) and 10 days (females)

ENVIRONMENTAL CONDITIONS
- Temperature: 19.5 °C to 24.0 °C
- Humidity: 43% to 70%.
- Air changes: 10 to 20 air changes per hour
- Photoperiod: A light system controller was adjusted to maintain a cycle of 12 hours light and 12 hours dark

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

> 2.53 - < 3.39 µm

Geometric standard deviation (GSD):

> 2.67 - < 3.01

Remark on MMAD/GSD:

The analysis of the aerodynamic particle-size distribution demonstrated that the Mass Median Aerodynamic Diameter (MMAD) was 2.53 μm and 3.39 μm (first and second samples, respectively) and the Geometric Standard Deviation (GSD) was 2.67 and 3.01 (first and second samples, respectively), indicating that at least 50% of the mass collected from the aerosol generated was within the respirable diameter (< 4 μm) (Table 4).

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION

Preliminary test
A preliminary test without animals was conducted to define the appropriate conditions to reach a test atmosphere with adequate particle-size.

Limit test
From the results obtained in the preliminary test without animals, it was observed that the conditions established for the limit test would reproduce the maximum attainable concentration in the chamber atmosphere.

Exposure equipment
The chamber used was a Jaeger Inhalation Chamber, Mark II with a Wright Dust Feeder integrated system coupled to a cyclone, with a big scraper and previously calibrated to a 4.0 RPM rotation, with 4.25 cm of diameter and 3.5 cm in height. The air eliminated was treated with a filter absolute model F – 771 K03 Trox and filter of activated carbon F – 760 Trox. The chamber has a positive pressure. The source of air used came from a compressed air (21% of oxygen and 79% of nitrogen). The volume was approximately1.5 litres.

Exposure principle
Rats were exposed to the aerosolized test item in plexiglass nose-only tubes applying a direct-flow exposure principle. The total airflow (primary + secondary) in the chamber was 10 L/min. Considering that there are twelve exits in the chamber (10 to allocate the animals during the exposure and 2 to make the collects), the dynamic flow was of approximately 833 mL/min/animal.

Airflow and exposure conditions
The airflow rate was monitored continuously, through the use of an analogical flow meter and was recorded during the exposure. The total airflow did not show any variation (10 L/min.) (Table 1).

During the period of animals exposure to the test substance, four measurements of temperature and humidity, equally spaced in time, were performed. The temperature and relative humidity in the animal’s breathing zone were maintained in the range between 19 and 25ºC and 30 and 70%, respectively.

Exposure principle justification
Nose-only tubes were chosen to accommodate the rats’ size and to allow the rat’s tail to remain outside the tube, avoiding restrained-induced hyperthermia. This exposure principle is preferable compared to whole-body exposure because of scientific and technical reasons - rapid attainment of steady-state concentrations, lower consumption of test substance and minimization of uptake by non-inhalation routes.

Mean actual concentration
Three equally time-spaced air samples from the vicinity of the breathing zone were taken with an air sampling pump previously calibrated to a 1.2 L/min flow rate to collect the aerosol in filters (Millipore Field Monitor for contamination analysis, 0.8 μm micropore size) for four minutes. The filters were weighed before and after sampling on an analytical scale.

Aerodynamic particle-size distribution
Two equally time-spaced air samples were taken from the vicinity of the breathing zone using an air sampling pump previously calibrated to a 0.500 L/min flow rate, to collect the aerosol in a Seven Stage Cascade Impactor (In-Tox, Albuquerque, New Mexico, U.S.A.) for five minutes. Before and after sampling, the stages were weighed.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Mean actual concentration (mg/L) = 2.99 ± 0.120 (maximum attainable concentration)

No. of animals per sex per dose:

5 males and 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: Animals were observed frequently during the exposure period. Immediately after the exposure period, the rats were removed from the chamber, their heads carefully cleaned of any material and transferred to the animal house facility. Following exposure, two clinical observations were made during the first 24 hours and then daily during a fourteen-day observation period. The clinical observations were recorded systematically and individually

- Frequency of observations and weighing: The body weight was measured on acclimatization, prior to exposure, on the day of exposure (day 0), the first, third, seventh and fourteenth days after exposure.

- Necropsy of survivors performed: Yes

- Other examinations performed: Microscopic examination of potential target organs was not considered necessary, due to the absence of compound-related clinical signs and macroscopic findings.

Statistics:

Only a limit test was performed, the four-hour inhalation LC50 was not calculated.

Preliminary study:

A preliminary test without animals was conducted to define the appropriate conditions to reach a test atmosphere with adequate particle-size. The maximum attainable concentration was 2.99 ± 0.120 mg/L.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.99 mg/L air (analytical)

Exp. duration:

4 h

Mortality:

No compound-related death was registered in this study.

Clinical signs:

other: No compound-related clinical sign was observed in this study. Individual data are displayed on Tables 5 and 6.

Body weight:

The mean body weight increased for both sexes in all post-exposure weighings, except in the first post-exposure weighing for the females (Table 3). All animals exceeded their initial body weight at the end of the observation period of 14 days. Individual body weights are displayed on Tables 9 and 10.

Gross pathology:

No compound-related macroscopic finding was registered in this study. Individual data are displayed on Tables 7 and 8.

Other findings:

- Histopathology: It was not considered necessary, due to the absence of compound-related clinical sign and macroscopic findings.

Interpretation of results:

GHS criteria not met

Conclusions:

The combined (males and females) median lethal concentration in a 4-hour nose-only exposure period (4-h LC50) to Musk Ketone inhaled by Wistar Hannover rats was greater than 2.99 mg/L.

Executive summary:

In an acute inhalation toxicity study (16073.417.084.17), a group of young adult Wistar Hannover strain rats (5/sex) were exposed to a test atmosphere of musk ketone (99.87%) for 4 hours (nose only) at a mean actual concentration of 2.99 ± 0.120 mg/L (maximum attainable concentration). Animals were then observed for 14 days.

LC50 male/female = > 2.99 ± 0.120 mg/L

The MMAD was 2.53 -3.39 μm and GSD was 2.67 - 3.01, indicating that at least 50% of the mass collected from the aerosol generated was within the respirable diameter (< 4 μm).  No compound-related death was registered in this study. No compound-related clinical sign was observed in this study. The mean body weight increased for both sexes in all post-exposure weighing, except in the first post-exposure weighing for the females. All animals exceeded their initial body weight at the end of the observation period of 14 days. No compound-related macroscopic finding was registered in this study. Histopathology was not considered necessary, due to the absence of compound-related clinical sign and macroscopic findings.

This acute inhalation toxicity test in rats is acceptable and satisfies the guideline requirement for an OECD 403 study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

2.99 mg/m³ air

Quality of whole database:

There is one key study available and it is an OECD guideline/GLP study. The quality of the database is high.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There was one acute oral toxicity study in rats available.

In an acute oral toxicity study (equivalent or similar to 401), Sprague-Dawley rats (5/dose/sex) were given musk ketone in corn oil by gavage at doses of 5000 mg/kg bw and observed for 14 days. No mortality was observed in male or female rats during the study. All animals exhibited sedation and/or piloerection at 1 hour following intubation, and tremors, some sedation, and respiratory abnormalities (depression and short, rapid respiration) at 3 and 6 hours following intubation. Test animals showed no toxic signs on day 1, and continued to remain normal during the remainder of the 14-day observation period. Body weights at days 0 and 14 were within a normal range for both male and female animals. A single animal had an enlarged spleen; otherwise, no gross pathological organ changes were observed in any animals. The LD50 (male/female) was >5000 mg/kg bw.

There was one acute inhalation toxicity study in rats available.

In an acute inhalation toxicity study (OECD 403/GLP), a group of young adult Wistar Hannover strain rats (5/sex) were exposed to a test atmosphere of musk ketone (99.87%) for 4 hours (nose only) at a mean actual concentration of 2.99 ± 0.120 mg/L (maximum attainable concentration). Animals were then observed for 14 days. The MMAD was 2.53 -3.39 μm and GSD was 2.67 - 3.01, indicating that at least 50% of the mass collected from the aerosol generated was within the respirable diameter (< 4 μm).  No compound-related death was registered in this study. No compound-related clinical sign was observed in this study. The mean body weight increased for both sexes in all post-exposure weighing, except in the first post-exposure weighing for the females. All animals exceeded their initial body weight at the end of the observation period of 14 days. No compound-related macroscopic finding was registered in this study. Histopathology was not considered necessary, due to the absence of compound-related clinical sign and macroscopic findings.  The LC50 male/female is > 2.99 ± 0.120 mg/L.

Both studies are acceptable to use in the human health hazard assessment.

Justification for classification or non-classification

Based on the available information in the dossier, the substance musk ketone (CAS No. 81-14-1) does not need to be classified for acute toxicity or specific target organ toxicity - single exposure when the criteria outlined in Annex I of 1272/2008/EC are applied.