Methanesulfonamide, N-[2-[(4,6-dimethoxy-1,3,5-triazin-2-yl)carbonyl]-6-fluorophenyl]-1,1-difluoro-N-methyl-

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Feb - 24 June 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Japan MAFF, Notification No. 12 Nousan-8147 (2000)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-[2-(4,6-dimethoxy-1,3,5-triazine-2-carbonyl)-6-fluorophenyl]-1,1-difluoro-N-methylmethanesulfonamide

EC Number:

620-056-5

Cas Number:

874195-61-6

Molecular formula:

C14H13F3N4O5S

IUPAC Name:

N-[2-(4,6-dimethoxy-1,3,5-triazine-2-carbonyl)-6-fluorophenyl]-1,1-difluoro-N-methylmethanesulfonamide

Test animals

Species:

rat

Strain:

other: Wistar, Hsd Cpb:WU (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan-Netherland
- Age at study initiation: approximately 2-3 months old
- Weight at study initiation: 178-194 g
- Housing: The animals were housed singly in conventional Makrolon® Type IIIH cages.
- Diet: standard fixed-formula diet (KLIBA 3883 = NAFAG 9441 pellets maintenance diet for rats and mice; PROVIMI KLIBA SA, 4303 Kaiseraugst, Switzerland); ad libitum
- Water: tap water; ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 40-60
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 2010-03-03 To: 2010-03-17

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

other: The test item was applicated as dry powder atmosphere.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:aluminium inhalation chamber
- Exposure chamber volume: 3.8 L
- Method of holding animals in test chamber: Animals were exposed to the aerosolized test substance in Plexiglas exposure tubes applying a directed-flow nose-only exposure principle.
- Air flow: During the exposure period air flows were monitored continuously and, if necessary, readjusted to the conditions required. Air flows were measured with calibrated flow-meters. The proper performance of mass flow controller used was measured utilizing a digital precision flow-meter calibration device (Bios Defender 510).
- Method of conditioning air: Compressed air was supplied by Böge compressors and was conditioned (i.e. freed from water, dust, and oil) automatically by a VIA compressed air dryer. Adequate control devices were employed to control supply pressure.
- System of generating dust: (Wright-Dust Feeder; WDF) This dust generator was delivered from BGI Inc. Waltham MA, (USA) and is used for dry powder dispersion with conditioned compressed air (28 L/min). The test substance is first filled into a reservoir of the device and is then compressed to a pellet using approximately 1 metric ton by a carver laboratory press (F.S. Carver INC. Wabash, IN 46992, USA). From this pellet defined amounts of the test substance were scraped off with 1.2 to 1.7 revolution/min and were then effectively dispersed using pressurized air (approx. 100 kPa). The resulting dry powder aerosol was then entrained directly into the chamber.
- Method of particle size determination: The particle-size distribution was analyzed using an ANDERSEN-TYPE Mark II impactor for dry dust application. The individual impactor stages had been covered by an aluminium foil with an adhesive stage coating (silicone spray), which was utilized for characterization of the dry powder atmosphere. Gravimetric analyses were made using a digital balance without drying. The parameters characterizing the particle-size distribution were calculated according to the following procedure: Mass Median Aerodynamic Diameter (MMAD): Construct a 'Cumulative Percent Found - Less Than Stated Particle Size' table; calculate the total mass of test substance collected in the cascade impactor. Start with the test substance collected on the stage that captures the smallest particle-size fraction, and divide this mass of the test substance by the total mass found above. Multiply this quotient by 100 to convert to percent. Enter this percent opposite the effective cut-off diameter of the stage above it in the impactor stack. Repeat this step for each of the remaining stages in ascending order. For each stage, add the percentage of mass found to the percentage of mass of the stages be low it. Plot the percentage of mass less than the stated size versus particle size in a probability scale against a log particle-size scale, and draw a straight line best fitting the plotted points. A weighted least square regression analysis may be used to achieve the best fit. Note the particle size at which the line crosses the 50% mark. This is the estimated Mass Median Aerodynamic Diameter (MMAD).
Calculation of Geometric Standard Deviation (GSD): Refer to the log probability graph used to calculate the Mass Median Aerodynamic Diameter. Provided that the line is a good fit to the data, the size distribution is log normal, and the calculation of the Geometric Standard Deviation is appropriate. Note that particle size at which the line crosses the 84.1% mark. Note the particle size at which the line crosses the 50% mark and calculate as follows: GSD = 84.1% mark / 50% mark.
- Treatment of exhaust air: The exhaust air was purified via cotton-wool/HEPA filters. These filters were disposed of by Bayer Schering Pharma AG.


TEST ATMOSPHERE
- Brief description of analytical method used: The test-substance concentration was determined by gravimetric analysis (filter: Glass-Fiber-Filter, Sartorius, Göttingen, Germany; digital balance). The mass collected by the filter was set to be the test substance (no constituents in the dry test substance powder which can evaporate). In order to get comparable conditions for the gravimetric evaluations of the aerosol atmosphere these glass fibre filters were allowed to equilibrate under specified conditions (15 min at room temperature).
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5000 mg/m³ (target concentration)
5297.5 mg/m³ (analytical concentration)

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Body weights were measured before exposure, on Days 1, 3 and 7, and weekly thereafter. Individual weights are also recorded at death. The appearance and behaviour of each rat were examined carefully several times on the day of exposure and at least once daily thereafter. The rectal temperatures were measured shortly after cessation of the exposure. A battery of reflex measurements was made on the first post exposure day.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, reflexes, rectal temperature, body weight

Statistics:

Analysis of variance (ANOVA): This parametric method checks for normal distribution of data by comparing the median and mean. The groups are compared at a confidence level of (1-a) = 95% (p = 0.05). The test for the between-group homogeneity of the variance employed Box's test if more than 2 study groups were compared with each other. If the above F-test shows that the intra-group variability is greater than the inter-group variability, then "no statistical difference between the groups" are available. If a difference is found then a pair wise post-hoc comparison is conducted (1- and 2-sided) using the Games and Howell modification of the Tukey-Kramer significance test. This program was originally obtained from BCTIC.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5 297.5 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

Mortality did not occur during the study period (see Table 2).

Clinical signs:

other: All rats tolerated the exposure without specific clincial signs or changed reflexes.

Body weight:

Statistical evaluations did not identify significant changes between the control and exposure groups, which may be of toxicological relevance.

Gross pathology:

Necropsy findings were unremarkable after exposure.

Other findings:

- Rectal temperature: Statistical comparison between the rats revealed slight but significant change at exposed female rats. This change is within biological range and not considered to be of toxicological relevance.

Any other information on results incl. tables

Technical information concerning generation of test atmospheres is provided below.

Table 1: Generation conditions and characterization of chamber aerosol atmosphere (average values)

Parameters	Control group	Exposed group
Target Conc. (mg/m³)	0	5000
Gravimetric Conc. (mg/m³)	Control air	5297.5
Dust Generator Type	-	WDF
Inlet Air Flow (L/min)	15	28
Exhaust Air Flow (L/min)	13	24
Temperature (mean, °C)	22.7	22.8
Rel. Humidity (mean, %)	≤ 5.5	≤ 5.1
MMAD (µm)	-	3.18
GSD	-	2.03
Aerosol Mass < 3 µm (%)	-	47.0
Mass recovered (mg/m³)	-	4705.0

MMAD: mass median aerodynamic diameter

GSD: geometric standard deviation

-: not applicable

WDF: Wright dust feeder II

Characterization of the test atmospheres: The real-time monitoring and filter analyses of the aerosol atmosphere from the breathing zone indicated that the exposure condition was appropriate over the 4-h exposure period. Repeated measurements made during exposure lead to an adjustment of the dust generation. Analysis of the particle-size distribution from the breathing zone demonstrated that the dust atmosphere generated was in the respirable range. It is demonstrated that particle-size distributions are equal over the exposure period. The total gravimetric concentration recovered by the cascade impactor was in the range of that concentration found by filter analyses. Humidity was lower in the dust atmosphere because of utilizing dry air for the dispersion. Temperature value in the inhalation chamber was in the range suggested by the testing guidelines.

Table 2: Acute inhalation toxicity 

Target Concentration[mg/L air]	Mortality	Clinical Signs
	N*	N*
Males
0	0/5	0/5
5.2975	0/5	0/5
Females
0	0/5	0/5
5.2975	0/5	0/5

*N= Number of animals/ number of animals used

 

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

DSD: not classified
CLP: not classified