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Specific investigations: other studies

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specific investigations: other studies
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
other: ASTM Method E981-84
GLP compliance:
yes (incl. certificate)
Type of method:
in vivo
Endpoint addressed:
respiratory irritation

Test material

Details on test material:
Name of test material (as cited in study report): Sodium Borohydride SF- Physical state: powder- Lot/batch No.: 42Y0Y09F- Storage condition of test material: room temperature

Test animals

other: CFW (SW) BR
Details on test animals and environmental conditions:
TEST ANIMALS - Source: Charles River Laboratories, Portage, Michigan, USA
- Age at study initiation: 4 weeks upon receipt
- Weight at study initiation: 28-31 g at selection
- Housing: initially 3 or 4 per cage for acclimation, then individually in suspended stainless steel cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: approximately 10 days
- Temperature (°C): 67-73 deg F (19-22 deg C)
- Humidity (%): 26-71%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 hours dar / 12 hours light
IN-LIFE DATES: From: April 4, 2001 To: April 12, 2001

Administration / exposure

Route of administration:
inhalation: dust
unchanged (no vehicle)
Details on exposure:
Nominal: 7.1, 2.4 and 12.2 mg/L
Gravimetric: 0.3, 0.1 and 0.57 mg/L
No vehicle
4 animals per dose
Particle size distribution: MMAD and GSD values of 5.16, 5.21 and 6.38 um and 2.28, 2.21 and 2.16, respectivey for actual mean concentrations of 0.30, 0.11 and 0.57 mg/L.
Analytical verification of doses or concentrations:
Duration of treatment / exposure:
30 min
Frequency of treatment:
one treatment
Post exposure period:
7 days
No. of animals per sex per dose:
4 males per dose

Results and discussion

Details on results:
No mortality occurred
Upper airway irritation was recorded in 4 of 4 animals for Groups 1 and 3 and 3 of 4 animals in Group 2. These animals demonstrated the characteristic pause during exhalation.
Respiratory rate depression was 44, 15 and 54% for Groups 1-3, respectively.
RD50 0.44 mg/L with 95% CL 0.35 to 0.62

Applicant's summary and conclusion

The RD50 in the mouse was determined to be 0.44 mg/L
Executive summary:

The study was conducted to determine the sensory irritant potential of Sodium Borohydride SF Powder in mice when administered via a head only inhalation exposure. The experimental design and methods were based on the American Society for Testing and Materials (ASTM) Method E981-84. Three groups of 4 male CFW (SW) BR mice were exposed by head-only inhalation exposure methods to a dust atmosphere of Sodium Borohydride SF Powder for 30 minutes (Plus the chamber equilibration time). The exposures were conducted on April 4, 2001 for Group 1 and April 5, 2001 for Groups 2 and 3 (Day 1). Observations were completed on April 12, 200l. The test article exposures were conducted in a 2.3 Liter glass head-only RD50 exposure chamber, as specified in the ASTM method. Exposure atmosphere concentrations were monitored once using standard gravimetric methods, and particle size distributions were determined once using a cascade impactor. Body weight measurements were obtained at receipt, just prior to exposure on Day 1, and at 7 days post exposure. Individual respiratory patterns were monitored and recorded continuously. Group mean respiratory rates were monitored and recorded continuously with a calibrated strip chart recorder. After the 7-day observation period, all mice were euthanized and discarded without necropsy. Particle size distributions were characterized by the mass medium aerodynamic diameter (MMAD) and the geometric standard deviation (GSD). Chamber temperature, relative humidity, and airflow were monitored and recorded once during each exposure. The 30-minute actual mean test article concentrations were 0.30, 0.11, and 0.57 mg/L. The particle size distributions were characterized by MMAD and GSD values of 5.16, 5.21, and 6.38 μm and 2.28, 2.21, and 2.16, respectively for the above chamber concentrations. Mean chamber temperature, relative humidity, and airflow, for the 30-minute exposures were 22°C, 9%, and 4.9 L/min, respectively. No mortality occurred during the conduct of this study. The observations of moribundity or ill-health were recorded for only 1 animal during the post exposure observation period. Group mean body weights remained within normal limits during the post exposure observation period. Upper airway irritation was recorded in 4 of 4 animals for Groups 1 and 3, and 3 of 4 animals in Group 2. These animals demonstrated the characteristic pause during exhalation. Respiratory rate depression was 44, 15, and 54% for Groups 1-3, respectively. These values resulted in an RD50 (respiratory rate depression) of 0.44 mg/L with 95% confidence limits of 0.35 to 0.62.