"2.3. Dose setting

A preliminary study had been performed with one male and one female for each test substance. Animals were exposed to the substances for 5 days per week at each dose level as follows. As for HCFC 225ca, exposure to 1500 ppm caused bloody diarrhea and loose feces, 5000 ppm caused sporadic crouching and somnolence during exposure. Although bloody loose feces subsided gradually and animals tolerated a 5-day exposure to 5000 ppm, body weight was decreased after the Based on the preliminary study, 1000 ppm for HCFC 225ca and 5000 ppm for HCFC 225cb were set as the dose for the main study.

2.4. Group constitution

Animals were divided into three groups so that each group contained a similar population (four males and three females) and group mean body weights were made equal. Each group was exposed to air only (control), HCFC 225ca or HCFC 225cb.

2.5. Exposure method

Animals placed in stainless steel, wire-mesh cages (240 W x 200 D x 360 H mm) for the inhalation study were exposed to the test substance within an exposure chamber (1.64 m3) for 6 h per day for 28 consecutive days. The vaporization system consisted of a supplementary tank, a test sample tank, a gas generator, and mixing chamber. Atmospheres were generated by bubbling nitrogen into the test substance and by blowing compressed air into the gas generator, which was at a constant temperature in a water bath. To avoid condensation, the vapor was diluted with compressed air in the mixing chamber. The vapor was diluted further to a final concentration with filtered air and was introduced at the top of the inhalation chamber and discharged from the bottom. Ventilation comprised 10.4 air changes per hour (supply volume: 17 m3/h). Based on output of a hydrocarbon meter (HCM-lB, Shimadzu Co.) indicating a relative concentration of the vapor in the chamber, the concentration of the vapor was constantly maintained by automatically controlling the flow of nitrogen. After 0.5, 3.0, and 5.5 h of exposure, 1.0 ml samples of the vapor in the chambers were taken with air-tight glass syringes and analyzed using a gas chromatograph (GC-14, Shimadzu Co.) fitted with a gas sampling valve, flame ionization detector, and polyethylene glycol bonded open tube column connected to chromatopack data system (CR-6A, Shimadzu Co.). The absolute concentration of the test substance was calculated by determining each peak area from GC output and measuring against a standard regression curve."

"Exposure concentration

The mean vapor concentration of HCFC 225ca was 1010 ± 40 ppm (range, 960-1160 ppm) for males and 1000 ± 30 ppm (range, 960-1060 ppm) for females compared to the target concentration of 1000 ppm. The mean concentration of HCFC 225cb was 5030 ± 170 ppm (range, 4670-5360 ppm) for males and 5040 ± 170 ppm (range, 4670-5360 ppm) for females compared to the target concentration of 5000 ppm."

Note: Dose levels were converted from ppm to mg/m3 by the extractor.

Male Marmosets