“28-Day Repeat Dose inhalation Toxicity Study

In this study, five groups of 10 male and 10 female rats were exposed to vapors of HFC 245fa, whole-body, 6 h/day for 28 consecutive days. The exposure levels were 0 (control), 500, 2000, 10,000 and 50,000 ppm. Additionally, two groups of five male and five female rats received concurrent exposure to 0 and 50,000 ppm for 28 days and then were held for a 2-week postexposure observation period.

The test atmospheres were generated as described for the 14-day study except that the test compound was vaporized in a copper coil warmed to 50°C. The test atmospheres were monitored by gc at least at hourly intervals. The animals were exposed in stainless steel and glass chambers, each with an internal volume of 0.75 m³. Temperature (23.2-24.7°C) and humidity (33-46%) were monitored and controlled during the exposures. The air flow through the chambers was approximately 150 liters per minute. Animals were observed daily both in home cages and during exposure. Detailed clinical observations, body weight measurements, and food consumption determinations were conducted weekly.

Blood and urine samples were collected during the final week of exposure for the main study population and at the end of the postexposure observation period for the remaining rats. All rats received an ophthalmic examination pre-exposure and all control and high exposure level rats received a similar examination prior to sacrifice. Hematologic examinations were conducted using a Bayer-Technician H*IE analyzer (Bayer Diagnostics, UK; reagents, Nycomed, UK). The following parameters were evaluated: packed cell volume, hemoglobin, red cell count, mean corpuscular hemoglobin concentration, mean corpuscular volume, total white cell count and differential count, platelet, Thrombotest (Baxter Healthcare, UK) and reticulocyte count. In addition, the same clinical chemistry parameters were evaluated as described for the 14-day exposure study. Urinalysis consisted of volume, pH, specific gravity, protein, reducing substances, glucose, ketone, bile pigments, urobilinogen, and haem pigments. In addition, urinary and blood fluoride levels were measured. At sacrifice, organ weight measurements were conducted on the adrenals, brain, epididymides, heart, kidneys, liver, lungs, ovaries, spleen, and testes. Liver peroxisome activity was determined as described for the 14-day study. A complete set of tissues was collected from all animals (Kawano et al., J 995). The eyes were preserved in Davidson's fixative, the testes and epididymides in Bouin's fluid, and the remaining tissues in 10% formalin. Tissues from all control and high exposure group animals were examined, as well as target organs from all other treatment groups.”

“Statistical Analysis

Where appropriate, all groups were compared to the respective control populations. The statistical methods have been described previously (Brock et al., 1995; Rusch et al., 1995).

Quantitative data were analyzed by Bartlett's test for homogeneity. If the data were heterogeneic, alogarithmithic transformation was performed to see if a more stable variance could be obtained. Data without significant heterogeneity were analyzed by one-way analysis of variance, and Williams test (Williams 1971, 1972) for dose response. The Kruskal-Wallis analysis (Hollander and Wolf, 1973) was used as a covariate in the analysis of covariance.”

"14-Day Study….

On the day prior to the final exposure, blood samples were collected for clinical evaluation. The parameters evaluated include creatinine phosphokinase (CPK), triglycerides, glucose, total protein, albumin, globulin (calculated), urea nitro gen, creatinine, alkaline phosphatase, glutamic-pyruvic transaminase (GPT), glutamic-oxaloacetic transaminase, total bilirubin, sodium, potassium, calcium, inorganic phosphorous, chloride and cholesterol. In addition, liver peroxisome activity was measured using the method of Angermuller and Fahimi (1981)."

Male Sprague Dawley CD Rats