The bioburden of silicone catheter and it's physical and chemical characteristics after irradiation were examined, and the following results were obtained.1. The maximum and minimum contaminants per a silicone catheter were 24 and 0,and the average was 2.36.2. The 84.7% of the 150 strains isolated from the silicone catheter was identified as bacilli by microbiological and biochemical tests, and Bacillus subtilis compried 66.0% of the strains. The D value of those strains was determined. The peak of D value was 1.1-1.4 kGy (0.11-0.14 Mrad).3. The sterilization dose at 10^<-6> of sterility assurance level was calculated to be 15 kGy (1.5 Mrad) by the formulas of bioburden ((1) and (3)).4. No significant differences were found between the irradiated samples and control up to 20 kGy (2 Mrad) in tensile strength, elongation, moduls, hardness, tear strength, eluate test. These results indicate that the silicone catheter can be sterilized by γ-irradiation.
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