Electron beam sterilization

After gamma or electron beam sterilization, the impact strength of a given grade decreases by 25% after 25 kGy or 30% after 100 kGy, and the ABS yellows more or less permanently. These results are examples only and cannot be generalized. 

Determine whether or not the I) value for the biological indicator varies as a function of the dose rate. With cobalt-60, dose rate differences are not of much concern (variance of 0.1-0.5 Mrad/hr), whereas electron beam sterilization might produce dose rate variances of several Mrads per min ... 

Plastic components (whether container or closure) can be sterilized using steam, ethylene oxide, hydrogen peroxide, or ionizing radiation. The y irradiation is accomplished off-site by a subcontractor with appropriate expertise as these methods are considered the province of specialists because of the extreme health hazards directly related to the sterilization method. Electron beam sterilization may also be done by a contractor, although compact lower energy electron beam systems have been introduced that allow sterilization in-house. Steam sterilization is ordinarily performed in house, though many common components are becoming available presterilized by the supplier. Preparation steps prior to sterilization vary with the component and the methods used to produce the component. Rubber components are washed to reduce particles, while this is less common with plastic materials. 

The use of radiation within a parenteral facility would have been considered unthinkable prior to the start of the twenty-first century. While y irradiation is typically a contracted service provided off-site, electron beam sterilization advances can make the installation of an in-house (and generally an in-line) system a real possibility. An in-line system would be utilized similarly to the gas/vapor systems described above for treatment of external surfaces for entry into either a clean room or isolator-based aseptic processing facility. The use of this same technology for terminal sterilization is also possible [1], Association for the Advancement of Medical Instrumentation (AAMI)/ISO 11137 provides widely accepted guidance on the development and validation of radiation sterilization processes. 

Electron beam sterilization of medical waste is an effective means to accomplish this purpose. Recent improvements have made the process economically competitive to be applied to infectious waste. It can be apphed to aU types of infectious wastes, including liquids. 

Odland TL. Electron beam sterilization of biological tissues. US Patent 6203755 B1 [issued 04.03.94]. 

As for the relative suitability of an electron beam (EB) facility vis-a-vis a cobalt-60 gamma facility, a key point is that although the ultimate chemistry is nearly identical in both cases, there is a notable difference in the penetration of the radiations. Another point is that the large capacity and consequent cost of EB machines require a relatively large production rate to justify their use. On the other hand, the EB machine, not being a radioactive source, is completely safe when switched off. Overall, since the sixties, sterilization by irradiation has steadily increased. However, most of this is by cobalt-60 gamma irradiation, the EB machines accounting for about a fifth or sixth of the total number of facilities. 

Three-dimensional processing of materials by electron beam to produce uniform isotropic irradiation of components, which are to be sterilized or bulk/surface modified. ... 

The major objective in validating a radiation sterilization process, regardless of whether the mode of radiation is cobalt-60, cesium-137, or electron beam, is to determine the D value of the indicator micro-organism used to monitor the process. With radiation sterilization, the D value is defined as the dose of radiation in Mrads or kilograys necessary to produce a 90% reduction in the number of indicator microbial cells. The D value depends on such factors as temperature, moisture, organism species, oxygen tension, and the chemical environment and/or phys-... 

Flexible medical packaging is well suited to SBC for use in form, fill and seal machines. SBC have excellent formability, which allows for nearly perfect replication and filling of molds. To make a peelable seal, the SBC would need to be co-extruded with a lower melting substrate to act as the adhesive layer. The SBC structure provides good web formability and good toughness. It then has the versatility to be sterilized by 7-radiation, ethylene oxide or electron beam. 

Most medical devices require sterilization before packaging and use. The most common methods for doing this include -irradiation, exposure to ethylene oxide (EtO) gas or electron beam (E-beam). Contact with radiation, ethylene oxide or electron beam can affect not only the microorganisms of concern, but also potentially the medical device or package. The physical properties were tested after irradiation to define any deleterious effect... 

Figure 1 7 0 MeV electron beam accelerator (Rhodotron with its scanned beam circled with the red line) in an EB/X-ray sterilization facility (courtesy ofIBA, Belgium).

Irradiation of polymers with y- or electron beams is an attractive alternative to chemical sterilization because of its speed, ease of control, and the absence of residue. Radiation treatment of polypropylene, however, also initiates chemical changes which lead ultimately to embrittlement. These changes in physical properties may not become apparent until some time after the treatment. The ability of antioxidants to prevent radiation damage does not always follow the trends observed in thermal oxidation, which has stimulated efforts to develop new stabilizers or optimized combinations of existing ones. 

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