Sterilization is used for killing unwanted microorganisms in medical devices, healthcare products, pharmaceuticals, and combination drug devices. There are many types of sterilization to choose from depending on your product and requirements: gamma, E-Beam autoclaving, ETO, and dry heat. But now there is a new kid on the block that addresses many of the limitations with current, popular techniques, X-ray sterilization. (While ‘new’, X-ray has been in ISO 11137 prior to 1994 and due to improvements in efficiencies and technology, X-ray is now the clear choice over gamma).
Like gamma and E-Beam sterilization, X-ray sterilization uses irradiation to disrupt the DNA of microorganisms on the product. The X-rays are high-energy, high-frequency, short-wavelength electromagnetic photons. This allows for X-ray sterilization to offer the best features of gamma and E-beam.
Best Penetration Characteristics
X-ray sterilization offers better penetration characteristics than either gamma or E-beam. The X-ray’s deeper penetration allows for this technique to be used on many products and packaging configurations that E-beam cannot. X-rays are able to be used on products made of all types of materials including metals, liquids, and high-density and multicomponent products. In addition, the deeper penetration allows for larger packaging configurations and pallets to be sterilized as well.
Dose Uniformity Ratio (DUR)
While gamma is able to penetrate most of the same materials and configurations as x-ray sterilization, there is great concern with the uniformity of the gamma dose. With gamma, the DUR can be of concern during sterilization. The use of x-rays solves this and allows for tight dose ranges to be held.
Reduced Polymer Reactions
One of the major concerns with any irradiation of polymers is the interaction and effects it has on the materials. High exposure can cause significant changes in the material properties and even color. With the short exposure time and improved DUR, x-ray sterilization can be used on products whose only previous option was the use of ethylene oxide.
Faster Processing Speeds
X-ray sterilization offers one of the fastest processing times of any sterilization technique. It does not have dwell time or outgas requirements of ETO and is able to sterilize products quicker than gamma. This can reduce the sterilization turnaround time in many cases by days.
Less Environmental Impact
Some sterilization techniques have potential impacts on the environment. In particular, ETO sterilization uses ethylene oxide gas which is very poisonous and has to be carefully monitored and controlled while gamma uses cobalt-60, a radioactive element that needs to have proper security measures and disposal after the cobalt is no longer being used.
With its advantages over almost all other current sterilization techniques, X-ray sterilization is the up-and-coming sterilization technique and warrants your consideration both for new products and for the transition of current products. Already included in international standards and FDA guidelines, the usage of X-ray sterilization is already approved by regulatory bodies. The current, biggest challenge, as with any new technology, is finding facilities that offer this service. This should not be a problem in the years to come.