Selection Guide for Gamma-Ray Sterilization-Compatible Resins: From Flexible Elastomers to Rigid Transparent Engineering Plastics
Gamma ray sterilization can lead to problems such as decreased physical properties, yellowing, and increased leaching if the wrong material is selected. This article introduces our lineup of gamma ray sterilization-compatible resins, from flexible elastomers to rigid transparent engineering plastics, along with how to use them.
Table of Contents [hide]
- 1.Widespread adoption of gamma ray sterilization
- 2.Challenges of resin degradation due to gamma ray sterilization
- 2.1.Deterioration due to oxidation and decomposition
- 2.2.Yellowing (discoloration)
- 2.3.Increase in eluted substances
- 3.Introduction to gamma-ray sterilization-compatible resins
- 3.1.Zelas™ TPS Gamma-ray Sterilization Compatible Series (Thermoplastic Elastomer)
- 3.2.Zelas™ CP (rigid, transparent, amorphous polyolefin resin)
- 3.3.XANTAR™ Radiation-Resistant Grade (Br-based) (Transparent Engineering Plastic)
- 4.If you are looking for gamma-ray sterilization compatible materials
The spread of gamma ray sterilization
Various methods are employed for sterilizing medical devices and pharmaceutical containers, including autoclaving, ethylene oxide gas (EOG) sterilization, hydrogen peroxide sterilization, and radiation sterilization. With regulations on EOG sterilization being strengthened to reduce EOG emissions by 50-90% compared to current levels by around 2030, gamma ray sterilization, which can uniformly sterilize the entire product in its final packaging, has grown to account for 40-60% of the global market when combined with electron beam sterilization. 1) While demand is high for disposable products, the range of applications is expanding beyond medical devices and pharmaceutical containers to include regenerative medicine and biopharmaceutical-related products, as well as diagnostic testing equipment.
<Advantages of gamma ray sterilization>
- No post-processing required: No gas residue removal process is needed, unlike EOG sterilization.
• No special packaging required: Sterilization is possible without using special packaging materials that allow gas to pass through.
• Suitable for heat-sensitive products: Can be used for products that would deform or deteriorate during autoclave sterilization.
Challenges of resin degradation due to gamma ray sterilization
While gamma ray sterilization is an excellent sterilization method, it has the drawback of potentially causing a decrease in physical properties or changes in appearance depending on the resin material used. This is one of the most important considerations when preparing materials for gamma ray sterilization.
Deterioration due to oxidation and decomposition
Gamma ray irradiation generates radicals in the resin, accelerating oxidation reactions. This leads to molecular chain severance (decomposition) or crosslinking, resulting in changes in physical properties such as reduced strength, embrittlement, and stickiness.
Yellowing (discoloration)
Polyvinyl chloride (PVC), polyolefins (PP and PE), and polycarbonate resin (PC) are known to be prone to yellowing after gamma ray irradiation.
Increase in leached substances
If low-molecular-weight substances generated by irradiation increase as elutes, the risk of contamination of drug solutions in liquid-contact applications such as pharmaceutical containers and infusion sets increases.
Introducing gamma-ray sterilization-compatible resins.
To address these challenges, it is essential to select materials that maintain their physical properties and appearance after gamma irradiation, and to use specialized materials with low elution for wetted applications. Mitsubishi Chemical offers a wide range of gamma-ray sterilization-compatible resins for various applications, from flexible elastomers to rigid engineering plastics.
Zelas™ TPS Gamma-ray Sterilization Compatible Series (Thermoplastic Elastomer)
Zelas™ TPS is a medical and pharmaceutical compound based on styrene-based thermoplastic elastomer (TPS), offering excellent rubber elasticity and sealing properties. While TPS materials generally yellow and exhibit increased leaching after gamma irradiation, Mitsubishi Chemical's newly developed Zelas™ TPS gamma-ray sterilization-compatible series features a formulation designed to resist yellowing even after gamma irradiation, maintaining its physical properties. In particular, the tube-grade MP6301C-2 is ideal as a next-generation tube grade, especially as a replacement for polyvinyl chloride (PVC) tubes, which are facing increasingly stringent regulations in Europe and the United States.
Main Use Cases
- IV Set Tubing (MP6301C-2): A safe infusion line made plasticizer-free, replacing conventional PVC tubing.
- Syringe gaskets, vial stoppers, infusion stoppers (PJ4302C-1, PJ4302G-1, PJ8302C-1): Gaskets for syringes and closures for lyophilized products (C: Uncolored, G: Gray)
- Cell culture tube (MP6301C): Combines high hygiene and low elution properties required in the fields of regenerative medicine and biopharmaceuticals.
Zelas™ CP (rigid, transparent, amorphous polyolefin resin)
Main Use Cases
CPhosphate tubes and vial containers: Contact components for drugs requiring low adsorption, such as antibody drugs and nucleic acid drugs.
Medical bag film: As a low-adsorption packaging material for pharmaceuticals that is compatible with gamma ray sterilization.
Cell culture plates and microfluidic devices: High transparency and low adsorption properties for regenerative medicine and research applications.
XANTAR™ Radiation-Resistant Grade (Br-based) (Transparent Engineering Plastic)
XANTAR™ is a high-performance polycarbonate (PC) resin provided by Mitsubishi Chemical. Polycarbonate is an engineering plastic with excellent transparency, impact resistance, and heat resistance, and has a long track record in the medical device field. In addition to being compatible with steam sterilization and EOG sterilization, XANTAR™ radiation-resistant grade (Br-based) is specially designed to suppress yellowing caused by gamma ray irradiation, and is also compatible with gamma ray sterilization and electron beam sterilization.
Significantly suppresses yellowing after gamma ray irradiation: Contains a special bromine-based stabilizer to suppress discoloration caused by irradiation. Maintains appearance quality even in medical devices where transparency is required.
Excellent transparency: High light transmittance, close to that of glass, ensures visibility of internal liquids, tissues, and devices.
High impact resistance: Due to the inherent toughness of polycarbonate, it can be used for thin-walled precision molded products.
Wide operating temperature range: -40°C to +120°C, suitable for a wide range of operating environments.
Compatibility with multiple sterilization methods: Compatible with gamma ray, electron beam, EOG sterilization, and autoclave sterilization.
Long-standing medical track record: Used in numerous medical devices including dialyzers (artificial kidneys) and artificial lungs.
If you are looking for gamma-ray sterilization compatible materials
Technical documentation regarding Zelas™TPS and Zelas™CP before and after gamma ray sterilization is available for download from the link below.
Mitsubishi Chemical offers sample provision and technical consultation regarding gamma-ray sterilization-compatible resins. We will propose the most suitable grade according to your application, so please feel free to contact us.
<Notes/Disclaimer>
Please verify the product's suitability for gamma ray sterilization yourself.
The data provided are representative examples of measurements obtained using our company's prescribed test methods, which are in accordance with the relevant test method.
The examples of uses described do not guarantee the results of applying our products to those uses.
Please consider any industrial property rights or usage conditions related to the described uses and applications.
• When handling our products (transportation, storage, molding, disposal, etc.), please note the materials used.
Please refer to the grade's technical documentation and Safety Data Sheet (SDS). Especially for food containers and packaging, medical components,
For use in safety equipment, children's toys, etc., please contact us separately.
In Japan, for colored products of each grade, the applicable law is the Industrial Safety and Health Act.
It contains a chemical substance whose name, etc., should be notified as listed in Appendix 9 of Article 18-2 of the Enforcement Order based on Article 57-2.
There may be cases where this is not possible. Please contact us for details.
• When exporting our products or products incorporating our products, we comply with the Foreign Exchange and Foreign Trade Act, etc.
Please comply with all relevant laws and regulations.
Due to the chemical substance management systems of each country, the chemical substances used in our products are subject to regulations.
Additional applications may be required, or export/import may not be possible. If you are the exporter or importer of our products...
If this is the case, please inquire about the regulatory compliance status in the relevant country.
<References>
1) Ministry of the Environment: Measures to Reduce Ethylene Oxide Emissions |https://www.env.go.jp/council/content/07air-noise02/000278096.pdf
Ministry of Health, Labour and Welfare: Risk Assessment of Priority Chemical Substances (Primary) - Ethylene Oxide |https://www.mhlw.go.jp/content/11121000/000533916.pdf
Japan External Trade Organization (JETRO)China's Volatile Organic Compound (VOC) Regulation Policy |https://www.jetro.go.jp/ext_images/world/qa/pdf/04C-110110.pdf
European commission Zero Pollution: Modernized rules on industrial and livestock rearing emissions come into effect |https://environment.ec.europa.eu/news/revised-industrial-emissions-directive-comes-effect-2024-08-02_en#:~:text=The%20revised%20l aw%20will%20cover%20additional%20sources%20of,administrative%20costs%2C%20and%20tighten%20conditions%20on%20granting%20derogations.
Federal Register :: National Emission Standards for Hazardous Air Pollutants: Ethylene Oxide Emissions Standards for Sterilization Facilities Residual Risk and Technology Review | https://www.federalregister.gov/documents/2024/04/05/2024-05905/national-emission-standards-for-hazardous-air-pollutants-ethylene-oxide-emissions-standards-for
EPA Fact SheetFinal Amendments to Air Toxics Standards for Ethylene Oxide Commercial Sterilization Facilities: Fact Sheet|https://www.epa.gov/system/files/documents/2024-03/factsheet_etosterilizers_final_3-14-24.pdf
GIPA (Global Industry Practices Alliance) A Comparison of Gamma, E-beam, X-ray and Ethylene Oxide Technologies for the Industrial Sterilization of Medical Devices and Healthcare Products |https://gipalliance.net/wp-content/uploads/2013/01/GIPA-WP-GIPA-iia-Sterilization-Modalities-FINAL-Version-2017-October-308772.pdf
