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lecture_15 - Packaging and Sterilization S. Laguette ME 128...

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Unformatted text preview: Packaging and Sterilization S. Laguette ME 128 Fall 2007 November 26, 2007 11/21/07 ME128 1 Packaging and Sterilization Packaging History Packaging Developments Packaging Advancements Sterilization Sterilization Methods 11/21/07 ME128 2 Packaging History In the 1970s, a need for high-performance packaging, driven by a rapidly growing device market Device manufacturers needed functional packaging for their sterile disposable (singleuse) devices. A package that could be sealed, sterilized, packed, and shipped, and then stored and opened easily and cleanly at the point of use. 11/21/07 ME128 3 Packaging History The state of the art in medical packaging prior to the early 1970s consisted primarily of film and paper bags, pouches, or boxes enclosed in an overwrap designed to protect the sterility of the package's contents. Traditional sterilization processes, such as steam or dry heat, were suited for only a few materials, such as vinyl-coated papers. 11/21/07 ME128 4 Packaging History Coincidentally, the key material that ultimately filled the bill was being introduced to market at the same time. DuPont's medical-grade Tyvek redefined packaging for the late 1970s. 11/21/07 ME128 5 Packaging History The 1980s and 1990s were noted for the rapid growth of medical device packaging and the growth of the key players in this market. DuPont continued to lead the market by working closely with major medical device manufacturers and packaging converters. The market for sterile device packaging expanded, particularly in the development of film-based pouch and form-fill-seal (FFS) packaging. 11/21/07 ME128 6 Packaging Developments During these decades, heat-seal coatings were developed for specific applications. Other significant materials-related developments include: Sealant films (with uncoated Tyvek). This combination provides a cost-effective solution for pouches and FFS forming webs. Specialty coatings. These coatings are ideal for highperformance applications where quality is critical and the ability to seal to semirigid trays is essential. High-temperature coatings. These coatings are suitable for dry-heat sterilization and autoclaving. 11/21/07 ME128 7 Packaging Developments High-altitude lidding. This lidding can withstand the internal pressures generated at high altitudes. Water-repellent aqueous coatings. Rather than providing a moisture barrier, these coatings repel water. Zoned-coating lidstock. This lidstock is designed for die-cut or FFS packaging. Autoclavable packaging. Both lidding and pouches can now withstand the autoclaving process. 11/21/07 ME128 8 Pouches Coated Tyvek Uncoated Tyvek 11/21/07 ME128 9 Materials Foil Tray Lidding 11/21/07 ME128 10 Packaging Advancements The next decade will require improved materials that provide more functionality and more flexibility. They will need to meet international standards. Key advancements will likely include: Zone-applied coatings that virtually eliminate coating and product contact. Product lines that are fully ISO 2002 and ISO 11607 compliant. More designed structures, possibly all films or film-foil combinations. Multilayer thermoformable plastics. More grades of Tyvek with functional distinctions. Multifunctional pouches that offer removable sterilization vents with a wide assortment of layers. On-line printable, bar-coded film pouches in roll form. Hybrid applications that combine device and drug packaging features. 11/21/07 ME128 11 Advancements 11/21/07 ME128 12 Sterilization Sterile: absence of all living organisms, particularly microorganisms: bacteria yeasts molds viruses Presence of even bacterium renders the component nonsterile Do not be fooled by the looks: a shiny stainless steel could be nonsterile whereas a rusty nail could be sterile 11/21/07 ME128 13 Sterilization How to determine sterility? Place the component within liquid microbiological culture media clear medium no microbiological growth sterile turbidity microbiological proliferation nonsterile 11/21/07 ME128 14 Sterilization Bioburden: Number of viable microorganisms on the implant just prior to sterilization 11/21/07 ME128 15 Sterilization How many nonsterile implants can we tolerate within a large batch? ideally none real world always have exceptions! given implant will remain nonsterile following exposure to a given sterilization process Generally accepted minimum SAL is 10-6: one out of one million implants will remain nonsterile after sterilization 11/21/07 ME128 Sterility Assurance Level (SAL): Probability that a 16 Sterilization How long should we sterilize to attain a SAL of 10-6? Test fewer of them and extrapolate to one million Process validation is critical Log of Fraction of NonSteril Implants 28/50 7/50 1/50 SAL = 10-6 Minutes of Exposure 11/21/07 ME128 17 Sterilization Sterilization Methods: Steam Sterilization (autoclaving) Ethylene Oxide Ionizing Radiation E-Beam Dry Heat Chemical 11/21/07 ME128 18 Steam Steam Sterilization (autoclaving) Kills microorganisms by denaturing protein and lipid complexes Exposing the implant to saturated steam at 121 C under high pressure. All surfaces should be contacted by steam Packaging permeable to steam 15-30 min 11/21/07 ME128 19 Steam Steam sterilization used for Intraoperative sterilization of metallic devices metallic surgical instruments heat resistant surgical supplies Efficacy Speed Process simplicity Lack of toxic residues limited to materials that can withstand high temperatures and pressures ME128 20 Advantages: Disadvantages 11/21/07 EtO Ethylene Oxide (EO) EO is very reactive, because its highly strained ring can be opened easily Kills germs by damaging their DNA-RNA Flammable, explosive, toxic and possibly carcinogenic 11/21/07 ME128 21 EtO Process Conditioning Sterilization Aeration A conveyor system automatically transfers the product from the conditioning room into the sterilization chamber. In this chamber, the product is treated with 100% Ethylene Oxide gas. (EO/Nitrogen is available for vacuum-sensitive products that are traditionally processed with Freon dilute mixtures.) After sterilization, the conveyer transfers the product into an aeration cell. The product remains in the aeration cell until the gas disperses and the product is safe to handle. 11/21/07 ME128 22 EtO EO is the method of choice for The sterilization of custom procedure kits containing unit dose drugs in hermetically sealed packages and/or other irradiation-sensitive materials Cellulosic and plastic products that exhibit discoloration with irradiation The sterilization of plastics whose physical properties degrade with irradiation Certain products that contain components that must be reclassified as drugs when processed with irradiation 11/21/07 ME128 23 EtO EO used for: surgical sutures intraocular lens ligament-tendon repair devices absorbable bone repair devices heart valves and vascular grafts High penetration Compatible with most materials toxic residuals ME128 24 Advantages Disadvantage 11/21/07 EtO 11/21/07 ME128 25 Radiation Radiation Sterilization gamma rays accelerated electrons Kills germs by ionization of key cellular components, particularly the DNA Gamma radiation sterilization using 60Co isotope most popular Conveyor carries implant around a matrix of 45x1 cm 60Co rods Longer time around rods greater dose Common dose 25 kGy (kilogray) 11/21/07 ME128 26 Radiation processing Cobalt source racks from Steris Isomedix Services are submersed under water when not exposed to a product. 11/21/07 ME128 27 Radiation Gamma radiations sterilization used for: surgical sutures metallic bone implants knee and hip prosthesis syringes neurosurgery devices some polymers (polyethylene, polyesters, polystyrene, polysulfones, polycarbonate) rapid effective controllable (dosimeters) high capital costs incompatible with several materials ME128 28 Advantages Disadvantage 11/21/07 References Carl D. Marotta, 19792004: Milestones in Medical Device Packaging ,Originally Published MDDI August 2004 Ozan Akkus, University of Toledo, Lecture series http://www.tolas.com/index.htm http://www.steris.com/isomedix/isomedix.cfm 11/21/07 ME128 29 ...
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