The type of packaging should be selected according to the required sterilization method. At the global level there is no doubt that in order to package biomedical articles, only products manufactured for this purpose should be used. This refers to products that meet the conditions for being considered medical grade.
Sterilization packaging is classified according to its origin or manufacturing as medical grade, non-medical grade and rigid container materials. Within these different types, there are materials that are disposable and others that are reusable. The term medical grade is used by the sterilization packaging industry to designate materials that are specially designed for packaging and whose preparation is standardized. This type of packaging has a controlled porosity no higher than 0.5 microns and water repellency.
Woven cloths
Appropriate cloths are those made of cotton and cotton with polyester with a count of 55 threads/cm2 distributed in the following way: warp, 28 threads/cm; weave, 27 threads/cm; total, 140 threads/inch2, in double wrapping. These are used for heavy packages that need resistant packaging. The cloth should be washed after each process and discarded in the case of any holes.
Instructions for use:
Cotton or cotton-polyester cloth packaging (140 threads/inch2) should be using with double wrapping. This is the least effective bacterial barrier. It can be used for ethylene oxide steam. It should be washed, free from lint and inspected prior to use.
“Jean” type cloth packaging (160 threads/inch2) should be used with double wrapping. It can be used for ethylene oxide steam. It should be washed, free from lint and inspected prior to use.
Cloth barrier (272 to 288 threads/inch2) is resistant to liquids and has good penetration by steam and ethylene oxide. Since they can retain moisture, the drying time should be increased. It should be washed, free from lint and inspected prior to use.
Woven cloths should be washed between each use in order to restore the moisture content and ensure the filtration capacity of the fibers. Continuous washing of textiles reduces their efficiency as a barrier, which means that their storage time may be reduced.
Given that this type of material is susceptible to deterioration and experiences changes when used, it should be rigorously examined prior to each use. In the case of holes or tears, adhesive patches should be used. Mending is not appropriate since it may alter the weave and allow the passage of particles.
It should be taken into account that textile material is not water repellent, which means that precautions to avoid moisture should be maximized by securing and protecting the packaging with a plastic cover if it is going to be stored for a long time. The cover also constitutes protection from penetration by dust.
Unwoven cloths
The type of packaging should be selected according to the required sterilization method. At the global level there is no doubt that in order to package biomedical articles, only products manufactured for this purpose should be used. This refers to products that meet the conditions for being considered medical grade.
Sterilization packaging is classified according to its origin or manufacturing as medical grade, non-medical grade and rigid container materials. Within these different types, there are materials that are disposable and others that are reusable. The term medical grade is used by the sterilization packaging industry to designate materials that are specially designed for packaging and whose preparation is standardized. This type of packaging has a controlled porosity no higher than 0.5 microns and water repellency.
Woven cloths
Appropriate cloths are those made of cotton and cotton with polyester with a count of 55 threads/cm2 distributed in the following way: warp, 28 threads/cm; weave, 27 threads/cm; total, 140 threads/inch2, in double wrapping. These are used for heavy packages that need resistant packaging. The cloth should be washed after each process and discarded in the case of any holes.
Instructions for use:
Cotton or cotton-polyester cloth packaging (140 threads/inch2) should be using with double wrapping. This is the least effective bacterial barrier. It can be used for ethylene oxide steam. It should be washed, free from lint and inspected prior to use.
“Jean” type cloth packaging (160 threads/inch2) should be used with double wrapping. It can be used for ethylene oxide steam. It should be washed, free from lint and inspected prior to use.
Cloth barrier (272 to 288 threads/inch2) is resistant to liquids and has good penetration by steam and ethylene oxide. Since they can retain moisture, the drying time should be increased. It should be washed, free from lint and inspected prior to use.
Woven cloths should be washed between each use in order to restore the moisture content and ensure the filtration capacity of the fibers. Continuous washing of textiles reduces their efficiency as a barrier, which means that their storage time may be reduced.
Given that this type of material is susceptible to deterioration and experiences changes when used, it should be rigorously examined prior to each use. In the case of holes or tears, adhesive patches should be used. Mending is not appropriate since it may alter the weave and allow the passage of particles.
It should be taken into account that textile material is not water repellent, which means that precautions to avoid moisture should be maximized by securing and protecting the packaging with a plastic cover if it is going to be stored for a long time. The cover also constitutes protection from penetration by dust.
Unwoven cloths
These cloths are a combination of cellulose and synthetic fibers or 100% synthetic fibers joined by methods other than traditional weaving. They are joined by the fusion of fibers and resins that are later dried. They are disposable, compared to reusable cloths, eliminating the need for washing and inspection.
Instructions for use:
Unwoven cloths are resistant to liquids and have good penetration by steam and ethylene oxide. Since they can retain moisture, the drying time should be increased.
Paper
It is important to discuss all existing types of paper and which ones are appropriate for the sterilization process.
Wrapping paper
This material is used for sterilization by steam autoclave. It is not considered to be an efficient barrier since it has memory, is not waterproof, generates lint, and does not have standardized porosity. Furthermore, given that in some cases its manufacture is not standardized, it can contain toxic waste as part of it composition.
Newspaper
Newspaper is of very poor quality. The ink resins mask spores and contain toxic salts (Pb and Hg). Furthermore, newspaper has very little resistance to tears and stains.
Recycled papers
This includes sulphite and wood paper, which are both of similar quality. Preparations are made of paper that is recycled and bleached with sodium sulphite (Na2SO3). During preparation, the pH, moisture, starch concentration (microbial food), resistance to tearing and porosity are all uncontrolled.
Kraft paper
White, monolucid kraft paper is made from cellulose. The difference with wrapping paper is that kraft paper has controlled porosity and its manufacture is standardized with regard to additives, water repellency and resistance. It is a paper with high mechanical resistance, obtained from the chemical paste made of blached wood.
The accepted grammage is 60 to 80 g/m2, with a moisture of 8%. It has a porosity of less than 0.3 micras, which means that it represents a good antimicrobial barrier under adequate storage conditions. It has a rough side (exterior) and a glossy side (interior), which means that it does not release lint.
The term “kraft paper” only applies to the material that brings together the aforementioned characteristics, as certified by a regulatory agency.
Instructions for use:
Double wrapping is recommended. It can be used for steam and ethylene oxide. It is a better barrier than muslin. It wrinkles easily. It should not be reused.
Surgical grade or medical grade paper
This is the ideal paper for the sterilization process. Its porosity of 0.1 micras is controlled. It should have no less than 55% long fibers (the rest are short fibers) made of pure cellulose (British Standards 6255:1989).
Optical bleaches are not added during the preparation of this paper. The grammage is 60 to 65 g/m2, its pH is neutral and it is highly resistant to tearing. This paper does not release lint, but it does release fibers if the paper is broken by the hand during opening.
A grammage of 60 to 80 g/m2 guarantees mechanical resistance. Thicker paper guarantees protection against the entry of bacteria. During sterilization, especially by steam, the structure of the paper fibers undergoes strong pressures. This paper is safe and blocks bacteria following one sterilization, but its capacity for protection decreases in successive sterilization processes.
Instructions for use:
It can be used for steam and ethylene oxide. It should not be reused.
Surgical grade crepe paper
This paper is made with cellulose paste and has a porosity of 0.1 micras, a grammage of 60 to 65 g/m2 and neutral pH. It is used instead of cloths to prepare high-volume packaging. Its characteristics of flexibility and resistance make it adequate for this use. Its characteristics have been defined in British Standards (SW 6254:1989). It is accommodative, liquid repellent, does not release lint, does not irritate the skin, is resistant and does not have memory.
Instructions for use:
It can be used for steam and ethylene oxide. It wrinkles easily. It should not be reused. It is used most commonly as the inner wrapping of packages.
Mixed paper
This paper is a combination of medical grade paper and a transparent polymer. It represents the most common packaging in sterilization services. It consists of a transparent sheet that allows the article to be seen and an opaque sheet (medical grade paper). It is resistant to tension, bursting and tearing, heat sealable, easy to open and has incorporated chemical indicators. The presentation of this material is in the form of sleeves that are adaptable to materials of different sizes and envelopes.
Instructions for use:
It is compatible with sterilization by autoclave with steam, ethylene oxide and formaldehyde steam.
Rigid containers
There are a wide range of containers on the market with different characteristics and compatible with different sterilization methods. They should be used according to manufacturer instructions. They can be made from aluminum, stainless steel, plastic, or plastic-metal combinations. Some contain bacterial filters and others have valves that provide a biobarrier. They are very effective since they do not break, do not release fibers, do not become contaminated, and are easily transported.
Rigid containers without filters
These include closed stainless steel boxes that transmit heat through conduction.
Instructions for use:
These are used exclusively for dry heat.
Rigid containers with filters
Rigid containers, in order to be compatible with other sterilization methods, should be perforated. Some of these perforated containers have an incorporated filter that permits their use without exterior packaging. These filters should be examined and replaced periodically according to manufacturer instructions in order to ensure their effectiveness.
Perforated containers without an incorporated filter should be packaged externally with packaging that is compatible with the selected sterilization method.
Instructions for use:
These are used for steam.
Polymers
Polymers are an absolute barrier against microorganisms and dust. Therefore, storage using these materials as a barrier can be very prolonged. Since they are transparent, they are also useful for visualizing the contents. There are various types:
Polyethylene
Since this is a thermolabile material, it can only be used at low temperatures. It is useful for ethylene oxide or ionizing radiation. The most adequate is low-density polyethylene (0.076 mm). A problem arises during its use since it is a material that is waterproof, which impedes the humectation of the material when sterilized by ethylene oxide (moisture is an essential factor in this process). The entrance of water (in the form of steam) into the package being sterilized by ethylene oxide would be solved through the use of a Pouch, also called a peelable bag or window package. The Pouch consists of one folio (film) side and one paper side. The folios are made using a pure petroleum base as raw material (non-chlorinated, as is the case with PVC), which means that they can be burned or stored since they do not produce dioxanes or furans. The folio behaves neutrally in groundwater in rubbish dumps and does not release toxic substances during thermal elimination. The folio is waterproof to liquids, air and gases and therefore blocks bacteria.
Film bags of medical grade polyethylene
These are temperature-stable and permeable to steam, but they do not tolerate vacuum gaps.
PVC (Polyvinyl Chloride)
This material is not recommended since it is labile to temperature and to ionizingradiation, forming ethylene chlorohydrin (a non-volatile fixed substance) as a response.
PVC absorbs large amounts of ethylene oxide and eliminates it very slowly. For example, the time needed to eliminate the substance at room temperature is1 to 2 weeks. It is not recommended as packaging for sterilization.
Polypropylene and polycarbonates
These are both heat-resistant materials that are formed by 3 layers that are thermally joined (SMS):
• Spunbond: formed by long fibers that provide strength.
• Meltblown: formed by short, disordered fibers that provide a barrier.
They are accommodative, non-toxic and water repellent.
Instructions for use:
They can be used in steam sterilization (resistant up to approximately 140 ؛C – 150 ؛C). Since they can retain moisture, the drying time should be increased. Polypropylene is the packaging of choice for sterilization with hydrogen peroxide plasma.
Nylon (poliamide)
This material is temperature-stable and permeable to steam, but does not tolerate vacuum gaps. Therefore, it breaks when used in steam autoclaves. It is not appropriate for sterilization by ionizing radiation. It has low permeability to ethylene oxide. There is a poliamide that tolerates up to 180 ؛C and can be used with dry heat.
Tyvek®
This material is a synthetic polymer and a spunbonded olefin that is made essentially of polyethylene fibers in a sheet that is similar to paper. It has excellent shielding characteristics. Its mechanical stability is high and it does not release fibers when opened. Its porosity is controlled for permeability to air, ethylene oxide or any other sterilizing gas. It is moisture resistant. It is durable and flexible at -73 ؛C. It shrinks at 118 ؛C and melts at 135 ؛C. In general, it should not be used above 65 ؛C. This material is optimal for gas sterilization: it leaves 100 times less EtO and formaldehyde after sterilization, which reduces the desorption time. It is a material with a never-ending amount of polyethylene fibers. It is impermeable to water and alcohol, can be heat-sealed and has an incorporated chemical indicator. The heat-seal temperature is lower than 120 ؛C. Correct sealing will be opaque and non-transparent.
Instructions for use:
This is the packaging of choice for sterilization with hydrogen peroxide plasma. It is also compatible with sterilization by ethylene oxide.
Wednesday, September 27, 2023
Refrences
Sterilization manual for health centers. Silvia I. Acosta-Gnass,Valeska de.
Please Check out file at the following link
Criteria for Selecting a Sterilization Packaging system
General Principles of Packaging
