Characteristics of Codubix® and Codubix® CT

1. Product characteristics
2. Sterilisation
3. Microbiological parameters
4. Chemical parameters
5. Physical parameters
6. Packaging

1. Product characteristics
Codubix® medical devices are knitted of polypropylene and polyester yarn, and have physical properties characteristic for both polymers. Codubix® prostheses used in the reconstruction of skull bone defects combine all the best features available on the market of biomaterials, without negative traits that may increase the risk of complications. They are characterised by high biological compatibility through the combination of proven technologies used in the manufacture of other biomaterials (e.g. vascular grafts). They have excellent immunological properties, high resistance to bending strengths, low basis weight, thermal conductivity similar to the bone, and zero liquid (of water, blood, etc.) absorption. They are chemically inactive, resistant to low and high temperatures. Despite their porosity they are resistant to infections, relatively susceptible to modelling during the implantation, and allow diagnostics without giving artefacts. The Codubix® is easy to sterilise, and does not cause local and systemic complications. The product is produced in a sterile and non sterile version and can undergo double sterilisation.

The skull bone prosthesis is made of polypropylene and polyester yarn. The polypropylene yarn has low mass density and low melting point (approximately 1450C), which enables to provide the rigidity and hardness to the prosthesis. The polyester yarn gives adequate flexibility and porosity, which allows a relatively large unit ​​contact area with the tissue, which contributes to fast tissue overgrowth.

The product is porous and has a non-uniform surface. The construction and nature of components allow to adjust the edges of the prosthesis using special scissors for cutting implants (bone forceps). Codubix® CT is a prosthesis upon individual order with preformed curve and contour. Both the standard the individually ordered prosthesis are available in a sterile and non sterile version. The offered sterile skull bone prosthesis are sterilised in validated conditions and in professional sterilisation equipment.

The prosthesis has high endurance at low specific weight. It is non-toxic and provides high degree of healing in. It has thermal conductivity comparable to that of a natural bone.

2. Sterilisation
The bone prostheses are steam sterilised (STEAM) – in accordance with the requirements of EN ISO 17665-1 and FP IX (2011).
Due to the unwound surface the Codubix® bone prostheses are steam sterilised (according to the standard the term “moist heat” is used). The application of this technique to obtain a sterile product provides safety of the product because of the lack of potential harmful factors contained in the sterilising medium. The steam sterilisation allows also for the immediate release of the product for sale without any additional period to wait – which is required during the sterilisation with ethylene oxide.

For non sterile products it is required to use a validated steam sterilisation technology under the conditions of 121°C for 20 min, in accordance with the requirements of EN ISO 17665-1 and FP IX (2011), included in the instructions of use.

3. Microbiological parameters
Markers of sterility given on the sterilisation packaging
The sterility of a product is confirmed by sterility tests of each production batch released to the market (research methodology according to FP IX (2011). Sterilisation markers on the packaging of the final product confirm that the product was exposed to a sterilisation process in conditions that ensure the sterility:

  • bacterial endotoxin content in accordance with the requirements of the USP monograph 161 (research methodology described in FP IX (2011) – semi-quantitative Gel Clot LAL Test Method) – the limit value: 20 EU/product, the content of endotoxin in serial products: less than 1.2 EU/product.

Most manufacturers do not perform this test. However, it is very important because some dead bacteria (endotoxins) have pyrogenic (fever producing) activity, and for these reasons the limit of the presence of dead bacteria in the product is specified.

  • microbiological purity – EN ISO 11737-1 (requirements: FP VIII (2008), page 477 – category II).

Before the sterilisation process in validated conditions tests are carried out to determine the content of microorganisms in the product in random samples. This ensures the complete safety of the product.

4. Chemical parameters

  • permanganate oxidability – PN-P-04896 – less than 0.08 mgO2/g

An important parameter of chemical purity – distinguishing Codubix® prostheses from those of competitors. Generally, this parameter shows the lack (or very low content) mainly of organic pollutants, but also some inorganic ones such as iron salts (II), sulphides, nitrates (III). For reference to the applicable requirements – clear water has oxidability exceeding 4mgO2/dm3. Chemical parameters are determined on the basis of the prepared aqueous extract.

  • UV absorbance at a particular wavelength – PN-P-04990 – far less than 0.3 at wavelengths of 230 and 245 nm.

The aqueous extracts of the finished products are analysed. In general, this parameter indicates the absence (or very low content) mainly of organic pollutants. For reference to the applicable requirements – clear water is characterised by the absorbance of 0.5 to 2 [1/cm].

  • substances soluble in petroleum ether – PN-P-04607 – far below the 1.5%

Most of products manufactured by TRICOMED SA are textiles. In order to facilitate the production process the fibres at the production stage are enriched with substances of different nature. At the stage of fibre processing and finishing processes most of the substances are removed to get pure fibre. This parameter allows to specify the amount the substances contained in the fibre, and assess the effectiveness of the fibre cleaning process.

  • pH of the tested sample – EN ISO 3071 – in the range of 5.5 to 8.0

Determination of the pH of the sample is important for the environment in which the product will be implanted. Too high or too low value can cause allergic reactions or irritation in the implantation site.

  • content of chloride ions – PN-P-04895 – less than 0.02mg CL1-/ g
  • content of ammonium ions – PN-P-04992 – less than 0.01mg NH4+/g
  • content of sulphate ions – PN-P-04781-04 – less than 0.05mg SO42-/g
  • content of heavy metal ions – PN-P-04991 – less than 0.01mg Pb2+/g

In case of medical devices there are also analysis performed to establish the content of some certain ions which may have harmful biological effects on the body. These include chloride ions, ammonium ions, sulphate ions and heavy metal ions.

5. Physical parameters

  • basis weight – SOP-KJF.08 – about 1900g/m2

The parameter specifies the weight of the material per square meter i.e. the amount of the artificial material implanted in the patient’s body.

  • thickness – PN-P-04890-01 – about 3.00 mm
  • height of curvature – IB IN-1/83 – from 8.60 to 24.00 mm (depending on the size)
  • bending strength (resistance to pressing) – PN-P-04890-03 – from min. 6.00 to min. 10.00 daN (depending on the size)

The tested physical parameters such as thickness, height, curvature, and bending strength are similar to a natural bone in the implantation site.

6. Packaging
A sterile Codubix® product is packed in double medical packaging – a paper-film sleeve with a gusset (BOM) appropriate for steam sterilisation. A non sterile Codubix® product is packed in a sleeve of polyethylene film and placed individually in a carton box. The same applies to a Codubix® CT implant upon individual order. Sterile version of the prosthesis is sterilised before a surgery in double paper-film packaging. The double packaging gives the opportunity to bring the product into the operating room while maintaining its sterility.

According to the declaration of the packaging manufacturer and on the basis of our own experience, as well as on the conducted research, the packaging used to sterilise the products meets the requirements of EN ISO 11607-1 and EN 868-5. It provides complete asepsis in the operating room, and the transparent film allows to see the content. Besides, the double packaging provides secure storage.

At the moment there are no implanted devices on the market that would be offered in two versions: sterile and non sterile. When choosing the implant the surgeon’s individual preferences and the complexity of the surgical case may be the decisive factor.

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