Question: What are the catalysts in medical silicones and what is the definition of medical grade silicones?
Answer: In medical silicones, only a platinum cure system is used due to the fact that this cure system does not produce any extractable. Peroxide silicone cure systems produce acid residue and out gassing of the peroxide as by-products and therefore, are not suitable for medical applications because they do not pass biocompatibility testing.
The term “medical grade silicone” simply implies to a silicone which is rigorously tested to certify into a Class VI material. There are three types of medical silicone: non-implantable grade, restricted grade, and unrestricted grade.
- Non-implantable grade medical silicone: Although it is classified as Class VI material, its applications should not be implantable. It can still be in the direct contact with skin and blood, as long as it is outside the human body.
- Restricted grade: This liquid medical silicone has exhibited superior compatibility with human tissues and body fluids, and an extremely low tissue response when implanted. The length of a medical silicone implant is generally less than 29 days, although it may vary accordingly to the liquid medical silicone manufacturers.
- Unrestricted grade: This medical silicone material is vigorously tested to ensure its capability and human use. It also meets or exceeds all USP Class VI and many ISO-10993 test requirements. In contrast with the restricted grade, the length of implant will be considered more than 30 days.
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