Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1998-05-28
1999-09-21
Nutter, Nathan M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
524284, 524300, 524306, 524312, 524313, 524314, 524399, 524400, 524425, 524456, 524763, 604403, C08K 511, C08L 2706
Patent
active
059555190
DESCRIPTION:
BRIEF SUMMARY
The subject of the present invention is the use of a chemical agent in plasticized polyvinyl chloride (PVC) compositions intended for the production of products made from biocompatible material, in particular blood lines, connections and containers used, for example, in transfusions and dialysis, to increase the radiation resistance of these products made from biocompatible materials without damaging their biocompatibility.
As is widely known, PVC is a polymeric material which is very widely used in numerous fields in the art: practically in each of these applications, it is nevertheless not used as such but in combination with a series of additives, in particular plasticizers, stabilizers and lubricants which enhance its mechanical characteristics, stability and machinability.
In the medical field, and in particular for the production of the range of devices, lines and containers intended for the treatment of blood and of its derivatives, the use of PVC plasticized with di(2-ethylhexyl)phthalate (commonly designated DOP) is known.
Although DOP is the plasticizer provided for by the Official Italian Pharmacopoeia, it has, on several occasions, been the subject of discussions connected with the contraindications, of a toxicological nature, linked to its use. It is clear that the use, in the medical field, of any material cannot ignore the evaluation of its possible toxicological aspects (that is to say of its biocompatibility).
The use of another plasticizer, tri(2-ethylhexyl)trimellitate (TOTM), whose biocompatibility has been experimentally verified, is also known.
The abovementioned plasticized PVC compositions for products made from biocompatible material exhibit, nevertheless, the main disadvantage of undergoing structural alterations when they are subjected to irradiations of penetrating rays as occurs, for example, if the product made from them undergoes sterilization with gamma or beta rays.
It is known, indeed, that products for medical use which are made from plasticized PVC should be sterilized before use. The sterilization methods normally used are the ethylene oxide-based process (designated hereinafter in the abbreviated form by ETO sterilization) and the irradiation of penetrating rays of the gamma or beta ray type (designated hereinafter as gamma sterilization or beta sterilization).
Gamma and beta sterilizations, although very effective from the point of view of the degree of sterilization obtained, produce, on the abovementioned plasticized PVC compositions, structural alterations with a possible emission of volatile substances, which are typically indicated by yellowing of the material. The phenomenon is more marked with conventional compositions containing DOP, to the extent that normally, for these materials, ETO sterilization is used, but it is also observed, although to a lesser degree, with materials containing TOTM.
A composition of PVC plasticized with di(2-ethylhexyl)adipate whose use is limited to the production of blood donating bags is also known from patent U.S. Pat. No. 4,222,379. Indeed, according to this patent, di(2-ethylhexyl)adipate is extractable and leads to a substantial reduction in the quantity of plasma haemoglobin during the storage of blood in PVC bags containing this plasticizer. Accordingly, it is recommended in this patent to limit contact between blood and PVC products containing this plasticizer. In addition, steam sterilization (in an autoclave) is recommended for these blood donating bags made from plasticized PVC.
A first subject of the present invention is therefore to solve the abovementioned problems encountered with products for medical use made from PVC and sterilized by irradiations of penetrating rays of the gamma or beta ray type.
Surprisingly, it has been found that it is possible to considerably reduce the susceptibility to structural alterations induced by irradiation of penetrating rays of the gamma or beta ray type of a plasticized polyvinyl chloride (PVC) composition suited to the production of products made from biocompatible material such
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D.S. Housel, Technical Papers--63.sup.rd Annual Technical Conference, Apr. 1985, Washington, DC, "Factors Infuencing Color Drift of Gamma Sterilized PVC Articles".
International Search Report.
Hospal AG
Nutter Nathan M.
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