Comparative Study on Elution of Polyvinylpyrrolidone on Dialyzers Using Ultraviolet Analysis and Iodine Method

It is known that poly(arylethersulfone)-based dialyzers can elute poly(N-vinyl-2-pyrrolidone) (PVP). With regard to chronic renal replacement therapy, this is a burden for the patient, because PVP is deposited in different organs and cannot be degraded or released from there; so elutable PVP has to be minimized. Usually, the iodine method is used for quantification of extractable PVP. To overcome the chain length dependency of this method, we used an ultraviolet method that is independent from the PVP chain lengths; so the absolute amount of eluted PVP can be quantified. The current study shows the amount of eluted PVP on differently sterilized low flux dialyzers (1.6 m(2), similar storage time, n = 12)-PS160 (Allmed, Egypt), F7HPS (Fresenius Medical Care, Germany), F16 (Wego, China), and B-16P (Bain, China). Using the ultraviolet method, the irradiated filters show a sum total of approximately 9 mg more eluted PVP compared with the steam-sterilized ones, whereas the iodine method shows a value about three times lower between different types of sterilization. The boundary conditions during the radiation sterilization could lead to PVP degradation instead of cross-linking. The resulting shorter PVP chains can be more easily rinsed out and can falsely decrease the calculated eluted PVP amount by using the iodine complexation method.

Automated summary

It is a burden for patients in chronic renal replacement therapy that poly(arylethersulfone)-based dialyzers elute poly(N-vinyl-2-pyrrolidone) (PVP), which cannot be degraded or released from organs. An ultraviolet method is used to quantify the absolute amount of eluted PVP independently from its chain lengths. The study shows that the irradiated filters elute approximately 9 mg more PVP compared to steam-sterilized filters, while the iodine method shows a value about three times lower between different types of sterilization.