Development of a Size Exclusion Chromatography metod for analysis of extraction solutions from urinary catheters

This project focused on developing a Size Exclusion Chromatography (SEC) methodwith Refractive Index (RI) detection for analysis of extraction samples from urinarycatheters to detect compounds that can be extracted from the catheter during use.Mobile phases, extraction fluids and sample concentrations were varied, as well aspore sizes of the columns, to investigate the applicability of this technique forcharacterization of the coating and potential leachables. Analyses of extractionsamples showed that this method can be used for analyses of polyvinylpyrrolidone(PVP), which is the main component in the coating, giving rise to the specialcharacteristics of the coating. No compounds could be detected from extraction ofuncoated catheters.Comparisons were made between different raw catheter materials, PVC and POBE,and differences in molecular weight distribution of the extracted PVP compoundswere seen, in spite of identical coating processes, indicating that the bonding of PVP inthe coating depends on raw catheter material. Furthermore, radiation effects alsodiffered, where a larger decrease in high-molecular weight fractions of PVP was seenwith increasing radiation dose from extracted PVC catheters, compared to thosefrom POBE. Analyses of radiated PVP powder showed opposite radiation effects thanthose from radiated catheters; that is, a steady increase in molecular weight withincreasing radiation dose, indicating cross-linking of PVP when radiated in powderform, and consequently chain-scission of high-molecular PVP fractions when radiatedbonded to the catheter coating.The SEC-RI method was concluded to be a useful tool for qualitative analyses of thedifferences in molecular weight distribution of PVP from the different extractionsamples, but showed low reproducibility in molecular weight calculations and therelative molecular weights calculated from these analyses differed significantly fromtrue molecular weights. This method could therefore not be used to give a goodestimation of true molecular weights