Polyurethane molecular weight determination in catheters via gel permeation chromatography

Antimicrobial catheter extrusions are loaded with an antiseptic drug in order to help prevent catheter-related infections. Previous research has shown that polymer molecular weight (Mw) can be used to control drug loading levels. Polyurethane based resin and catheter shaft extrusion samples were chosen based on a range of melt flow index (MFI) values to establish a Mw distribution using gel permeation chromatography (GPC) for future drug loading experiments. Resin Mw ranged from 115 kDa to 40 kDa while extrusion Mw ranged from 94 kDa to 54 kDa. A dynamic aging test revealed polyurethane extrusion Mw was stable through a 6 month accelerated aging (AA) process at temperature settings between 37 C and 55 C. A method evaluation test revealed the method of evaluating extrusion Mw is not dependent on sample concentration or section of catheter extrusion.