A cannula comprising a polymeric material which is phthalate-free, yet retains flexibility, workability and elongation properties so as to avoid kinking when bent. Also disclosed is a method of manufacturing a cannular device comprising extruding a flexible, biocompatible, phthalate-free polymeric composition through a round die into a tube, pulling the tube through a water bath at a rate established according to a predetermined function, and cutting the tube to for a cannular device, wherein the predetermined function periodically modulates a pulling rate.