High strength biomedical materials
High strength biomedical materials and processes for making the same are disclosed. Included in the disclosure are nanoporous hydrophilic solids that can be extruded with a high aspect ratio to make high strength medical catheters and other devices with lubricious and biocompatible surfaces.
1. A process for making a hydrophilic porous solid tube, comprising:
with a polymeric mixture comprising at least one water soluble polymer and a solvent, the polymeric mixture having a concentration of at least 10% w/w of the at least one water soluble polymer, performing the steps of:
heating the polymeric mixture to achieve a temperature above the melting point of the polymeric mixture,
extruding the polymeric mixture as a tube; and
removing the solvent from the tube at a temperature above a freezing point of the solvent until the tube is a porous solid, with the tube being a porous solid that comprises the at least one water soluble polymer, and the porous solid tube is made without covalent crosslinking agents that form covalent crosslinks between polymers extruded to make the porous solid, wherein
the porous solid tube includes interconnected pores having a pore size of up to 100 nm in diameter and a Young's modulus of 5-100 MPa, at equilibrium water content (EWC) of the porous solid tube.
2. The process of claim 1 wherein, the polymeric mixture is never heated above a boiling point of the polymeric mixture, and the polymeric mixture is extruded at temperatures below a melting point of the polymeric mixture.
3. The process of claim 1 comprising extrusion around a core, with the porous solid tube being formed around the core.
4. The process of claim 1 wherein the at least one water soluble polymer comprises a polymer selected from the group consisting of poly(vinyl alcohol) (PVA), poly(acrylic acid), polyethylene glycol, and poly(vinyl pyrrolidone).
5. The process of claim 1 wherein the at least one water soluble polymer comprises a first polymer at a first concentration and a second polymer at a second concentration, with the first concentration being from 10%-60% w/w and the second polymer being from 1%-10% w/w, with the w/w being the weight of the polymer relative to the total weight of all of the polymers and the solvent in the mixture.
6. The process of claim 1 , wherein the mixture further comprises a radiopaque agent.
7. The process of claim 1 wherein the porous solid tube is extruded to have an aspect ratio of at least 10:1.
8. The process of claim 1 comprising combining the at least one water soluble polymer and the solvent while heating the polymeric mixture.
9. The process of claim 1 wherein the solvent is selected from the group consisting of water, an alcohol, ethanol, an organic solvent miscible with water, and combinations thereof.
10. The process of claim 1 wherein the tube is extruded into a bath, oven, or a chamber filled with gas.
11. The process of claim 1 comprising extruding the solid porous tube to have, at EWC, an outer diameter of the tube from 0.02 to 0.5 inches and an inner diameter of the tube from 0.01 to 0.4 inches, with the outer diameter being at least 0.001 inches larger than the inner diameter.
12. An article, comprising:
a hydrophilic porous solid tube comprising at least one crosslinked water soluble polymer that forms the porous solid tube, the porous solid tube including interconnected pores having a pore size of up to 100 nm in diameter, with the porous solid tube having a solids content from 33% to 90% w/w at equilibrium water content (EWC) and a Young's modulus of 5-100 MPa at EWC, with the porous solid tube being free of covalent crosslinks between polymers that form the porous solid tube.
13. The article of claim 12 with the tube having an aspect ratio of at least 10:1.
14. The article of claim 12 wherein at least 50% w/w of the at least one crosslinked water soluble polymer being poly(vinyl alcohol) (PVA).
15. The article of claim 12 wherein the at least one crosslinked water soluble polymer comprises a polymer selected from the group consisting of PVA, poly(acrylic acid), polyethylene glycol, and poly(vinyl pyrrolidone).
16. The article of claim 12 wherein the at least one crosslinked water soluble polymer comprises a first hydrophilic polymer and a second hydrophilic polymer, with the second hydrophilic polymer being present in an amount from 1 part to 1,000 parts relative to 10,000 parts of the first polymer.
17. The article of claim 12 further comprising a radiopaque agent.
18. The article of claim 12 wherein the Young's modulus is from 10 to 100 MPa at EWC.
19. The article of claim 12 wherein, at EWC, an outer diameter of the porous solid tube is from 0.02 to 0.5 inches and an inner diameter of the porous solid tube is from 0.01 to 0.4 inches, with the outer diameter being at least 0.001 inches larger than the inner diameter.
20. A catheter comprising a hydrophilic porous solid tube comprising at least one crosslinked water soluble polymer that forms the porous solid tube, the porous solid tube including interconnected pores having a pore size of up to 100 nm in diameter and having a solids content from 33% to 90% w/w at equilibrium water content (EWC) of the porous solid tube and a Young's modulus of 5-100 MPa, at EWC of the porous solid tube, with the porous solid tube being free of covalent crosslinks between polymers that form the solid tube.
21. The catheter of claim 20 wherein the interconnected pores of the hydrophilic solid tube have a pore size of 1-100 nm.
22. The catheter of claim 20 with at least 50% w/w of the at least one water soluble crosslinked polymer being poly(vinyl alcohol) (PVA).
23. The catheter of claim 20 wherein the catheter is a central venous catheter, a peripherally inserted central catheter (PICC), a tunneled catheter, a dialysis catheter, a peripheral central catheter, a midline catheter, a peripheral catheter, a dialysis access catheter, an urinary catheter, a neurological catheter, a peritoneal catheter, an intra-aortic balloon pump catheter, a diagnostic catheter, an interventional catheter, or a drug delivery catheter.
24. The catheter of claim 20 comprising a plurality of lumens.
25. The catheter of claim 20 wherein the Young's modulus is from 10 to 100 MPa at EWC.
26. The catheter of claim 20 wherein, at EWC, an outer diameter of the catheter is from 0.02 to 0.5 inches and an inner diameter of the tube is from 0.01 to 0.4 inches, with the outer diameter being at least 0.001 inches larger than the inner diameter.
27. The catheter of claim 20 having an aspect ratio of at least 10:1.
28. The catheter of claim 20 having an aspect ratio of at least 50:1.
29. The catheter of claim 20 wherein the at least one water soluble polymer comprises a first hydrophilic polymer and a second hydrophilic polymer, with the second hydrophilic polymer being present in an amount from 1 part to 1,000 parts relative to 10,000 parts of the first polymer.
30. The catheter of claim 20 further comprising a radiopaque agent.
31. The catheter of claim 20 wherein the Young's modulus is from 10 to 100 MPa at EWC.
32. The catheter of claim 20 consisting essentially of the at least one water soluble polymer and a radiopaque agent.
33. The catheter of claim 20 with a swelling of 50% w/w or less at EWC.