The Importance Of Proper Material Selection In The Medical
Device Development Process
(With Special Reference To Thermoplastic Polyurethanes)
Selection Process : Manufacturers Now Looking Outside
with expertise in material selection will often be able to
help a manufacturer with the right selection of materials
and processes, as well as help optimize its design to make
it more manufacturing friendly, without sacrificing the
most critical functional property of the device. It might
offer a variety of processes under one roof, advice on
Consideration Often Overlooked In The Design Or
In the late
1980s to early 1990s, it was most of the time, compared to
the last decade when it has become much less and as
industry has become more familiar and comfortable with
newer polymers and their versatility. Still about 10
percent to 20 percent of the time OEMs overlook material
considerations. There are one or two out of 10 cases where
we see a material mismatch, especially from new start-up
companies where they have good mechanical or bio engineers
but lack material science knowledge or insight.
A Company Has Made Material Selection An Afterthought?
Manufacturing issues in terms of bonding or cracking after
on economic considerations and long-term cost
effectiveness, there can be one of three options: modify
the surface with secondary treatments and/or primers,
formulate it with more stabilizers or other additives,
and/or replace it with a more compatible material.
advances that have been made to thermoplastic
polyurethanes in the medical device arena?
with some more visible than others, like :
Polycarbonate-based soft segment to enhance short-term or
initial biostability compared to polyether backbone
Hydrophilic grades of PUs which have high MVTR and can
absorb up to 70 percent by weight, suitable for drug
Combination of silicone and polyurethanes to enhance
UV cross-linkable polyurethane for non-compliant/compliant
combination film properties
Low set, high elongation, rubber-like thermoplastic
urethane for urethane stretch fiber
Optically clear urethanes
High flex modulus polyurethanes at >180,000 PSI at RT
Polyurethane gloves and condoms now commercially available
Softer TPUs at lower than 80 Shore A hardness
Specialty additive formulations to make it easier to
process and more stable against heat, UV, and hydrolytic
thermoplastic polyurethanes evolve in the next few years?
Still more rubber-like properties—lower durometer, higher
elongation, lower set, yet tough.
More work with nanoparticle-filled urethanes.
More development in cross-linkable technology and water
swellable for drug delivery applications.
Better barrier properties and lower permeability of 02,
CO2, and N2 gases.
Shape-memory polyurethanes with multiple Tg.
[Abstracted from an Interviews with Mr Tilak Shah,
President, Polyzen Inc., a manufacturer of medical
balloons, tissue bags, and other disposable medical
products in Apex, NC. After arriving from India in
1968 with a bachelor’s degree in chemistry and a minor
in physics from Bombay University, he earned a
master’s degree in chemistry from City College in New
York. The interview was published in “Medical Design
Technology”, Click here for Web
Link (http://www.mdtmag.com/scriptsShowPR.asp?PUBCODE=046&ACCT=0001618&ISSUE=0503&RELTYPE=PR&PRODCODE=3030&PRODLETT=A) .