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PVC - A Persistent,
Versatile Choice!
Plasticizers – The flexibility and hardness of
the PVC compound are adjusted by the amount of
plasticizer. Traditionally phthalates have largely been
used as a plasticizer since they
offer flexibility, transparency, durability, and
longevity in products. One of the most regular
plasticizers, di(2- ethylhexyl ) phthalate (abbreviated
as DEHP) is an organic chemical derived from fossil
fuels. Use of DEHP for medical use has been prohibited
(except for blood bags). This is due to the potential
toxicity due to leaching out of DEHP. There are various
chemistries commercially available for plasticizers.
Some commonly used plasticizers for medical products are
DEHT, DINCH, DOA, Citrates, TOTM. The main consideration
for the selection of plasticizers in the medical
application of PVC is migration, chemical, biological &
toxicological properties, and its compliance with REACH,
MDR, FDA directives. Sterilization of the end product
also affects the selection of plasticizers.
Regulations - There are
several regulations worldwide which the PVC compound
must comply with, based on its applications. Some of
these are - REACH, US FDA, RoHS, MDR, VDI, NSF,
California Proposition 65, ISO and Biocompatibility.
PVC in Medical - Medical
device industry has been revolutionized ever since the
use of single-use of medical devices. The use of PVC has
improved medical safety drastically by reducing the risk
of infections caused by multiple uses of traditional
devices.
One of the oldest and widest uses of PVC has been for
blood bags (collection, processing & storage of blood &
blood components). PVC has been proven to offer several
advantages over other plastics and has replaced glass
for blood bags since 1950. It offers safe
transportation, better shelf life, permeability to
preserve platelets, can be steam & gamma sterilized and
stored at low temperatures, does not burst or tear
during centrifuge, is translucent, relatively easy to
manufacture, and is cost-effective.
The non-kinking characteristic is one of the critical
requirements during the usage of medical tubing since it
may cause serious complications and life-threatening
situations for the patient. The chemical structure of
PVC ensures effective anti-kink qualities; hence it is
vastly used in the manufacturing of kink-resistant
tubing.
Since the last few years, PVC rigid has successfully
replaced expensive engineered resins like Polycarbonate
and has proven to offer equal strength, rigidity, and
clarity. This has resulted in significant savings and
helped to reduce device costs.
Due to its low cost and versatility PVC remains a
product of choice for single-use devices in dialysis,
infusion, transfusion, drainage, respiratory and
cardiology. PVC can be compounded with selected metals &
polymers to meet antimicrobial requirements or with
pigments and UV filters for light-sensitive drugs. PVC
goes equally well with several radiopaque substances
which augment its use in radiology. PVC in combination
with other materials is used to create co-polymer tubing
and molding parts to enhance its usefulness in the
delivery of sensitive drugs.
PVC is one of the most frequently used and investigated
plastics for pharmaceutical packaging. Its benefits to
price ratio remain unmatched and it is mainly used as a
blister, container & delivery system. Very often PVC is
coated or laminated with PVDC, COC or PCTFE to enhance
the protective and barrier properties.
PVC is also largely used in hospital interiors due to
its durability, chemical resistance, low maintenance
costs, and affordability.
Conclusion
The beginning of making any PVC compound is to identify
its end application. PVC has been the most widely used
plastics in healthcare and has consistently been in use
for a long time. The options in the selection of
ingredients & techniques, together with the right
temperature, time, speed, and manufacturing conditions
make the compound versatile. The when, how, and how much
affect the reproducibility of the compound batch after
batch. Undoubtedly, PVC compounding is often compared to
cooking, only knowing the ingredients does not guarantee
the same taste as prepared by a master chef!
A Persistent, Versatile Choice, Indeed!!. |
