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Weighing a scant eight
ounces per pair, human kidneys are absolutely requisite
for life. They filter waste and regulate water, acidity,
and electrolyte blood levels. Kidneys release hormones
that adjust blood pressure, coax bone marrow to make
red blood cells, and even supply nourishing glucose
if starvation looms. As organs go, they are a jack-of-all-trades.
So, it’s a wonder, really, that a dialysis machine
can keep people alive by assuming kidney duties. It’s
an everyday miracle that over a million people require,
and the patient load grows by nearly 100,000 people
per year worldwide. It is an intimate relationship –
dialysis patient and machine – with life or death
consequences, and one that demands exacting manufacture
of dialysis filters.
Low Viscosity, Balanced Curing
Rohm and Haas is improving production of this precision
device by introducing a new generation of polyurethane
potting compounds, which are integral components of
dialysis filters. Disks of cured potting compounds firmly
secure bundled, hollow filter fibers inside the dialysis
filter housing, while leaving the tiny channels inside
the filter fibers clear for maximum blood throughput.
Now marketed by Dow Corning as MG-825A and MG-825BS,
the new products boast several advances over previous
versions. They exhibit low viscosity, allowing perfect
distribution between the many thousands of filter fibers
during centrifugation. A balanced curing profile complements
excellent flow properties; highly reactive polyurethane
prepolymers cure faster than similar products. Once
in place, the compounds securely bond the fibers together
and into the plastic housing – preventing blood
and dialysis solution from mingling.
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Dialysis
Filters:
Precision Kidney Stand-ins
Dialysis cleanses
blood of toxins by forcing it through
dialysis filters fitted with bundled
semipermeable fibers – as many
as 10,000 natural or synthetic fibers
encased inside a plastic filter housing.
Running against this flow, a solution
called dialysate passes by the fibers,
absorbs toxins and water through osmosis
and ultrafiltration, and is discarded. |
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Reliable Bonds to Synthetic Fibers, Higher Productivity
The new potting compounds bond very
reliably to different fiber types on the market: materials
like polysulphone and polyethersulphone are becoming
top choices as natural cellulose use declines. “Synthetic
fibers remove more toxins from the blood more quickly,
thus reducing total dialysis time,” comments Helmut
Aschmann, technical service manager for the polyurethane
compounds portion of medical adhesives, who says customers
asked Rohm and Haas to adapt its products to synthetic
materials.
Synthetic fibers plus mechanical
stability of the potting compounds also help them to
better endure steam sterilization during the final manufacturing
step. Many companies are moving away from older sterilization
methods like gamma ray and ethylene oxide and replacing
them with low-cost, effective steam sterilization. Synthetic
fibers, paired with adaptable, capable products like
MG-825 and MG-825BS, aid markets such as China, South
America, India and the Middle East that are beginning
their own filter production operations.
Further, the innovative new potting
compounds enhance productivity – a significant
objective for manufacturers seeking to halve current
filter prices from 10 to 12 euros to 5 to 8 euros. “Faster
curing translates to time savings during manufacturing,”
says Henri Guiraud, Rohm and Haas global business development
manager, medical adhesives applications. “For
instance, companies can cut the potting compound disks
to open the fibers sooner after curing.”
Principles of cGMP, Strict Toxicity
Testing
Strengthened by its medical adhesives
alliance with Dow Corning, Rohm and Haas continues to
invest substantially in its medical adhesives business;
the dialysis market alone is growing at almost 10 percent
yearly. Steps like instituting principles of cGMPs underpin
that commitment. The Rohm and Haas Bremen, Germany plant,
which manufactures these potting compounds, adheres
closely to critical principles of cGMPs by using dedicated
reactors, preventing contamination, and maintaining
strict raw material traceability and consistency. “Adherence
to these critical principles is atypical at an industrial
facility. However, it is essential to ensuring the safety
and efficacy of medical devices,” emphasizes Irena
Ziec, Rohm and Haas regulatory, EHS and process engineer,
who says the above are just a few examples of cGMPs
implemented at the Bremen facility.
Also essential? Thorough toxicity
testing. For instance, the company extensively vetted
the potting compounds to ensure they don’t cause
cytotoxicity (harm to cells) or sensitization (reactions
that follow repeated exposures to a material) in dialysis
patients. “Our customers inspect the completed
filters for safety,” Ziec adds, “but having
our verified testing information on a component makes
that job easier.”
Facilitating Dialysis Availability
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“We anticipate
growing globally with this product line,”
concludes Guiraud, who says potting compounds
also appear in blood oxygenators. “We see
opportunities in Asia, the Middle East, the United
States. But most important, these filters save
lives, and many more people need dialysis than
receive it. It’s gratifying to make it more
affordable and available.”
Until science delivers humankind
another miracle – a cure for kidney disease
– Rohm and Haas hones its contributions
to the next best thing. |
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