Althin Medical, Inc.

Other

Baxter International Inc.

Kees Ruzius

George Washington

Thanh Van Nguyen

John M Radovich

Timothy B Meluch

Lalith K Silva

Ben Fernandez

Hamid Jaanine

Anders Althin

Raymond Elsen

Lalith Silva

Chung-Yuan Chiang

The present invention discloses, inter alia, a composition useful for producing a hemogeneous, semipermeable membrane, the composition comprising (1) a polysulfone compounds, (2) a solvent, such as sulfolane, antypyrine, &#x3b4;valerolactam, diethyl phthalate, and mixtures thereof, and (3) a non-solvent, such as poly(ethylene glycol), di(ethylene glycol), tri(ethylene glycol), glycerol, and mixtures thereof. Another aspect of this invention discloses methods for fabricating semipermeable membranes by homogeneously mixing the composition of the polysulfone compound, solvent, and non-solvent, melting the composition, and melt-spinning the molten composition. Another aspect of the present invention includes homogeneous, melt-spun, semipermeable membranes useful for liquid separation processes, such as, but not limited to, microfiltration, ultrafiltration, dialysis, and reverse osmosis.

Melt-spun polysulfone semipermeable membranes and methods for making the same

The present invention discloses, inter alia, a composition useful for producing a homogeneous, semipermeable membrane, the composition comprising (1) a polysulfone compound, (2) a solvent, such as sulfolane, antypyrine, &dgr;-valerolactam, diethyl phthalate, and mixtures thereof, and (3) a non-solvent, such as poly(ethylene glycol), di(ethylene glycol), tri(ethylene glycol), glycerol, and mixtures thereof. Another aspect of this invention discloses methods for fabricating semipermeable membranes by homogeneously mixing the composition of the polysulfone compound, solvent, and non-solvent, melting the composition, and melt-spinning the molten composition. Another aspect of the present invention includes homogeneous, melt-spun, semipermeable membranes useful for liquid separation processes, such as, but not limited to, microfiltration, ultrafiltration, dialysis, and reverse osmosis.

Semipermeable membranes are disclosed for purifying aqueous biological fluids. The membranes are particularly suitable for purifying extracorporeal blood via hemodialysis. The membranes, preferably configured as hollow fibers, are made from a hydrophilic polymeric material, preferably cellulose acetate. Features of the membranes include an ultrafiltration coefficient (K.sub.uF) of about 15 to about 55 mL/hr/mmHg/m.sup.2 (thus termed 'high-flux' type membranes), a urea mass transfer coefficient (K.sub.oV (Urea)) of at least 38.times.10.sup.-3 cm/min, and a ratio of K.sub.oV (urea)/K.sub.uF of at least 2.5.times.10.sup.-3. Hollow fibers of such membranes suitable for hemodialysis have a lumen diameter of about 175 to about 210 .mu.m and a wall thickness of about 10 to about 35 .mu.m. According to disclosed methods for making the membranes, a melt comprising about 32 to about 40% w/w cellulose acetate, about 5 to about 10% w/w glycerine, and about 50 to about 67% w/w polyethylene glycol is extruded to make hollow fibers; the fibers are cooled, cold-stretched, water-leached, and replasticized using a glycerine solution.

High-flux hollow-fiber membrane with enhanced transport capability and

Semipermeable membranes are disclosed for purifying aqueous biological fluids. The membranes are particularly suitable for purifying extracorporeal blood via hemodialysis. The membranes, preferably configured as hollow fibers, are made from a hydrophilic polymeric material, preferably cellulose acetate. Features of the membranes include an ultrafiltration coefficient (K.sub.uF) of about 15 to about 55 mL/hr/mmHg/m.sup.2 (thus termed 'high-flux' type membranes), a urea mass transfer coefficient (K.sub.oV (urea)) of at least 38.times.10.sup.-3 cm/min, and a ratio of K.sub.oV (urea)/K.sub.uF of at least 2.5.times.10.sup.-3. Hollow fibers of such membranes suitable for hemodialysis have a lumen diameter of about 175 to about 210 .mu.m and a wall thickness of about 10 to about 35 .mu.m. According to disclosed methods for making the membranes, a melt comprising about 32 to about 40% w/w cellulose acetate, about 5 to about 10% w/w glycerine, and about 50 to about 67% w/w polyethylene glycol is extruded to make hollow fibers; the fibers are cooled, cold-stretched, water-leached, and replasticized using a glycerine solution.

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Miami, FL, United States of America

Kees Ruzius