Lalith K Silva

US Patent:

6881337, Apr 19, 2005

Filed:

Jan 22, 2001

Appl. No.:

09/767558

Inventors:

Timothy B. Meluch - Miramar FL, US
Chung-Yuan Chiang - Pembroke Pines FL, US
Hamid Jaanine - Fort Lauderdale FL, US
Thanh Nguyen - Pembroke Pines FL, US
John M. Radovich - Fort Lauderdale FL, US
Kees Ruzius - Miami FL, US
Lalith K. Silva - Chamblee GA, US
George Washington - Miramar FL, US

Assignee:

Baxter International Inc. - Deerfield IL

International Classification:

B01D039/16

US Classification:

21050041, 21050027, 264 41, 264 49

Abstract:

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, δvalerolactam, 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.

US Patent:

56434529, Jul 1, 1997

Filed:

Oct 21, 1994

Appl. No.:

8/327431

Inventors:

Anders Althin - Miami Lakes FL
Ben Fernandez - Miami FL
Raymond Elsen - Miami Lakes FL
Kees Ruzius - Miami FL
Lalith Silva - Miami Lakes FL
George Washington - Miami FL

Assignee:

Althin Medical, Inc. - Miami FL

International Classification:

B01D 7116

US Classification:

21050023

Abstract:

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.

US Patent:

62184415, Apr 17, 2001

Filed:

May 24, 1999

Appl. No.:

9/317657

Inventors:

Timothy B. Meluch - Miramar FL
Chung-Yuan Chiang - Pembroke Pines FL
Hamid Jaanine - Fort Lauderdale FL
Thanh Nguyen - Pembroke Pines FL
John M. Radovich - Fort Lauderdale FL
Kees Ruzius - Miami FL
Lalith K. Silva - Atlanta GA
George Washington - Miramar FL

International Classification:

C08J 900
C08G 7520
B01D 3900

US Classification:

521 80

Abstract:

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,. delta. -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.

US Patent:

50394207, Aug 13, 1991

Filed:

Aug 16, 1990

Appl. No.:

7/568041

Inventors:

Elias Klein - Louisville KY
Lalith K. Silva - Louisville KY

International Classification:

B01D 1300

US Classification:

210645

Abstract:

Hydrophilic semipermeable membranes based on copolymers of acrylonitrile and hydroxy-C. sub. 2 -C. sub. 4 -alkyl esters of (meth)acrylic acid are provided. The membranes have a substantial water regain at equilibrium, a wide range of ultrafiltration rates, and low solute adsorption by ion-exchange or hydrophobic interaction mechanisms. The membranes are particularly suitable for processing protein containing fluids, especially biological fluids such as blood or plasmas.

US Patent:

57360464, Apr 7, 1998

Filed:

Nov 20, 1996

Appl. No.:

8/752871

Inventors:

Anders Althin - Miami Lakes FL
Ben Fernandez - Miami FL
Raymond Elsen - Miami Lakes FL
Kees Ruzius - Miami FL
Lalith Silva - Miami Lakes FL
George Washington - Miami FL

Assignee:

Althin Medical, Inc. - Miami Lakes FL

International Classification:

B01D 7116

US Classification:

21050023

Abstract:

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.