The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 01, 1997
Filed:
Oct. 21, 1994
Anders Althin, Miami Lakes, FL (US);
Ben Fernandez, Miami, FL (US);
Raymond Elsen, Miami Lakes, FL (US);
Kees Ruzius, Miami, FL (US);
Lalith Silva, Miami Lakes, FL (US);
George Washington, Miami, FL (US);
Althin Medical, Inc., Miami, FL (US);
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.