Akzo N.v.

Other

Akzo N.v. of Arnhem/nederland

Werner Henne

Gustav Dunweg

Michael Pelger

Werner Bandel

Raimund Pohle

Friedrich Lawitzki

Werner Schmitz

Michael Diamantoglou

Ulrich Baurmeister

Walter Brodowski

Helmut Schulze

Jurgen Scheuren

Erich Kessler

Klaus Gerlach

Dialysis membranes are disclosed, in the shape of hollow fibers composed of cellulose regenerated from copper-ammonia solution, having a continuous hollow cavity and a closed wall, wherein in any cross-section normal to the direction of the fiber axis the difference of the distance to the outer wall surface and the distance to the inner wall surface, each measured from the fiber midpoint, varies along the periphery, the fiber midpoint being the midpoint of the circle circumscribing the fiber cross-section, and the cross-section normal to the direction of the fiber axis possessing the shape of a circle, a deformed circle, an ellipse, a kidney-shaped deformed ellipse, or a deformed quadrangle. In one particular embodiment, the wall thickness of the hollow fiber along its periphery at least once continuously increases to a maximum thickness and decreases to a minimum thickness, the respective maximum and minimum thicknesses being spaced approximately equally about the periphery, with all portions of maximum thickness having the same maximum thickness and all portions of minimum thickness having the same minimum thickness.

Dialysis membrane of cellulose in the shape of a hollow fiber, and

A method for production of porous hollow polymer fiber membranes. A homogeneous mixture is prepared from at least two components where one component is a fusible polymer (10 to 30 percent) and a solvent component (70-90%) is inert relative to the polymer and where said components form a binary system having in the liquid state a region of complete miscibility as well as a miscibility gap. The mixture is extruded at a temperature above the phase segregation temperature of the mixture through a hollow fiber nozzle into a spinning tube containing a solvent inert to the polymer and having a temperature below the segregation temperature. Fiber and liquid are moved in the spinning tube in the same direction at about the same speed. After solidification the hollow fiber membrane is washed with a solvent. A liquid mixture containing biological cells and macromolecules is passed through the membrane produced for filtration and a filtration factor for human blood proteins with molecular weights of from about 60,000 to 3 million results of at least about 0.7.

Hollow fiber membrane for plasma separation

A cleaning treatment is disclosed for the blood compartments of dialyzators which is effected still in the preparation stage. The dialyzators contain membranes of cellulose in the form of hollow filaments, tubes or flat foils. The cleaning treatment embraces the following measures: washing with water or aqueous solutions and evacuation of the compartments, then filling with a mixture of water, glycerin and alcohol and drying after a renewed evacuation--or, filling with water or aqueous solutions and subsequently closing the entrance and exit of the blood compartment. As a third measure, the compartments are sterilized with gamma radiation and/or ethylene oxide and/or superheated steam.

Cleaning treatment for blood compartments of dialyzators

A dialysis membrane used for hemodialysis having a structure comprised of flat films, blown films or tubular threads of substitution-modified cellulose, in which the effects of complement activation and leukopenia are clearly reduced. The average degree of substitution of the modified cellulose is 0.02 to 0.07. Dialysis membranes, which have proven successful within the scope of the invention, contain modified cellulose, having a structure represented by the formula cellulose-Z, wherein Z represents the group --R'--X--Y.

Dialysis membrane of modified cellulose with improved biocompatibility

A single or multilayer dialysis membrane, constructed as a flat film, a tubular foil or especially as hollow fibers, the membrane being made of a regenerated cuprammonium cellulose which may be unmodified or partly modified by alkyl, carboxyalkyl or hydroxyalkyl groups, and said membrane being characterized by an ultrafiltration capacity at 37.degree. C. of 7 to 30 ml/hr.multidot.m.sup.2.mmHg, an average molecular permeability, based upon vitamin B12, of about 3.multidot.10.sup.-3 to 12.multidot.10.sup.-3 cm/min, and a water retention value of more than 145%, calculated according to the German Industrial Standard (DIN) 53814. The new membrane is prepared by the known cuprammonium process but with the addition of a finely ground CuO with a maximum particle size of 20 microns to the standard cuprammonium solution. After casting, extruding or spinning this solution into a coagulating bath, e.g. an alkaline coagulating bath, the regenerated and shaped cellulosic film, foil or filament is given an acid treatment, preferably with sulfuric acid, sufficient to substantially remove the solid CuO particles and to provide a significantly higher pore volume content and other favorable properties in the final membrane.

Dialysis membrane and method of making

Method for the production of membranes for artificial organs, in the form of tube foils, flat foils or hollow filaments, into which metals and/or metal compounds are incorporated, in which a metal salt solution is introduced into a membrane composed of a polymer, the membrane is then attacked with gaseous precipitation agent and brought to reaction for precipitation. The improvement is having the introduction of the metal salt solution and the attack with gas take place in a membrane-containing module for an artificial organ, by leading the metal salt solution and the gaseous precipitation agent successively through a space enclosed by the membrane, provided for the flow-through of blood.

Catalytic membranes in artificial organs

Dialysis membranes are described in which two or more hollow fibers of cellulose regenerated from cuoxam solution are spun together and connected to each other parallel to the fiber axis. The connection may be in the form of crosspieces, which should be between about 1 and 3 times the thickness of the hollow fiber walls. A novel process for preparation of the dialysis membrane hollow fibers is also disclosed.

Process for production of dialysis membrane hollow fiber chains

A multilayer cellulosic membrane for blood dialysis and a method for the production of said membrane by regeneration from separately extruded cuprammonium cellulose solutions brought together to form two or more permanently adhered layers, each layer forming a seal against blood penetration through the leakage points of an adjacent layer, the resulting multilayer membrane thus being substantially free of blood leakage over the total thickness of the membrane. Especially preferred membranes for blood dialysis are those in which the layer arranged on the blood side of the diaphragm contains a modified cellulose chemically bound with an antithrombogenic substance.

Cellulosic membrane for blood dialysis

A dialyzing membrane, especially for hemodialysis, formed as a hollow fiber, tubular foil or flat sheet by regeneration of cellulose from a cuprammonium solution, the membrane comprising at least two firmly adhered cellulosic layers including at least one dialyzing layer consisting essentially of a semipermeable regenerated cellulose and at least one adsorbent layer consisting of said regenerated cellulose containing embedded therein fine particles of an adsorbent material in an amount of up to 95% by weight with reference to the dry weight of the adsorbent layer, preferably 1 to 90% and especially 20 to 70% by weight, when the adsorbent layer is part of a hollow fiber structure. The dialyzing membrane of the invention is produced by a method requiring at least two cuprammonium cellulose solutions, one of which is free of adsorbent particles and another of which contains a suspension of adsorbent particles, the different solutions being spun from adjacent spinning slots for immediate layer to layer contact and then introduced over a short air gap into a coagulating or precipitating bath to entrap the adsorbent particles in the spun layer in which the particles were originally suspended. Isopropyl myristate is particularly advantageous as a liquid filler for the axial duct or canal of a hollow membrane.

Dialyzing membrane with adsorbent layer

A flexible artificial kidney, capable of being worn directly on the body of the patient, and characterized by a flexible hollow retentate chamber of about 3 to 50 cm.sup.3 in volume surrounded by a jacketed flexible dialysate chamber of about 300 to 5,000 cm.sup.3 in volume, preferably such that the dialysate chamber is at least about 100 times larger than the retentate chamber. Blood inlet and outlet lines to and from the retentate chamber are passed in fluid tight relationship through the jacketed wall of the dialysate chamber which in turn has a closable opening for filling and discharging the dialysate liquid. This artificial kidney is especially effective when adsorbent materials are added to the liquid in the dialysate chamber.

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Wuppertal, Germany

Werner Henne