Akzo N.v.

Akzo Nobel N.v.

Michael Pelger

Helmut Schulze

Ulrich Baurmeister

Werner Henne

Michael Diamantoglou

Walter Brodowski

Joachim Behnke

Gustav Dunweg

Hans-Gunther Breidohr

Panajotis Argyriadis

Ernst Berg

Properties of cellulosic membranes such as the length and the ultrafiltration rate are stabilized by warmth/humidity conditioning, whereby temperatures in a range of about 30.degree. to 60.degree. C. and relative humidities in a range of about 10 to 60% are suitable. The membranes may be enveloped at a relative humidity of about 40 to 60% and at about 20.degree. to 25.degree. C. in a packaging which is at least substantially impermeable to the passage of moisture before being subjected to the conditioning.

Process for the stabilization of the properties of cellulosic membranes

A device for separating gas bubbles from infusion fluids or human-body fluids by means of fluid-repellent, gas-permeable, microporous degassing elements with a casing, which has an inlet opening for the fluid to be degassed, an outlet opening for the degassed fluid, and at least one outlet opening for gas. The degassing element is disposed at least in the area of the casing in which gas bubbles occur, wherein the degassing element comprises at least one degassing capillary whose inner cavity is closed against the passage of fluid, and an outlet opening for the gas. Preferably, this device is used as an infusion filter, in which case a wettable, gas-impermeable microporous filter is additionally disposed in the casing. The wettable, gas-impermeable microporous filter may comprise filter capillaries, in which case the filter capillaries and the degassing capillaries can be disposed in such a way that they have only one common embedment.

Device for separating gas bubbles from fluids

The invention relates to a process for obtaining extractive-material-reduced cellulose with a low LAL reaction, wherein cotton linters or wood pulps, subsequent to the customary digesting treatment, are subjected for 1 to 10 hours to hydraulic washing with water, lye with a concentration of less than 5 g/l alkali content, or with a diluted acid containing less than 5 g/l acid at temperatures of 120.degree. to 180.degree. C. and under a pressure of 2 to 20 bar. The resulting cellulose is used for the manufacture of hemodialysis and/or hemofiltration membranes in the form of flat membranes, tubular membranes or hollow filaments by regeneration of a cellulose solution containing the extractive-material-reduced cellulose with a low LAL reaction. The regeneration may be effected from solutions of cellulose cuoxam, cellulose xanthate, or solutions of cellulose in tertiary amine oxide or in an LiCl-containing solvent.

Process for producing extractive-material-reduced cellulose

The invention relates to a dialysis membrane of regenerated cellulose and to a process for its production. Isocyanate prepolymers with an average molecular weight of 300 to 50,000, which are soluble in organic solvents other than solvents reacting with isocyanate groups and dissolving cellulose, are bound chemically at least to one membrane surface of the dialysis membrane. The dialysis membrane of the present invention substantially eliminates the symptoms of leukopenia and complement activation.

Cellulose dialysis membrane with improved biocompatibility

The invention relates to a method for the production of a dialysis membrane of regenerated cellulose. Isocyanate prepolymers with an average molecular weight of 300 to 50,000, which are soluble in organic solvents other than solvents reacting with isocyanate groups and dissolving cellulose, are bound chemically at least to one membrane surface of the dialysis membrane. The dialysis membrane made by the process of the present invention substantially eliminates the symptoms of leukopenia and complement activation.

Production of cellulose dialysis membrane with improved biocompatibility

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.

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Wuppertal, Germany

Michael Pelger