The present disclosure relates to semipermeable membranes which are suitable for blood purification, e.g. by hemodialysis, which have an increased ability to remove larger molecules while at the same time effectively retaining albumin. The membranes are characterized by a molecular retention onset (MWRO) of between 9.0 kD and 14.5 kD and a molecular weight cut-off (MWCO) of between 55 kD and 130 kD as determined by dextran sieving curves and can be prepared by industrially feasible processes excluding a treatment with salt before drying. The invention therefore also relates to a process for the production of the membranes and to their use in medical applications.

The present disclosure relates to a dialyzer comprising a bundle of semipermeable hollow fiber membranes which is suitable for blood purification, wherein the dialyzer has an increased ability to remove larger molecules while at the same time it is able to effectively remove small uremic toxins and efficiently retain albumin and larger proteins. The invention also relates to using said dialyzer in hemodialysis.

The present disclosure concerns a hemodialyzer for the purification of blood and use thereof. The hemodialyzer comprises a bundle of hollow fiber membranes, wherein the hollow fiber membranes have an inner diameter (d.sub.B) within the range of 168-175 m, a fiber wall thickness (.sub.m) within the range of 25-26 m, and an effective length (L) within the hemodialyzer within the range of 207-287 mm. The bundle of hollow fiber membranes has a packing density within the range of 57.5-60.0%, and a total membrane surface area (A.sub.tot) within the range of from 1.64 to 1.73 m.sup.2.

The present disclosure relates to a hemodialysis membrane for the treatment of restless leg syndrome (RLS), especially in severe and very severe cases and/or in patients which suffer from kidney failure and already receive hemodialysis. The present disclosure therefore also relates to methods of treating restless leg syndrome. The treatment and method encompasses using a hemodialysis membrane which is characterized in that it comprises at least one hydrophobic polymer and at least one hydrophilic polymer and in that it has a MWRO of between 8.5 and 14.0 kD and a MWCO of between 55 kD and 130 kD.

In embodiments of the invention, there is provided a dialyzer or filter comprising hollow fibers, in which blood flows on the exterior of the hollow fibers, and dialysate or filtrate may flow on the inside. The external surfaces of the hollow fibers may have properties of smoothness and hemocompatibility. The fiber bundle may have appropriate packing fraction and may have wavy fibers. Optimum shear rates and blood velocities are identified. Geometric features of the cartridge, such as pertaining to flow distribution of the blood, may be different for different ends of the cartridge. Air bleed and emboli traps may be provided. Lengthened service life may be achieved by combinations of these features, which may permit additional therapies and applications or better economics.

The invention relates to an undulated thermostable hollow fiber membrane of reduced wall thickness, wherein the wall thickness amounts to 20 m or greater and 30 m or less and the waveform of the hollow fiber membrane exhibits a wavelength in the range of from more than 1 mm and less than 5 mm. In particular, the invention relates to a method for producing an undulated thermostable hollow fiber membrane of lower wall thickness.

The present disclosure relates to semipermeable membranes which are suitable for blood purification, e.g. by hemodialysis, which have an increased ability to remove larger molecules while at the same time effectively retaining albumin. The membranes are characterized by a molecular retention onset (MWRO) of between 9.0 kD and 14.5 kD and a molecular weight cut-off (MWCO) of between 55 kD and 130 kD as determined by dextran sieving curves and can be prepared by industrially feasible processes excluding a treatment with salt before drying. The invention therefore also relates to a process for the production of the membranes and to their use in medical applications.

In embodiments of the invention, there is provided a dialyzer or filter comprising hollow fibers, in which blood flows on the exterior of the hollow fibers, and dialysate or filtrate may flow on the inside. The external surfaces of the hollow fibers may have properties of smoothness and hemocompatibility. The fiber bundle may have appropriate packing fraction and may have wavy fibers. Optimum shear rates and blood velocities are identified. Geometric features of the cartridge, such as pertaining to flow distribution of the blood, may be different for different ends of the cartridge. Air bleed and emboli traps may be provided. Lengthened service life may be achieved by combinations of these features, which may permit additional therapies and applications or better economics.

A hollow fibre membrane having a coiled, a hemihelix, a helical or an undulated native form, in which the membrane can be stretched by up to 4-times its original length with no plastic deformation, and wherein the native form of the membrane is produced by the asymmetric flow of liquid polymer through an opening of a die or nozzle.

Hollow-fibre membrane having at least one first curl in the form of a first wave which is characterized by a first oscillation plane and a first wavelength and at least one second curl in the form of a second wave which is characterized by a second oscillation plane and a second wavelength, characterized in that the first oscillation plane and the second oscillation plane confine an angle with one another which is different from zero.