JPS60114268A - Washing of semipermeable membrane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present hollow cellulosic fibers are used in a wide range of clinical applications for acute dialysis in patients with end-stage renal disease, for life support in patients with end-stage renal disease, and for various other reasons. Used in dialysis machines. Despite the large number of successful uses of such dialyzers,
Some disadvantages and shortcomings remain.

It has been observed that, from time to time, a small number of patients suffer from undesirable effects believed to be due to certain unknown extractable components of hollow cellulosic fibers, particularly such fibers made by the well-known cuprammonium process. There is.

According to the invention, the hollow fibers are radiation sterilized, removing a large amount of undesirable extractable components from the fibers and then restoring the desired flexibility and softness to the fibers, while simultaneously A special cleaning method for hollow cellulosic fibers is proposed, which provides increased protection against radiation damage that can occur when cleaning.

Special Publication No. 55-23620 titled "Method for sterilizing dialysis equipment" by Senkyugi ■■ Ekaitoshi Co., Ltd. states that the semi-permeable membrane of a dialysis machine is sterilized with water or a non-toxic water-soluble substance such as salt or glycerin. Wetting with an aqueous solution is taught. This is claimed to inhibit radiation damage when the acid film is radiation sterilized.

January 14, 1983 entitled “Radiation Resistant Dialyzer Membrane”
U.S. Patent Application No. 458.107 of Mo1thop et al.
3 to 25% by volume of an organic polyol such as glycerin and 75 to 97% by volume of a volatile non-reactive solvent.
The present invention teaches a method of applying a substantially anhydrous dispersion of dialysis membranes and subsequently draining the dispersion from the dialysis membrane, thereby making the dialysis membrane resistant to radiation damage. This is distinguished from the cited 13 patent publication in that it is a substantially anhydrous system.

Rowley et al. U.S. q) No. 3,592.
No. 672 is 1. A dry, stabilized rewettable semipermeable cellulose ester or ether ester and its preparation are disclosed. While wet with water, Wllk extracts most of the water from the membrane, causing an organic solution that is miscible with water.
1, and then treated with IIIA in a non-polar hydrocarbon solvent.
Contact Flj! It is possible. The water-miscible organic solvent contains a water-soluble polyol such as glycerin.

Manos U.S. Patent No. 4. oso, 743-z-ba,
11. with water by contacting the membrane prepared with water with a solution of a water-miscible and water-immiscible l8 medium and removing the solution. ``1j Discloses a method for drying a slag membrane.

Bodnar at al's US 1t! i permit no. 4, 22
No. 7+295 discloses a means of manufacturing an artificial kidney from a hollow fiber dialyzer, and provides a general background example of the extensive prior art of hollow fiber dialyzer molding.

Lipps, US Pat. No. 3,54e,-"Zo9, hydrolyzes two cellulose esters, plasticizes the fibers while wet with an aqueous non-volatile lubricant such as glycerin, and then Teach them how to dry them before using them in the production of separation cells.

5cott, J. 11o11ow Fibers
:, Manufacture and Application
ion, Noyes I)ata Corporation
on, Park Ridge, New Jersey
(1981), pages 99 and 100, discuss the Lipps patent cited above.

One horse was released on June 9, 1980, and “Me th
odand Composition for Cle
Co-5arno titled “aningFifers”
US Patent Application No. 1,571,777 teaches cleaning polysulfone ultra-U overcoat with a water/8 solution of non-enzymatic hydrolyzate and lower alcohol. 1 s of said hydrolyzed water
: The agent may be a strong inorganic acid or base.

In accordance with the present invention, a method is provided for treating bundles of hollow cellulosic fibers for use in blood contacting diffusion devices.

Extracted from the fiber! Acid water, preferably at pH 1 to 5 and typically at pH 2 to 4, is used to remove the components. 8. Let the liquid pass through the bore of the hollow fiber. A substantially anhydrous liquid of a water-miscible organic polyol having a molecular weight of less than 200 and a volatile non-reactive solvent is then passed through the bore. The bundle is then dried to remove the solvent.

Cellulose fibers are copper ammonia tyla°, such as Nishi F
Hollow L% fiber 4 sold by Enka company
It is preferable for -e because it is Cupropf+an, which is the name of Bran of A material.

The organic polyol is preferably glycerin, but
It may also be ethylene glycol, propylene glycol, diethylene glycol, or class J2 glycols and similar compounds which are miscible with water and can therefore be absorbed into the membrane 4A 1'4 as plasticizers.

It is generally preferred that the aqueous acid is acetic acid.

It is volatile for complete removal and has the advantage of being able to be used in stainless steel processing equipment with less corrosion due to the ease of carrying out the process of the present invention. Other acid melts that can be used are typically acids with non-toxic residues such as lactic acid, citric acid, dilute hydrochloric acid, or acidic organic chelating agents such as glycine and EDTA. contains, contains.

The volatile non-reactive solvent is most conveniently an alcohol such as isopropanol, but eg ethanol and other solvents may also be used if desired. Typically,
ZO to 70% by volume of the organic polyol may be present in 80 to 30% by volume of the JiJi non-reactive solvent. Preferably 25 to 65% by volume of glycerin or other polyol may be present, the remainder being volatile solvent.

The term "substantially anhydrous" as used above does not contemplate the exclusion of small amounts of absorbed water, etc. present in the organic polyol and the Mi-photoactive non-reactive solvent. However, it is undesirable to add large amounts of ice to the liquid, as it is more difficult to dry the membrane after adding water than after adding a more volatile solvent. And when the water is allowed to remain and the product freezes, it forms crystals,
The membrane may be torn.

Alternatively, the volatile non-reactive solvent is not an alcohol, such as those sold under the trade name Freon by DuPont, in particular Ll,2-1-lichlor-L2,2
- Volatile chlorofluorocarbons such as trichloroethane and 1-fluorothane! Carbon may also be used. It is likewise possible to use mixtures of these with alnylene.

By the treatment of the present invention, leachable components of the fibers are removed by acid washing]
One of the significant leachable components that can be partially removed in two sheets and thus removed is the large percentage of copper used to produce cellulose hollow fibers in the Cumonia process. Similarly, the hollow fiber bundles can be exposed to radiation and protected by the absorbed polyol, and their ultraporous filtration and other properties are significantly less degraded by the present invention.

The bundle of hollow fibers can be fixed in a tubular housing according to conventional hollow fiber dialyzer manufacturing methods before passing through the acid water/8 solution, botting both ends, and opening the bore after botting. .

An aqueous acid solution and then a solvent dispersion of a polyol can be passed through the bores of the bundle by pumping each solution from one end of the bore of the hollow fibers to the other. As the polyol/8 liquid passes through the bores of the hollow fibers, a protective film of polyol is deposited against the material 51 of the hollow fibers. During fabrication, when the hollow fibers are housed, it is desirable to clean their outer surfaces with wood powder at the same time as their bores.

The method of the present invention has advantages over previous methods in that it is significantly less expensive than other hollow fiber processing methods, particularly those using Freon-based solvents.

The idea of cleaning dialyzer bundles with an alcohol/glycerin mixture was introduced in Mo1Ll+o, filed January 14, 1983.
Although disclosed in U.S. Pat. No. 458,107 to p. is applied to wet-washed bundles rather than to dry-build hollow fiber bundles. Therefore, high glycerin concentrations are typically used in the present invention because the remaining water in the bundle tends to dilute the solvent and the glycerin in the solvent displaces water, etc. in the bundle.

Not only can the invention be applied with the benefit of providing protection against radiation damage to bundles of hollow fibers that are sterilized by radiation, but it also applies to bundles of hollow fibers that are sterilized by other methods, for example by ethylene oxide sterilization. It can be used to take advantage of the advantageous economics of the invented method.

As a specific example, a hollow fiber dialyzer of known design (CI?15, sold by Trahenol Laboratories, Inc., Deerfield, Illinois)
．． 11 dialyzers) were initially charged with 4.00 tr of dilute acetic acid (5 to 10% by volume of glacial acetic acid in water) through each dialyzer blood flow path.
processed by passing

After this, 30% or 50% glycerin dissolved in isopropyl alcohol was passed through the blood flow path of the dialyzer to remove water from the system and deposit the glycerin into the hollow fibers. After this, the dialyzer was air-dried by blowing warm air through the blood channels.

The treated dialysers showed thicker (reduced copper-containing leaching fractions) in subsequent leaching experiments. They also exhibited ultra-wide filtration after gamma irradiation that was comparable to comparable dialysers sterilized with ethylene oxide. Indicated.

Corresponding dialyzers that were not treated in the manner described above showed a significant loss in ultrafiltration capacity after gamma irradiation sterilization compared to above.

The above is provided for illustrative purposes and is not intended to limit the scope of the invention as defined in the claims.

Claims (1)

[Claims] +l) passing an aqueous acid solution of pH 1 to 5 through the bores of hollow cellulosic fibers used in a diffusion device in contact with blood to remove extractable components from the fibers;
passing through said bore a substantially anhydrous dispersion consisting of 20 to 70% by volume of an organic polyol liquid having a molecular weight of less than 200 and 80 to 30% by volume of a volatile unreacted solvent; A method for treating a bundle of hollow cellulosic fibers for use in a blood-contacting diffusion device, the method comprising drying the fiber bundle to remove the /8 medium. (211iif Acid water/8 liquid is acetic acid/8 liquid. (3) The organic polyol is glycerin. (4) Jit-induced non-reactive/ 8. The method of paragraph 1, wherein the solvent is an alcohol. (5) The method of paragraph 41, wherein the volatile non-reactive solvent is isopropanol. (6) The substantially anhydrous dispersion contains 25 to 65 volumes of glycerin. %, and the remainder is the first volatile solvent.
Section method. (7) The fiber bundle is then subjected to radiation sterilization.
Section method. (8) The method of claim 1, wherein the bundle is secured to a tubular housing and botted at both ends before passing through the acid aqueous solution, and the bore is opened after botting. (9) removing extractable components from the fibers by passing an aqueous acid solution of pH 1 to 5 through the bores of the hollow cellulosic fibers used in the diffusion device in contact with blood; Substantially anhydrous fraction 1, the remainder consisting essentially entirely of a volatile non-reactive solvent selected from the group consisting of isopropanol and ethanol.
1. A method of treating a bundle of hollow cellulosic fibers for use in a blood contacting diffusion device, comprising: 1 passing a liquid through the bore; and drying the bundle of fibers to remove the solvent. . 00) The method of claim 9, wherein while so treating said hollow fibers, the outer surface of said hollow fibers is simultaneously treated with said aqueous acid solution and then with said substantially anhydrous dispersion. 1J11 The method of claim 9, wherein the aqueous acid solution and the substantially anhydrous dispersion are each forced through the bore by pressure. (τ゛) The method according to item 9, wherein the acid aqueous solution is an acetic acid aqueous solution.