JPH0310343B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for sterilizing an osmosis device using a semipermeable membrane, and more specifically, a method that enables sterilization of the osmosis device without deteriorating the semipermeable membrane, and that improves the ease of handling and storage of the sterilized osmosis device. The present invention relates to a method of sterilizing an infiltration device that can be used as a method of sterilization. Osmosis devices are widely used in fields such as blood purification using artificial kidneys, dialysis, reverse osmosis, and gas separation. Dialysis osmosis devices must be completely sterilized before use. Formalin, ethylene oxide, high-pressure steam, gamma rays, etc. are used for this sterilization treatment, and each of them has its own unique effects. Among these, the sterilization method using gamma ray irradiation is a method that treats the object in its packaged state. It has been evaluated as a particularly preferred sterilization method because it is highly effective and has an excellent sterilization effect. However, it is known that the semipermeable membranes used in osmosis devices deteriorate due to gamma ray irradiation.
Sterilization methods such as those described in this issue have been proposed. In the proposed invention, when sterilizing by gamma ray irradiation, the semipermeable membrane is brought into a wet state with a moisture content higher than the saturated moisture content, and the purpose of preventing deterioration itself seems to have been achieved to some extent. However, in the proposed invention, since it is necessary to maintain the semipermeable membrane in a wet state, the weight of the osmosis device becomes large, and transportation and handling are inconvenient, and furthermore, a large amount of sterilized water must be prepared, leading to high costs. ing. Moreover, since the semi-permeable membrane is purposefully kept in a moist state where bacteria can easily grow, it is thought that bacteria can grow even in the short time between packaging and sterilization, resulting in complete sterilization. It may take a considerable amount of time to obtain the product, which may result in higher costs or safety issues, and in some cases, gamma ray irradiation may be completed before sterilization is complete. I'm not satisfied. Furthermore, if the number of viable bacteria increases before sterilization, there is a risk that a large amount of pyrogenic substances such as metabolic products and dead bacteria will remain, so it cannot be said that this method can be immediately put into practical use. Therefore, in order to solve this problem, complicated additional measures such as keeping the product in a low temperature storage state for a waiting period before sterilization processing are required, which is extremely uneconomical. The present inventors focused on these circumstances and conducted research to provide a new sterilization method that does not have the above disadvantages and does not deteriorate the semipermeable membrane, which is the intended purpose. Based on the measurement results of the pH and ultraviolet absorption spectra of the extract obtained by passing body fluids through the device, it was concluded that the deterioration of the semipermeable membrane was due to oxidation of the membrane material. The present invention was completed as a result of further research based on the above reasoning, and its gist is that after creating an inert gas atmosphere inside the infiltration device, which is a semipermeable membrane housed in a container, gamma rays are irradiated. It exists at the point where it does. That is, the present invention creates an atmosphere during gamma ray irradiation under conditions in which oxidative deterioration of the membrane material does not progress by filling the inert gas in the infiltration device, and also releases the inside of the infiltration device from the above-mentioned excessively wet state. This prevents the growth of bacteria before gamma ray irradiation, and also achieves improvements in weight, safety, economic efficiency, etc. Examples of the inert gas used in the present invention include all kinds of gases and mixed gases thereof that do not substantially react with the membrane material, and specific examples include N ₂ , CO ₂ , He, Ar, etc. can be mentioned. Among these, water-soluble gases such as CO ₂ are recommended as particularly preferred inert gases because they rapidly dissolve in the filling liquid such as blood introduced into the infiltration device and do not generate bubbles in the filling liquid. Semipermeable membrane materials include cellulose acetate such as cellulose diacetate and cellulose triacetate, as well as cellulose acetate saponified cellulose, cuprammonium cellulose polysulfone, polyurethane, polyacrylonitrile, polymethyl methacrylate, polyethylene, vinyl acetate copolymer, and polyvinyl. Examples include alcohol and polypropylene. Naturally, the parts constituting the infiltration device other than the membrane material should be made of materials that do not deteriorate due to gamma rays. The present invention is roughly configured as described above, and can obtain the effects as summarized below. (1) Gamma ray irradiation to semipermeable membranes, etc. is carried out in an inert gas atmosphere, so there is no oxidative deterioration of the membrane. (2) Since there is no need to keep the inside of the infiltration device in a wet state, the weight of the infiltration device can be reduced, making it easier to handle, and there is almost no bacterial growth between packaging and gamma ray irradiation. Therefore, there is no need for special preservation treatment such as low-temperature preservation. (3) With these, sterilization by gamma ray irradiation can be effectively performed, and a penetration device that can be safely applied to applications such as artificial kidneys can be obtained. Examples will be described below. [Test method] Japan Medical Plastics Association: Dialysis membrane eluate test for draft standards for artificial kidney devices According to the test method above, cellulose acetate membrane was irradiated with 5.0 Megarad gamma rays with various atmospheric gases. Characteristics before and after
Shown in the table.

【table】

[Table] As shown in the table above, the results of the eluate test of the membrane material after gamma ray irradiation with inert gas filling were almost constant regardless of the type of gas, and passed the above criteria. This is a significant improvement over the results previously obtained. Furthermore, after gamma ray irradiation with inert gas sealed in the membrane material, no significant difference was observed in the urea, creatinine, and vitamin B ₁₂ clearance and ultracapacity of the membrane material compared to the values before irradiation. No change in material performance was observed. Although the device before irradiation passed the test, it cannot be used as an artificial kidney device unless it is sterilized by gamma ray irradiation.

Claims (1)

[Scope of Claims] 1. A method for sterilizing an infiltration device, which comprises creating an inert gas atmosphere inside the infiltration device in which a semipermeable membrane is housed in a container, and then irradiating it with gamma rays. 2. The method for sterilizing a permeation device according to claim 1, wherein the inert gas is carbon dioxide or nitrogen. 3. A method for sterilizing an osmosis device according to claim 1 or 2, wherein the semipermeable membrane is a cellulose acetate membrane.