Sterilization method

Abstract

The invention relates to a fractional vacuum sterilization method for objects such as blood tubing systems or cassette systems, which are sterilized in outer packagings. The spatial extent of the outer packaging during the evacuation step is minimized here by inserting a packing into the sterilization chamber and thereby achieving an efficient gas exchange through the gas-permeable outer packaging. The number of vacuum-pressure cycles required to establish a saturated sterilization medium atmosphere in the outer packaging and in the object to be sterilized is thereby reduced.

Claims

1. A method for sterilizing sterilization items in an evacuable sterilization chamber, characterized by the following method steps: a) introducing at least one sterilization item and at least one packing into the evacuable sterilization chamber, characterized in that the packing is a flexible sealed gas-containing, gas-impermeable hollow body, b) hermetically sealing the sterilization chamber, c) evacuating the sterilization chamber and thereby lowering the pressure, d) introducing a sterilization medium into the sterilization chamber and thereby raising the pressure, e) repeating steps c) through d) at least once, f) leaving the sterilization medium in the sterilization chamber for a predetermined period of time to achieve a predetermined level of disinfection, g) evacuating the sterilization chamber, h) flooding the sterilization chamber with a sterile gas, i) repeating steps g) through h) as needed to remove the sterilization medium from the sterilization chamber and the sterilization item, j) opening the sterilization chamber, k) removing the sterilization item and the packing from the sterilization chamber.

2. The method according to claim 1, characterized in that the pressure is lowered to less than 110 mbar abs. in step c).

3. The method according to claim 1, characterized in that the pressure is raised to more than 2 bar abs. in step d).

4. The method according to claim 1, characterized in that the hollow body is a plastic bag.

5. The method according to claim 1, characterized in that the sterilization item is in a gas-permeable outer packaging.

6. The method according to claim 5, characterized in that the gas-permeable outer packaging is flexible.

7. The method according to claim 1, characterized in that the sterilization item has air-filled hollow spaces that are open to the environment.

8. The method according to claim 5, characterized in that the sterilization item is a tubing system.

9. The method according to claim 5, characterized in that the sterilization item is a cassette system.

10. The method according to claim 1 using a sterilization device comprising the evacuable sterilization chamber having the at least one packing, a vacuum generator, means for supplying a sterilization medium, and a control unit or regulating unit for performing the method.

Description

(1) Exemplary embodiments of the invention are shown in the figures.

(2) FIG. 1 shows the course of the process in the form of a flowchart.

(3) FIG. 2 shows a schematic view of an exemplary sterilization device.

(4) FIG. 3 shows schematically the sterilization chamber of a sterilization device according to the prior art with sterilization item(s) in an outer packaging in a vented condition (A) and in an evacuated condition (B).

(5) FIG. 4 shows schematically an embodiment of a sterilization chamber of a sterilization device according to the invention with sterilization item(s) in an outer packaging in the vented state (A) and in the evacuated state (B).

DESCRIPTION

(6) In the method according to the invention, sterilization item(s) and the packing are introduced into the sterilization chamber in the first step 100. The sterilization chamber is then hermetically sealed in a step 101 and then is evacuated in a step 102. Once the desired vacuum has been achieved, the introduction of the sterilization medium 103 begins. The evacuation 102 and the introduction of the sterilization medium 103 are repeated until an almost saturated atmosphere of the sterilization medium has been achieved in the sterilization chamber. Then the sterilization item(s) is incubated 104 until reaching the desired degree of disinfection. The sterilization chamber is then evacuated again in a step 105 and is next aerated with a sterile gas in a step 106. The steps 105 and 106 are repeated until the sterilization medium has been removed almost completely from the sterilization chamber. After a last aeration 106, the sterilization chamber may be opened and the sterilization item(s) may be removed.

(7) FIG. 2 shows a device according to the invention for sterilization. A packing 30 the volume of which can expand greatly during the evacuation steps 102 and 105 is situated in the sterilization chamber 10. The evacuation takes place via a vacuum pump 50 which is connected to the sterilization chamber. In addition a means for supplying a sterilization medium 20 is connected to the sterilization chamber 10. The sterilization medium may be introduced from this vessel 20 through a pump 40 into the sterilization chamber, but the sterilization medium may also be transferred to the sterilization chamber through the vacuum pump 50. The sterilization medium may be supplied into the vessel 20 from a means for generating this sterilization medium 110. This may be a steam generator or an ozone generator, for example. In addition, the sterilization chamber 10 has a line to a source for a sterile gas 120.

(8) FIG. 3 shows a sterilization chamber 10 with sterilization item(s) 70 according to the prior art. The sterilization item(s) 70 is in an outer packaging. FIG. 3A shows the sterilization chamber 10 in the evacuation or vacuum phase. The outer packaging here is inflated to the maximum volume of the packaging.

(9) FIG. 4 shows a detail of a sterilization device according to the invention. A packing 30 embodied as a plastic bag is arranged between two outer packagings with sterilization item(s) 70 in the sterilization chamber 10. In FIG. 4A, the sterilization chamber 10 is shown at ambient pressure or in the phase with loading with sterilization medium. FIG. 4B shows the sterilization chamber 10 in the evacuation or vacuum phase. In contrast with the prior art, the plastic bag 30 here has been inflated up to its maximum volume. The dimensions in the sterilization chamber 10 are selected so that expansion of the outer packaging around the sterilization item(s) is prevented due to the space required by the plastic bag 30 in the evacuation phase. In contrast with the plastic bag 30, the outer packaging is gas-permeable, so that the air is forced out of the packaging by the plastic bag 30. Since the spatial displacement of the plastic bag is much lower at ambient pressure, the plastic bag and the sterilization item(s) may easily be inserted into and removed from the sterilization chamber.

(10) Due to the method according to the invention and the device according to the invention, the number of required vacuum-pressure cycles can be reduced. A shortening of the sterilization time, savings of sterilization medium and energy can thereby be achieved.