METHOD FOR ENSURING MICROBIOLOGICAL PURITY OF A SINGLE-USE DEVICE, AND COVER FOR A FLUID CONNECTION OF A SEPARATION UNIT FOR USE IN SUCH A METHOD

Abstract

A method for ensuring a microbiological purity of a single-use device for carrying out a biotechnological process, the single-use device including at least one gamma-sterilizable component which is formed from materials suitable for a sterilization by gamma radiation, and at least one non-gamma-sterilizable subunit which contains a material unsuitable for a sterilization by gamma radiation. Both the component and the subunit each have an area that comes into contact with a process medium when the biotechnological process is carried out. The method includes the steps of sterilizing the gamma-sterilizable component by gamma radiation; protecting the medium-contacting area of the gamma-sterilizable component by a sterile barrier; sterilizing the non-gamma-sterilizable subunit with superheated steam; protecting the medium-contacting area of the non-gamma-sterilizable subunit by a sterile barrier; removing the sterile barriers; and mounting the gamma-sterilized component and the superheated steam-sterilized subunit in the single-use device immediately after removing the sterile barriers.

Claims

1. A method of ensuring a microbiological purity of a single-use device for carrying out a biotechnological process, wherein the single-use device comprises at least one gamma-sterilizable component which is formed from materials suitable for a sterilization by gamma radiation, and at least one non-gamma-sterilizable subunit which contains a material unsuitable for a sterilization by gamma radiation, both the component and the subunit each having a medium-contacting area that comes into contact with a process medium when the biotechnological process is carried out, and wherein the method comprises steps of: (a) sterilizing the gamma-sterilizable component by gamma radiation; (b) protecting the medium-contacting area of the gamma-sterilizable component by a sterile barrier; (c) sterilizing the non-gamma-sterilizable subunit with superheated steam; (d) protecting the medium-contacting area of the non-gamma-sterilizable subunit by a sterile barrier; (e) removing the sterile barriers; and (f) mounting the gamma-sterilized component and the superheated steam-sterilized subunit in the single-use device immediately after removing the sterile barriers.

2. The method according to claim 1, characterized in that a time period between removing a sterile barrier and mounting the associated gamma-sterilized component or the associated superheated steam-sterilized subunit, respectively, is in each case shorter than four minutes.

3. A method of ensuring a microbiological purity of a single-use device for carrying out a biotechnological process, wherein the single-use device comprises at least one gamma-sterilizable component which is formed from materials suitable for a sterilization by gamma radiation, and at least one non-gamma-sterilizable subunit which contains a material unsuitable for a sterilization by gamma radiation, both the component and the subunit each having a medium-contacting area that comes into contact with a process medium when the biotechnological process is carried out, and wherein the method comprises steps of: (a) sterilizing the gamma-sterilizable component by gamma radiation; (b) protecting the medium-contacting area of the gamma-sterilizable component by a sterile barrier; (c) sterilizing the non-gamma-sterilizable subunit with superheated steam; (d) protecting the medium-contacting area of the non-gamma-sterilizable subunit by a sterile barrier; (e) additionally covering the medium-contacting area of the gamma-sterilizable component with at least one first closure, and/or additionally covering the medium-contacting area of the non-gamma-sterilizable subunit with at least one second closure; (f) removing the sterile barriers and later removing the first and/or second closure; and (g) mounting the gamma-sterilized component and/or the superheated steam-sterilized subunit in the single-use device immediately after removing the first and second closures, respectively.

4. The method according to claim 3, characterized in that a time period between removing the respective sterile barrier and mounting the associated gamma-sterilized component provided with a first closure and/or the associated superheated steam-sterilized subunit provided with a second closure is in each case shorter than three hours, and in that the time period between removing the first and second closures, respectively, and mounting the associated gamma-sterilized component and superheated steam-sterilized subunit, respectively, is in each case shorter than two minutes.

5. The method according to claim 3, characterized in that at least one of the first and second closures constitutes a particle input reducing barrier having a clearance of at most 100 m.

6. The method according to claim 1, characterized in that step (b) is performed before step (a) and/or step (d) is performed before step (c).

7. The method according to claim 1, characterized in that the sterile barrier for the superheated steam-sterilized subunit comprises a closed envelope completely surrounding the subunit.

8. The method according to claim 7, characterized in that the envelope is formed from a watertight but water vapor-permeable nonwoven fabric.

9. The method according to claim 1, characterized in that the medium-contacting area of the subunit is covered by a second closure, the second closure being a lid, before sterilization with superheated steam and until the superheated steam-sterilized subunit is mounted, the second closure having at least one passage opening which can be selectively uncovered and closed.

10. The method according to claim 9, characterized in that the non-gamma-sterilizable subunit includes at least one functional unit, the at least one functional unit being a separation unit, having a fluid connection which is covered by a second closure.

11. The method according to claim 10, characterized by the following steps or measures: attaching the second closure onto the fluid connection of the functional unit; uncovering the passage opening if the passage opening is closed; packing the non-gamma-sterilizable subunit into a closed envelope; sterilizing the packed subunit with superheated steam with the passage opening uncovered; after sterilizing with superheated steam: closing the passage opening in the closed envelope; unpacking the superheated steam-sterilized subunit from the closed envelope; and removing the second closure immediately prior to mounting the subunit.

12. The method according to claim 1, characterized in that the medium-contacting area of the gamma-sterilizable component remains covered by a first closure, by a blind cap, a sterile connector or a jacket, prior to the sterilization by gamma radiation and until the gamma-sterilized component is mounted.

13. The method according to claim 12, characterized in that the gamma-sterilizable component comprises at least one connecting pipe and/or a plurality of interconnectable manifold assemblies for connecting a plurality of separation units and/or at least one connecting hose line, wherein the gamma-sterilizable component includes at least one fluid connection that is covered by the first closure.

14. The method according to claim 1, characterized in that the sterile barrier for the gamma-sterilizable component comprises a closed primary packaging completely surrounding the component.

15. The method according to claim 1, characterized in that the superheated steam-sterilized subunit and the gamma-sterilized component are mounted on a biological safety cabinet or in a clean room, in an area of a clean room that is separated by walls.

16. A lid for a fluid connection of a separation unit of a non-gamma-sterilizable subunit for use in a method according to claim 3, the lid comprising: a base body for accurately fitting the lid to the fluid connection; at least one passage opening that provides a fluid communication between the medium-contacting area of the separation unit and immediate surroundings of the separation unit after the lid has been attached to the fluid connection; and a mechanism for selectively uncovering and closing the at least one passage opening, the mechanism including a closing body which is transferable between a closed position, in which the closing body covers the at least one passage opening, and an open position, in which the closing body does not cover the at least one passage opening; and an actuating element which is used for manually actuating the mechanism; wherein the lid is a reusable component, which is further formed at least mainly of stainless steel.

17. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Further features and advantages of the invention will be apparent from the description below and from the accompanying drawings, to which reference is made and in which:

[0046] FIG. 1 shows a perspective view of a single-use device for carrying out a biotechnological process;

[0047] FIG. 2 shows a top view of the single-use device from FIG. 1;

[0048] FIG. 3 shows a separation unit with connecting hose lines and connectors;

[0049] FIG. 4 shows a lid for a fluid connection of a separation unit;

[0050] FIG. 5 shows an exploded view from the side of a connecting pipe with a plurality of fluid connections; and

[0051] FIG. 6 shows a top view of the connecting pipe of FIG. 5.

DETAILED DESCRIPTION

[0052] FIGS. 1 and 2 show a single-use device 10 for carrying out a biotechnological process in an assembled state.

[0053] The single-use device 10 comprises a plurality of separation units 12 arranged in a rigid holder 14 in a predefined grid. The separation units 12 may generally be filter capsules, chromatography columns, or membrane adsorbers.

[0054] The fluid connections (inlets and outlets) 16 of the separation units 12 are interconnected via rigid connecting pipes 18 or hose lines. Connecting hose lines 20 are connected to the connecting pipes 18 for supplying and discharging medium.

[0055] Furthermore, a sterile air filter 22 is connected to an upper connecting pipe 18 for jointly venting all of the separation units 12.

[0056] The single-use device 10 may include still further components. However, the exact structure and operation of the single-use device 10 are not of essential importance to the invention described herein.

[0057] The single-use device 10 is a large device for use in commercial manufacturing involving a large media throughput (production scale). In such devices, a plurality of separation units are connected to each other, in particular more than three 30-inch filter capsules (approx. 850 mm in length). This is to be distinguished from smaller devices that are used in laboratories for experimental purposes or process development (laboratory scale).

[0058] The single-use device 10 is intended to be delivered to the user as a whole and, as far as possible, in a sterile condition or at least with as low a germ load (bioburden) and other contamination by particles or the like as possible. Basically, in this connection, a sterilization by gamma radiation is preferred, since with this method the dimensional accuracy of the components can, as a rule, be guaranteed.

[0059] However, in the present case, the single-use device 10 includes at least one separation unit 12 that is not suitable for a sterilization by gamma radiation. This is the case, in particular, if the filter material or membrane material would be so severely damaged by the energy dose (e.g., 25 kGy) typically administered during gamma sterilization that its intended function can no longer be guaranteed. Examples of such unsuitable materials are polytetrafluoroethylene (PTFE), polypropylene (PP) and polyvinyl chloride (PVC).

[0060] The separation units 12 not sterilizable by gamma radiation are sterilized as subunits in an autoclave using superheated steam, either individually or in combination and, if desired, together with further components. Such a subunit may only be of a size that allows it to be accommodated in the autoclave.

[0061] When dividing the single-use device 10 into subunits, a further criterion has to be taken into account in addition to the external dimensions: It must be ensured that, during the treatment in the autoclave, especially the inner surfaces of the separation units 12 come into contact with the superheated steam to a sufficient extent and for a long enough time. This is of particular importance if a plurality of separation units 12 are connected to one another, such as by the connecting pipes 18, or are connected to hose lines 20, so that the superheated steam cannot enter the separation units 12 directly through the fluid connections 16. There is then basically the risk that the superheated steam does not, or not quickly enough, reach all of the relevant surfaces to ensure sufficient sterilization.

[0062] In practice, it has been found that the total length of a subunit through which the superheated steam has to flow should not exceed 1800 mm. This is shown in FIG. 3 by reference to an example in which the total length through which flow has to pass, of a filter capsule 12 with two connected hose lines 20 and connectors 24 at the free ends, is approximately 1800 mm.

[0063] In the following, it will be described on the basis of a preferred exemplary embodiment how a prespecified purity, in particular a prespecified microbiological purity, of the single-use device 10 is ensured until the entire single-use device 10 is put into operation on a user's premises.

[0064] First, the superheated steam sterilization of a subunit having a separation unit 12 is described. If applicable, this description is to be transferred to the further separation units 12 of the same subunit or to the separation units 12 of further subunits.

[0065] Those face sides of the separation unit 12 at which one or more free fluid connections 16 are located (i.e. fluid connections 16 to which no connecting pipe 18 and no hose line 20 or the like is connected prior to sterilization) are provided with a closure. In the exemplary embodiment described herein, a lid 26 as shown in FIG. 4 is employed as the closure. The lid 26, which is formed primarily of stainless steel, is a reusable component, i.e. it can be used for further sterilization processes.

[0066] The lid 26 essentially consists of a base body 28 having one or more through passage openings 30, a locking pin 32, and a closure mechanism for selectively exposing and closing the passage openings 30.

[0067] The base body 28 is precisely matched to the outer contour of the associated face side of the separation unit 12 and can be fixed in place at the separation unit 12 by means of the locking pin 32.

[0068] The closure mechanism includes a closing body 34 which can assume two defined, stable positions: a closed position, in which the closing body 34 firmly rests against the base body 28 and covers the passage openings 30, and an open position, in which the closing body 34 is raised so that it does not cover the passage openings 30.

[0069] The closure mechanism is adapted to be manually actuated by means of an actuating element 36, i.e. the closing body 34 can be transferred to the respective other position by pushing or pulling the actuating element 36.

[0070] In the fixed position of the lid 26, the fluid connection(s) 16 of the separation unit 12 are in fluid communication with the immediate environment of the separation unit 12 via the passage openings 30 when the closing body 34 is in the open position. When the closing body 34 is in the closed position, however, there is no, or virtually no, fluid communication between the interior of the separation unit 12 and the environment, i.e. a possible particle input is largely prevented. The base body 28 and the closing body 34 are designed such that in the closed position the lid 26 has a clearance of at most 100 m, preferably at most 50 m and further preferably at most 10 m, so that correspondingly larger particles are prevented from entering.

[0071] After attaching the lid 26 onto the face side of the separation unit 12 (and, if applicable, another lid 26 onto the other face side), the subunit is packed into an envelope, ensuring beforehand that the passage openings 30 are exposed. The envelope is made of Tyvek or a comparable material which, on the one hand, is watertight and can serve as a sterile barrier under normal ambient conditions but, on the other hand, is permeable to water vapor. The envelope is closed by welding.

[0072] Subsequently, the subunit inside the envelope is placed in the autoclave and sterilized with superheated steam under predefined conditions (e.g., 40 min at 121 C. or 30 min at 131 C.). The superheated steam passes through the envelope and reaches the outer surfaces of the subunit and through the uncovered passage openings 30 into the interior of the separation unit 12. The passage openings 30 are dimensioned to be sufficiently large for this purpose. The passage openings 30 also ensure that sufficient pressure equalization can take place during the superheated steam sterilization so that the separation unit 12 does not deform plastically.

[0073] The envelope will remain closed after sterilization and serves as a sterile barrier for the subunit until the single-use device 10 is assembled.

[0074] The remaining components of the single-use device 10 are sterilized by gamma radiation before being assembled. Prior to irradiation, the open fluid connections 16 of the connecting pipes 18 and of the connecting hose lines 20 are also covered by closures, in this case in the form of seals 38 and blind caps 40, which are fitted by means of connectors 24, such as tri-clamp connectors. This is shown in FIGS. 5 and 6 using a Z-shaped connecting pipe 18 as an example. The closures and any aids for fastening them are made of a gamma radiation-resistant material and are designed so as to effectively prevent any particle ingress through the fluid connections 16, with the clearance dimensions being comparable to the preferred clearance dimensions for the fluid connection 16, covered by the lid 26, of the separation unit 12. In principle, the closures may also be designed as sterile barriers.

[0075] The connecting pipes 18 and connecting hose lines 20 are then packed in a primary packaging which serves as a sterile barrier. Sterilization of these components is then performed in the packaged state, which is why for the primary packaging a material should also be selected the properties of which are not significantly impaired by gamma radiation in the dose customary for a sterilization.

[0076] The single-use device 10 is assembled either at the manufacturer's orafter transport of the sterile-packaged subunits and further componentsat the user's, and preferably on a biological safety cabinet that allows sterile connecting, or in an area of a clean room separated by walls.

[0077] Prior to unpacking the subunit from the envelope, the passage openings 30 of the lid 26 are closed. This is done with the envelope closed by grasping the actuating element 36 and actuating the closure mechanism. Despite the envelope being located in between, the distinctive actuating element 36 can be easily located by feeling it.

[0078] By closing the passage openings 30, the lid 26 provides protection against particle input and, if required, even a sterile barrier, even after the subunit has been unpacked, so that an ingress of contaminants into the interior of the separation unit 12 is largely prevented.

[0079] Likewise, after unpacking, the blind caps 40 serve as a protection against particle input, preferably even as sterile barriers, and in this way largely prevent any contaminants from being able to penetrate into the interior of the connecting pipes 18 or the connecting hose lines 20.

[0080] Nonetheless, when assembling the single-use device 10, the envelope or the primary packaging should in each case be opened as late as possible in order to keep the exposure to the environment of the fluid connections 16 covered by the closures as short as possible. Owing to the closures, however, the exposure may be up to a total of three hours. However, less than two hours is preferred, even better less than one hour and ideally less than half an hour.

[0081] During this time, each separation unit 12 is placed in its intended position in the rigid holder 14. The connecting pipes 18 and connecting hose lines 20, if not already preassembled, are laid out ready. Only immediately before connecting a component are the lids 26 and/or blind caps 40 removed from the fluid connections 16 required for the respective connection. After removal of a lid 26 or a blind cap 40, the exposure of the respective open fluid connection 16 to the environment should be kept significantly shorter. Preferably, this time interval is less than two minutes, better, less than one minute and, ideally, less than 30 seconds. Assembly in a cleanroom class better than ISO 8 is then not imperative under these preconditions.

[0082] Usually, first the connecting pipes 18 are connected to the separation units 12 in the manner described above, before the connecting hose lines 20 are then connected to the connecting pipes 18. In any case, a self-contained system has been established in the end.

[0083] If the assembly is already carried out at the manufacturer's, that is, not at the later user's, the assembled single-use device 10 is packaged as a whole in a package serving as a sterile barrier and delivered to the user.

[0084] After the single-use device 10 has been set up and/or assembled on the user's premises, the blind caps 40 on the free hose ends remain in place until the connecting hose lines 20 are connected to a medium supply and/or discharge as part of putting the device into operation.

[0085] Further safety measures for the work steps described above during the assembly of the single-use device 10 require the wearing of sterile gloves and a protective mask. The otherwise usual cleanroom clothing is obligatory.

[0086] Two persons are intended for the assembly of the single-use device 10, in particular in order to achieve the desired short exposure of open fluid connections 16. The first person is in charge of unpacking and making the components ready. The second person removes the lids 26 and the blind caps 40 from the fluid connections 16 and establishes the intended fluid communications, i.e., works primarily at those locations that are critical to the cleanliness inside the components through which medium flows.

[0087] In addition, work surfaces, tools and storage containers are cleaned separately.

[0088] The single-use device 10 with its separation units and other components has been described by way of example only. In addition or as an alternative to the separation units 12, other functional units may also be provided that are not suitable for sterilization by gamma radiation, such as sensor arrangements having electronic data storage devices which would be impaired by gamma radiation.

[0089] In place of the lid 26 described, a different closure having a comparable functionality may also be used for the separation units 16 or other functional units. An example of this is a plug made of silicone or a similar material with one or more slits, which is fitted on a fluid connection 16 of a separation unit 12. During heating in the autoclave, the plug will expand and the slits will form passage openings so that superheated steam can enter the interior of the separation unit 12 through the passage openings formed in this way. During subsequent cooling, the plug will shrink back to its normal size so that the passage openings will close and an ingress of contaminants through the slits is largely avoided. It is also possible to place an air-permeable or superheated steam-permeable dust bag around the fluid connection 16 as a protection and to fix it in place there.

[0090] For (selectively) connecting the separation units 12 and/or functional units, a plurality of directly interconnectable, gamma-sterilizable manifold assemblies may also be used, which are attached directly to the face sides of the separation units 12 or functional units.

LIST OF REFERENCE NUMBERS

[0091] 10 single-use device [0092] 12 separation unit [0093] 14 holder [0094] 16 fluid connection [0095] 18 connecting pipe [0096] 20 (connecting) hose line [0097] 22 sterile air filter [0098] 24 connector [0099] 26 lid [0100] 28 base body [0101] 30 passage opening [0102] 32 locking pin [0103] 34 closing body [0104] 36 actuating element [0105] 38 seal [0106] 40 blind cap