Abstract:
Device and method for sterility testing, in particular of pharmaceutical products, includes a closed sterility test system having at least two test containers, in each case having an integrated test filter, an outlet connecting branch arranged below the test filter and an inlet connecting branch which is arranged above the test filter and can be connected with a tube connection via a sampling device to a sample container. The tube connection of the test container in each case has a distributing component via which a fixed tube connection to an associated nutrient medium container is formed and can be used to feed an associated nutrient medium to the test container.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a device for sterility testing, in particular of pharmaceutical products, comprising a closed sterility test system having at least two test containers, in each case having an integrated test filter, an outlet connecting branch arranged below the test filter and an inlet connecting branch which is arranged above the test filter and can be connected with a tube connection via a sampling device to a sample container. The invention furthermore relates to a method for sterility testing, in particular of pharmaceutical products, in which at least two test containers of a closed sterility test system are filled with an identical sample quantity from a sample container, and the samples are filtered in the test containers, and in which, after an intermediate optional washing process, the test containers are filled with different nutrient media.  
         [0003]     2. Description of the Related Art  
         [0004]     Regular sterility checks are required for the use of many medicinal and pharmaceutical products. In particular, sterility tests have to be carried out in accordance with the regulations, which are specified in the pharmacopeiae, for using medicines.  
         [0005]     In the case of the obligatory membrane filtration method for fluid medicaments—medicaments which are present in solid form may also be first of all dissolved for this using suitable means—two or more identical sample quantities are in each case fed to a test container where they are filtered by a microporous membrane having a pore size of 0.45 μm. The filtrate is then let out of the test containers and the test containers are cleaned using a sterile washing solution possibly from residues which inhibit the growth of germs. The test containers are then filled with different nutrient media, for example with thioglycolate as nutrient medium  1  and with casein soyapeptone as nutrient medium  2 , and, with the inlet connecting branch closed, incubated in accordance with the valid pharmacopeiae for example “USP 25” and “EP 4”, at an appropriate temperature for a predefined time, aerobically (with the air filter open) or anaerobically (with the air filter closed). In the event of contamination, a cloud-like opaqueness is formed in the (clear) nutrient fluid.  
         [0006]     In order to carry out the sterility test, presterilized disposable sterility test systems which form a system which is closed as far as possible are preferred in order to avoid defective (“falsely positive”) results. Systems of this type are known from EP 0 118 601 A1 and under the designations Steritest™ from Millipore S. A., and Sterisart® from Sartorius Ag. The Sterisart® system, which is known from Sartorius AG&#39;s brochure, comprises two transparent, cylindrical test containers with a slightly conical upwards profile which are connected to a sampling device, for example a piercing cannula, by means of a flexible double tube and a Y-distributing component. In the test containers, a respective membrane filter is clamped fixedly in a lower part of the container. The lower part of the container furthermore has a central discharge connecting branch which can be closed with a stopper. The upper part of the container has an inlet connecting branch and a vent having an integrated microporous air filter. The vent can be covered with a rubber cap. The double tube can be fitted into a pump head of a peristaltic hose pump in order to convey samples, washing solutions and nutrient media. Color-coded tube clips are prefitted on the tube connections in order to be able to close and open tube connections according to requirements.  
         [0007]     The known sterility test system has been proven in principle. A disadvantage, however, is that it is not optimized in respect of handling with the smallest possible risk of error and in the costs for production and the testing process. In particular, after the filtration process and the washing process, the nutrient media have to be decanted successively via the sampling device into the test containers, or at least two sampling devices to which a respective tube connection to a test container is connected would be required. In order to fill the test containers with the nutrient media, separate nutrient medium containers have to be provided and connected. For this purpose, in the case of a common sampling device, the tube connection has to be connected first of all to the first nutrient medium container, then separated again from the latter and subsequently connected to the second nutrient medium container (in the case of more than two test containers and nutrient media, the process is repeated the appropriate number of times). All these working steps are relatively time-consuming, susceptible to error and conceal the risk of intermediate contamination which may lead to a false positive test result.  
         [0008]     It is therefore the object of the present invention to improve the known sterility test system in such a manner that it is associated with a reduced risk of error, and that it is more cost-effective in production and in use.  
       SUMMARY OF THE INVENTION  
       [0009]     This object is achieved according to the invention in conjunction with the subject device for sterility testing by the fact that the tube connection of the test container in each case has a distributing component via which a fixed tube connection to an associated nutrient medium container is formed and can be used to feed an associated nutrient medium to the test container.  
         [0010]     Owing to the fact that the nutrient medium containers are integrated in the sterility test system, the risk of error during handling is reduced. The test containers are already connected to the nutrient media containers via distributing components and tube connections, so that a significant improvement in the direction of a completely closed test system is obtained. Furthermore, the test containers can be filled simultaneously and directly with the different nutrient media from the nutrient medium containers, as a result of which the expenditure of time on the sterility test can be reduced overall. Finally, the user does not have to separately order and store the nutrient media—one order number suffices for the entire system—so that outlay on purchasing and storage is reduced.  
         [0011]     According to one preferred embodiment of the invention, the distributing components assigned to the nutrient medium containers are designed as T-components.  
         [0012]     T-components are particularly cost-effective, and, during the production of the sterility test system, can simply be plugged onto the corresponding tube ends in a fluid-tight and sterile manner.  
         [0013]     According to a further preferred embodiment of the invention, a flow-interrupting means is arranged in each case on the tube connection, mounted upstream of the distributing component of the nutrient medium container on the sampling-device side.  
         [0014]     The flow-interrupting means make it possible in a simple manner to release the feed from the sample container and, after a desired sampling quantity has been removed, to block it again in order, for example, then to initiate the feed of nutrient medium.  
         [0015]     According to a further preferred embodiment of the invention, a flow-interrupting means is provided in each case on the tube connection, adjacent to the nutrient medium container, and can be used to empty the nutrient medium container in a specific manner.  
         [0016]     This ensures in a simple manner that the nutrient media only flow in to the tube connections when the test containers are to be filled with the nutrient media.  
         [0017]     The above-mentioned object is also achieved according to the invention in conjunction with the subject device for sterility testing by the fact that a collecting container is connected fixedly to the outlet connecting branches of the test containers, via a distributing component and via tube connections assigned to the distributing component, so that, with the aid of flow-interrupting means arranged on the tube connections, the filtrate can be fed either to the collecting container or to an outlet.  
         [0018]     In contrast to the previous open outlet connecting branches of the test containers, the collecting container which is integrated in the sterility test system provides a simple and sterile possibility of catching the filtered sample fluids. This is advantageous in particular in the case of expensive pharmaceutical products, for example blood derivatives, in order to be able to reuse the filtrates. In addition, the handling of the integrated collecting container is particularly simple. No separate catching containers with sterile closures have to be provided.  
         [0019]     According to one preferred embodiment of the invention, the distributing component assigned to the collecting container is designed as an X-component, in which a flow-interrupting means is arranged on each leg of the X-component.  
         [0020]     The X-shaped distributing component makes it possible in a particularly simple manner to catch the sample filtrate in the collecting container and to conduct the washing filtrate into the outlet.  
         [0021]     According to a further preferred embodiment of the invention, the collecting container is designed as a flexible bag.  
         [0022]     Flexible bags as collecting containers are particularly cost-effective, are available pre-sterilized in any desired size and take up only a small amount of space when packed.  
         [0023]     According to a further preferred embodiment of the invention, the test containers are designed as flexible bodies. These bodies may be formed from a transparent, soft plastic material. The flexible containers may, in particular, be of cylindrical or tent-shaped design. The flexible containers may also be designed as folding bodies.  
         [0024]     Owing to the fact that the test containers are designed as flexible bodies, the size of the packaging and therefore the costs for sales and storage are reduced. The test containers may be produced, for example, from soft PVC or from polymer or polyolefin materials and transported and stored as flat bodies in a collapsed or folded state. When they are being filled, the test containers then take on an extended shape in accordance with their construction and the degree of filling. The production costs are also reduced, since the casting molds for the conventional, different, bottle- or canister-shaped test containers are not needed. In addition, the flexible construction permits, within the rules of the pharmacopeiae, a somewhat larger filter membrane surface than the conventional, rigid containers, as a result of which the filtration duration can be shortened.  
         [0025]     According to a further preferred embodiment of the invention, the nutrient medium containers are designed as flexible bags. The nutrient medium containers may also be designed as chamber-shaped regions in an interconnected container system.  
         [0026]     The use of simple, flexible plastic bags as nutrient medium containers is particularly cost-effective, weight-saving and takes up little packaging space. An interconnected container system makes it possible for the sterility test system to be made even more compact.  
         [0027]     According to a further preferred embodiment of the invention, the tube connections between the distributing components of the nutrient medium containers and the test containers can be held by a peristaltic hose pump.  
         [0028]     The use of a hose pump for conveying the sample fluid, the nutrient fluid and the washing fluid permits a rapid conveying of a predefined quantity of fluid via one or else simultaneously a plurality of tube connections. For this purpose, the distributing components to the nutrient medium bags are arranged in such a manner and the tube lengths to the test containers are configured in such a manner that convenient insertion of the tube, or of the tubes, into the pump head of the peristaltic pump is possible.  
         [0029]     According to a further preferred embodiment of the invention, the hose pump has a clamping position for interrupting the flow in the tube connections.  
         [0030]     With the aid of the clamping position, the flow through the inserted tube can be interrupted. In particular, this enables flow-interrupting means which are mounted on the tube connection, upstream of the distributing component of the nutrient medium container on the sampling-device side to be omitted, which is cost-effective.  
         [0031]     According to a further preferred embodiment of the invention, the sampling device is designed as a cannula device.  
         [0032]     The cannula device permits a simple, sterile taking of samples. It may comprise, for example, a single needle, or a double needle. For taking samples, the needle is simply inserted into the customary plastic bottles or plastic bags having the sample fluid. In addition, a venting cannula may be provided.  
         [0033]     According to a further preferred embodiment of the invention, the flow-interrupting means can be designed as tube clips and/or breakable flow stoppers and/or valves.  
         [0034]     The various flow-interrupting means make it possible to control, on the various tube connections, a feed of the various fluids during the handling of the sterility test system in a manner which is comfortable, effective and cost-effective and adapted to the particular requirements.  
         [0035]     The known methods for sterility testing have the disadvantage of not being optimized in respect of their expenditure in terms of time and costs and with regard to a low risk of error.  
         [0036]     It is therefore a further object of the present invention to improve the known methods for sterility testing in such a manner that they operate more rapidly, cost-effectively and reliably.  
         [0037]     This object is achieved according to the invention in conjunction with the subject method for sterility testing by the fact that the nutrient media are fed simultaneously from nutrient medium containers, which are integrated in the sterility test system via fixed tube connections, to the test containers.  
         [0038]     The simultaneous filling of the test containers from the nutrient medium containers integrated in the sterility system makes it possible to shorten the preparation of the system for incubation purposes, and therefore the overall test time. Intermediate working steps for changing connections between sample container and external nutrient media containers, and the insertion of a cannula into nutrient medium containers are omitted, which saves on time and costs and reduces the risk of external contaminations.  
         [0039]     According to one preferred embodiment of the invention, the filtrate of the samples is fed to a collecting container which is mounted downstream of the test containers and is integrated fixedly in the sterility test system.  
         [0040]     The integration of a collecting container enables an expensive filtrate to be caught in a cost-effective and reliable manner. This further reduces the costs of using the system.  
         [0041]     Further details of the invention emerge from the following detailed description and the attached drawings, in which preferred embodiments of the invention are illustrated by way of example. 
     
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
       [0042]      FIG. 1  shows a schematic overall illustration of a sterility test system.  
         [0043]      FIG. 2  shows the sterility test system in an enlarged cutout during the simultaneous filling of two test containers with two nutrient media.  
         [0044]      FIG. 3  shows a detailed view of the test containers together with a collecting container.  
         [0045]      FIG. 4  shows a detailed view of two foldable test containers: (a) in a collapsed state; and (b) in an unfolded state.  
         [0046]      FIG. 5  shows a flow diagram of a sterility test in five individual illustrations.  
         [0047]      FIG. 6  shows the flow diagram with a filtrate being caught.  
         [0048]      FIG. 7  shows a further design of the test container in a tent-shaped body: (a) in an empty state; and (b) in a partially filled state.  
         [0049]      FIG. 8  shows a further design of the test container as a cylindrical body: (a) in an empty state; and (b) in a partially filled state.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]     A device for sterility testing essentially comprises a sterility test system 1, with integrated nutrient media containers  7 ,  7 ′.  
         [0051]      FIG. 1  illustrates the complete sterility test system  1  in an overview. The system comprises two test containers  2 ,  2 ′ which are connected via two tube connections  3 ,  3 ′ by means of a Y-flow distributor (not illustrated) to a sampling device  4 , advantageously in the form of a piercing cannula. The cannula  4  serves to remove a sample from a sample container (not illustrated). Between the sampling device  4  and the test containers  2 ,  2 ′, a respective distributing component  6 ,  6 ′, advantageously in the form of a T-component, is arranged in the tube connections  3 ,  3 ′. A respective fixed tube connection  5 ,  5 ′ emerges from the distributing components  6 ,  6 ′ and is connected to the nutrient media containers  7  and  7 ′, respectively. The nutrient medium containers  7 ,  7 ′ are assigned flow-interrupting means  25 ,  25 ′, for example a breakable stopper, or a two-way directional control valve, which prevent an unintentional emptying of the containers  7 ,  7 ′ into the tube connections  5 ,  5 ′. Further flow-interrupting means, advantageously two tube clips  8 ,  8 ′ are provided for disconnecting the tube connections  3 ,  3 ′ toward the sample container.  
         [0052]     Referring to  FIG. 2 , the test containers  2 ,  2 ′ can be designed, in a construction which is known per se, as two transparent, cylindrical hard plastic containers which have a slightly conical upward profile with a container upper part  18 ,  18 ′ and a container lower part  19 ,  19 ′. A respective test filter, or a filter membrane  20 ,  20 ′ is fixedly clamped, in accordance with the pharmacopeiae, between the components  18 ,  18 ′ and  19 ,  19 ′. The container lower part  19 ,  19 ′ furthermore has a central outlet connecting branch  21 ,  21 ′ (see  FIG. 3 ) which can be closed by a stopper (not illustrated). The container upper part  18 ,  18 ′ has, on the lid side, an inlet connecting branch  14 ,  14 ′ and a vent with an integrated, microporous air filter  16 ,  16 ′. A tube clip  15 ,  15 ′ may additionally be connected upstream of the inlet connecting branches  14 ,  14 ′. The vent or the air filter  16 ,  16 ′ can be covered with a rubber cap  17 ,  17 ′.  
         [0053]     In one embodiment which is illustrated in  FIG. 4 , the test containers  2 ,  2 ′ are designed as folding bodies, preferably made from a transparent soft plastic.  FIG. 4   a  illustrates the folding bodies in a folded state, and  FIG. 4   b  illustrates them in an expanded state. The folding bodies have a rectangular base area into which the membrane  20 ,  20 ′ is fitted. The inlet connecting branches  14 ,  14 ′ and outlet connecting branches  21 ,  21 ′, and the feedings and removals by the tube connections can be arranged, particularly in a manner saving on construction space, laterally on the bottom parts of the folding bodies, the inlet connecting branch  14 ,  14 ′, of course, being arranged above the test filter  20 ,  20 ′ and the outlet connecting branch  21 ,  21 ′ being arranged below the test filter  20 ,  20 ′. A handle component  24  is formed in each case on the upper lid region for easy handling. Further embodiments of the test containers  2  as tent-shaped bodies, or as cylindrical bodies are shown in  FIGS. 7 and 8 , the containers  2  being illustrated in each case in an empty, collapsed state a) and in a partially filled, expanded state b).  
         [0054]     The double tube  3 ,  3 ′ can be inserted into a pump head (not illustrated) of a peristaltic hose pump  13  in order to convey samples, washing solution and nutrient media. For this purpose, the connecting parts of the double tube  3 ,  3 ′ between the T-components  6 ,  6 ′ and the test containers  2 ,  2 ′ are designed in a length sufficient in order to ensure comfortable and secure handling. The pump head may also have a clamping position for interrupting the flow.  
         [0055]     A collecting container  12 , preferably designed as a flexible, sterile bag, can be connected fixedly to the outlet connecting branches  21 ,  21 ′, as illustrated in  FIG. 3 . The collecting container  12  is fixedly connected to the outlet connecting branches  21 ,  21 ′ via a distributing component  10 , preferably designed as an X-component, and via tube connections  23 ,  23 ′. Tube clips  9 ,  9 ′, and  11 ,  11 ′ are prefitted on each leg of the X-component, advantageously in color-coded form, in order to be able to close and open the tube connections  23  and  23 ′ as required. An outlet  22  which remains free is provided on an open side of the distributing component  10 .  
         [0056]     A method for sterility testing, of pharmaceutical fluids, is essentially based on the fact that nutrient media are simultaneously supplied to test containers  2 ,  2 ′ from nutrient media containers  7 ,  7 ′, which are integrated in a sterility test system  1  via fixed tube connections  5 ,  5 ′.  
         [0057]     The method can advantageously be carried out with the above-described device, as illustrated in the flow diagram in  FIG. 5 .  
         [0058]      FIG. 5-1  shows the sterility test system  1  after removal from the packaging together with the integrated nutrient media containers  7 ,  7 ′, filled with different nutrient media (TSB and thioglycolate), and with the double tube  3 ,  3 ′ inserted into the pump head of the peristaltic hose pump  13 . The tube clips  8 ,  8 ′ and  15 ,  15 ′ are open.  
         [0059]      FIG. 5-2  shows the system during the taking of the sample and the filtration of the sample. The hose pump  13  conveys two identical sampling quantities into the test containers  2 ,  2 ′ where they are filtered by the test filter  20 ,  20 ′. The filtrate runs off via the outlet connecting branches  21 ,  21 ′.  FIG. 5-3  indicates a washing process, in which the containers  2 ,  2 ′ and the membranes  20 ,  20 ′ are cleansed of residues.  FIG. 5-4  shows the simultaneous filling according to the invention of the test containers  2 ,  2 ′ with the nutrient media. In this case, the tube connections  3 ,  3 ′ toward the sampling device  4  are blocked by the tube clips  8 ,  8 ′, and the flow-interrupting means  25 ,  25 ′ are opened, so that, with the aid of the hose pump  13 , the nutrient media containers  7 ,  7 ′ empty simultaneously into the test containers  2 ,  2 ′. Finally,  FIG. 5-5  shows the system prepared for incubation. The tube connections  3 ,  3 ′ are capped, and the free ends are placed onto the openings of the air filters  16 ,  16 ′ and, in addition, the tube clips  15 ,  15 ′ are closed. As a result, the containers  2 ,  2 ′ are hermetically sealed (anaerobic incubation).  
         [0060]     A further flow diagram for illustrating the method together with an integrated collecting container  12  is illustrated in  FIG. 6 . The manner of procedure corresponds to that of  FIG. 5 . However, here the filtrate of the sample is conducted into the collecting container  12  ( FIG. 6-2 ). For this purpose, the clip  11  toward the collecting container  12  is opened and the clip  11 ′ toward the outlet  22  is closed. By contrast, the filtrate of the washing solution is let out via the outlet  22  ( FIG. 6-3 ). Before the test containers  2 ,  2 ′ are filled with the nutrient media, the two clips  9 ,  9 ′ and the clip  11  are closed ( FIG. 64 ). Finally, the collecting container  12  is separated off ( FIG. 6-5 ). The filtrate which has been decanted in sterile form is then available for further utilization. cl List of Reference Numbers  
                                             List of reference numbers                                     1   Sterility test system            2, 2′   Test container            3, 3′   Tube connection            4   Sampling device            5, 5′   Tube connection            6, 6′   Distributing component            7, 7′   Nutrient media container            8, 8′   Flow-interrupting means            9, 9′   Flow-interrupting means           10   Distributing component           11, 11′   Tube clip           12   Collecting container           13   Hose pump           14, 14′   Inlet connecting branch           15, 15′   Flow-interrupting means           16, 16′   Air filter           17, 17′   Covering cap           18, 18′   Container upper part           19, 19′   Container lower part           20, 20′   Test filter           21, 21′   Outlet connecting branch           22   Outlet           23, 23′   Tube connection           24   Handle component           25, 25′   Flow-interrupting means