Abstract:
A pharmaceutical container with an improved peelable seal is provided, wherein the container is may be made of a flexible polymeric film and comprises at least one peelable seal comprising at least two substantially straight sections ( 7, 8 ) which are connected by a rupture zone ( 5 ), characterized in that the. The rupture zone ( 5 ) of the peelable seal is may be curved over its whole length between the straight sections ( 7, 8 ). The container is may be used for storing pharmaceutical substances, solutions for dialysis, solutions for infusion and/or agents for nutrition.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a container for storage of pharmaceutical agents, which has a peelable seal with a curved rupture zone that is easy to open even at high seal strengths. Furthermore, the present invention relates to a method for producing said container and to the use of said container for storing pharmaceutical substances, solutions for dialysis, solutions for infusion and/or agents for nutrition.  
       BACKGROUND OF INVENTION  
       [0002]     Flexible containers from polymer films are widespread for storing pharmaceutical substances solutions for dialysis, solutions for infusion and/or agents for nutrition. For opening filled containers or compartments of said containers, several materials and methods for producing peelable seals (peelable heatsealed welds) have been developed. In contrast to permanent welded seals, peelable seals can be ruptured by tensile force or by pressing on an adjacent container chamber that is filled with a liquid. It should be guaranteed to open the seal without damages at the container material or leakage. The peelable seal strength should be high enough for production and transport and still low enough to easily open the bag.  
         [0003]     In order to simplify the opening of peelable seals, such seals have been provided with so-called rupture zones, whereby the opening force is locally reduced and the manual opening of the peelable seals is facilitated. Such seal can readily be opened by different handling techniques.  
         [0004]     European patent document EP 0 700 280 concerns a multi-layer polymer film for a multi-chamber medical bag for preparation of mixed medical solutions, which has at least two chambers which are separated from each other by a peelable seal. European patent document EP 0 700 280 suggests a V-shaped rupture zone. In this case, the seal opens first at the point of the V since there is created the highest force on the seal.  
         [0005]     European patent document EP 0 893 982/International Publication Number WO97037628 relates to flexible polymeric containers with an improved long term storage capacity for parenterally administered medical fluids. The container comprises an outer sealed airtight envelope and an inner container filled with one or several medical agents. The inner container comprises peelable seals having rupture zones. The rupture zones of the peelable seals are V-shaped and, therefore, comprise a point where two straight seams meet in an angle. A small or sharp angle will be easy to rupture by the user, but it will at the same time create a risk for unintentional opening when handling the container. In contrast, a very large angle will provide a seam that is difficult to open. Therefore, European patent document EP 0 893 982 suggests an angle of the seals in the rupture zone of 120° to 140°.  
         [0006]     A first preferred opening procedure mentioned in European patent document EP 0 893 982 is to gently roll up the container from the upper side and thereby make use of the volume of the largest chamber to exert a pressure large enough to rupture the seal in its weakest point and peel apart the seam towards the sides of the container. This technique is designated as the rolling method. Another preferred way of opening the seal is to pull the front and the rear walls of the inner container apart from one another by a careful pulling motion so a rupture is formed in the weakest spot of the seal which thereby may be easy to peel apart. This technique is designated as the pulling method.  
         [0007]     The document further describes a rupture zone having two straight seams meeting in a region formed as a curved part. The rupture zone still comprises straight sections.  
         [0008]     The two most common complaints concerning medical containers with a peelable seal are: (1) peelable seals are already opened at arrival to customer and (2) a film failure when opening peelable seals.  
         [0009]     There is always a balance between the demands to have a peelable seal that is strong enough to withstand the manufacturing process and is easy to open for the customer. Flexible containers with peelable seals of low seal strength, e.g. 5 to 10 N/30 mm, can be readily opened, but seals of low strength can be damaged during manufacturing and transport.  
         [0010]     For this reason, it is advantageous to manufacture peelable seals with a seal strength at least 30 N/30 mm, and better 40 N/30 mm. However, the inventors have found that the polymeric film is frequently torn when the peelable seal with a V-shape as disclosed in European patent document EP 0 893 982 and a strength of at least 30 N/30 mm is opened by the pulling method, resulting in leakages in the bag. This problem might be avoided by using the rolling method, which should allow a more controlled opening by applying a more even pressure on the weak seal.  
         [0011]     The inventors have, however, found that the V-shaped rupture zone according to EP 0 893 982 shows a relatively high resistance against manual opening of the seals by the rolling method when the seal strength is equal or higher than 30 N/30 mm.  
         [0012]     High resistance against opening means that a higher burst pressure registered inside the liquid-filled bag is required for opening the seal. It is a major drawback for the applicant in daily routine when a relatively high burst pressure is required for opening peelable seals. Thereby, the handling of the bag is impaired. By applying a high burst pressure the seal opens rapidly in one step instead of opening at first in the rupture zone and peels slowly apart towards the sides of the container in a second step.  
         [0013]     When a container with three chambers is used which are filled with different solutions, a sudden and fast opening of peelable seals is undesirable, because it is not possible to control which seal is opened at first. Even though the bag-design is the most important point for a controlled mixing order of the chambers contents, an uncontrolled opening of the seals as mentioned above might also result in a uncontrolled mixing of the bag contents.  
         [0014]     In order to reach a controlled opening of the peelable seals, it is desired that the rupture zone opens in a first step and in a second step the remaining part of the peelable seal. Experiments of the inventors have shown that this can hardly be reached with conventional V-shaped seals, especially when V-shaped seals are hardly to open due to high seal strengths of at least 40 N/30 mm.  
       SUMMARY OF THE INVENTION  
       [0015]     An object of the present invention is to provide a container with a peelable seal that can be readily opened without the danger of destroying the container. In particularly, it is an object of the present invention is to provide a flexible container with a well functioning peelable seal design, wherein 
        the seal should be easy to open when the seal strength is ≦40 N/30 mm;     the seal should not open by slight pressure on the bag that occurs during storage and transport;     the seal should not open rapidly and in one step, the seal may open in two steps—first the rupture zone and then the remaining part; and     the seal should open by rolling as long as the seal is peelable—in this case, the seal should easily open up to seal strengths of 40 N/30 mm.        
 
         [0020]     The above mentioned objects may be attained by a container made of a flexible polymeric film comprising at least one peelable seal having at least two substantially straight sections which are connected by a rupture zone, wherein the rupture zone of the peelable seal is curved over its whole length between the straight sections.  
         [0021]     The one or more rupture zones of the peelable seal connect substantially straight sections of the peelable seal. Substantially straight means that said sections can either be absolutely straight or minimally bent with respect to the dimensions of the container. Preferably, the sections that are connected by the curved rupture zone are absolutely straight.  
         [0022]     A peelable seal according to the present invention can contain more than one rupture zones and more than two straight sections. However, it is preferred that it contains two straight sections that are connected by one rupture zone. In the latter case, the rupture zone is in a specific preferred embodiment located on half of the length of the peelable seal, resulting in two straight sections of equal length.  
         [0023]     The rupture zone of the peelable seal is curved over its whole length between the straight sections. The term curved means that there are neither straight sections nor any kinks or angles within the rupture zone. A curved shape according to the present invention comprises circular shapes, S-shapes and ellipsoidal shapes and irregular curved shapes, wherein circular and ellipsoidal shape mean that the curved rupture zone is formed as an arc of a circle or an arc of an ellipse. It is to be understood in this connection that the terms “arc of an circle” or “arc of an ellipse” are equivalent to a segment of a circle or segment of an ellipse.  
         [0024]     In an embodiment of the invention, the curved rupture zone of the seal is formed as an arc of a circle with a radius of 5 to 75 mm, more preferably 10 to 30 mm and most preferably 20 to 25 mm, wherein the radius is measured from the centre of the circle to a point on the outer edge of the seal, wherein the outer edge is the edge that is more dislodged from the central point of the circle than the inner edge.  
         [0025]     When the curved rupture zone is formed as an arc of a circle, said arc has preferably a central angle of at least 60°, more preferably 60° to 180°, especially 90° to 150°.  
         [0026]     It is also advantageous that the rupture zone is S-shaped, wherein a preferred S-shape is made up of two connected half circles with a radius of 5 to 75 mm, more preferably 10 to 30 mm and most preferably 20 to 25 mm. The radius is again measured from the centre of the circle to an outer edge of the seal.  
         [0027]     The straight sections of the peelable seal can enclose an angle or the sections can be parallel to each other or in line with each other. When the straight sections form an angle, such angle is preferably from 120° to 180° and more preferably from 150° to 180°.  
         [0028]     When the straight sections are parallel to each other, the distance (dislocation) between the straight parallel sections is preferably from 10 to 60 mm, more preferably 15 to 40 mm and most preferably 20 to 35 mm.  
         [0029]     In an embodiment of the invention, the curved rupture zone is formed as an arc of a circle with a central angle of 90° and the straight sections are parallel to each other.  
         [0030]     The width of the seal can vary between the straight sections and the rupture zone. In absolute values the seal width of the straight sections is preferably from 2 to 10 mm, more preferably from 5 to 8 mm, and the seal width of the rupture zone is from 2 to 10 mm, preferably from 5 to 8 mm. The width of the straight sections may be different than the width of the rupture zone. Preferably, however, the seal width of the straight sections and the seal width of the rupture zone are the same.  
         [0031]     The rupture zone is preferably positioned in the middle of the seal, so it can be successively opened from the middle towards the sides, since this may enable a highly reproducible opening procedure by the user from the outside of the bag. The rupture zone typically has a length of less than half the entire seal, preferably less or equal than about 40% of the seal and more preferably less than about 30% of the seal length. In a more preferred embodiment of the present invention, the length of the rupture zone amounts to 3 to 10 %, more preferably 5 to 7% of the length of the peelable seal. But it can also be advantageous when length of the rupture zone is 7 to 13%. In absolute values, the length of the rupture zone is preferably 20 to 40 mm.  
         [0032]     In an embodiment of the invention, the container is made of a flexible polymeric film having a region with a higher melt point designated as its outside and having a region with lower melt point designated as its sealing inside which can be sealed together by means of conventional welding tools to permanent or peelable seals. It is to be understood that the inner region is intended to face the stored agent or agents and can form both permanent seals and different peelable seals when subjected to different welding conditions or operations.  
         [0033]     The film may be made of at least two different polymer layers wherein the inside layer is a sealant layer that is capable of forming both permanent seals and peelable seals when subjected to welding at different temperatures.  
         [0034]     A preferred multilayer polymer material for the manufacture of a container according to the present invention is described in European patent document EP 0 739 713 and known under the trademark Biofine™.  
         [0035]     Another multilayer polymer material can have the following structure:  
         [0036]     The inner sealant layer is preferably based on polyolefins, such as polyethylenes or polypropylenes of various qualities which are chemically inert to the stored fluids, autoclavable, weldable and possible to recycle. The terms “polyethylenes” and “polypropylenes” are intended to include both homopolymers and copolymers having such mentioned characteristics unless otherwise is specified. Preferably, the sealant layer is based on a polyethylene homopolymer, a polyethylene copolymer, a polypropylene homopolymer, a polypropylene copolymer a polyethylene-polypropylene-copolymer and/or a mixture of polypropylene with polyethylene.  
         [0037]     It is preferred for the inner, sealant layer to comprise a high amount of polyolefin, especially polypropylene, in order to benefit from its capacity of being inert towards the stored fluids and for facilitating the manufacturing of a container by means of different welding techniques. It is especially preferred that this layer can form both leaktight, but controllably rupturable, peelable seals at a predetermined temperature and permanent highly consistent seals when welding it together with different conditions such as different welding temperatures or welding pressures.  
         [0038]     However, since many conventional polyolefins, in particular polypropylenes, often have an insufficient flexibility and a certain brittleness, it is desirable to combine them with a polymer having an elastic property. In an embodiment according to the present invention, it is therefore preferred to combine the polyolefin of the sealant layer with a supplementary elastomer to improve its flexibility and resilience.  
         [0039]     The thermoplastic elastomer that may be compounded with the polyolefin in the inner sealant layer is preferably selected from the group comprising a styrene-ethylene/butylene-styrene-triblock polymer (SEBS), a styrene-ethylene/propylene-styrene-triblock polymer (SEPS), a styrene-butadiene-styrene-triblockpolymer (SBS), and/or a styrene-isoprene-styrene triblock polymer (SIS).  
         [0040]     The outer layer preferably comprises a flexible polymeric material with a high melting point that provides the material with an improved stability at the high temperatures locally reached during the welding. Suitable materials can be found among certain polyesters and copolymers thereof (copolyesters) and in particular cycloaliphatic polyesters.  
         [0041]     There may be at least one interior layer between the outer layer and the inner sealant layer comprising an thermoplastic elastomer.  
         [0042]     Another material that is suitable for the type of containers according to the present invention is Excel™ from McGaw Inc., a multilayered polymeric material of about 200 micrometer thickness which is described in the European patent document EP 0 228 819. Excel™ has a multilayered structure substantially comprising: 
        a) an inner, sealant layer facing the medical fluid consisting of a mixture of a polyethylene/polypropylene copolymer (FINA Dypro Z 9450) and KratonB G1652 from Shell (a styrene/ethylene/butadiene/styrene (SEBS) copolymer);     b) a middle, tie layer of pureKratonB G1652; and     c) an outer, release layer of Ecdel™ B 9965 (or 9566 or 9967) from Eastman Chemical Co, which is a cycloaliphatic thermoplastic copolyester (a copoly(ester ether), a condensation product of the trans isomer of 1,4-dimethyl-cyclohexanedicarboxylate, of cyclohexanedimethanol and hydroxyterminated polytetramethylene glycol).        
 
         [0046]     Other types of multilayered polymeric films, such as those described above may also be used in the present invention. Such other types of multilayered polymeric films may be made of at least two different polymer layers, wherein the inside layer is a sealant layer that is capable of forming both permanent seals and peelable seals are described in European patent document EP 0 893 982, European patent document EP 0 700 280 and International Publication Number WO 01/42009, as well as methods for their production and methods for welding peelable seals.  
         [0047]     The container or bag with peelable seals as described before may be enclosed in an overpouch with a high oxygen barrier. The overpouch film may be a multi-layer structure including PET, a thin glass coating and polypropylene. Suitable overpouches are for example described in European patent document EP 0 893 982. An oxygen absorber may be placed between the container and the overpouch.  
         [0048]     An embodiment of the present invention provides a method for forming the inventive container and a method for forming the above described peelable seal. Generally, hot bar heat sealing or impulse heat sealing processes may be used for producing permanent and peelable seals according to the present invention.  
         [0049]     Suitable peelable seal welding temperatures for the above mentioned Biofine™ films are in the range of 122 to 130° C. Such seals are suitably leaktight after being subjected to conventional mechanical package tests and are objectively easy to open. They are also suitably leaktight after the container has been subjected to steam sterilization. Suitable welding temperatures for forming permanent seals with Biofine™ film are in the range of 130 to 160° C.  
         [0050]     When Excel™ is used as multilayer film material for the manufacture of containers, the temperature for welding peelable seals is 113 to 120° C. and the temperature for welding permanent seals is 130 to 160° C.  
         [0051]     In an embodiment of the present invention, the container, as described above, may be used for storing pharmaceutical substances, solutions for dialysis, solutions for infusion and/or agents for nutrition. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0052]      FIG. 1  schematically illustrates a plan view of a first type of container according to the present invention.  
         [0053]      FIG. 2  schematically illustrates a plan view of a second type of container according to the present invention.  
         [0054]      FIG. 3  schematically illustrates a plan view of a third type of container according to the present invention.  
         [0055]      FIG. 4  illustrates a straight peelable seal according to the prior art.  
         [0056]      FIG. 5  illustrates a seal with a V-shaped rupture zone according to the prior art.  
         [0057]      FIG. 6  illustrates a first preferred embodiment of a seal with a rupture zone according to the present invention.  
         [0058]      FIG. 7  illustrates a second preferred embodiment of a seal with a rupture zone according to the present invention.  
         [0059]      FIG. 8  illustrates a third preferred embodiment of a seal with a rupture zone according to the present invention.  
         [0060]      FIG. 9  illustrates a fourth preferred embodiment of a seal with a rupture zone according to the present invention.  
         [0061]      FIG. 10  is an illustration of sampling that shows peelable seal-positions W 1 , T 1 , F 1 , W 2 , T 2 , F 2  for tensile testing with a container according to  FIG. 3  (see Example 1).  
         [0062]      FIG. 11  is an illustration of sampling that shows peelable seal-positions S 1 , S 2 , S 4  and S 4  for tensile testing with a container according to  FIG. 1  (see Example 2). 
     
    
     DETAILED DESCRIPTION  
       [0063]     In the following, embodiment examples of the apparatus and method in accordance with the invention are explained in more detail by reference to the drawings.  
         [0064]     Referring now to  FIG. 1 , a first container according to the present invention is illustrated. The container includes a first chamber  20 , a second chamber  21 , and a third chamber  22 . The three chambers are filled with three different parenterally administerable nutrients in fluid form which, just before their administration to the patient, shall be homogeneously mixed together to form a total parenteral nutrition (TPN) solution. In this embodiment, the first chamber  20  is filled with carbohydrates containing aqueous solution, i.e. glucose, the second chamber  21  is filled with amino acid and/or electrolytes containing aqueous solution and the third chamber  22  with lipid emulsion, i.e. the fat component. It should be noted that although three chambers are present in the embodiment, more chambers can be used. It should also be noted that the contents of the three chambers might vary and that other alternative contents are possible as well. It is according to the invention possible to change the assignment of said ingredients to said chambers. That is, any of the ingredients can be filled in any of the chambers. In another embodiment chamber  22  contains amino acid solution and chamber  21  contains lipid emulsion. Moreover, electrolytes can also be contained in the carbohydrates containing aqueous solution.  
         [0065]     The flexible container is preferably formed from a blown film of 280 or 320 mm width such that only the upper border zone and the lower border zone are sealed together. The upper border zone  23  has a suspension arrangement  24  in the form of an opening so that the container may be hung for bedside administration of the ingredient mixture. The lower border zone  25  has an administration port system  26  for dispensing the medical mixed fluid and introducing supplementary agents according to the patient&#39;s requirements.  
         [0066]     The administration port system  26  comprises three ports inserted into the lower border zone  25  of the container. All ports can be used for filling the chambers. Moreover, port  26   a  is also provided as an additive injection port for injecting compatible additives directly into the chamber/chambers using a needle or syringe under aseptic conditions. Port  26   b  is also provided as an infusion port for administration of the product to the patient. Port  26   c  is in this preferred embodiment closed with a cap after filling the chamber.  
         [0067]     Which type of port that should be connected to the different chambers depends on the arrangement of the departments. In the specific embodiment, port  26   a  is inserted into the lower border zone below the second chamber  21 , port  26   b  below the first chamber  20 , and port  26   c  below the third chamber  22 . In another preferred embodiment, the additive port  26   a  is below third chamber  22 . Ports belong to the prior art and are described, e.g. in European patent document EP-A-0 811 560.  
         [0068]     The container is made of a multi-layer polypropylene-based film, e.g. as described in European patent document EP-A-0 228 819 or European patent document EP-A-0 739 713 (Biofine™) that can form both peelable seals and permanent seals using hot bar heat sealing or impulse heat sealing process.  
         [0069]     The container as a primary bag is enclosed in an overpouch with high oxygen barrier. The overpouch film is a multi-layer structure including PET, a thin glass coating and polypropylene. The thin glass coating provides the oxygen barrier properties. An oxygen absorber is placed between the primary and secondary bags.  
         [0070]     The first chamber  20  has a larger volume than the second and third chambers  21 ,  22 , respectively. The first chamber  20  is arranged in the horizontal upper portion as well as in the vertical right side portion of the container, the upper portion extending about ⅓ of the total length between the upper and lower border zones and the right side portion extending about ⅓ of the total width of the container between the right and left border zones. The second chamber  21  is arranged in the vertical middle portion of the container below the upper part of the first chamber, the middle portion extending about ⅓ of the total width of the container. The third chamber  22  is arranged in the vertical left side portion of the container below the upper part of the first chamber, the left side portion extending about ⅓ of the total width of the container.  
         [0071]     The three chambers of the container are separated by three highly leaktight welded seams, The first chamber  20  is separated from the second chamber  21  by a first leaktight seam  27  (seal  1 ), the second chamber  21  is separated from the third chamber  22  by a second leaktight seam  28  (seal  2 ) and the first chamber  20  is separated from the third chamber  22  by a third leaktight seam  29 .  
         [0072]     The first seam  27  bas a horizontal extending portion  27   a  as well as a vertical extending portion  27   b,  whereas the second seam  28  has a vertical extending portion and the third seam  29  has a horizontal extending portion only. The first, second and third seams have a common upper end  30 .  
         [0073]     In the embodiment, beginning from the left border zone  31  the horizontal third seam  29  extends about ⅓ of the width of the container at about ⅓ of the length of the container between the first and third chambers. Beginning from the end of the third seam  29  the second seam  28  extends in vertical direction to the lower border zone  25  of the container separating the second and third chambers. Also beginning from the end of the third seam  29  the horizontal portion  27   a  of the first seam  27  extends about ⅓ of the width of the container at about ⅓ of the length of the container, and the vertical portion  27   b  of the first seam extends from the end of the horizontal portion in vertical direction to the lower border zone  25  separating the first and second chambers.  
         [0074]     The first and second seams are formed as peelable seals comprising rupture zones  32 ,  33 . The third seam  29  is preferably also formed as a peelable seal, wherein it has an opening strength that is equal to or higher than the opening strength of the first and second seals, respectively. Seam  29  might, however, also be formed as a permanent seal.  
         [0075]     In the specific embodiment, the first peelable seal  27  comprises a first rupture zone  32  zone and the second peelable seal  28  comprises a second rupture zone  33  to avoid ripping the film when opening the seals. The curved opening zones are formed such that the seals slowly open in two steps, i.e. in a first step at the opening zone and in a second step at their other portions.  
         [0076]     The transition zone  34  between the horizontal and vertical portions  27   a,    27   b  of the first seam  27  is also formed as a rupture zone  34 , but the transition rupture zone has preferably a larger radius of curvature than the other rupture zone  32  of the first peelable seal  27 . A larger radius results generally in a higher opening force of the peelable seal, so that generally rupture zone  32  opens before rupture zone  34 . The function of the bag is, however, not affected if rupture zone  34  opens before zone  32  as long as seal  27   b  opens all the way to the bottom of the bag before rupture zone  33  opens.  
         [0077]     The rupture zones of both seals can be arranged anywhere from the lower border zone up to the fluid level. A preferred placement is at least 50 mm above the border zone  25  (bottom seal) and at least 50 mm below the fluid level of a mixed bag. The optimal placement of the rupture zone is, however, approximately halfway between the lower border zone and the fluid level.  
         [0078]     The flexible container according to the invention is easy to handle in a controlled manner. In order to mix the solutions for preparation of the parenteral fluid, the container is rolled up from the upper border zone  23  towards the lower border zone  25 . By rolling the container up fluid pressure is building up in the chambers. When the pressure is high enough the first peelable seal  27  opens at the rupture zone  32 , i.e. the zone with the smallest radius. By further rolling the container up the fluid pressure further increases and the other portions of the first peelable seal  27  continue to open starting from the rupture zone  32  in both directions. The seal opens down to the lower border zone and up to the fluid level. When the fluid level is reached there is no more pressure on the seal and the seal will not further open. After opening the first seal  27  the second seal  28  is opened at the rupture zone  33 . In the same way as for the first seal, the seal opening of the second seal propagates up and down. Therefore, the first and second solutions of the first and second chambers  20 ,  21 , respectively, are mixed in a first step, and the mixture of the first and second solutions and the third solution are mixed in a second step. This is guaranteed by having preferably higher weak seal strength for the third seal with respect to the second and first seal, respectively. If, nevertheless, the third and first seals would have the same seal strength, the curved opening zone of the first seal guarantees the opening of the first seal before the second seal will open.  
         [0079]     Even if the horizontal portions of the seals would have a lower seal strength as the vertical portions, the transition rupture zone  34  of the first seal guarantees the opening of the first seal  27  before the second seal  28 .  
         [0080]      FIG. 2  shows another container, according to the present invention, with peelable seals. The container includes a first chamber  36 , a second chamber  37  and a third chamber  38 , which are separated from each other by leaktight seams  40  and  41 . The first chamber is designated to be filled with a first solution, the second chamber is designated to be filled with a second solution and the third chamber is designated to be filled with a third solution. The first chamber  36  is separated from the second and third chambers  37 ,  38  by a first leaktight seam  40 . The second and third chambers are separated from each other by a second leaktight seam  41 , wherein both seams  40 ,  41  have an intersection  43 . In the embodiment of  FIG. 2 , seams  40  and  41  are perpendicular to each other and form a “T”.  
         [0081]     At least a part of the first seam  40  is provided with a rupture zone  39  according to the present invention, which was described in detail before and which can be opened for fluid communication between the first and at least one of the second or third chambers. The whole leaktight seam  40  might also be formed as a separation zone.  
         [0082]     The first chamber  36  has preferably a larger volume than the second and third chambers  37 ,  38 , respectively. The first chamber  36  is preferably arranged in the horizontal upper of the container, the upper portion extending about the total width of the container between the right and left border zones  31   a  and  31   b.  In the embodiment of  FIG. 2 , the volume of the first chamber  36  is about the half of the volume of the whole container. A peelable seal  40  with a rupture zone  39  extends horizontally between the border zones  31   a  and  31   b,  and in nearly equal distance to the upper border zone  23  and to the lower border zone  25 , thereby dividing the container in two halves and separating first chamber  36  from the second and third chambers  37 ,  38 .  
         [0083]     The second and third chamber  37 ,  38  are located in the lower half of the container and separated by a peelable seal  41 , which is perpendicular to seal  40  and extends vertically between the peelable seal  40  and the lower border zone  25 . Seal  41  might be located in such a way that chambers  37  and  38  have the same volume. In the embodiment shown in  FIG. 2 , however, second chamber  37  has a larger volume than third chamber  38 .  
         [0084]     The peelable seal  40  comprises a rupture zone  39  to avoid ripping the film when opening the seal. The rupture zone  39  is in the preferred embodiment of  FIG. 2  arranged between chambers  36  and  37 . A preferred placement is at least 50 mm away from the border zones  31   a  and  31   b.  When first chamber  36  is filled with electrolytes and/or carbohydrate containing aqueous solution, i.e. glucose, the second chamber  37  is filled with amino acid containing aqueous solution and the third chamber  38  with lipid emulsion, the rupture zone is preferably located between chambers  36  and  37 , as shown in  FIG. 2 .  
         [0085]     The three chambers are filled with three different parenterally administerable nutrients in fluid form which, just before their administration to the patient, are homogeneously mixed together to form a total parenteral nutrition (TPN) solution. In the embodiment, the first chamber  36  is filled with carbohydrates containing aqueous solution, i.e. glucose, the second chamber  37  is filled with electrolytes and/or amino acid containing aqueous solution and the third chamber  38  with lipid emulsion, i.e. the fat component. It should be noted that although three chambers are present in the embodiment, more chambers can be used. It should also be noted that the contents of the three chambers might vary and that other alternative contents are possible as well. It is according to the invention possible to change the assignment of said ingredients to said chambers. That is, any of the ingredients can be filled in any of the chambers. Moreover, electrolytes may also be contained in the carbohydrates containing aqueous solution.  
         [0086]     The flexible container, in the embodiment of  FIG. 2 , is formed from a blown film such that only the upper border zone and the lower border zone are sealed together. The upper border zone  23  has a suspension arrangement  24  in the form of an opening so that the container may be hung for bedside administration of the ingredient mixture. The chambers  36 ,  37  and  38  are each provided with one port ( 42   a,    42   b,    42   c ), wherein the ports are located in the upper and lower border zone  23 ,  25 , respectively. The ports  42   a,    42   b,    42   c  serve for filling the bag, dispensing the medical mixed fluid and/or introducing supplementary agents according to the patient&#39;s requirements.  
         [0087]     In the embodiment of  FIG. 2 , part  42   a  is provided for filling, port  42   b  is provided for administration of the bag content to a patient and port  42   c  is an additive port for injecting additives into the bag. Which type of port that should be connected to the different chambers depends on the arrangement of the departments. Ports belong to the prior art and are described, e.g. in European patent document EP-A-0 811 560.  
         [0088]     Both leaktight seams are formed as peelable seals. According to the invention, the leaktight seams are arranged and the rupture zone are formed such that, in use of the container for preparation of the medical mixed solution, first seam  40  and the second seam  41 , which are formed as peelable seals, open in a sequential order, wherein the opening starts at the rupture zone of the first seam  40 . Thereby, the ingredients of the chambers are mixed one after another.  
         [0089]     According to the embodiment shown in  FIG. 2 , the leaktight seams  40 ,  41  are arranged and the rupture zone  39  is formed such that, in use of the container, for preparation of the medical mixed solution the rupture zone is opened by exerting pressure on the container beginning from the upper portion down to the lower portion of the container. According to a further embodiment, the rupture zone  39  and the seams  40 ,  41  are peelable seals to be opened by rolling up the container.  
         [0090]     By rolling the container from the upper portion down fluid pressure builds up in the first chamber. When the pressure is high enough peelable seals  40 ,  41  open one after the other so that the fluids are mixed. The arrangement of the peelable seals according to invention allows a controlled mixing and the problem of damage of the container is reduced.  
         [0091]     The flexible container, according to the embodiment shown in  FIG. 2 , is easy to handle in a controlled manner. In order to mix the solutions for preparation of the parenteral fluid, the container is rolled up from the upper border zone  23  towards the lower border zone  25 . By rolling the container up, fluid pressure is built up in the chambers. When the pressure is high enough, the peelable seal  40  starts to open at the rupture zone  39 , i.e. the zone with the smallest radius. Seal  40  continues to open in direction of the border zone  31   a  and in direction of the intersection with seal  41 . Secondly, the intersection between seal  40  and  41  opens and the opening propagates in direction of the lower border zone  25 . A part of seal  40  between seal  41  and seal  31   b  may remain unopened even though it is peelable.  
         [0092]     As a result, the contents of chambers  36  and  37 , which are preferably electrolytes and/or carbohydrate containing aqueous solution and amino acid containing aqueous solution, mix in the first step and chamber  38 , which preferably contains lipid emulsion, remains closed. In the second step, when the intersection between seal  40  and  41  opens, the third chamber  38  is also opened. Therefore, the first and second solutions of the first and second chambers  36 ,  37 , respectively, are mixed in a first step, and the mixture of the first and second solutions and the third solution in chamber  38  are mixed in a second step.  
         [0093]     In principle, all of the polymeric film materials previously described (e.g. Excel), can be used. The container according to  FIG. 2  is made of a multi-layer polypropylene-based film, e.g., as described in European patent document EP-A-0 228 819 or European patent document EP-A-0 739 713 (Biofine™) that can form both peelable seals and permanent seals using hot bar heat sealing or impulse heat sealing process.  
         [0094]     The container as a primary bag is enclosed in an overpouch with high oxygen barrier. The overpouch film is a multi-layer structure including PET, a thin glass coating and polypropylene. The thin glass coating provides the oxygen barrier properties. An oxygen absorber is placed between the primary and secondary bags.  
         [0095]      FIG. 3  shows another container, according to the present invention, with peelable seals. All reference symbols in  FIG. 3  have the same meaning as in  FIG. 2 . The container is separated into three chambers  36 ,  37 ,  38 , by two peelable seals  40  with rupture zones  39 . The peelable seals both extend horizontally between the border zones  31   a  and  31   b.  All three chambers also extend between the border zones  31   a  and  31   b  and they are arranged one upon the other. By rolling the container from the from the upper border zone  23  towards the lower border zone  25 , fluid pressure is built up in chamber  36 . When the pressure is high enough, the upper peelable seal  41  between chamber  36  and  37  opens at the rupture zone  39  and the contents of both chambers can mix in a first step. By further rolling, the lower peelable seal that separates chamber  38  is also opened, and the mixture of the first and second solutions and the third solution in chamber  38  are mixed in a second step.  
         [0096]      FIG. 4  shows a straight peelable seal according to the state of the art which has no rupture zone (seal type A). The seal width  14  is 20 mm.  
         [0097]      FIG. 5  shows a peelable seal with two straight sections  7 ,  8  and a V-shaped rupture zone  5  according to the state of the art (seal type B). The seal width  14  is 5 mm, the width of the rupture zone  17  is 150 mm and the height  9  of the rupture zone is 30 mm. Reference symbol  13  stands for the total length of the seal.  
         [0098]      FIG. 6  shows, in detail, a shape of a peelable seal according to the present invention (seal type C) with two straight sections  7 ,  8  and a rupture zone  5 . The seal width  14  is 7 mm and the radius  15  is 90 mm. The width of the rupture zone  17  is 145 mm and the height of the rupture zone  9  is 43 mm.  
         [0099]      FIG. 7  shows another shape of a peelable seal (seal type D) according to the present invention, wherein the rupture zone  5  is formed as an arc of a circle with a central angle  18  of 145°. The radius  15  is 20 mm. The straight sections  7 ,  8  are located parallel to each other with a dislocation  16  of 15 mm. The seal width  14  is 7 mm. Reference symbol  13  stands for the total length of the seal.  
         [0100]      FIG. 8  shows another shape of a peelable according to the present invention (seal type E) with rupture zone  5  that is S-shaped between end points  6   a  and  6   b.  The S-shaped rupture zone is formed from two half circles with a radius  15  of 15 mm. The straight sections of the seal  7 ,  8  are located parallel to each other with a dislocation  16  of 60 mm. The seal width  14  is 7 mm. Reference symbol  13  stands for the total length of the seal.  
         [0101]      FIG. 9  shows another shape of a peelable seal (seal type F) according to the present invention, wherein the rupture zone  5  is formed as an arc of a circle with a central angle  18  of 90°. The radius  15  is 20 mm. The straight sections  7 ,  8  are located parallel to each other with a dislocation  16  of 20 mm. The seal width  14  is 7 mm. Reference symbol  13  stands for the total length of the seal.  
       EXAMPLES  
       [0102]     In the following examples the invention is illustrated wherein it is to be understood that these examples do not limit the scope and idea of the invention.  
       Example 1  
       [0103]     A) General Procedure for Forming a Container According to  FIG. 3   
         [0104]     Containers as shown in  FIG. 3  were manufactured from a cast, polyolefin-based film (Excel). The peelable seals were welded at different temperatures from 113-120° C. to achieve different weld strengths, 3 seconds and 4 bar.  
         [0105]     Permanent seals were welded at 130° C., 1.5 seconds and 4 bar. Welding was performed with the hot bar technique.  
         [0106]     B) Performed Tests  
         [0107]     Bags according to  FIG. 3  have been manufactured according to the above procedure with different shapes of peelable seals shown in FIGS.  4  to  8 . Three different peelable seal strengths were used that were about 10 N, 20 N and 30 N. Every sample group contained 20 bags. 10 bags were filled with water and seven of these were overwrapped and sterilised with a water spray autoclave cycle (F 0 =12, temperature 121° C.). The following tests have been performed on each sample group.  
         [0108]     Tensile Test:  
         [0109]     Tensile test was performed on 30 mm wide strips using an Instron tensile tester. Test strips were taken from position F 1 , T 1 , W 1  and F 2 , T 2 , W 2  (see  FIG. 10  for positions). Initial grip separation was set to 50 mm. Test speed was set to 500 mm/min. Maximum force was measured.  
         [0110]     Non sterilised bags: The seal strength was measured on 5 bags.  
         [0111]     Sterilised bags: The seal strength was measured on 2 bags.  
         [0112]     Burst Test:  
         [0113]     Restrain plates with an opening of 50 millimetre have been used. The pressure has been registered directly inside the bag using a pressure sensor. Incoming pressure has been set to 0.3 bar. The weak seals were opened in peak direction, i.e., seal  1  was opened before seal  2 .  
         [0114]     Non sterilised bags: Burst test has been performed on 5 bags.  
         [0115]     Sterilised bags: Burst test has been performed on 2 bags.  
         [0116]     Manual Opening of Bags  
         [0117]     The peelable seals are manually opened by the roll method. The degree of difficulty was rated 1 to 5 according to below definition.  
         [0118]     1=Very easy  
         [0119]     2=Easy  
         [0120]     3=Some resistance but no problem to open  
         [0121]     4=High resistance but possible to open with big effort  
         [0122]     5=Not possible to open  
         [0123]     Non sterilised bags: Manual opening was performed on 3 bags.  
         [0124]     Sterilised bags: Manual opening was performed on 3 bags.  
         [0125]     C) Test Results for Different Seal Designs  
         [0126]     The tests were performed on bags with different seal shapes A to E as shown in  FIGS. 4-8 . Seal shapes C to E were inventive examples and shape A was a straight seal reference and shape B was a reference example according to the state of the art of European patent document EP 0 893 982.  
         [0127]     Seal Shape A ( FIG. 4 —Reference Example)  
         [0128]     In the table below the total average value for seal strength, measured at 6 positions, is noted.  
                                           Seal strength of   Seal strength of           non-autoclaved   autoclaved bags       Sample ID   bags (N/30 mm)   (N/30 mm)                   10 N   11   43       20 N   16   42       30 N   27   43                  
 
         [0129]     In the table below the average values for the burst test is noted.  
                                                                                                       Burst value of       Burst value of               non-autoclaved       autoclaved bags           bags (bar)       (bar)            Sample ID   Seal 1   Seal 2   Seal 1   Seal 2                    10 N   0.13   0.12   0.44   0.44       20 N   0.20   0.18   &gt;0.55   &gt;0.55       30 N   0.30   0.28   &gt;0.55   &gt;0.55                  
 
         [0130]     Seal Shape B ( FIG. 5 —Reference Example)  
         [0131]     In the table below the total average value for seal strength, measured at 6 positions, is noted.  
                                           Seal strength of   Seal strength of           non-autoclaved   autoclaved bags       Sample ID   bags (N/30 mm)   (N/30 mm)                   10 N   10   35       20 N   19   36       30 N   31   39                  
 
         [0132]     In the table below the average values for the burst test is noted.  
                                                                                 Burst value of       Burst value of               non-autoclaved       autoclaved bags           bags (bar)       (bar)            Sample ID   Seal 1   Seal 2   Sea1   Seal 2               10 N   0.07   0.06   0.26   0.29       20 N   0.15   0.13   0.29   0.28       30 N   0.24   0.23   0.29   0.27                  
 
         [0133]     Seal Shape C ( FIG. 6 )  
         [0134]     In the table below the total average value for seal strength, measured at 6 positions, is noted.  
                                           Seal strength of   Seal strength of           non-autoclaved   autoclaved bags       Sample ID   bags (N/30 mm)   (N/30 mm)                   10 N   13   36       20 N   19   36       30 N   29   37                  
 
         [0135]     In the table below the average values for the burst test is noted.  
                                                                                 Burst value of       Burst value of               non-autoclaved       autoclaved bags           bags (bar)       (bar)            Sample ID   Seal 1   Seal 2   Seal 1   Seal 2               10 N   0.08   0.09   0.30   0.30       20 N   0.14   0.16   0.31   0.31       30 N   0.24   0.23   0.33   0.32                  
 
         [0136]     Seal Shape D ( FIG. 7 )  
         [0137]     In the table below the total average value for seal strength, measured at 6 positions, is noted.  
                                           Seal strength of   Seal strength           non-autoclaved   of autoclaved bags       Sample ID   bags (N/30 mm)   (N/30 mm)                   10 N   10   37       20 N   20   37       30 N   28   41                  
 
         [0138]     In the table below the average values for the burst test is noted.  
                                                                                 Burst value of       Burst value of               non-autoclaved       autoclaved bags           bags (bar)       (bar)            Sample ID   Seal 1   Seal 2   Seal 1   Seal 2               10 N   0.04   0.05   0.16   —       20 N   0.06   0.07   0.20   0.21       30 N   0.10   0.11   0.22   0.25                  
 
         [0139]     Seal Shape E ( FIG. 8 )  
         [0140]     In the table below the total average value for seal strength, measured at 6 positions, is noted.  
                                           Seal strength of   Seal strength of           non-autoclaved   autoclaved bags       Sample ID   bags (N/30 mm)   (N/30 mm)                   10 N   14   46       20 N   21   47       30 N   35   52                  
 
         [0141]     In the table below the average values for the burst test is noted.  
                                                                                 Burst value of       Burst value of               non-autoclaved       autoclaved bags           bags (bar)       (bar)            Sample ID   Seal 1   Seal 2   Seal 1   Seal 2               10 N   0.05   0.05   —   —       20 N   0.07   0.08   0.19   0.19       30 N   0.14   0.12   0.22   0.20                  
 
         [0142]     Comparison and Discussion  
         [0143]     In the table below a summary for the seal shapes A to E is shown. The degrees of difficulty for manual opening of the bag are listed. The table further shows the maximum seal strength as measured for the different seals and the corresponding burst pressure. The burst pressure values for a seal strength of 20 N/30 mm and 40 N/30 mm were extrapolated in order to allow a better comparison between different seal shapes.  
                                                   Rating   Maximum seal   Burst pressure at   Burst           for   strength for easy   maximum openable   pressure at       Seal   manual   manual opening   seal strength   20 N/30 mm       Shape   opening   (N/30 mm)   (bar)   (bar)                   A (ref.)   2-4   10   0.13   0.23       B (ref.)   3   30   0.23   0.15       C   3   30   0.25   0.15       D   2-3   41   0.21   0.08       E   2-3   52   0.22   0.07                  
 
         [0144]     The results show that a straight peelable seal (shape A) is limited to a low seal strength to remain easily openable. Seals B (reference example according to the state of the art of European patent document EP 0 893 982) and C can be easily opened at higher seal strengths while inventive seal shapes D and E can be easily opened even at high seal strengths. A seal that is easily opened at high seal strengths is preferred from a manufacturing point of view since a high seal strength enhances processability and transportation properties. An infusion bag with a seal strength as low as reference example A requires some kind of support of .the seal during transportation, i.e. a fold along the seal line.  
         [0145]     A comparison of seals C and D shows that by decreasing the radius of the rupture zone and at the same time adjust one of the straight sections of the peelable seal parallel to the other creating a gap seals of a higher strength can be opened.  
       Example 2  
       [0146]     A) General Procedure for Forming a Container According to  FIG. 1 .  
         [0147]     Containers as shown in  FIG. 1  were manufactured from a blown tube film (Biofine) based on polyolefins. The peelable seals were welded at different temperatures from 122 to 128° C. to achieve different weld strengths, 3 seconds and 4 bar using the hot bar technique. The rupture zone (peak) was placed at 40 mm, 100 mm and 160 mm from the bottom weld. The total bag length was 400 mm, the bag width was 280 mm and the total length of the peelable seals was 260 mm. The total fluid volume in the bag was 1500 ml.  
         [0148]     Permanent seals were impulse welded.  
         [0149]     B) Performed Tests  
         [0150]     Bags according to  FIG. 1  have been manufactured according to the above procedure with different peak positions. Peelable seals were welded at 122, 124, 126 and 128° C. Every sample group contained 10 bags. The bags were not autoclaved. The following tests have been performed on each sample group.  
         [0151]     Tensile Test:  
         [0152]     Tensile test was performed on 30 mm wide strips using an Instron tensile tester. Test strips were taken from position S 1 , S 2 , S 3  and S 4  (see  FIG. 11  for positions). Initial grip separation was set to 50 mm. Test speed was set to 500 mm/min. Maximum force was measured.  
         [0153]     The seal strength was measured on 3 bags.  
         [0154]     Burst Test:  
         [0155]     No restrain plates have been used. The pressure has been registered directly inside the bag using a pressure sensor. Incoming pressure has been set to 0.3 bar. The weak seals were opened in peak direction i.e. seal  1  was opened before seal  2 .  
         [0156]     Burst test was performed on 3 bags.  
         [0157]     Manual Opening of Bags  
         [0158]     The peelable seals are manually opened by the roll method. The degree of difficulty was rated 1 to 5 according to below definition.  
         [0159]     1=Very easy  
         [0160]     2=Easy  
         [0161]     3=Some resistance but no problem to open  
         [0162]     4=High resistance but possible to open with big effort  
         [0163]     5=Not possible to open  
         [0164]     Manual opening was performed on 4 bags.  
         [0165]     C) Test Results for Different Peak Positions  
         [0166]     Peak Position 40 mm  
         [0167]     In the table below the peelable seal strengths, burst values and ratings for manual opening at different welding temperatures are shown.  
                                                                                               Welding   Peelable seal       Rating for manual       temperature   strength   Burst value (bar)   opening            (° C.)   (N/30 mm)   Seal 1   Seal 2   Seal 1   Seal 2                    122   16   0.17   0.12   1.5   1.9       124   21   0.20   0.14   2.3   3.0       126   26   0.25   0.17   3.0   3.3       128   37   0.32   0.28   3.5   4.7       130   46   &gt;0.30   &gt;0.30   5.0   5.0                  
 
         [0168]     Peak Position 100 mm  
         [0169]     In the table below the peelable seal strengths, burst values and ratings for manual opening at different welding temperatures are shown.  
                                                                                               Welding   Peelable seal       Rating for manual       temperature   strength   Burst value (bar)   opening            (° C.)   (N/30 mm)   Seal 1   Seal 2   Seal 1   Seal 2                    122   16   0.12   0.09   1.0   1.0       124   21   0.16   0.11   1.8   2.0       126   27   0.19   0.12   1.8   2.0       128   37   0.28   0.16   2.5   2.7       130   45   &gt;0.30   &gt;0.30   4.0   4.0                  
 
         [0170]     Peak Position 160 mm  
         [0171]     In the table below the peelable seal strengths, burst values and ratings for manual opening at different welding temperatures are shown.  
                                                                                               Welding   Peelable seal       Rating for manual       temperature   strength   Burst value (bar)   opening            (° C.)   (N/30 mm)   Seal 1   Seal 2   Seal 1   Seal 2                    122   16   0.14   0.09   1.3   2.3       124   21   0.17   0.10   2.0   3.5       126   28   0.21   0.13   2.4   4.3       128   37   0.28   0.19   3.0   5.0       130   45   &gt;0.30   &gt;0.30   5.0   5.0                  
 
         [0172]     Comparison and Discussion  
         [0173]     In the table below a summary for peak positions 40, 100 and 160 mm is shown. The degrees of difficulty for manual opening of the bag are listed at different seal strengths.  
                                                                                     Peelable   Rating for manual   Rating for manual   Rating for manual       Welding   seal   opening with   opening with peak   opening with peak       temperature   strength   peak position 40 mm   position 100 mm   position 160 mm            (° C.)   (N/15 mm)   Seal 1   Seal 2   Seal 1   Seal 2   Seal 1   Seal 2               122   16   1.5   1.9   1.0   1.0   1.3   2.3       124   21   2.3   3.0   1.8   2.0   2.0   3.5       126   27   3.0   3.3   1.8   2.0   2.4   4.3       128   37   3.5   4.7   2.5   2.7   3.0   5.0       130   45   5.0   5.0   4.0   4.0   5.0   5.0                  
 
         [0174]     The results show that peelable seals with a high peak position are easier to open than Peelable seals with a low peak position. When the peak position is too high, close to the fluid level of the mixed bag as in peak position 160 mm seal  2  the seal becomes more difficult to open. A comparison of the peak positions evaluated in this example shows that a peak position of 100 mm is the preferred position.