Patent Publication Number: US-7717897-B2

Title: Medical fluid container with concave side weld

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation-in-part of U.S. Ser. No. 11/477,007, which was filed Jun. 28, 2006 now abandoned and was a continuation-in-part of U.S. Ser. No. 11/315,840, which was filed Dec. 21, 2005 now U.S. Pat. No. 7,530,974 and was a continuation-in-part of U.S. Ser. No. 11/023,889, which was filed Dec. 23, 2004 now U.S. Pat. No. 7,488,311. The foregoing applications are expressly incorporated in their entirety herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to the field of containers for holding medical fluids for administration to patients. As used herein the term “medical fluids” includes medical, biological and veterinary fluids. Thus the “patients” could be humans, fish, animals, reptiles, amphibians, birds, etc. More particularly, the present invention relates to flexible autoclavable intravenous (IV) fluid containers or bags and non-PVC polyolefin film for their construction. The invention provides long shelf life flexible IV fluid containers that have a low moisture vapor transmission rate and can be terminally sterilized using high temperature treatment, i.e., sterilized after filling to deactivate microorganisms inside the containers (e.g., autoclaving). 
     Over thirty years ago, the introduction of a flexible IV container raised the issues of water loss and port closure system integrity testing. A flexible container material system and suitable port closures had to be designed. The most common design selected was some sort of PVC mono-layer film container with a very low cost closure system. Placing another material with higher barrier properties as an overwrap around the filled container solved the issue of the water loss during shelf life. The entire system would then be steam sterilized and delivered to the customer for use. 
     Polyvinyl Chloride (PVC) is a standard, widely used plastic packaging material used to manufacture flexible containers (bags and pouches) for the administration of small volume parenterals (SVP), often referred to as mini-bags; large volume parenterals (LVP); and various enteral nutritional and liquid preparations. These containers are often utilized for patient hydration and/or to supply pharmaceutical preparations, medicines, vitamins, nutritionals, and the like. Heretofore, PVC has proven to be advantageous because of its resistance to heat, which allows the containers to be terminally sterilized using high temperature treatment. 
     However, PVC also has its shortcomings. PVC films in the thickness range needed to be acceptably flexible for IV fluid containers typically do not provide a high moisture vapor barrier (MVB). The moisture vapor transmission rate (MVTR) of flexible PVC containers is so high that an overwrap is required to increase the shelf life of the fluids contained therein by providing improved moisture vapor barrier (MVB) properties, as compared to the MVB properties of PVC alone. In other cases, an overwrap is used to contain any leakage and help the port system of the flexible containers to survive autoclaving (i.e., high temperature treatment) or shipping and handling damage. In some cases, and particularly for SVP packages (or bags), multiple SVP packages are placed into one overwrap package. Disadvantageously, once the one overwrap package has been opened, the shelf life of the individual SVP packages contained therein is limited to approximately 30 days, because of the poor MVB properties of PVC. Thus, if a practitioner opens an overwrap containing SVPs, but does not use all of the SVPs in a timely manner, the SVP packages must be discarded approximately 30 days after the overwrap is opened. A similar shelf life problem exists with PVC containers for large volume parentals (LVPs), which are typically manufactured with an individual overwrap over each container. In either case, the overwrap represents added packaging cost and weight, contributes to environmental waste, and depletes petroleum and other resources. 
     As time passed and new materials and technologies were brought to the pharmaceutical industry, laminated or multilayer materials typically including three or more layers have come to the forefront for use in IV flexible containers. These materials incorporate an integrated overwrap type film layer to provide the flexible IV container with similar water vapor protection as the separate overwrap system. 
     To perform well, an intravenous medical fluid container must: 1) drain uniformly, preferably with a readable falling meniscus; 2) have minimal air volume so that patient air embolisms are not an issue; and 3) leave minimal residual volume upon draining so the patient accurately receives the prescribed amount of drug or fluid. Only if the container is flexible, can all of these objectives can be met simultaneously. A flexible container, as the term is used herein, means a container that collapses upon draining, such as a bag for example. Rigid containers, of course, do not change shape substantially upon draining. Semi-rigid containers have substantially the same shape in a filled state and in a drained state, i.e., they may deform some while draining but do not permanently collapse without application of external forces when drained. Semi-rigid containers or plastic bottles also require significant amounts of included air or venting to drain properly. Anyone who has poured milk from a semi-rigid plastic container or oil from a semi-rigid can will appreciate that semi-rigid containers tend to drain sporadically and often unpredictably unless properly vented. Undesirable reversing of flow or suctioning can occur with semi-rigid containers. Heretofore, flexibility has been pursued in conventional intravenous fluid containers by making the material or film of the bag or container very thin (i.e., on the order of a few mils), using a material with a very low modulus of elasticity, or both. However, low modulus materials or thin films tend to melt at temperatures lower than typical US or European autoclave temperature requirements, and have an undesirably high moisture vapor transmission rate such that an overwrap is required for each container. 
     Materials other than PVC, such as polyolefins (e.g., polyethylene or polypropylene), nylon, or a composite material, either laminated or co-extruded structure (including both monolayer and multilayer structures), and the like, have been proposed for SVP and/or LVP. One advantage is to reduce or eliminate the use of PVC because of environmental concerns. Another advantage of materials such as polypropylene or polyethylene is that they have better MVB properties than PVC. However, manufacturers and regulatory agencies have been hesitant to eliminate overwraps due to concerns regarding sterility and possible handling damage to and/or leakage from port closure system of polyolefin flexible medical fluid containers. Reliable, economical, longer shelf life, lower moisture vapor transmission rate flexible medical fluid containers have yet to be realized due to port closure deficiencies, the multitude of materials to be selected and/or blended, as well as the many, often conflicting design constraints that must be met. Among these constraints are cold impact strength for “drop tests”, capability to withstand the high heat autoclave cycles required in the United States and Europe, USP requirements, drug concentration and assay requirements, allowed fill volume, filling equipment and manufacturing process tolerances, aesthetic appearance (clarity, gloss, haze, wrinkling), printability, drainability, and types and levels of extractables permitted. 
     Another advantage to replacing PVC with a material such as polypropylene or polyethylene is that products such as pure deionized water (U.S.P. for injection) cannot be effectively packaged in PVC because by-products from the PVC packaging material leach into the pure deionized water, contaminating it, whereas materials such as polyolefins can be formulated so as to minimize by-products that leach into the pure deionized water. 
     Access ports are commonly used in infusion solution containers to administer solutions to a patient, or to add medicaments or other solutions to the container prior to administration. Current solution containers typically may include a dedicated outlet port for solution administration to a patient and a dedicated inlet port for the addition of diluent or other ingredients to the container. 
     The outlet port is intended to be coupled to an administrative set and is therefore commonly referred to as the administrative port, whereas the inlet port is designed to permit the injection of therapeutic agents and nutrients into the partially filled container and is sometimes identified as the additive port. Such a container may contain a partial filling of a sterile solution such as saline or dextrose to function as a diluent for the injected additive. Alternatively, the container may house the drug and the diluent can be added by injection into the container through the additive port. The diluted drug or nutrient is then administered to a patient by means of the administrative port and an administrative set that may be either directly or indirectly (i.e., through another solution set) coupled to the patient. Strict limits or tolerances are often imposed on the assay or concentration of the drug to be delivered. Meeting these limits, especially if the filled container is stored for an extended period of time, is difficult if the moisture barrier of the container is too high. 
     Other challenges in the fabrication of flexible containers exist. Conventional flexible containers or IV bags have substantially straight longitudinal sides. The containers have an outer peripheral seam or weld that joins together the front and back portions of the container wall. The seam extends straight along the substantially straight longitudinal sides of the container and curves in a convex manner at the corners of the bag. However, changes in the path of the outer peripheral seam of the container at the corners can cause wrinkling and undesired tacking or blocking together of the material in the interior of the container at or near the corner. 
     Therefore, an object of this invention is to provide an improved medical fluid container. 
     A further object of the invention is to provide containers with port closure assemblies that improve the safety and ease of handling when fluids are to be withdrawn or introduced. 
     Another object of the invention is to provide a port fill tube configuration that increases container sealing reliability, as well as the ease and efficiency of manufacture. 
     A further object of the invention is to provide a container with container wall formed of a multiple layer polyolefin material selected so as to meet the demanding requirements for terminally sterilized IV containers. 
     A further object of the invention is to provide a flexible container with a longitudinal side seam configuration that is more ergonomic for handling purposes, and reduces wrinkling and undesired material tacking or blocking. 
     A further object of the invention is to provide an improved method of fabricating and filling medical fluid containers. 
     A further object of the invention is to provide an improved method of packaging and storing medical fluid containers. 
     A further object of the invention is to provide a container that weighs less than PVC but provides a better moisture vapor transmission rate. 
     These and other objects will be apparent to those skilled in the art. 
     SUMMARY OF THE INVENTION 
     A container for medical fluids has a container body formed of a multiple layer polyolefin film and includes one or more fluid ports therein. The ports can include a fill tube and a port closure system for association with the fill tube to seal the port closed. The container body, fill tube, and port closure system is free of PVC and DEHP. 
     A port closure system for use with a fluid container having fluid ports may include administrative and additive port closure assemblies. The administrative port closure assembly receives a piercing pin and includes an administrative housing which seals closed one fluid port. A sleeve extends from an interior surface past a base surface in the administrative housing. The sleeve has an upper portion and a lower portion, of differing diameters. A cap assembly mates with the administrative housing, sealing the interior surface of the administrative housing. A removable cap provides access to the interior surface. 
     The additive port closure assembly receives a needle and includes a reseal housing which seals closed another fluid port. A cap assembly mates with the reseal housing, sealing an interior face of the reseal housing. As with the administrative port closure assembly, a removable cap provides access to the interior face. A reseal element is mechanically retained, secured or captured between the reseal housing and cap assembly. 
     The port housings and the fill tubes include various features which facilitate the reliable fabrication and use of the container. 
     The multiple layer polyolefin film is selected for, among other factors, its impact strength, low moisture vapor transmission rate, its ability to survive autoclaving and heat sealing, and its excellent compatibility with the material of the fill tubes and the port closure assemblies. 
     In another aspect of the invention, the fluid container includes a flexible elongated container body having a fluid reservoir formed therein surrounded by a container wall including a front portion and a back portion and one or more longitudinal side edges. The front and back portions are sealed together along an outer peripheral seam, which is adjacent to at least one of the longitudinal side edges, to define the fluid reservoir. The outer peripheral seam follows a concave path with respect to a longitudinal axis of the container, and can also curve inwardly with respect to one or more of the side edges. The side edges can be straight or curve inwardly toward the central axis of the container as well. The container with a concave curved side seam is easy to grasp and handle, resistant to interior and exterior wrinkling, and resistant to tacking or blocking of the film inside the container near the corners. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial exploded perspective view of the port closure system of the present invention in use with a fluid container. 
         FIG. 2  is a partial perspective view of the port closure system of the present invention in use with a fluid container, needle and piercing pin set. 
         FIG. 3A  is a partial sectional exploded view of the port closure system of the present invention in use with a fluid container. 
         FIG. 3B  is a partial sectional assembled view of the port closure system of the present invention in use with a fluid container. 
         FIG. 4  is a sectional view of the additive port closure assembly of the present invention. 
         FIG. 5  is a sectional view of the additive port closure assembly of the present invention in use with a needle. 
         FIG. 6A  is a side view of the cap assembly of the present invention. 
         FIG. 6B  is a perspective view of the cap assembly of the present invention. 
         FIG. 6C  is an enlarged partial sectional view of the notched portion of the cap assembly taken along line  6 C- 6 C in  FIG. 6B . 
         FIG. 7  is a sectional view of the reseal element of the present invention. 
         FIG. 8  is a perspective view of the 
         FIG. 9  is a sectional view of the administrative port closure assembly of the present invention in use with a piercing pin set. 
         FIG. 10  is a cross sectional view of one embodiment of the administrative port closure assembly of the present invention. 
         FIGS. 11-15  are cross sectional views of additional administrative port closure assembly embodiments. 
         FIGS. 16-17  are perspective views of additional port closure system embodiments. 
         FIG. 18  is a cross sectional view similar to  FIG. 4  of an alternative embodiment of the additive port closure assembly. 
         FIG. 19  is an enlarged partial cross sectional view of a portion of the additive port closure assembly from  FIG. 18  prior to the cap assembly being joined to the reseal housing. 
         FIG. 20  is an enlarged partial cross sectional view of the additive port closure assembly and shows the area encircled by the line  20 - 20  in  FIG. 18 .  FIG. 20  is similar to  FIG. 19  but shows the same area after the cap assembly is joined to the reseal housing. 
         FIG. 21  is a front plan view of a fill tube port according to one embodiment of the invention. 
         FIG. 22  is a sectional view of the fill tube taken along line  22 - 22  in  FIG. 21  and shows the non-circular transverse cross-section of the lower portion of the fill tube. 
         FIG. 23  is a side elevation view of the fill tube of  FIG. 21 . 
         FIG. 24  is a longitudinal sectional view of the fill tube taken along line  22 - 22  in  FIG. 21 . 
         FIG. 25  is a top plan view of a container according to one embodiment of the present invention. 
         FIG. 25A  is top plan view of a container according to another embodiment of the present invention. 
         FIG. 25B  is top plan view of a container according to another embodiment of the present invention. 
         FIG. 26A-26C  is a series of sectional views showing the tooling, film and the lower portion of the fill tube of  FIG. 21  before and during attachment to the body of the container according to the present invention. 
         FIG. 27  is an enlarged cross-sectional view of the container of the present invention taken along line  27 - 27  in  FIG. 25 . 
         FIG. 28  is a simplified schematic diagram that shows the composition of one embodiment a multilayer polyolefin film which can be used to form the front and back portions of the container wall. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION 
     With reference to  FIGS. 1-3B ,  25 , and  27 , the flexible long shelf life autoclavable fluid container  12  has a container body  1  with a fluid reservoir  2  formed therein surrounded by a flexible container wall  3 . The container wall  3  has a front portion  3 A and a back portion  3 B. The container body has at least one port  14 ,  16  formed therein. In one embodiment, there are two ports  14 ,  16  located at the same end of the container  12 , which has an elongated container body  1 . 
     With reference to  FIGS. 1-3B  and  25 , a port closure system  10  is shown for use with a fluid container  12  which has a flexible container body  1  having at least one port  14 ,  16  therein. A pair of ports (i.e., two ports) can be provided as first and second fluid ports  14  and  16  accessible respectively with a syringe needle  18  and piercing pin set  20 . Fluid ports  14 ,  16  include fill tubes  13 ,  15  respectively, which are elongated in one embodiment. 
     With reference to  FIGS. 21-24 , the fill tubes  13 ,  15  can be substantially identical in one embodiment and each have a distal end  17 , a proximal end  19  and a fluid passage  21  that extends from the proximal end  19  to the distal end  17 . The fill tubes  13 ,  15  are attached to the container body  1  as described below so that the fluid passage  21  of the fill tube  13 ,  15  is in fluid communication with the fluid reservoir  2  in the interior of the container body  1 . The fill tubes  13 ,  15  have a generally cylindrical upper portion  23  adjacent to the distal end  17  and a lower portion  25  adjacent to the proximal end  19 . The upper portion  23  of the fill tube  13 ,  15  has a generally cylindrical cavity  27  formed therein for receiving one of the port closure assemblies described in greater detail herein. The upper portion  23  of the fill tube  13 ,  15  also includes an annular flange  29  that extends radially outward. The flange  29  helps protect the user&#39;s fingers from inadvertent contact with a needle, cannula or spike when accessing the ports  14 ,  16 . The upper portion  23  of the fill tube  13 ,  15  has an outer surface  31  below the flange  29 . 
     The outer surface  31  has at least one notch  33  formed thereon. In one embodiment, the outer surface  31  has a plurality of circumferentially spaced notches  33  formed thereon. In another embodiment, a pair of equally space opposing notches  33  is provided. The notch or notches  33  can be used to orient the fill tube  13 ,  15  for attachment to the container body  1 . The notch or notches  33  can take on many possible configurations and shapes. In one embodiment, the notch  33  has a flat bottom and extends longitudinally along the outer surface  31  of the fill tube  13 ,  15 , it provides a useful place for the user to grasp and hold the fill tube  13 ,  15 . 
     As best seen in  FIGS. 21-24 , the lower portion  25  of the elongated fill tube  13 ,  15  has a non-circular transverse cross-section for a substantial portion of its length. In one embodiment, the non-circular cross-section is rhomboidal or semi-rhomoidal. In another embodiment, the non-circular cross-section is selected from a group of shapes consisting of oval, semi-oval, elliptical, semi-elliptical, rhomboidal and semi-rhomboidal. The non-circular cross-section is defined by a first axis and a second axis transverse to the first axis. The first axis terminates at opposite ends that define the width of the lower portion  25  of the fill tube  13 ,  15 . The second axis terminates at opposite ends that define the depth of the lower portion  25  of the fill tube  13 ,  15 . In one embodiment, the width of the lower portion  25  of the fill tube is greater than the depth, such that the first axis is a major axis and the second axis is a minor axis of the transverse cross-section of the lower portion  25  of the fill tube  13 ,  15 . The notch or notches  33  on the upper portion  23  of the fill tube  13 ,  15  can be perpendicular to the first or major axis of the lower portion  25 , so that automated equipment can easily orient the fill tube  13 ,  15  properly for attachment to the container body  1  as described below. 
     The lower portion  25  of the fill tube  13 ,  15  has an outside radius R 1  formed on the opposite ends of the major axis of the transverse cross-section. In one embodiment, the radius R 1  is approximately 0.005 to 0.015 inch. In another embodiment, the radius R 1  is approximately 0.005 to 0.010 inch. In yet another embodiment, the radius R 1  is approximately 0.008 inch. The radius R 1  has been found to contribute to the strength and reliability of the fill tube/container body interface or heat seal weld. Improved material flow and fusion at the critical junction Y of the container back, container front and fill tube has been observed with the improved fill tube design. 
     The lower portion  25  of the fill tube  13 ,  15  can have an outside radius R 2  formed on at least one of the opposite ends of the minor axis of the transverse cross-section. In the embodiment shown in  FIG. 22 , an outside radius R 2  of approximately ⅛ to ¼ inch is formed on both of the opposite ends of the minor axis. In another embodiment, the radius R 2  is approximately 0.150 to 0.200 inch. In yet another embodiment, the radius R 2  is approximately 0.178 inches. The radius R 2  provides a large, smooth area for heat sealing, adhesion or other attachment means and a light, uniform, unwrinkled stretch of the container body film over the lower portion  25  of the fill tube  13 ,  15  without over-stretching or over-thinning the container body film material. 
     Fill tubes  13 ,  15  having a lower portion  25  with a width of approximately ½ inch and a depth of about ¼ inch have been found to provide acceptable filling and draining characteristics. In one embodiment, the fill tube  13 ,  15  is about 0.75 to two inches long. In another embodiment, the length of the fill tube  13 ,  15  is about 1.4 to 1.8 inches. In another embodiment, the fill tube  13 ,  15  is about 1.5 inches long. The relatively long fill tube lengths help to prevent a standard one inch or 1½ inch long needle, spike or cannula from accidentally penetrating the container wall  3  of the container  12  or IV bag through the passage  21  of the fill tube  13 ,  15 . 
     The fill tube  13 ,  15  has a fill tube wall  35  that has sufficient thickness and rigidity to prevent an eighteen gauge needle from being pushed through the wall  35  on a path P that is perpendicular to the wall  35  when a force of three to six lbs. is applied. In one embodiment, the fill tube wall  35  has a substantially uniform thickness of between about 0.9 and 1.5 mm. In another embodiment, the wall  35  is approximately 1.2 mm. The rigidity of the wall  35  is derived from its material, which is described in greater detail below. Table 1 below is a comparison of the force required to puncture the fill tube wall with an eighteen gauge needle perpendicular to the surface for the present invention and commercially available IV bags or flexible containers. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Needle Puncture Comparison 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Item 
                 Present 
                 Baxter 
                 Braun 
               
               
                   
                 Tube Specifications 
                 Invention 
                 Viaflex ™ 
                 Excel ™ 
               
               
                   
                   
               
               
                   
                 General Composition 
                 Rigid 
                 Soft 
                 Soft 
               
               
                   
                 Wall Thickness (mm) 
                 1.2 
                 0.9 
                 1.5 
               
               
                   
                 Tube Length (mm) 
                 39 
                 39 
                 22 
               
               
                   
                 Force to Puncture (lb) 
                 6.11 
                 1.04 
                 2.68 
               
               
                   
                   
               
            
           
         
       
     
     With reference to  FIGS. 1-3B , the ports  14 ,  16  are connected by a body portion  124  that comprises a flexible web of top and bottom sheets of multilayer film extending transversely across and sealed by heat welding or other means to each other and to the fill tubes  13 ,  15 . With the flexible web  124 , the fill tubes  13 ,  15  of the ports  14 ,  16  can be independently moved or manipulated. The lower portion  25  of each of the fill tubes  13 ,  15  is attached to the container body  1  and the fill tubes  13 ,  15  are spaced apart sufficiently for a user to insert at least one finger therebetween (“fingers” as used herein can include a thumb). With a width of approximately ½ inch for the lower portion  25  of the fill tube  13 ,  15 , a spread S of about one inch can be achieved by placing the centerlines of the tubes  13 ,  15  of the ports  14 ,  16  about 1.5 inches apart. The projection of the fill tubes  13 ,  15  from the container body  1 , the location of the flange  29 , or the length of the upper portion  23  of the fill tubes  13 ,  15  can also be selected to provide adequate space for one of the user&#39;s fingers. 
     With reference to  FIGS. 2-5 , the port closure system  10  includes two port closure assemblies; with the first port assembly being an additive port closure assembly  22  adapted to provide needle  18  sterile access to the first fluid port  14 . The additive port closure assembly  22  is adapted to be assembled and sterilized as a subassembly prior to association and use with the fluid container  12 . 
     The additive port closure assembly  22  includes a port housing  24  (hereinafter “reseal housing  24 ”) adapted to seal closed the first fluid port  14  by attachment to the fill tube  13 . The reseal housing  24  has a base face  26  adapted to be associated with the first fluid port  14  or fill tube  13  and an interior face  28  adapted to face outwardly from the first fluid port  14 . An open cylinder  30  extends from the interior face  26  to the base face  28  and has an upper rim  32 . A reseal diaphragm  34  is connected to the open cylinder  30  to seal the open cylinder  30  closed to fluid flow from the container  12 . The reseal diaphragm  34  is opened to fluid flow once pierced by needle  18 . A reseal flange  36  extends generally radially from the open cylinder  30 . The reseal flange  36  protects the user from accidental pricks when applying needle  18  to the additive port closure assembly  22 . 
     The reseal flange  36  and open cylinder  30  are also oriented and arranged to accommodate a commercially available needle-less access system (not shown) being integrated with the reseal housing  24 . U.S. Pat. No. 5,924,584 describes one embodiment of a needle-less access system suitable for the present invention; said description is expressly incorporated herein in its entirety. 
     With reference to  FIGS. 3A-6C , a cap assembly  38  of additive port closure assembly  22  is connected to the reseal housing  24 . In general, the cap assembly  38  includes an under shell  40  shaped to mate with the interior face  28  of the reseal housing  24 . Once mated, the cap assembly  38  seals the interior face  28  from potential contamination. A sealed opening  42  is provided in cap assembly  38 , and a removable cap  44  provides access to the sealed opening  42  and the interior face  28 . Once the removable cap  44  is detached, the additive port closure assembly  22  need not be re-sterilized, as the cap assembly  38  operates as a sterile barrier to shield the interior face  28  from potential contamination. Removable cap  44  is tamper evident as it cannot be reconnected once removed. Furthermore, if the cap  44  is pierced while still in place, it clearly shows that a hole has been made in the cap (i.e., tampering has taken place). 
     The cap assembly  38  is of unitary construction and includes a crown  46  connected to the removable cap  44  by an annular frangible area  48 . The term “frangible area” as used herein refers to any breakable area or any area with some form of breakable seal. 
     The crown  46  of the cap assembly  38  has an outer shell  50 . The sealed opening  42  extends between the outer and under shells  50  and  40  and provides access to the interior face  28  when the removable cap  44  is detached. A retaining rim  54  extends from the under shell  40  and around the sealed opening  42 . A crown flange  56  extends generally radially from the sealed opening  42 . The crown flange  56  protects the user from accidental pricks when applying needle  18  to the additive port closure assembly  22 . 
     A notch area  58  is formed on the cap assembly  38  and is operatively associated with the frangible area  48  to weaken the frangible area  48  near the notch area  58 . One skilled in the art will appreciate that the notch area  58  can be on the removable cap  44 , as shown in  FIG. 6C , or on the crown  46  without detracting from the invention. The notch area  58  can be formed in a variety of force focusing shapes, including but not limited to a partial pyramid shape, a V-shape, or a partial conical shape. 
     A cover  60  of the removable cap  44  is sealed over the sealed opening  42  by the frangible area  48 . The cover  60  has a thickness sufficient to resist manual piercing by needle  18  or piercing pin  20 . Due to the melt temperature of the material of the cover  60  being in the range of 129-144° C. and the presence of an air chamber under the cover once assembled, the cover  60  is adapted to shape changes during heat sterilization, which allows a user to discern the sterilized state of the additive port closure assembly  22  due to the shape of cover  60 . 
     A pull element  62  of the removable cap  44  is connected to the cover  60  to allow a user to manually tug on the pull element  62  to sever the frangible area  48  and separate the cover  60  from the crown  46 . The pull element  62  includes a lever  64  connected to one side of the cover and adjacent to the crown  46 . The lever  64  is positioned adjacent the notch area  58  and focuses the user tugging force on the pull element  62  at the notch area  58 . The lever  64  includes an area of narrowed cross section that defines a pull force concentrator. The pull force concentrator is adjacent the frangible area  48  and near the notch area  58 . Preferably the pull force concentrator is defined by a transverse groove  65  having rounded side walls in the top of the lever  64 , although other shapes, orientations and locations will not detract from the invention so long as the structure focuses or concentrates the user tugging force on the pull element at the notch area  58 . 
     A pull tab  66  is connected to the lever  64  by a pull ring  68  and positioned opposite the lever  64  on the pull ring  68 . The pull tab  66  provides an area for a user to manually grip and tug on the pull element  62 . 
     At least one pivot element  70  is radially spaced from the frangible area  48  and circumferentially spaced from the lever  64  on the pull ring  68 . More preferably, a pair of pivot elements is positioned so each pivot element is equally spaced about ninety degrees away from the lever  64 . The pivot elements  70  contact the crown  46  and pivot to absorb any impact forces on the pull element  62  to prevent inadvertent damage to the frangible area  48 . Additional pivot elements may be utilized as needed. 
     With reference to  FIGS. 3A ,  4 ,  5  and  7 , a reseal element  72  of the removable cap  44  is positioned between the under shell  40  of the crown  46  and the interior face  28  of the reseal housing  24 . The reseal element  72  has an annular shoulder  74  extending radially from a central core  76 . The annular shoulder  74  splits the central core  76  into an upper core  78  having a raised surface  80  and a lower core  82 . 
     The raised surface  80  extends beyond the sealed opening  42  in the cap assembly  38  when the removable cap  44  is detached. The exposed raised surface  80  provides a convenient swabbable area to sterilize during subsequent uses. 
     The lower core  82  is received within the open cylinder  30  of the reseal housing  24 . The diameter of the lower core  82  is selected relative to the diameter of the open cylinder  30  such that the open cylinder  30  presses radially inward on the lower core  82  to provide a seal therebetween and to re-seal the reseal element  72  itself when punctured. In other words, the lower core  82  is frictionally fitted or forcibly pressed into the open cylinder  30  of the reseal housing  24 . This frictional fit provides one means of securing or retaining the reseal element  72  in the reseal housing  24  for subsequent assembly operations. 
     An annular lip element  84  is connected to an outer rim  86  of the annular shoulder  74 . The junction of the rim  86  and the lip element  84  has a fillet or inside radius  85 . The lip element  84  extends transversely to the annular shoulder  74  in two directions. The upper and lower inside edges of the lip element  84  have a chamfer, inside radius or fillet  87  thereon to assist in molding and guide the retaining rim  54  or rim  32  toward the annular shoulder  74 . The annular lip element  84  has an inside diameter greater than the outside diameter of the retaining rim  54  and an outside diameter less than the outer diameter of the crown flange  56 . The reseal element  72  is mechanically retained, held, secured, or more particularly clamped in place by the retaining rim  54  of the crown  46  and the upper rim  32  of the open cylinder  30 , which upon the cap assembly  38  and reseal housing  24  being connected together are received between the central core  76  and the lip element  84  so as to retain the annular shoulder  74 . The uncompressed height of the annular shoulder  74  can be selected to be equal to, or more preferably greater than, the distance between the retaining rim  54  and the rim  32  when the cap  44  and reseal housing  24  are joined. Selecting an uncompressed height greater than the available distance provides a desirable clamping force or sealing on the resilient material of the reseal element  72  at the shoulder  74 . Alternatively, there may initially be a small gap between the retaining rim  54  and the upper surface of the shoulder  74 . The gap may remain or be eliminated when, upon heat sterilization of the assembly  22 , the cap  44  deforms. In the latter case, the rims  32 ,  54  abut or contact the lower surface and upper surface respectively of the annular shoulder  74 . Thus, the crown  46  and the reseal housing  24 , along with the annular shoulder  74  and the lip  84  of the reseal element, cooperate to provide a substantially permanent mechanical second means of securing the reseal element  72 , which can be independent of the fit between the reseal element  72  and the open cylinder  30  and eliminates the need for separate fasteners, solvent bonding or swaging the reseal element  72  in place. In addition to positively retaining the reseal element  72  in place, the cap assembly  38  provides a removable cap  44  that seals the reseal element  72  from contamination until use. Despite the fact that the reseal element  72  is neither solvent bonded nor swaged into place, its securement is unaffected by component size, needle gauge, insertion force on the needle  18  or the removal of the cap  44 . The reseal element  72  is automatically mechanically retained in place and constrained against movement both axially and radially primarily by the connection of the crown  46  and reseal housing  24 . 
     With reference to  FIGS. 1-3B ,  9 , and  10 , an administrative port closure assembly  88  is shown as the second port closure assembly of the port closure system  10 . The administrative port closure assembly  88  is adapted to provide piercing pin set  20  sterile access to the second fluid port  16 . The administrative port closure assembly  88  is also adapted to be assembled and sterilized as a subassembly prior to association and use with the fluid container  12 . 
     With reference to  FIGS. 1 ,  9  and  10 , the administrative port closure assembly  88  includes a second port housing  90  (hereinafter “administrative housing  90 ”) adapted to seal closed the second fluid port  16  by attachment to the fill tube  15 . A base surface  92  is adapted to be associated with the second fluid port  16  or fill tube  15  and an interior surface  94  is adapted to face outwardly from the second fluid port  16 . 
     A seal ring  95  extends from the base surface  92  and is adapted to be sealably received within the second fluid port  16 . The seal ring  95  has a stiff construction and large diameter of about ⅝″ to provide improved user handling of administrative port closure assembly  88 . An optional stiffening hoop or rib  97 , more preferably a pair of spaced ribs  97 , extends radially inwardly on the seal ring  95  to stiffen the seal ring and resist deformation during heat sealing to the port  16  and later autoclave heat sterilization. 
     A sleeve  96  extends from the interior surface  94  past the base surface  92  and within the seal ring  95 . The sleeve  96  is recessed below sealed opening  42  of second cap assembly  38  connected to the administrative housing  90 . This recess protects the sleeve from inadvertent contamination of interior surface  94  when the administrative port closure assembly  88  is opened. The sleeve  96  has an upper portion  98  and a lower portion  100 . The upper portion  98  is adjacent the interior surface  94  and has an opening  104  with a lesser diameter than the lower portion  100 . The diameter difference between the upper and lower portions  98  and  100  allows the sleeve  96  to receive and sealably associate with differently sized piercing pin sets  20 , and to accommodate diameter variation among various piercing pin sets  20 . 
     In the embodiment disclosed in  FIG. 10 , the upper portion  98  has a substantially uniform wall thickness and is tapered inwardly into a bullet nose configuration where the exterior surface is convex and the interior surface is concave. The taper can be formed by any number of well-known manufacturing techniques, including but not limited to cutting, rolling (with or without heat) and swaging. The taper of the upper portion  98  is preferably curvilinear, but linear taper can also be used. During use the user&#39;s fingers are within ¼″ of the sleeve  96 , allowing the user to easily control the position of the sleeve  96  with respect to piercing pin sets  20 . 
     The sleeve  96  and the seal ring  95  are connected at a flexible annular junction  102  at a base  114  for the sleeve to form a unitary body. The flexible junction  102  allows for some minor displacement of the sleeve  96  with respect to the rigid seal ring  95  during use. 
     An air-filled moat  106  is positioned between the seal ring  95  and the sleeve  96  on the base surface  92 . The moat  106  allows the seal ring  95  to contract and expand as needed based on internal pressure of the container  12  during the heat sterilization cycle. Thus, the moat  106  protects the sleeve  96  from significant permanent deformation that could lead to leaks or unacceptable insertion or withdrawal force requirements. The connection between the seal ring  95  and sleeve  96  provides a clamping or sealing force on piercing pin set  20  (not shown) during pin insertion and withdrawal. In addition to being physically separated from the sealing ring  95  except at the base  114 , the sleeve  96  is protected by the seal ring  95  and moat  106  from potential distortion during autoclaving, since the moat  106  reduces outside pressure against sleeve  96  during autoclaving. 
     An administrative diaphragm  110  is connected to the sleeve  96  to seal the sleeve  96  closed to fluid flow. The administrative diaphragm  110  is opened to fluid flow once pierced by piercing pin set  20 . 
     An administrative flange  112  extends generally radially from the seal ring  95 , and thus from the sleeve  96 . The administrative flange  112  around the sleeve  96  creates an effective target area for the user to apply the piercing pin set  20  toward and protects the user from accidental pricks. 
     A second cap assembly  38  is connected to the administrative housing  90  to form the administrative port closure assembly  88 . The under shell  40  is shaped to mate with the interior surface  94  of the administrative housing  90 . Once mated, the cap assembly  38  seals the interior surface  94  from potential contamination. The removable cap  44  provides access to the sealed opening  42  and thus the interior surface  94 . Once the removable cap  44  is detached, the administrative port closure assembly  88  need not be re-sterilized, as the cap assembly  38  operates as a sterile barrier to shield the interior surface  94  from potential contamination. 
     With reference to  FIG. 1 , during manufacture of the port system  10 , port housings  24 / 90 , cap assembly  38  and reseal element  72  are mold formed. The additive port closure assembly  22  is formed by positioning reseal element  72  between the cap assembly  38  to the port housing  24 , and permanently connecting the cap assembly  38  to the port housing  24 . The administrative port closure assembly  88  is formed by connecting the cap assembly  38  to the port housing  90 . Port closure assemblies  22 / 88  are connected together by ultrasonically welding or radiant thermofusion welding the cap assembly  38  to the port housing  24 / 90 . Port closure assemblies  22 / 88  are sterilized by irradiation. The irradiated pre-sterilized port closure assemblies  22 / 88  form subassemblies that are subsequently associated with or attached to the fluid container  12 . The fluid container  12  is sealed to the irradiated port closure assemblies  22 / 88  by conventional means, including but not limited to ultrasonically welding, radiant thermofusion welding, or hot tongue heat sealing. The associated port closure assemblies  22 / 88  and fluid container  12  are then terminally heat sterilized by autoclaving after filling. 
     Port closure assemblies  22 / 88  are formed of a polymer blend that does not degrade during the irradiation, sterilization, radiant thermofusion welding, and ultrasonic welding. The term “degrade” as used herein refers to degradation to such an extent that the material is no longer suitable for its intended purpose. The polymer blend also provides ultrasonic sealability, radiant thermofusion sealability, and prevents coring when the polymer is punctured. The term “coring” as used herein refers to the process of a polymer fragmenting upon piercing so as to result in the formation of loose polymer particulate. The ability of polymer blend to be sealed by ultrasonic bonding and/or radiant thermofusion eliminates the need for any solvent or swaged bonding; and also eliminates the need to provide additional frictional force fit components to hold the port closure system  10  together. Additionally, the polymer blend provides a balance between insertion and withdrawal forces for improved handling by users. 
     Materials are selected for the IV fluid container  12 , fill tube  13 ,  15 , port housings  24 ,  90 , and cap assembly  38  to provide, in conjunction with their design, the required container and port system functionality. While the difference in function among these parts requires different physical properties that may be supplied by a variety of materials, the materials must be compatible on a molecular level to enable them to be joined together without adhesives. 
     The fill tube  13 ,  15  is formed of a material that is sealable to the inner sealant surface of the IV fluid container  12  and the port housings  24 ,  90 . It must be able to be autoclaved without deformation that significantly affects its appearance or function of providing a channel between the container  12  and the ports  14 ,  16 . For sealant surfaces of containers  12  and port housings  24 ,  90  that comprise polyolefins such as polypropylene homopolymers, polypropylene copolymers, or blends of polypropylene copolymers with materials providing elastomeric properties, the fill tube  13 ,  15  preferably comprises a polypropylene homopolymer or copolymer. A homopolymer provides better dimensional stability through autoclaving, while a copolymer provides better compatibility with an IV container  12  that has a copolymer sealant surface. For container sealant surfaces and port housings that comprise random polypropylene copolymers or blends of random polypropylene copolymers with materials providing elastomeric properties, the fill tube  13 ,  15  preferably comprises a random polypropylene copolymer with ethylene content from about 2% to about 6% and a melting point from about 129° C. to about 145° C. To reduce deformation with autoclaving at 125° C., the random polypropylene copolymer more preferably has an ethylene content of about 2.4-3.5% and a melting point of about 145° C. Specifically, a random polypropylene copolymer, Total Petrochemicals 7825, has been found to produce the best results at autoclave temperatures up to about 125° C. with a container  12  with polypropylene copolymer sealant layer and port housings  24 ,  90  comprising a blend of polypropylene copolymers. 
     The administrative port housing  90  must be heat sealable to both the fill tube  13  and cap assembly  38 , as well as be stable to gamma radiation from 18-45 kGy, or at least 18-32 kGy. The administrative port housing  90  must be autoclavable up to about 125° C. without deformation that significantly affects its function of being able to accept and retain a piercing pin  20  with acceptable forces. Preferably the material selected for the administrative port housing  90  has a high melt temperature and good elastomeric properties. A material blend is preferred to provide properties not available from individual materials. A polypropylene based material is preferred primarily for its chemical compatibility with the polypropylene fill tube  13 . Further material selection is dependent on radiation stability, autoclave temperature, and the range of piercing pin diameters to be used. Generally, polypropylenes with higher melting points such as homopolymers or copolymers with low ethylene content, for example Total Petrochemicals  7825  that has about 2.4-3.5% ethylene content, withstand autoclaving with less deformation. However, they have relatively high moduli, which increases piercing pin insertion force and limits the range of piercing pin diameters that may be used. They are also less stable to gamma radiation unless purposely stabilized with additives. While their performance may be improved by blending them with lower moduli, radiation stable polyolefins, it is preferable to use a high ethylene content (about 6% or greater) random copolymer as the base material. The high ethylene content improves radiation stability and lowers the modulus while maintaining acceptable resistance to autoclave deformation. It also reduces the concentration of the softening material required. Such softening material often has a lower melting point or is tacky and difficult to injection mold. Preferably a high ethylene content random polypropylene copolymer, such as Total Petrochemicals Z9470, is used for the base material. 
     While an unmodified high ethylene content random polypropylene copolymer may provide acceptable performance with a single piercing pin diameter, it is preferable to soften the material with polyolefin copolymers such as thermoplastic polyolefin elastomers (TPEs) or plastomers to broaden the range of acceptable piercing pin diameters and improve radiation stability. Acceptable performance also may be obtained with low ethylene content polypropylene random copolymer base materials with an appropriate selection of TPE/plastomer and blend ratio. Similar to polypropylene copolymers, softer TPEs and plastomers generally have lower melting points. Ethylene-hexene and ethylene-octene copolymer flexomers or plastomers have very low moduli and melting points (72° C. and 55° C., respectively) substantially below the autoclave temperature of 125° C. However, when blended with a low ethylene content random copolymer at a ratio of 70% polypropylene copolymer/30% flexomer or plastomer, they provide adequate softening and autoclave dimensional stability. An ethylene-octene flexomer or plastomer, such as Dow Affinity EG8100, can be used to reduce piercing pin insertion force. Polypropylene random copolymers with ethylene-propylene rubbers copolymerized in the copolymer matrix, such as Basell&#39;s Adflex materials, provide less softening than flexomers or plastomers but have higher melt temperatures (approximately 144° C.). They are highly suitable for softening a high ethylene content random polypropylene copolymer base material, such as Total Petrochemicals Z9470, because they reduce stiffness without reducing autoclave dimensional stability. Basell Adflex KS359P is one material that has been found to provide effective softening and radiation stability. Blends made from 40% Z9470/60% KS359P to 70% Z9470/30% KS359P may be used, with blends of about 70% Z9470/30% KS359P being more preferred. 
     The port cap assembly  38  must be sealable to both the administrative and additive port housings  90 ,  24  and stable to gamma radiation from 18-45 kGy, or at least 18-32 kGy. It must be autoclavable up to about 125° C. without deformation that significantly affects its function of maintaining sterility and being opened with an acceptable pull force. Key to an acceptable opening performance is developing an appropriate combination of material stiffness and tear detail thickness. The pull ring  68  or pull element  62  may snap off prior to opening the cap  44  with an excessively stiff material or thick tear detail. The pull ring  68  may stretch without opening the cap  44  or the cap  44  may deform during autoclaving with a material that is too soft. Materials that minimally provide the required properties are high ethylene content polypropylene copolymers such as Total Petrochemicals Z9470 and random heterophasic polypropylenes such as Borealis Bosrsoft SD233CF. However, it is preferred to lower the opening force by using a TPE modifier. To maximize sealability to the administrative port housing  90 , it also is preferred that the same materials be used in the same or similar ratio as used in the port housing  90 . Basell Adflex KS359P again is highly suitable in that it provides softening without a loss in autoclave dimensional stability. A range of 100% Z9470/0% KS359P to 70% Z9470/30% KS359P is acceptable, with 70% Z9470/30% KS359P being more preferred. 
     Similar to the administrative port housing  90 , the additive port housing  24  must be sealable to both the fill tube  13  and cap assembly  38  and stable to gamma radiation from 18-45 kGy, or at least 18-32 kGy. It must be autoclavable up to about 125° C. without deformation that significantly affects its function of being able to be pierced by a needle  18  without coring. To resist coring, it is preferred that the selected material has elastomeric properties. Polypropylene random copolymers with ethylene-propylene rubbers copolymers copolymerized in the copolymer matrix, such as Basell Adflex materials, are elastomeric and sealable to the 70% Z9470/30% KS359P port cap. Adflex KS359P is preferred among the Adflex materials for coring performance because it is the most elastomeric in the current Adflex product line. To improve seal strength by maximizing chemical compatibility and to improve ejection during injection molding, it is preferred to use the same materials in the same 70%/30% blend ratio as the cap assembly  38 . To maximize coring performance at the intended port diaphragm  34  thickness of 18 mils, a range of 40% Z9470/60% KS359P to 0% Z9470/100% KS359P is preferred. To optimize injection molding, sealing, and coring performance, a 40% Z9470/60% KS359P blend is more preferred. The range may be adjusted depending upon diaphragm thickness, with thicker diaphragms generally requiring a higher elastomeric concentration. The blend of resins used for the various parts to be sonic or heat welded must provide melting points that are not so dissimilar as to prevent proper sealing security or reliability. 
     With reference to  FIG. 11 , a still further embodiment of administrative port closure assembly  88  includes many of the same features as the embodiment of  FIG. 10 , but instead of the tapered sleeve end further includes a small wiper  116  adjacent the aperture  104  of sleeve  96  to seal against piercing pin set  20  (not shown). The sealing of the wiper  116  against the piercing pin set  20  (not shown) reduces the chance for fluid to leak out during activation. It will be understood to those skilled in the art that various methods including but not limited to swaging at the aperture  104  could be used to form the wiper  116 . The wiper  116  could also be combined with a tapered sleeve end of  FIG. 10 . 
     With reference to  FIG. 12 , a still further embodiment of administrative port closure assembly  88  includes some of the features of the embodiment of  FIGS. 9-11  but further includes a pre-pierced administrative seal washer  118  having a wiping diameter  119 , retained, secured, held, or more particularly (especially once heat sterilized) clamped in place between the retaining rim  54  and an administrative rim  120  extending from shoulder  102 . The administrative seal washer  118  seals against piercing pin set  20  (not shown). To moderate and balance the forces required to insert and withdraw the pin set  20 , the wiping diameter  119  can be centrally located and the pre-pierced diameter can be gradually increased as distance from the wiping diameter increases. 
     With reference to  FIG. 13 , a still further embodiment of administrative port closure assembly  88  includes some of the features of the embodiment of  FIG. 12  but includes an administrative reseal  118 A similar to the reseal element  72  of the additive port closure assembly  22 , retained, secured, held, or more particularly clamped in place between the retaining rim  54  and an administrative rim  120  extending from shoulder  102 . Similar to the reseal element in the additive port closure assembly  22 , the administrative reseal  118 A is clamped by the rims  54  and  120 , especially once the assembly  88  is heat sterilized. The administrative reseal  118 A seals against piercing pin set  20  (not shown). Since the reseal element  118 A completely seals the opening  104  of the sleeve  96 , the diaphragm  110  is optionally excludable in this embodiment. The central diaphragm  121  of the reseal  118 A is relatively thick (greater than 0.050 inch or 1.27 mm) in the embodiment of  FIG. 13 . A still further embodiment can combine the features of  FIGS. 12 and 13  so that the reseal element  118 A includes a thin (0.010-0.050 inch or 0.254-1.27 mm) central diaphragm  121  rather than a pre-pierced opening or wiping diameter  119  or the thick central diaphragm  121  of at least 0.050 inch or 1.27 mm shown in  FIG. 13 . This thin diaphragm configuration is advantageous in that it makes the reseal element easier to mold and does not leave flash in undesirable areas. 
     With reference to  FIG. 14 , a still further embodiment of administrative port closure assembly  88  includes some of the same features as the embodiment of  FIG. 10 , but further includes an either injection molded or extruded administrative sealing washer  118 B with an inner diameter  119 A that seals against piercing pin set  20  (not shown). The sealing washer  118 B is retained, secured, held, or more particularly (especially once the assembly is heat sterilized) clamped in place between the retaining rim  54  and the sleeve  96 . 
     With reference to  FIG. 15 , a still further embodiment of administrative port closure assembly  88  includes a small wiper  116  similar to the embodiment of  FIG. 11 , but the wiper  116  and sleeve  96  form a unitary body that is molded through co-injection molding so that small wiper  116  has a different polymer content than sleeve  96 . The wiper  116  is formed of isoprene and will generate holding forces during activation with the piercing pin set  20  (not shown). 
     With reference to  FIG. 16 , another embodiment of port closure system  10  replaces cap assemblies  38  with cover foils  122 . The cover foils  122  are made of pealable film stock. In this embodiment reseal element  72  is swaged in place. A body portion  124  joins the administrative port assembly  88  and additive port assembly  22 . 
     With reference to  FIG. 17 , a further embodiment of port closure system  10  includes the same features as the embodiment of  FIG. 16 , and further includes a handle element  126  joining the port assemblies  22 ,  88  so as to define a space  127  between the handle portion  126  and the fluid container  12 , thus permitting a user to loop fingers around handle portion  126 . Additionally, additive port assembly  22  is sized smaller than administrative port assembly  88  and is positioned lower with respect to the administrative port assembly  88 , to further distinguish the additive port assembly  22  from the administrative port assembly  88 . 
     With reference to  FIGS. 18-20 , a further embodiment of the additive port closure assembly  22  includes a reseal housing  24  and reseal element  72  as described above. However, the under shell  40 A of the cap assembly  38  differs in some respects from the under shell  40  previously described. The under shell  40 A of the crown  46  includes at least one sealing element  150  for engaging the lip  84  of the reseal element  72 . Preferably the sealing element  150  engages the top surface  89  of the lip  84 . 
     Although one skilled in the art will appreciate from this disclosure that the sealing element  150  can take various forms and shapes, in the embodiment shown, the sealing element  150  includes at least one protrusion  152  that extends downwardly from the under shell  40 A and defines  154 ,  156  troughs on either side thereof. The protrusion  152  can be generally V-shaped in cross section and have angled sides  158 ,  160  that converge to form a blunt, rounded tip  162 . Preferably the protrusion  152  extends around the under shell  40 A in a circular pattern. The circular pattern can be broken to form circumferentially spaced protrusions or can be unbroken to form a continuous annular protrusion. Alternatively, the sealing element  150  can include a plurality of concentrically arranged protrusions  152 . 
     As best seen in  FIG. 20 , the sealing element  150  engages the lip  84  between the under shell  40 A and the interior or inner surface  28  when the under shell  40 A of the crown  46  is connected, attached or joined to the inner surface  28  of the reseal housing  24  as described above. The tip  162  and angled sides  158 ,  160  of the protrusion  152  or sealing element  150  contact and sealingly engage the top surface  89  of the lip  84 . The reseal element  72  resiliently deforms around the protrusion  152 . The engagement of the protrusion  152  with the resilient reseal element  72  provides a clamping force on the lip  84 , clamping it between the protrusion  152  on the under shell  40 A and the inner surface  28  of the reseal housing  24 . When the sealing element  150  includes one or more protrusions  152  arranged a sufficiently closed annular pattern, this arrangement provides an effective seal against liquids, vapors and gases that might otherwise pass around the reseal element  72 . The invention assists in preventing contamination from reaching the inner surface  28  when the user removes the detachable cap  44 . Undesirable ingress and egress of liquids, vapors or gases is prevented during the sterilization of the port closure assembly  22  or the fluid container  12  to which the port closure assembly is attached. This embodiment of the invention provides the additional benefit of further restraining the reseal element  72  against movement that might otherwise occur during insertion or withdrawal of a needle  18  or similar piercing member. 
     One skilled in the art will appreciate that the principles of  FIGS. 18-20  can be applied alone or in combination with other features disclosed herein. By way of example and not limitation, the principles are applicable to administrative port closure assemblies that utilize a reseal element, such as the embodiment of  FIG. 13 . 
     With reference to  FIGS. 4 and 10 , the port housings  24 ,  90 , which are sealingly attached to the cap assembly  38  and fluidly seal the ports  14 ,  16  respectively in one embodiment by attachment to the flange  29  of the fill tube  13 ,  15 , each can include additional beneficial features. The port housing  24 ,  90  has an undercut or annular recess  91  formed on an annular portion of the base face  26  or base surface  92  respectively. The annular portion of the base face  26  or base surface  92  also has a chamfered outer edge  93  and a contact ring  99  located between the annular recess  91  and the chamfered outer edge  93 . In one embodiment the contact ring  99  is smooth, planar and substantially horizontal. The recessed, chamfered, and ringed configuration provides a good contact surface at the ring  99  for attaching the port housing  24 ,  90  to the cap assembly  38  by ultrasonic welding, and later for attaching the port closure system or assemblies  22 ,  88  to the fill tubes  13 ,  15  at the flange  29  by hot tongue welding or other means. The annular recess  91  and the chamfered outer edge  93  also help eliminate or redirect into harmless areas any flash from molding of the port housing  24 ,  90  or hot tongue welding. 
     The construction and fabrication of the flexible container  12  or bag of the present invention will now be described in greater detail. As mentioned earlier, the container  12  includes a container body  1 . As best seen in view of  FIG. 27 , in one embodiment, the container body  1  has front and back portions  3 A,  3 B, which can be separate double wound sheets of flexible multiple layer polyolefin film sealed together by heat sealing or other means along an outer peripheral seam  5 . In another embodiment, the front and back portions  3 A,  3 B could be formed by folding a single sheet of film over upon itself. 
     In one embodiment, a conventional non-PVC polypolyolefin film commercially available from Sealed Air Corporation under the trade designation CRYOVAC M312 is used in the container  12  with the port closure system of the present invention. This material has been found to exhibit excellent compatibility with the non-PVC materials preferred for the fill tubes  13 ,  15  and port closure systems. As best seen in  FIG. 28 , each sheet of the CRYOVAC M312 material defining the front and back portion  3 A,  3 B has five layers. The first layer L 1 , which is also referred to herein as a sealant layer or the inner layer, is a polypropylene layer that is adapted to be heat sealed, welded or fused to itself using conventional attachment techniques, including but not limited to heat welding. The second layer L 2 , which is also referred to as a base, outer or release layer, is a polyester layer adapted to contact and release from the heat sealing tool. A polyethylene middle barrier layer L 3  is disposed between the inner and outer layers L 1 , L 2 . An inner tying layer L 4  is located between the middle layer L 3  and the inner layer L 1 . An outer tying layer L 5  is located between the middle layer L 3  and the outer layer L 2 . The tying layers L 4 , L 5  attach the first layer L 1  and the second layer L 2  respectively to the third or middle layer L 3 . 
     Containers  12  filled with approximately 500 ml or 1000 ml of medical fluids, with the port closure system  10  described herein and a container wall  3  of CRYOVAC M312 film having an overall thickness of about 8 mils have been shown to provide a shelf life up to or greater than 24 months and a moisture vapor transmission rate (MVTR) of less than about 0.060 g/100 in 2 -day. On-going tests indicate that the shelf life might be extendable up to 36 months, dependent on acceptable fill volume and assay values for the product. Containers  12  of 500 ml or larger made of this film and the port closure system disclosed herein do not require supplemental moisture barriers or overwraps on the individual containers to achieve these results. As shown in Table 2 below, these containers  12  compare favorably in terms of MVTR to conventional containers constructed of monolayer PVC film. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Direct WVTR Rate Comparison Between 
               
               
                 PVC and Polyolefin Container 
               
            
           
           
               
               
               
            
               
                   
                   
                 Test Result 
               
               
                   
                   
                 (Tested at 25 Deg. C. and 
               
               
                   
                 Material 
                 40% RH) 
               
               
                   
                   
               
               
                   
                 PVC without overwrap 
                  0.24 g/100 sq. in. - day 
               
               
                   
                 Polyolefin (CRYOVAC M312) 
                 0.053 g/100 sq. in. - day 
               
               
                   
                   
               
            
           
         
       
     
     The polyolefin container  12  can be fabricated by taking double wound film from either a blown film or cast film process and feeding it into a bag fabricator as a continuous web. The containers  12  or bags are normally made side by side on the web of film with the fill ports  13 ,  15  protruding from one edge of the web. 
     The film first has label copy applied to it via one or more conventional processes. Hot stamping, lithography, thermal transfer printing or a combination of these can be employed to place any necessary label information onto the container. 
     The film is then opened and fill tubes  13 ,  15  are place between the two film sheets or front and back portions  3 A,  3 B as illustrated in  FIG. 26A . The fill tubes  13 ,  15  are then heat sealed to the two sheets of film or the front and back portion  3 A,  3 B by a tool T. 
     The film is then passed through a perimeter sealing press that further seals the fill tubes  13 ,  15  between the sheets  3 A,  3 B, creates the perimeter or outer peripheral seal  5 , and separates the containers. 
     The individual bags are then turned so that the fill tubes  13 ,  15  extend vertically. Then the fluid reservoir  2  of the container body  1  is filled with a predetermined volume of medical solution through one or more of the fill tubes  13 ,  15 . Of course, only one fill tube may be sufficient for some applications. 
     The top of the fill tube flanges  29  is then radiantly heated to accept the port assemblies  22 ,  88 . Simultaneously, the base face or base surface  26 ,  92  of the port housings  24 ,  90  is radiantly heated. The heat source is then removed and the port assemblies  22 ,  88  and the fill tubes  13 ,  15  are pressed together under controlled pressure and time conditions. 
     Another way of bonding the port assemblies  22 ,  88  to the fill tubes  13 ,  15  is via ultrasonic welding. In this process the port assemblies  22 ,  88  and the fill tubes  13 ,  15  are pressed together while ultrasonic energy is passed through them. Once the ultrasonic energy has been applied, the parts continue to be held tightly together until the materials have resolidified. 
     The filled containers  12  are placed into an autoclave for steam heat sterilization to assure that the final product is sterile. The container contents are steam sterilized using a cycle of 121+4/−0 degrees C. with a peak dwell of 15 minutes for the coldest container. 
     A plurality of the individual filled containers  12  are then placed in a shipping carton, stored, eventually shipped to a user. 
     The flexible container or IV bag  12  of  FIG. 25  has substantially straight longitudinal sides. The container has an outer peripheral seam  5  that joins together the front and back portions  3 A,  3 B of the container wall  3 . The seam  5  can be formed by well known conventional processes, including but not limited to heat welding, ultrasonic welding, etc. The seam  5  or weld extends straight along the substantially straight longitudinal sides of the container body  1  and curves in a convex manner at the corners of the bag  12 . However, it has been discovered that changes in the path of the outer peripheral seam  5  of the container  12  near the corners can cause kinking, wrinkling and undesired tacking together of the material in the interior of the container near the corner when the bag  12  is filled. The tacking is especially evident after autoclaving, may detract from the clarity of the film, may adversely affect drainage, and may be perceived by users as a defect of the bag  12  or its contents. 
     The present invention provides a solution to these problems by providing a flexible fluid container or bag  12 , as exemplified in  FIGS. 25A ,  25 B and  27 . The container or bag  12  has a flexible elongated container body  1 . As seen in  FIG. 27 , the body  1  has a fluid reservoir  2  formed therein. The fluid reservoir  2  is surrounded by a container wall  3  that includes front and back portions  3 A,  3 B. 
     The container body  1  has a pair of generally opposing longitudinal side edges  37 ,  39 . Although many symmetrical and non-symmetrical shapes are possible without detracting from the invention, a symmetrical shape is illustrated such that the container body  1  has a central longitudinal axis  41 . The container body  1  includes a top edge  43  and a bottom edge  45  opposing the top edge  43 . The top edge  43  and the bottom edge  45  extend transverse to the central axis  41  of the container body  1 . The container body  1  has a hole  47  formed therethrough adjacent the top edge  43  for hanging the container  12 . The container body  1  also has a pair of sealed ports, for example as previously described, at the bottom edge  45 , although other port structures and configurations will not detract from this aspect of the invention. The front and back portions  3 A,  3 B of the container wall  3  are sealed together by heat sealing, adhesive, bonding, welding or other conventional joining means along an outer peripheral seam  5  to form the reservoir  2  so as to contain fluid therein. The outer peripheral seam  5  extends adjacent to at least one of the opposing longitudinal side edges  37 ,  39 . 
     In one embodiment, the seam  5  follows on a concave path with respect to a longitudinal axis of the container body  1 , such as the central longitudinal axis  41 , without regard to the path of the longitudinal side edge  37 ,  39  to which it is adjacent. In another embodiment, the seam  5  follows a concave path with respect to both the central longitudinal axis  41  and at least one of the side edge or edges  37 ,  39  to which it is adjacent. In other words, at least one of the longitudinal side edges  37 ,  39  is substantially straight and the outer peripheral seam  5  curves inwardly with respect to that side edge  37  or  39 . The distance between the longitudinal side edge  37 ,  39  of the container and the seam  5  generally increases as the seam approaches the middle of the container and decreases as the seam  5  approaches the top and bottom ends of the container. In another embodiment, such as illustrated in  FIG. 25A , both of the opposing longitudinal edges  37 ,  39  are straight and the seam  5  curves inwardly with respect to both of the opposing longitudinal edges  37 ,  39 . In yet another embodiment shown in  FIG. 25B , the longitudinal side edges  37 ,  39  also curve inwardly. The side edges  37 ,  39  can vary in distance from or be parallel to the curved seam  5 . The latter embodiment can be helpful in reducing the amount of material present in the finished container  1  without endangering the integrity and reliability of the welded seam  5 . 
     Although other paths for the curved peripheral seam  5  are contemplated, a generous (full or nearly full) radius extending along nearly the entire inside edge of the seam  5  as shown in  FIGS. 25A and 25B  produces good results. On a bag  12  approximately 9.25 inches long and 4.0 inches wide, a concavity ratio of bag length over concavity (the maximum offset inwardly of the inside edge of the seam versus a real or hypothetical straight outside edge of the seam or bag) of approximately 53 produced good results. On the other hand, a concavity ratio of approximately 29 on a 7.25 inch bag failed to reduce wrinkles and film blocking. On this basis, it is believed that a concavity ratio of at least about 35 is desirable and that concavity ratios in a range of about 40 to 70 will significantly reduce wrinkles and film blocking that might otherwise occur upon autoclaving of the container  12 . 
     The front and back portions  3 A,  3 B can be formed in a variety of ways and from a variety of materials, including but not limited to the film can be the low MVTR polyolefin DEHP-free and PVC-free multiple layer film previously discussed in this application, without departing from the scope of this aspect of the invention. In one embodiment, the front portion  3 A and the back portion  3 B can each be formed of a separate sheet of flexible film. The film of the front portion  3 A can be identical from a materials standpoint to the film of the back portion  3 B or differing films and/or materials can be used. In another embodiment, the front portion  3 A and the back portion  3 B are formed from a unitary sheet of the film that is folded along the top, bottom or side to form the front portion  3 A and the back portion  3 B. This positions the inner layer of the front portion  3 A in facing or superimposed relation to the inner layer of the back portion  3 B. 
     The shape of the front portion  3 A can also differ from the shape of the back portion  3 B. The shape or shapes of the front and back portions  3 A,  3 B can be multilateral. By way of example only and not limitation, the sheet or sheets of film that make up the front and back portions  3 A,  3 B cam be substantially rectangular. 
     The container of the present invention with a curved side seam is easy to grasp and handle, resistant to interior and exterior wrinkling, and resistant to tacking or blocking of the film inside the container near the corners. 
     One skilled in the art will appreciate that the present invention can be applied to flexible containers for enteral nutritional or other medical fluids as well. 
     From the foregoing, it can be seen that the present invention accomplishes at least all of the stated objectives. The invention provides a port closure system that reduces the possibilities of contamination during storage and use, improves the ease of handling when fluids are to be withdrawn or introduced, and increases the ease and efficiency of manufacture. The invention provides a container that is free of PVC and DEHP. The container has a low MVTR, which enables greater manufacturing tolerances around the target fill volume.