Abstract:
The combination of a bag and tubes connected thereto for use in pharmaceutical manufacturing and for holding health care related solutions is formed entirely of silicone. This avoids the previous problem of the releasing into the held fluids of plasticizers or plastic additives contained in the PVC material making up prior bags.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a bag assembly for use in pharmaceutical manufacturing and for holding health care related solutions and, more particularly, to an improved bag assembly manufactured of silicone. 
     At the present time, virtually all bags used by the pharmaceutical industry and for holding health care related solutions (such as intravenous bags) are manufactured of polyvinyl chloride (PVC). PVC is a commonly used inexpensive plastic material which is naturally hard. To soften such material so that it can be used as a flexible bag and as flexible tubing, plasticizers such as phthalate esters are added to the PVC to soften it. Recently there has been concern that phthalates may leach from the PVC to which they have been added, thereby contaminating aqueous fluids held in PVC bags and traveling through PVC tubing. Since PVC bags are used to store intravenous solutions and blood for transfusions, phthalates which leach from the PVC are infused directly into a patient&#39;s bloodstream. It would therefore be desirable to have a phthalate-free bag and tubing for such purposes. 
     SUMMARY OF THE INVENTION 
     It is known that silicone is a relatively inert chemical in aqueous solutions, i.e., it does not react with contacting liquids or leach chemicals into contacting liquids. Accordingly, the present invention provides the combination of at least one silicone tube having an open central passageway and a flexible silicone membrane formed into a tubular shape with opposed ends. The membrane tubular shape is larger in diameter than the tube. Each tube extends into a respective end of the membrane so that the respective open central passageway of the tube is in communication with the interior of the tubular shaped membrane. Each of the membrane ends is flattened and sealed to itself and to a respective tube, thereby forming a bag assembly. 
     In accordance with an aspect of this invention, the flexible silicone membrane is formed as a seamless tube. 
     In accordance with another aspect of this invention, the flexible silicone membrane is a silicone sheet having opposed edges overlapped and joined together so that the membrane attains a tubular configuration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing will be more readily apparent upon reading the following description in conjunction with the drawings in which like elements in different figures thereof are identified by the same reference numeral and wherein: 
     FIG. 1 is a plan view of a first embodiment of the present invention; 
     FIG. 2 is a perspective view of an alternate embodiment of the present invention; 
     FIG. 3 is a cross sectional view taken along the line  3 — 3  in FIG. 1; and 
     FIG. 4 is a cross sectional view taken along the line  4 — 4  in FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, FIG. 1 shows a first embodiment of a combination of a silicone bag and tubes constructed according to the present invention. As shown, the inventive combination, designated generally by the reference numeral  10 , includes a flexible silicone membrane  12  which is formed as a seamless thin-walled tube having opposed ends  14 ,  16 . The difference between the embodiment shown in FIG.  1  and the embodiment shown in FIG. 2 is that in FIG. 2, the membrane  18  is originally a sheet and is formed into a tubular shape by having its opposed edges  20 ,  22  overlapped and joined together, as by adhesive or the like, to attain a tubular configuration. (Liquid silicone is a preferred adhesive.) In all other respects, the embodiments shown in FIGS. 1 and 2 are identical. 
     The inventive combination  10  also includes a pair of silicone tubes  24 ,  26 . Each of the tubes  24 ,  26  has an open central passageway  28  (FIG.  4 ). The wall of each of the tubes  24 ,  26  is considerably thicker than the membrane  12 , so that each tube  24 ,  26  is not as flexible as the membrane  12 . 
     The tubular shape of the membrane  12  is larger than the diameter of each of the tubes  24 ,  26  (which are preferably, but not necessarily, equal in size) and each of the tubes  24 ,  26  extends into a respective one of the opposed ends  14 ,  16  of the membrane  12  so that the respective open central passageway  28  of each tube  24 ,  26  is in communication with the interior of the tubular shaped membrane  12 . Preferably, the tubes  24 ,  26  are arranged substantially coaxially. Each of the ends  14 ,  16  of the membrane  12  is flattened and sealed to itself and to a respective one of the tubes  24 ,  26 , as by adhesive or the like. Thus, the membrane  12  forms a compartment, or bag, of variable capacity. The maximum capacity of a bag is determined by the spacing between the opposed ends  14 ,  16  and by the diameter of the tube formed by the membrane  12 ,  18 . 
     At the distal end of each of the tubes  24 ,  26  remote from the membrane  12 , the tube is terminated by a silicone flange  30  surrounding the open central passageway  28 . A stainless steel backup cup  32  having a central bore  34  is slidably mounted on each of the tubes  24 ,  26 . The backup cup  32  has an inner surface portion  36  which is complemental to the surface  38  of the flange  30  which faces the membrane  12 . The surface  36  of the backup cup  32  is terminated by a flange  40 . Thus, the backup cups  32  provide support for the flanges  30  and allow a pair of tubes  24 ,  26  to be coupled together by clamps secured to the flanges  40 , holding the flanges  30  so that there is communication between the passageways  28  of the tubes which are coupled together. 
     The assembly  10  can be constructed to have any desired capacity. As presently contemplated, the capacity will probably be in the range from about 750 ml up to about 5 liters, but larger capacity assemblies, even up to one thousand liters, are within the scope of this invention. Further, the assembly  10  is not limited to any specific use, although it is presently contemplated that it will be used for storage (and cryogenic shipment) of intermediate or concentrated drug products during manufacture in an industrial setting. 
     Accordingly, there has been disclosed an improved bag assembly for use in pharmaceutical manufacturing and for holding health care related solutions which does not release any plasticizers or plastic additives into the solutions. While illustrative embodiments of the present invention have been disclosed herein, it is understood that various modifications and adaptations to the disclosed embodiments are possible and it is intended that this invention be limited only by the scope of the appended claims.