CONTAINER FOR MEDICAL FLUIDS

Abstract: A collapsible medical container having an integrated non-collapsible capillary tube, formed by the production tools when blow moulding the container, for determining the level of remaining fluid during the administration to the patient.

Description: Container for medical fluids Field of invention The present invention is directed to a collapsible medical container having an integrated non-collapsible capillary tube, formed by the production tools when blow moulding the container, for determining the level of remaining fluid during the administration to the patient. Background of the invention In the handling of collapsible containers for medical fluids, there has been a problem to correctly determine the level of remaining fluid during the administration to the patients, due to the distortion of the pre-printed volume scale on the wall when the container gradually collapses. It has therefore been previously attempted by manufacturers to overcome this problem, in order to provide collapsible containers by which both the medical staff and the patients easily can survey the infusion procedure. The German patent DE 38 26 456, in the name of Fresenius AG, discloses a bag arrangement by which determination of the liquid level is possible, independently of its collapse. This arrangement comprises a separate non- collapsible tube in communication both with the chamber constituting the collapsible bag and with the environment through a bacterial filter. It is, however, a rather complicated system that must be separately assembled by several independent pieces after the manufacture of the collapsible bag. It will also consist of a number of different materials which in order to be recycled must be dismembered and individually collected. Such a bag will in most cases be disposed without the opportunity of recollection and will therefore not comply with the requirements that many medical authorities will demand on medical articles to be introduced on the market. The U.S. patent 4,639,251, discloses another solution to this problem by providing a flexible bag containing medical liquids having a hquid level indicating device consisting of a pair of spaced apart rollers which are used to manually stretch the collapsible bag and to obtain a correctly readable liquid level. Besides being laborious to use, this construction has the same drawbacks as the previously mentioned arrangement, because it is made from several parts. It would therefore be highly desirable to provide a collapsible bag which could be more environmental friendly and which will admit an easy reading of the liquid level. Description of the invention It is an object of the present invention to provide such a collapsible medical container for medical fluids that can both withstand autoclavation and easily be recycled to new containers in a single process. Another object of the present invention is to provide a collapsible medical container from which it is easy to determine the remaining amount of medical fluid without being forced to any additional measures. This is attained by the container according to claim 1, having a capillary tube for liquid level measuring made in the same process and in the same material to make it cheap and environmental friendly by its capacity of being easy to recycle in a single process. Fig. 1 schematically shows a side view of container according to the present invention. Fig 2. is a schematical cross-sectional view of the container along the line A-A of the container shown in Fig. 1. The present invention is related to a blow moulded, collapsible container made of a polymeric material intended to store and administer a medical fluid. A predetermined part of the container comprises a stiffened capillary tube which when filled with said fluid together with a printed scale on the container wall, also formed with the same moulding step, enables a correct determination of the liquid level and the remaining volume of administerable fluid, when the container gradually collapses during the administration. The collapsible container is preferably made sufficiently flexible so that its opposing sides readily come together when the medical liquid is administered by the gravity or by a pump device. The stiffened capillary tube is formed as an integrated part of the container wall, when blow moulding the container from a parison of polymeric material by means of a moulding tool with a suitable correspondent shape. The moulding tool preferably has a shape corresponding to the cross-sectional shape, as seen in Fig. 2. Two oppositely placed capillary tubes are thereby formed when the two rims of the polymeric material are stiffened in the tool. It is however, fully conceivable to, within the scope of invention, to select moulding tools with other shapes which for example forms a single capillary tubing. As best comprehended by the schematic Fig. 1, a predetermined part of the parison is formed to parallel rims stiffened to capillary tubes, whereas the remaining part of the parison can be formed and conventionally sealed in its bottom and its top to a flexible container, for example to the illustrated bottle-formed shape. As also demonstrated in Fig. 1 , the bottom of the container can be made with a means for mounting during the sealing, and after filling the container, the top can be formed with a cap by means of a top forming tool, for example as disclosed in the Swedish patent apphcation 9303123-5. The top and the bottom parts of the container are preferably formed to shoulders and the capillary tubes will extend a predetermined distance into these curved parts. Preferably, the capillary tubes will extend to the point of said curved parts where the radius of curvature has its maximum. The precise arrangement of this forming process can by means of conventional tools and the appropriate dimensions of the container and its parts therefore can be readily determined by the skilled person. It is preferred that all the parts of the containers according to the invention are produced by essentially the same polyolefin or at least comprise the same polyolefin as an essential component. It is to be understood that to a certain degree other polymeric materials, such as the elastomers incorporated in Santoprene® may be used in resilient parts of the cap or the ports. Preferred polymeric materials for forming the inventive containers are polyethylene or polypropylene of various medical grades with good transparency and capacity of withstanding heat or radiation sterilization without suffering from degradation and reduced compatibility with the liquid during storage. The inventive containers are suitable for the storage of about 100 to 2000 ml of a wide range of storage sensitive medical fluids, like rinsing fluids, parenterally administerable drugs and parenteral nutrients comprising lipid emulsions, amino acids and carbohydrates. The method of producing preferred embodiments of containers according to the invention is a blow-fill-seal method, whereby a parison of polymeric material is formed in suitable tool with an extruder, in the same manner as disclosed in the Swedish patent application SE 9303123-5. The capillary tubes, thereafter are blow formed on a predetermined part of the parison by the stiffening of opposite rims in a moulding tool having a shape corresponding to the cross-sectional shape, as shown in Fig. 2, into straight, parallel capillary tubes. The bottom of the parison is then formed to a desired container shape and sealed by a conventional welding process and optionally mounting a mounting device is formed to conveniently handle the container during the administration. The container is thereafter filled with medical fluid with a conventional aseptic or sterile filling procedure and sealed at the top with a conventional top forming tool, whereupon a pierceable cap or a conventional saddle port for fluid communication is attached. The remaining volume of medical fluid be easy to read accurately from containers produced in this manner, even if the container body succesively collapses during the administration. The containers are cheap and simple to produce from polymeric material possible to recycle in a single operation. They will have the advantage of a low residual volume, no introduction of environmental air to the admimstration system, when filled they have a low headspace and most importantly, they will enable a correct volumetric reading without any extra measures although the container gradually collapses during the administration.

Claims: Claims 1. A blow moulded autoclavable collapsible container made of a polymeric material intended to store and administer a medical fluid provided with a scale to determine the level of fluid characterized in that it has a stiff capillary tube filled with said fluid in connection with said scale, which is an integrated part of the container wall. 2. Container according to claim 1, wherein said capillary tube is formed when blow moulding the container from a parison of polymeric material by forming a rim which is stiffened in a coπespondingly shaped moulding tool. 3. Container according to claim 2, wherein oppositely place rims are formed into capillary tubes along a predetermined part of the parison by means of said shaped moulding tool. 4. Container according to any preceding claim characterized in that its parts consists of substantially the same polyolefin. 5. Method of producing a collapsible container of having means integrated in its walls for correctly reading the level of its remaining contents characterized by blow forming a parison of a polymeric material, forming and stiffening at least one rim to at least one capillary tube by means of a correspondingly shaped moulding tool, forming and sealing the bottom of container, filling said container with a medical fluid and sealing it by forming a sealing cap with a top forming tool. 6. Method according to claim 5 wherein two oppositely placed parallel tubes are formed by said moulding tool.

Inventors: ANDERSSON GUNNAR, PETTERSSON BERT, ANDERSSON, GUNNAR, PETTERSSON, BERT
Applicants: PHARMACIA & UPJOHN AB
Application year: 1996
Main classification: A61J1
IPC codes: A61J1