EP0288250A2

EP0288250A2 - Retortable liquid dispensing bags

Info

Publication number: EP0288250A2
Application number: EP88303530A
Authority: EP
Inventors: David Scarrow
Original assignee: DRG UK Ltd; DRG Flexpak Ltd
Current assignee: DRG Medical Packaging Supplies Flexpak Ltd
Priority date: 1987-04-23
Filing date: 1988-04-20
Publication date: 1988-10-26
Also published as: GB8709653D0; EP0288250A3

Abstract

A liquid dispensing bag 10 has at least one port 16;20 with an inner closure 24 and a removable outer closure 26;40 provided by a plug 26;40 which is sealed into an outer portion of the port which can be torn away. The tearing away is facilitated by a line of weakness 34 A radial flange 36;43 on each side of the line of weakness 34 protects the surface exposed by tearing from finger contact. The plug 26;40 has a major portion 30 that is sealed into the removable portion of the port, and a portion 32 of lesser diameter that extends towards the inner closure 24. This reduces the volume of air trapped between the closures, and hence the risk of problems due to expansion on autoclaving. The major and lesser portions are connected via a chamfer 31;41. This is located adjacent the line of weakness 34, and acts to prevent the flanges from being welded together on autoclaving.

Description

The present invention relates to liquid dispensing bags which can be sterilised by heating. It is particularly concerned with bags for medical applications, e.g. for use with parenteral, irrigation and dialysis fluids.
A type of bag which is generally known is made of plastic film, and has one or more ports (provided by separate tubes) which are sealed between front and back portions of plastic film material, so as to extend from the interior of the bag to the exterior. Generally, when a filled bag is sent to its ultimate user, each port is sealed at its outer end, in a manner that allows the user to open it when required. Thus, as disclosed in our British patent specification GB 2,160,184, there may be a weakened region provided between a pair of radial flanges. The outer part of the port can thus be torn away, the flanges shielding the tear region from finger contact. To be effective, the flanges must be close together. There is thus a risk that they will become sealed together if the bag is heat-sterilised (particularly if it is first overwrapped and then autoclaved).
Various types of port also have an intermediate closure. Thus when the user opens the outer end of a port, the bag is still sealed by some form of ruptural membrane, through which he may then insert a hypodermic needle or spike. Thus the bag as manufactured includes a port having two spaced closures. The volume between them will usually contain air or other gas. If the bag is heated for sterilisation, this gas endeavours to expand, and there is a danger that something will rupture. It is therefore known to furnish ports with expansion chambers. However, this is often undesirable, since it adds yet more constraints on the design and manufacture of the bag.
We have found that the use of a novel form of plug for closing a port can ameliorate these problems.
Thus the present invention provides a liquid dispensing bag having a port extending from the interior to the exterior of the bag; the port having an inner closure and an outer closure and, between them, tear-off means comprising a weakened region and a pair of closely spaced radial flanges, one on each side of the weakened region; the outer closure being provided by a plug member having an outer sealing portion and a spigot portion of lesser diameter which extends within the port towards the inner closure so as to reduce the gas space in the port; the transition between the sealing and spigot portions being a chamfered region which extends across at least an outer portion of the weakened region.
Surprisingly, it has been found that insertion of such a plug so that the chamfered region is properly positioned has the effect of urging and/or holding the flanges apart, so that they are much less susceptible to mutual welding. The outer portion may be sealed into the port on autoclaving.
The outer sealing portion must not extend into the weakened region, or it may seal to the port wall therein and interfere with tearability. The chamfer must extend across at least the outer portion of the weakened region or the resistance to mutual welding of the flanges is not achieved.
An embodiment of the invention will now be described in greater detail with reference to the accompanying drawing, in which:

Fig. 1 is a schematic view, partly in section, of an end region of a bag embodying the invention;
Fig. 2 is a view of an administration port after opening; and
Figs. 3 and 4 are like views of the opened port with further components inserted.

The bag 10 is made from transparent plastics film peripherally sealed to form a liquid enclosure 12. A plurality of ports (in this example four) are sealed into the bag at one end, by the pattern of heat seals 14. Each port comprises a tubular conduit which extends from the liquid enclosure 12 to the exterior. The ports shown are a giving port 16; a filling tube 18; an administration port 20; and an additional port 22. The giving port 16 is closed by an intermediate membrane 24. This membrane 24 is located interiorly of the outer bag seals 14. Thus the port 16 can be RF welded into position using electrodes movable into a welding position from outside the bag (one electrode being passed into the port through the outer end).
The port 16 also has an outer closure provided by a plug 26. The plug has an outer cap portion 28, a sealing portion 30, and an inner spigot portion 32 which terminates slightly above the membrane 24. The transition between the sealing portion 30 and the spigot portion 32 is formed as a chamfer 31. The outer portion of the giving port 16 is adapted to be torn away together with the plug 26 (most simply by a twisting motion). In this example, this is achieved by means of a formation as disclosed in our specification GB 2,160,184. Thus, just above the edge of the bag 10, there is a weakened region 34 between a pair of radial flanges 36. Above the flanges, there are finger grips 38. As explained in our earlier specification, the radial flanges 36 are very close together so as to assist in keeping the ultimate user's fingers away from contact with the ruptured edge of the port when the outer end portion is torn away.
The sealing portion 30 of the plug is a tight fit within the port, and the material is such that, when the bag is autoclaved, a seal is produced. Indeed, both of the sealing portion 30 and the spigot portion 32 have relatively greater diameters than are shown in the schematic drawing. Thus the spigot portion 32 occupies most of the internal volume of the port between the sealing portion 30 and the membrane 24, but without substantial frictional engagement; and it does not seal on autoclaving. The chamfer 31 is accurately located so as to extend in the region between the flanges 36. It is found that the act of inserting the plug 26 at the correct depth displaces the flanges 36 slightly, and holds them apart.
The administration port 20 has a similar plug 40 and tear-off formations 42. Again, the plug 40 has a chamfer 41 located so as to bridge the region between the flanges 43 of the tear-off formations 42. On top of the membrane 24, there is a rubber septum 44 located within the port. A needle guide 46 extends for some way above it. Again, the intermediate membrane 24 is located inwardly of the outer bag seal. As well as permitting RF welding of the port, this enables the membrane 24 to shield the septum 44 from liquid in the bag.
The filling port 18 has a simple seal 48 at its outer end. There is no intermediate seal and so it does not need arrangements as provided for the giving and administration ports 16,20. The additional port 22 has a snap-off closure arrangement 50 located just above the top of the bag. This may be as disclosed in WO 81/01105 of Baxter Travenol Laboratories Inc.. At its outer end, it has a formation 52 for releasably engaging a cap. The formation may be a pair of flanges forming part of a Luer lock. An injection site cap or a simple screw closure cap may be applied.
Much variation is possible in the use of the invention. Many different types of port and combination of port may be used. For example, an administration port may be "swabbable". This can be achieved by omitting the needle guide and having the rubber septum adjacent the tear-off line. Desirably, the septum is shaped to serve as a needle guide. Thus a septum could resemble in form an elongated combination of the septum 44 and guide 46 shown in the figure, but be installed the other way up, with its flat head adjacent the tear-off line.
Fig. 2 shows an administration port 20 which has been opened, i.e. after the outer portion has been torn away (together with the plug 40). Material may then be injected into the bag, via a syringe needle passed through the guide 46 and septum 44. The port 20 may then be closed by inserting a closure plug 60 as shown in Fig. 3. This is intended to be non-removable. Thus it has a simple cylindrical head 62 which is received almost wholly within the port 20.
Some users prefer to inject material via a swabbable port. To cater for this we provide a swabbable insert plug 64 which can be pressed into an opened port 20, as shown in Fig. 4. The plug 64 has a head portion 66; a body portion 68 that fits sealingly within the port 20; and a spigot portion 70 that fits within the needle guide 46. The plug has an axial hole 72, which may open out at the top to guide in a needle. The hole 72 is closed by a swabbable rubber septum 74 which is clamped to the top of the head portion 66 by a cap 76 which embraces the head portion and has a central aperture 78 in register with the hole 72.
After use, the insert plug 64 may be removed and replaced by a closure-plug 60.

Claims

1. A liquid dispensing bag (10) having a port (16;20) extending from the interior to the exterior of the bag (10); the port (16;20) having an inner closure (24) and an outer closure (26;40), the outer closure being provided by a plug member (26;40) having an outer sealing portion (30) and a spigot portion (32) of lesser diameter which extends within the port (16;20) towards the inner closure (24) so as to reduce the gas space in the port; the transition between the sealing and spigot portions (30;32) being a chamfered region (31;41); the port (16;20) having tear-off means between the closures (26;40,24) comprising a weakened region (34) and a pair of closely spaced radial flanges (36;43), one on each side of the weakened region; characterised in that the chamfered region (31;41) extends across at least an outer portion of the weakened region (34).

2. A liquid dispensing bag according to claim 1 wherein said port is an administration port (20); and including a swabbable insert plug (64) adapted to be sealingly inserted into the port after the outer portion has been torn away; the swabbable insert plug comprising a plug portion (68) with an axial hole (72) closed at the top by a swabbable septum (74).

3. A liquid dispensing bag according to claim 1 or claim 2 having an administration port (20) and a giving port (16) each having a said inner closure (24), an outer closure provided by a said plug member (26;40), and a said tear-off means (34,36;43).