Multiple chamber flexible container

A flexible container comprises a receptacle divided into two chambers by an openable, fluid-tight barrier formed between the interior surface of the receptacle and the exterior surface of a hollow member contained in the receptacle. The barrier is maintained closed by a removable sealing band applied around the exterior of the receptacle. The removal of the band allows the wall surface of the receptacle to separate from the exterior surface of the hollow member, thereby opening a passage between the two chambers. The container is manufactured by a process comprising the steps of: (a) providing a tube of resiliently-deformable material; (b) sealing a first end of the tube; (c) expanding the tube to a desired shape; (d) partially filling the expanded tube with a first material; (e) inserting an uninflated balloon into the expanded tube; (f) inflating the balloon so that its exterior surface is spaced from, and proximate to, the interior surface of the tube; (g) applying the sealing band around the exterior surface, of the tube with sufficient tightness to sealingly close the space between the balloon and the tube; (h) filling at least part of the tube between the balloon and the second tube end with a second material; and (i) sealing the second tube end.

BACKGROUND OF THE INVENTION 
This invention relates generally to the field of flexible containers or 
bags of the type commonly used in the medical field for storing materials 
to be delivered to a patient intravenously or parenterally. More 
particularly, it relates to such a container which is divided into two or 
more compartments or chambers, each holding a different material, wherein 
the compartments are separated by a removable barrier, so that the 
contents of the compartments can be allowed to intermix prior to 
administration to the patient. 
In the medical field, it is often necessary, when administering intravenous 
medication or parenteral nutrition, to combine two or more materials which 
must be stored separately. For example, parenteral nutrition frequently 
makes use of a solution of dextrose and amino acids. Such a solution 
cannot remain stable for extended periods of time; hence separate storage 
of the dextrose and the amino acids is necessary. Also, certain drugs that 
are administered intravenously can only be stored in a dry, powdered form, 
and must therefore be dissolved in a liquid diluent prior to 
administration. 
While the two (or occasionally more) components of the intravenous or 
parenteral solution must be separately stored, it is obviously necessary 
to provide for a quick and convenient mixing of the components in a 
closed, sterile system just prior to administration. To this end, flexible 
containers have been devised, in various configurations, with multiple 
chambers or compartments separated from each other by selectively 
rupturable or frangible seals or barriers. For example, U.S. Pat. Nos. 
4,519,499; 4,465,488; and 4,458,811 disclose multi-chambered containers 
for medical applications, wherein the chambers are separated by a 
frangible barrier. Other containers having a frangible or rupturable 
barrier between two or more compartments are disclosed in the following 
U.S. Pat. Nos.: 3,175,558; 3,294,227; 3,429,429; 3,462,070; 3,608,709; 
3,744,625; 3,756,389; 3,891,138; 3,964,604; 3,950,158; 3,983,994; 
4,000,996; 4,226,330; 4,227,614; and 4,402,402. 
Prior art containers which utilize a rupturable barrier or seal have 
several drawbacks. Specifically, in many prior art devices, the action of 
mechanically breaking or rupturing the barrier or seal must be undertaken 
with a great deal of care, lest damage result to the container itself. In 
addition, in some prior art containers of this type, there is a 
possibility of some fragmentation of the barrier or seal. While in many 
applications such fragmentation might not present any significant problem, 
in some applications, such as intravenous infusion, the danger of injury 
to the patient may be present. As a result, many practitioners in the 
medical field find the prior art multi-chamber containers difficult or 
inconvenient to use. 
In most, if not all, of the frangible-barrier devices, the strength of the 
seal or barrier, and therefore the force needed to break it, depend, in 
substantial part, upon the physical characteristics of the material 
forming the barrier. Thus, to assure uniformity in the strength of the 
seal or barrier, its physical specifications must be precisely controlled, 
thereby adding to the cost of such containers. Moreover, the relatively 
complex structure of such frangible seals and barriers also adds to the 
cost of manufacture. Such relative complexity, however, was felt to be 
unavoidable due to the need to provide good seal integrity while 
minimizing the chances of inadvertent rupture. 
Thus, there has been a long-felt, but as yet unsatisfied, need for a 
multi-chamber container in which the chambers remain isolated from each 
other until the mixing of their respective contents is desired, and yet 
which provides this function with a sealing mechanism that is both 
economical to manufacture and easy to use without undue concern about 
either inadvertent inter-chamber leakage or damage to the container 
itself. 
SUMMARY OF THE INVENTION 
Broadly, the present invention is a flexible container comprising an 
elongate, close-ended flexible receptacle divided into two compartments by 
an openable, fluid-tight barrier formed between the exterior surface of a 
hollow member contained in the receptacle and the interior wall surface of 
the receptacle itself, wherein the barrier is closed by removable sealing 
means applied around the exterior of the receptacle. The removal of the 
sealing means allows the wall surface of the receptacle to separate from 
the exterior surface of the hollow member, thereby opening a passage 
therebetween which allows communication between the two compartments and 
the intermixing of their respective contents. 
In a specific preferred embodiment of the invention, the hollow member is 
an inflated balloon or bubble of resilient plastic material, and the 
sealing means includes a strip or band of flexible material that is 
removably applied or wrapped around the exterior of the receptacle so as 
to bring the interior wall surface of the receptacle into sealing 
engagement with the exterior surface of the balloon. This sealing 
engagement thus divides the receptacle into two fluid-tight compartments 
or chambers, one on each side of the balloon. The material in each 
compartment is thereby isolated from the material in the other compartment 
until the sealing strip or band is removed to open the passage 
communicating between the two chambers. 
A unique advantage of this invention is the lack of any structural or 
sealing member that is ruptured or broken inside the container. In fact, 
the seal or barrier between the two chambers is opened by simply peeling 
the sealing strip off of the receptacle, so that there is no rupturing or 
breaking apart of any element of the device. Thus, the above-described 
disadvantages associated with prior art devices having breakable or 
rupturable seals or barriers are not associated with the present 
invention. In addition, good seal integrity is maintained with the present 
invention, while minimizing chances of leakage between the chambers due to 
accidental breakage of the seal or barrier. Moreover, these advantages are 
achieved with a structure that is both economical to manufacture and 
simple to use. 
Another aspect of the invention is the novel method of manufacturing the 
above-described container. Briefly, the method comprises the steps of (a) 
providing a tube of resiliently-deformable material (e.g., a suitable 
thermoplastic); (b) sealing one end of the tube; (c) expanding the tube to 
a predetermined shape; (d) partially filling the expanded tube with a 
first material (e.g. a diluent) so that the first material is contained 
near the sealed end; (e) inserting an uninflated balloon into the tube 
through the other (open) end; (f) inflating the balloon so that the 
exterior surface of the balloon is spaced from, and proximate to, the 
interior surface of the tube so as to define a circumferential passage 
therebetween; (g) applying a removable sealing member around the exterior 
surface of the tube with sufficient tightness to close the passage; (h) 
filling at least part of the tube between the balloon and the open end 
with a second material (e.g., a powdered medication); and (i) sealing the 
second end of the tube. 
This method can be implemented on a mass production basis, and requires 
little in the way of precision machining (other than, possibly, the molds 
in which the tubes are expanded and formed). In addition, the method 
allows a precise metering of the materials with which the container is 
filled. The result is a highly-efficient, economically-implemented 
manufacturing method. 
The above-described advantages of the present invention, as well as other 
advantages, will be more fully appreciated from the detailed description 
which follows.

DETAILED DESCRIPTION OF THE INVENTION 
1. The Container of FIGS. 1 through 5 
FIGS. 1 through 5 illustrate a preferred embodiment of a flexible, 
multi-chamber container 10 constructed in accordance with the present 
invention. The container 10 comprises an elongate tubular receptacle 12 
having a sealed distal end 14 and a sealed or closed proximal end 16. The 
receptacle 12 is made of a resiliently-deformable plastic material, 
preferably a thermoplastic elastomer, selected for hydrolytic stability 
and biological inertness. One such material is a polyurethane marketed by 
the Upjohn Company under the trademark PELLETHANE 2363. Another suitable 
material is a styrene ethylene-butylene styrene modified block copolymer 
marketed under the trademark C-FLEX TPE by Concept Polymer Technologies, 
Inc., of Clearwater, Fla. Alternatively, polyvinyl chloride or 
polyethylene materials may be suitable. Typical physical characteristics 
for the material may advantageously be derived from the following table: 
TABLE 1 
______________________________________ 
Characteristics 
Units ASTM Method 
______________________________________ 
Durometer Hardness 
50 .+-. 5 Shore A 
D-2240 
Tensile Strength 
1400 .+-. 200 PSI 
D-412 
at 23.degree. C. 
Tensile Modulus 
300 .+-. 50 PSI 
D-412 
at 300% 
Elongation 800% .+-. 100% 
D-412 
at Break at 23.degree. C. 
Tear Strength 160 .+-. 30 lbs/in. 
D-624 
(Method-Die C) 
______________________________________ 
The distal end 14 of the receptacle 12 is preferably sealed along a 
flattened seam with an aperture 18 provided therein, for purposes to be 
described below. The proximal end 16 is formed into a reduced diameter 
nipple 19, as shown. The entire receptacle 12 is preferably of a unitary 
seamless (except for the distal end seam) construction, as will be 
described in connection with the detailed description of the manufacturing 
method which follows. 
As shown in FIGS. 2, 4, and 5, disposed in the interior of the receptacle 
12 is a hollow bubble or balloon 20. The balloon 20 may be made of a 
similar material to that of the receptacle 12, and it is inflated with 
air, as will be described below. As best shown in FIG. 4, the balloon 20 
has an inflated circumference that is slightly smaller than the internal 
circumference of the receptacle 12, so that the exterior surface of the 
balloon 20 is spaced from, and proximate to, the interior surface of the 
receptacle. Thus, a substantially circumferential passage 22 (FIG. 4) is 
defined between the exterior surface of the balloon 20 and the interior 
surface of the receptacle 12. 
The passage 22, best shown in FIG. 4, is selectively openable by means of a 
removable sealing band or strip 24, best shown in FIGS. 2 and 3. The 
sealing strip 24 is made of a flexible material, such as, for example, a 
plastic strip or a cellulose "shrink-fit" band. The strip or band 24 is 
applied around the exterior surface of the receptacle 12 with sufficient 
tightness to create a fluid-tight barrier or seal between the exterior 
surface of the balloon 20 and the interior surface of the receptacle 12. 
This seal or barrier created by intimate surface-to-surface contact 
between the receptacle 12 and the balloon 20 effectively divides the 
interior of the receptacle into two fluid-tight compartments or chambers: 
a first, or distal, chamber 26, and a second, or proximal, chamber 28. 
Thus, as shown in FIG. 2, a first material 30 can be contained in the 
distal chamber 26, and a second material 32 can be separately contained in 
the proximal chamber 28 without leakage of one material into the other. 
The first material, for example, may be a liquid diluent in which the 
second material, in particulate or powdered form, is soluble. 
Alternatively, both materials can be liquids which are mixable with each 
other. 
If the sealing strip 24 is a plastic band, it can advantageously be held in 
place by a layer of adhesive 34 (FIG. 3), with an end tab 36 that can be 
grasped to unwrap the strip 24 from the receptacle 12. A similar tab can 
be provided on a shrink-fit cellulose band, as is well-known in the art. 
When the strip 24 is peeled or unwrapped, the resiliency of the receptacle 
cause it to spring back to its original shape, as shown in FIG. 4, thereby 
separating the interior surface of the receptacle 12 from the exterior 
surface of the balloon to open the passage 22. The open passage 22, in 
turn, provides communication between the distal chamber 26 and the 
proximal chamber 28, thereby allowing the contents of the two chambers to 
intermix, as indicated by the numeral 37 in FIGS. 4 and 5. 
The container 10 is stored with the sealing strip in place to maintain a 
fluid-tight barrier between the two chambers, thereby isolating their 
respective contents from one another. A protective end cap 38 (FIG. 1) may 
be provided to fit over the nipple 19, thereby to protect the nipple from 
inadvertent rupturing. When it is desired to dispense the container's 
contents, the sealing strip 24 is removed to open the passage 22, as 
described above. The end cap 38 is removed, and an appropriate conduit 
(not shown) may be inserted into the nipple 19. To facilitate the mixing 
of the two materials, the container 10 may be agitated. In most 
applications, such as intravenous or parenteral infusion, the container 10 
may be suspended from a support stand (not shown) with the distal end 14 
uppermost and the proximal end 16 hanging downwardly, as shown in FIG. 5. 
To this end, the aperture 18 in the distal end 14 is provided, so that a 
hook 39 or the like on the support stand may be inserted therein. When the 
container 10 is thus inverted, the balloon 20 floats upwardly toward the 
distal end 14, thereby occupying the portion of the receptacle formerly 
comprising the distal chamber 26. This action diminishes the volume of the 
distal chamber 26 while expanding, distally, the volume of the proximal 
chamber 28, so that the contents of the distal chamber are displaced 
proximally into the proximal chamber, thereby enhancing the intermixing of 
the two materials. Furthermore, the balloon 20 floats upwardly away from 
the container outlet in the nipple 19, leaving an unobstructed path for 
the gravity flow of the mixture from the container. In addition, the 
balloon 20 tends to keep the wall of the receptacle 12 from collapsing on 
itself as the container empties, thereby further aiding the free flow of 
the contents therefrom. 
2. The Method of Manufacture (FIGS. 5-16) 
FIGS. 6 through 17 illustrate the steps of a method of manufacturing the 
container shown in FIGS. 1 through 5. 
As shown in FIG. 6, the manufacturing process begins by providing a tube 40 
formed from one of the above-described thermoplastic materials. The tube 
40 (which is to become the receptacle 12) may be continuously extruded 
into the interior of an axially-segmented mold, which is divided into two 
opposed radial mold halves 42a and 42b. The mold half 42a is divided into 
three axial segments: an upper segment 44a, a middle segment 46a, and a 
lower segment 48a. Likewise, the mold half 42b is similarly divided into 
an upper segment 44b, a middle segment 46b, and a lower segment 48b. The 
lower segment 48a has a horizontal slot 50 which is dimensioned to receive 
a projection 52 extending inwardly from the opposed lower segment 48b. The 
middle segments 46a and 46b are separately removable from the mold halves 
42a and 42b, as will be explained below. 
When the tube 40 is extruded to the desired length into the mold, it is cut 
(by conventional means, not shown) where indicated by the dashed line 54 
in FIG. 6, thereby forming an open proximal end 56 of the tube 40. The 
mold halves are closed, bringing the lower mold segments into contact with 
each other to close the distal end of the tube 40 along a fluid-tight seal 
or seam 58, as shown in FIG. 7. 
As best shown in FIGS. 11 and 12, when the mold halves 42a and 42b are 
brought together, the projection 52 on the lower mold segment 48b acts as 
a die or a punch, cutting a scrap section 60 out of the seam 58 to form 
the aperture 18 described above with respect to the discussion of FIGS. 1 
through 5. As can be seen in FIG. 11, the slot 50 is outwardly tapered to 
facilitate removal of accumulated scrap sections 60. 
Turning once again to FIG. 7, after the mold halves 42a and 42b have 
closed, the mold is stationed under an air nozzle 62 which is inserted 
into the open proximal end 56 of the tube 40. As the nozzle 62 is 
inserted, a retaining collar 64 movably mounted on top of the mold is 
moved radially inwardly to provide stability. The nozzle 62 is tapered to 
allow insertion through the proximal tube end 56, so that the nozzle's tip 
66 is surrounded by the upper portions of the upper mold segments 44a and 
44b. The nozzle 62 has a sealing flange 68 near the tip 66. 
The wall of the tube 40 is captured between the flange 68 and a peripheral 
neck 70 extending radially inwardly from the upper mold segments 44a and 
44b, thereby forming an air-tight seal. With the nozzle 62 thus seated, 
filtered, compressed air is blown through the nozzle 62 into the tube 40. 
Since the thermoplastic material of the tube is still warm and, therefore, 
moldable, the blown air expands the tube outwardly against interior walls 
of the mold until the tube assumes the configuration of the mold surface. 
The tube 40 then acquires the desired shape of the previously-described 
receptacle 12. 
The air nozzle 62 is then withdrawn, and the air vented from the tube. The 
expanded tube is allowed to cool so that its configuration is fixed as the 
thermoplastic material sets. The expanded tube 40, still in the mold, is 
then stationed under a first metering nozzle 72, which is inserted into 
the open proximal end of the tube 40, as shown in FIG. 8. The closed 
distal or bottom end of the tube 40 is filled from the first metering 
nozzle 72 with a pre-measured amount of the first material 30, of a type 
previously described. The first material 30 fills only part (on the order 
of 25 percent to 35 percent) of the volume of the tube 40. 
The metering nozzle 72 is then withdrawn, and the mold with the 
partially-filled tube is stationed at a balloon-insertion mechanism, as 
shown in FIGS. 9 and 10. At this station, an uninflated balloon 20, 
disposed at the of a hollow inflation conduit or needle 74, is inserted 
into the tube 40 through the open proximal end. The balloon 20 is made of 
a thermoplastic material, such as one of the materials mentioned above. 
Advantageously, the balloon is made of a material similar to that of the 
tube 40. At this stage, the balloon 20 is sufficiently warm to be inflated 
by air injected through the needle 74 until its predetermined volume is 
attained, as shown in FIG. 10. The predetermined volume of the balloon 20 
is such that its external circumference is somewhat less than the internal 
circumference of the tube 40, as previously discussed in connection with 
the description of the container of FIGS. 1 through 5. Thus, as previously 
discussed, the exterior surface of the balloon 20 and the interior surface 
of the tube 40 form the above-described circumferential passage 22 
therebetween. When the balloon 20 has been thus inflated, the needle 74 is 
withdrawn, and the material of the balloon, still being warm, seals itself 
around the hole left by the needle 74 before any significant deflation of 
the balloon takes place. 
Next, as shown in FIG. 13, the middle mold segments 46a and 46b are 
removed, exposing the middle of the expanded tube 40. The sealing strip 24 
is then applied around the exterior of the tube in the area left exposed 
by the removal of the middle mold segments 46a and 46b. As previously 
described, the sealing strip 24 may be a strip or band of resilient 
plastic material held in place by a suitable adhesive, or it may be a 
cellulose band that is applied by shrink-fitting. In either case, the 
sealing strip is applied with sufficient tightness to constrict the tube 
wall against the exterior surface of the balloon 20, thereby sealingly 
closing the passage 22 and creating a fluid-tight seal between the 
interior tube wall and the exterior balloon surface. The barrier thus 
created by the balloon 20 and the interior tube wall divides the tube 40 
into the distal chamber 26 and the proximal chamber 28, as previously 
described. 
After the sealing strip 24 is applied, the divided tube 40, still in the 
mold, is stationed under a second metering nozzle 76, as shown in FIG. 14. 
The second metering nozzle 76 is inserted into the open proximal end of 
the tube 40, and the proximal chamber is partially filled from the nozzle 
66 with a pre-measured amount of the second material 32, of the type 
previously described. 
When the proximal chamber 28 is filled with the desired amount of the 
second material 32, the second metering nozzle 76 is withdrawn. At this 
stage, the nipple 19 at the proximal end of the tube 40 is formed and 
sealed by the means shown in FIG. 15. The nipple-forming means comprises a 
radially-movable circumferential sealing mold 78 that is disposed on or 
near the top surface of the upper mold segments 44a and 44b. The sealing 
mold 78 moves radially-inwardly while the proximal tube end is 
heat-softened (by conventional means), so that when the sealing mold 78 
closes in its radially-innermost position, the sealed nipple 19 is formed. 
Finally, as shown in FIGS. 16 and 17, the finished container 10 is removed 
from the mold, and the protective end cap 38 is installed on the nipple 
19. 
From the foregoing description, it will be apparent that the present 
invention provides a number of significant advantages For example, the 
seal or barrier between the two chambers is removed without fracturing or 
rupturing any structure within the container. Thus, potential harm from 
fragments of such structure is avoided. Moreover, the opening procedure 
(i.e., removal of the sealing strip), being a gentle, non-destructive 
action, minimizes the possibility of damage to the container. Thus, 
containers made in accordance with the present invention are easier to use 
than prior art devices. In addition, the strength of the inter-chamber 
barrier in the present invention does not depend, in any substantial part, 
upon the physical characteristics of the materials used, since the barrier 
is formed by an intimate, surface-to-surface contact rather than a 
mechanical connection or attachment. Thus, the physical characteristics of 
these materials need not be as precisely controlled as in many prior art 
devices. This feature, and the invention's relative simplicity of 
construction, make the present invention relatively economical to 
manufacture. Yet, despite the invention's relative simplicity, good seal 
integrity can be provided with the invention's design. 
Although a preferred embodiment of the invention has been described herein, 
it will be appreciated that a number of variations will suggest themselves 
to those skilled in the pertinent arts, in addition to those variations 
previously mentioned. For example, the container can easily be provided 
with three or more isolated chambers by providing two or more bubbles and 
sealing strips. Thus, for example, a three-chamber container can be 
provided with an empty middle or "buffer" chamber that can be used to 
enhance the mixing action and to provide a redundant barrier between the 
two chambers that hold the materials to be mixed. Alternatively, each of 
the three chambers can be filled with a separate material. Also, the 
thermoplastic materials mentioned above for the receptacle 12 and the 
bubble 20 are exemplary only. Other materials will be found that are 
suitable for use in a variety of applications, wherein the container 
materials are chemically inert in the presence of the substances used to 
fill the chambers. The manufacturing process disclosed herein can be 
readily modified to accommodate these variations and modifications in the 
structure of the container. These and other modifications should be 
considered within the spirit and scope of the invention, as defined in the 
claims which follow.