Technical field of the Invention
The present invention relates to a novel way of packing a gas eluting dry powder product in a pressure nil bag system.
Background of the Invention
Pharmaceutical packaging design is increasingly becoming more complex. An increasing number of biological drugs is forcing special considerations be given to protect these drugs and ensure their effectiveness. Intensified competition in the pharmaceutical industry is causing more importance to be placed on packaging as a tool-both visually and functionally. A stronger focus on decreasing medication errors presents an urgent need to develop packaging systems that are more predictable, more dependable, and easier to use. Growing regulatory scrutiny by various authorities warrants more consideration into the packaging of these drugs. New regulations that require stricter guidelines for packaging and the demand for packaging more complex drugs propose new challenges to provide innovative packaging solutions while being cost effective.
The design of packaging must take into account needs of the product, manufacturing and distribution. The containment, safe storage and safety during transit are the fundamental principles in packaging. The challenge therefore is to develop cost-effective niche market packaging that can be deployed in disparate global locations for the emerging personalized medicine market and to provide packaging innovations that result in meeting new regulatory requirements.
One such area is the packaging of bulk powders. Pharmaceutical powders are transported in bottles (plastic and glass) and drums (plastic and also metal). Sometimes the same are transported in collapsible containers to add moisture protection and also to bring down the cost of freight. There are a lot of antibiotic/effervescent/ chemical powders (hereafter referred to as powder/powders) used in the pharmaceutical industry which when exposed to heat or moisture or a combination of both tend to give out gases. These gases aid the formation of possible internal overpressures, which would cause bulging and/or bursting of said bag, and at the same time may allow air to enter the container that would prejudice the quality of the product. In order to allow the gases a proper vent to escape,

containers fitted with valves were developed. These containers are beneficial for reasons in addition to those associated with storage and transport. For example, removal of the air from the storage container inhibits the growth of destructive organisms such as moths, silverfish and bacteria which require oxygen to survive and propagate.
In the case of bags fitted with valves, there is the risk that this type of system will choke or block valves where powders and granular materials are being handled. Accumulated powder can condense inside the nozzle base preventing smooth movement of the nozzle and can cause the nozzle to stick and not function properly. In addition airflow through the valve openings may cause loss of powder material from within, along with the escaping gases. Also available are composite packages involving two or more layers. However, in these packages, the inner plastic layer is generally bonded in some way to the outer layers. This results in problems in recycling of used packages. Moreover the whole package has to be discarded even if the outer layer is spoiled or damaged.
Furthermore, in case of powders, the possibility of bag rupturing increases if the vents for the gases are clogged partially or completely with the particulate material.
Therefore, there is a requirement to provide a package and a method of packaging to reduce, or overcome at least some of the above-mentioned problems, or at least to provide a useful alternative.
Accordingly, a flexible package has been designed which comprises an outer packaging to act as a protective or transit packaging combined with an inner packaging which is removable from the outer packaging. The inner packaging acts to provide a hygienically packed product that has not been contaminated. This inner packaging or the inner bag is only closed and not sealed. The inner packaging is contained inside at least one outer packaging which is sealed and houses a recloseable membrane based valve.
Therefore the flexible package provides a simplified way:
(a) to transport large quantities of powders without contaminating it with dust and moisture,

(b) to preserve the integrity of the package by allowing uninterrupted exit of the
generated gases, and
(c) to reduce the weight of the package.
There has been an unfulfilled need therefore for an improved bag that provides:
1. An outer packaging that acts as a protective and provides a hygienically
packed product that has not been contaminated during shipping.
2. A system in which the valve is more resistant to failure due to abuse or rough
handling of the bag in the area of the valve.
3. A system in which the valve is resistant to clogging due to the accumulation of
the powder within the valve.
4. A reusable, collapsible, evacuable storage container.
The objective of the invention is therefore to provide a flexible packaging as described above which is readily manufactured and can provide a sealed multiple bag-in-bag approach.
Summary of the Invention
It is one aspect to provide a pressure nil bag system comprising:
(a) a filled inner bag, surrounded by but removable from at least one outer bag,
the inner bag closed but not sealed, and
(b) a sealed outer bag accommodating a recloseable membrane based valve.
In one of the embodiments, the inner bag is placed into another bag (hereafter referred to as middle bag) before enclosing it in the outer bag. Embodiments include vacuum sealing the middle bag or the outer bag. Alternatively, both the middle bag and the outer bag are vacuum sealed.
According to other embodiments, the middle and the outer bags are permanently sealed. The permanent seal may be achieved by the application of heat.
In one of the embodiments, the mouth of the inner bag is closed by twisting and thereafter securing with a cable tie or any other similar means.

The inner bag is formed of a flexible material which is strong, tough and substantially impermeable to the passage of gas. The material of construction comprises one or more of polyethylene, bi-axially oriented polypropylene, polyethylene terephthalate or a laminated or tripartite structure comprising an aluminum foil disposed between two flexible polyethylene layers or between one layer of polypropylene and another layer of polyethylene.
The middle bag is constructed either using the same material as the inner bag or in case vacuum needs to be applied, a polyethylene terephthalate based laminate is used. The laminate structure comprises polyethylene, biaxially oriented polyamide or polyethylene terephthalate in the inner layer; metal foil as the middle layer and an outer polyester layer, such as polyethylene terephthalate.
The outer bag is made of any material that is gas impermeable so as to retain the vacuum applied. It is particularly a material which is structurally strong and yet flexible so as to provide protection for inner bag, such as a laminate.
The laminate may comprise an intermediate layer of metal and outer and inner layers of a plastic heat-sealable coating, such as polyethylene, polyvinylchloride, polyesters, polyurethane, polyvinyl alcohol, polyamides, ethylene vinyl acetate copolymer, polyamides and nitrite polymers.
According to another embodiment, the outer bag further comprises a barrier layer which protects photosensitive product, for example it may include a UV barrier.
The outer bag comprises a hole, in which a unidirectional valve is inserted and an opening through which the inner bag is placed inside. The valve allows any gases within the package to gain egress to the exterior of the package, while precluding the ambient atmosphere to gain egress into the interior of the package.
The valve includes an inner portion which is in communication with the interior of the package and an outer portion which is in communication with the exterior of the package, i.e. ambient atmosphere.

Particularly, the valve is constructed similar to those of US Pat. No. 5,480,030 (Sweeney et al.) whose disclosures are incorporated herein by reference.
According to one of the embodiments, valve is prepared from an elastic material, such as silicone rubber and comprises a flexible membrane that flexes to allow air to flow out of the bag through air holes but bars the passage of air into the bag.
According to another aspect, there is provided a method of packaging a gas eluting dry powder product, said method including the steps of:
(a) filling the inner bag with the gas eluting dry powder product and closing the
bag,
(b) enclosing the inner bag into an outer bag housing a recloseable membrane
based valve,
(c) sealing the outer bag,
(d) applying vacuum to the outer bag through the valve to extract excess air, and
(e) sealing the valve.
According to one of the embodiments, the inner bag is preliminarily enclosed within a middle bag which is then enclosed within an outer bag.
Embodiments include vacuum sealing the middle bag or the outer bag. Alternatively, both the middle and outer bags are vacuum sealed.
While not intended to be limited by any theory, it is believed that the system may work as described below.
The gas eluting powder product, in due course of time will generate gases in the inner bag. Since this bag is not sealed, the gas will come out in the middle or outer bag. When the pressure of gas inside crosses a preset limit, the valve opens and the gas is let out. In case there is a middle bag without a valve then the middle bag will exert pressure on the outer bag. When activated by pressure the air from the outer bag will be expelled through the valve.
Other features, advantages and embodiments of the invention will become apparent to those of ordinary skill in the art by the following description.

Detailed Description of the Invention
FIG. A shows pressure nil bag systems in accordance with the present invention.
The pressure nil bag system of Fig. A includes an inner bag 1 and an outer bag 2. Gas eluting powders may be enclosed in the inner bag. The inner bag may be twist tied with a cable tie 3 and not sealed and can be placed inside the outer bag. The outer bag can be sealed from the ambient environment via seal 6 and valve assembly 4. Excess air in the outer bag may then be evacuated through valve assembly so as to compress the contents of the outer bag. The outer bag includes a hole in which to install valve assembly, and an opening 5, through which inner bag may be placed for storage.
Fig B & C show pressure nil bag systems that include an inner bag 1, a middle bag 7 and an outer bag 2. Gas eluting powders may be enclosed in the inner bag. The inner bag may be twist tied with a cable tie 3 and not sealed and can be placed inside the middle bag 7. The middle bag includes an opening 5, through which the inner bag may be placed for storage. The middle bag is sealed via a seal 8 and valve assembly 4. The middle bag is then placed inside the outer bag 2 through an opening 9. Fig B shows pressure nil bag systems in which the outer bag is sealed via a seal 6. In Fig. C the outer bag of the pressure nil bag system is sealed via a seal 6 and further includes a valve assembly 10.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, different materials could be used for the various elements of the container, and different valve and cap structures could be used. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

WE CLAIM:
1. A pressure nil bag system comprising:
(a) a filled inner bag, surrounded by but removable from at least one outer bag,
the inner bag closed but not sealed, and
(b) a sealed outer bag accommodating a recloseable membrane based valve.

2. The pressure nil bag system according to claim 1 wherein the inner bag is placed
into a middle bag before enclosing it in the outer bag.
3. The pressure nil bag system according to claim 2 wherein the middle bag and the
outer bags are vacuum sealed.
4. The pressure nil bag system according to claim 1 wherein the mouth of the inner
bag is closed by twisting and thereafter securing with a cable tie.
5. The pressure nil bag system according to claim 4 wherein the material of
construction of the inner bag comprises one or more of polyethylene, bi-axially
oriented polypropylene, polyethylene terephthalate or a laminated or tripartite
structure comprising an aluminum foil disposed between two flexible polyethylene
layers or between one layer of polypropylene and another layer of polyethylene.
6. The pressure nil bag system according to claim 2 wherein the middle bag is
constructed using polyethylene, bi-axially oriented polypropylene, polyethylene
terephthalate or a laminated or tripartite structure comprising an aluminum foil
disposed between two flexible polyethylene layers or between one layer of
polypropylene and another layer of polyethylene or a polyethylene terephthalate
based laminate comprising polyethylene, biaxially oriented polyamide or
polyethylene terephthalate in the inner layer; metal foil as the middle layer and an
outer polyester layer, such as polyethylene terephthalate.
7. The pressure nil bag system according to claim 1 wherein the outer bag is
constructed of a laminated material comprising an intermediate layer of metal and
outer and inner layers of a plastic heat-sealable coating, such as polyethylene,

polyvinylchloride, polyesters, polyurethane, polyvinyl alcohol, polyamides, ethylene vinyl acetate copolymer, polyamides and niterile polymers.
8. The pressure nil bag system according to claim 7 wherein the outer bag further
comprises a barrier layer which protects photosensitive product.
9. The pressure nil bag system according to claim 1 wherein the valve includes an
inner portion which is in communication with the interior of the package and an
outer portion which is in communication with the exterior of the package.
10. A method of packaging a gas eluting dry powder wherein said method includes
the steps of:

(a) filling the inner bag with the gas eluting dry powder product and closing the
bag,
(b) enclosing the inner bag into an outer bag housing a recloseable membrane
based valve,
(c) sealing the outer bag,
(d) applying vacuum to the outer bag through the valve to extract excess air, and
(e) sealing the valve.