WO2017123197A1

WO2017123197A1 - Nonmetallic oxygen absorber

Info

Publication number: WO2017123197A1
Application number: PCT/US2016/012865
Authority: WO
Inventors: Brian K. Brady; Narasimharao Dontula; Stanislav E. Solovyov
Original assignee: Multisorb Technologies, Inc.
Priority date: 2016-01-11
Filing date: 2016-01-11
Publication date: 2017-07-20

Abstract

A multilayer structure including a hydroxylated polymer layer having first and second sides, including a nonmetallic light activatable oxygen absorbing composition characterized by an activation wavelength range, a first moisture barrier layer disposed on the first side, and a second moisture barrier layer disposed on the second side. At least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

Description

NONMETALLIC OXYGEN ABSORBER

FIELD OF THE INVENTION

[0001] The invention broadly relates to oxygen absorbers, more specifically to a nonmetallic oxygen absorber, and even more particularly to an ultraviolet radiation activated nonmetallic oxygen absorber.

BACKGROUND OF THE INVENTION

[0002] Many applications require an oxygen barrier and/or absorber. For example, some pharmaceutical tablets and food products degrade upon exposure to oxygen. Preventing or reducing exposure to oxygen can prolong the useful life of such items. Hence, packaging materials and separate inserts to packaging often are provided with oxygen absorbing and barrier characteristics.

[0003] Some materials used to make packaging form effective oxygen and moisture barriers without additional components included. For example, polychlorotrifluoroethylene (PCTFE) is substantially impermeable to water and oxygen. However, such materials are too expensive for some applications. Moreover, some of these materials are difficult to process, especially thermoforming.

[0004] Typical reduced metal based oxygen absorbers require moisture to be present in order to promote oxygen absorption. Thus, it is difficult to provide oxygen absorbing barriers in applications that must also remain substantially dry because no or insufficient moisture will be present to promote oxygen absorption. Moreover, some packaging operations, e.g., meat processing and packaging, include inspection for foreign metal objects. Metallic based oxygen absorbers may be detected thereby leading to process losses or downtime due to false positive detections.

[0005] Some oxygen absorbers based on quinone are known, but they have not been successfully used in thermoformed packaging such as blister packs. Some quinone based absorbers are activated by ultraviolet (UV) light. A problem with UV light activation is that activation itself renders the material in which the quinone is carried less UV transmissive. This limits the effectiveness of UV activation of quinone based absorbers. [0006] A further problem with multilayer thermoformable structures is that the thermoformability of the materials making up the structure can degrade during formation, and become less suitable for forming blisters or other thermoformable packaging.

[0007] In view of the foregoing there is a need for an oxygen absorbing and/or barrier system that does not require moisture for activation, that permits effective activation by UV light, and that can be formed without degrading its suitability for subsequent thermoforming into packaging such as blisters.

BRIEF SUMMARY OF THE INVENTION

[0008] An embodiment of the present invention broadly comprises a multilayer structure including a hydroxylated polymer layer having a nonmetallic light activatable oxygen absorbing composition characterized by an activation wavelength range, a first moisture barrier layer disposed on a first side of the hydroxylated polymer layer, and a second moisture barrier layer disposed on a second side of the hydroxylated polymer layer opposite the first side. At least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

[0009] Another embodiment broadly comprises a multilayer structure article having a body including a hydroxylated polymer layer having a nonmetallic light activatable oxygen absorbing composition characterized by an activation wavelength range, a first moisture barrier layer disposed on a first side of the hydroxylated polymer layer, and a second moisture barrier layer disposed on a second side of the hydroxylated polymer layer opposite the first side. At least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

[0010] A further embodiment broadly comprises a method of forming a nonmetallic oxygen absorbing multilayer structure including: a) dissolving a nonmetallic light activatable oxygen absorbing composition in a quantity of water to form a first composition, wherein the nonmetallic light activatable oxygen absorbing composition has an activation wavelength range; b) adding a hydroxylated polymer into the first composition to form a second composition; c) heating and mixing the second composition; d) cooling the second composition; e) coating the second composition on a first moisture barrier layer; f) drying the second composition on the first moisture barrier layer; and, g) coating a second moisture barrier layer on the second composition opposite the first moisture barrier layer. At least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

[0011] A still further embodiment broadly comprises a container for extending the shelf life of oxygen and moisture degradable pharmaceutical products including a thermoformable nonmetallic, non-water activatable oxygen absorbing moisture impermeable sealable layer forming a plurality of pill receiving chambers.

[0012] These and other objects and advantages of the present invention will be readily appreciated from the following description of preferred embodiments of the invention and from the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

Figure 1 is a top perspective view of an article formed from a nonmetallic oxygen absorbing structure, i.e., a blister pack;

Figure 2 is a bottom perspective view of the article of Figure 1; Figure 3 is a cross-sectional view of an embodiment of a nonmetallic oxygen absorbing structure including several optional layers; and,

Figure 4 is a process flow diagram depicting an embodiment of forming a nonmetallic oxygen absorbing structure.

DETAILED DESCRIPTION OF THE INVENTION

[0014] At the outset, it should be appreciated that like reference numbers on different drawing views identify identical, or functionally similar, structural elements of various embodiments of the invention. While the present invention is described with respect to what are presently considered to be certain preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects.

[0015] Furthermore, this invention is not limited to the particular methodologies, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. [0016] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be understood that the use of "or" in the present application is with respect to a "non-exclusive" arrangement, unless stated otherwise. For example, when saying that "item x is A or B," it is understood that this can mean one of the following: (1) item x is only one or the other of A and B; or, (2) item x is both A and B. Alternately stated, the word "or" is not used to define an "exclusive or" arrangement. For example, an "exclusive or" arrangement for the statement "item x is A or B" would require that x can be only one of A and B. Furthermore, as used herein, "and/or" is intended to mean a grammatical conjunction used to indicate that one or more of the elements or conditions recited may be included or occur. For example, a device comprising a first element, a second element, and/or a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element.

[0017] As used herein, "blister", "blister pack" and "single dose unit" may be used interchangeably and are intended to refer to structures commonly used to contain single dose of pharmaceutical materials, and all structures similar thereto. "Moisture barrier", as used herein, is intended to mean a material which impedes the transmission of moisture. Such materials have water vapor transmission rates (WVTR) as dictated by the needs of the overall multilayer structure. For example, some applications may require a WVTR of 0.07 g

^ while other applications may require a lower WVTR such as 0.02

\00in² - 24hrs

σ

^ Moisture barrier characteristics may be altered by a variety of means, e.g. ,

\00in² - 24hrs

applying more layers of moisture barrier materials, applying thicker layers of moisture barrier materials, applying different moisture barrier materials. It should be appreciated that the foregoing WVTRs are not intended to limiting, and the WVTR for each particular embodiment is dictated by the needs of the overall multilayer structure. [0018] Although many methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.

[0019] This disclosure includes a new multilayer, nonmetallic oxygen absorbing structure, uses of that structure and methods of forming the structure. In some embodiments, the structure forms a thermoformable oxygen absorber. An example of a present multilayer structure is depicted in Figure 3 as multilayer structure 40.

[0020] In some embodiments, the structure, an active oxygen and passive moisture barrier, comprises a polyvinylidene chloride (PVDC) layer, an amorphous polyethylene terephthalate (APET) layer, a PVOH layer comprising quinone, and a sealant layer. As the quinone containing layer is activated by ultraviolet light, the PVDC and APET layers must be ultraviolet transmissive layers and/or the sealant layer must be an ultraviolet transmissive layer. Thus, the quinone may be activated from either side or from both sides. As used herein, transmissive means sufficiently transmissive to allow the quinone to be activated by a UV light source. Powerful UV sources will require lower transmissivity than less powerful sources. In view of the foregoing, it should be appreciated that the foregoing structure is thermoformable such that a variety of molded articles may be manufactured using the present structure.

[0021] Further, we have discovered that the thermoformability of some or all of the layers forming the multilayer structure may be degraded during formation. More specifically, some of the layers, especially, but not limited to the APET layer, may crystallize or recrystallize if the process is not carefully controlled. APET may recrystallize if subjected to a combination of excessive temperature and time. That is, both the temperature and the time must be controlled during processing of the multilayer film to avoid recrystallization of the layers, especially the APET layer. If the APET layer recrystallizes significantly, it may become less transmissive of UV light and more difficult or impossible to activate completely.

[0022] First layer 42 (optional) - E.g. , PVDC

[0023] PVDC provides a passive moisture barrier while being transmissive to ultraviolet wavelengths. In some embodiments, PVDC is deposited as an emulsion coating.

[0024] Other materials may also be used to form the first layer. Examples of materials include but are not limited to: ethylene vinyl alcohol (EVOH), Aclar® barrier films available from Honeywell, PCTFE, SiOx (although not thermoformable), and metallized layers (although not UV transmissive).

[0025] Second layer 44 - E.g. , APET

[0026] APET, in part, permits the present structure to be thermoformable. However, such thermoforming must be performed without recrystallizing or the APET will become hazy, a characteristic typically undesirable in end uses of the present structure. APET is also ultraviolet transparent and provides structural support for the present layered structure. Moreover, layer 44, alone or in combination with layer 42, forms a passive moisture barrier.

[0027] Other thermoformable materials may also be used to form the second layer. Examples of materials include but are not limited to: PVC, Polypropylene, PETG, Polycarbonate, polyolefin, HIPS (high impact polystyrene), ABS, and other materials if thermoforming not required for a particular application. Examples of suitable non- thermoformable materials include but are not limited to: bi-axially oriented polyethylene terephthalate (BOPET), polystyrene, oriented polypropylene (OPP), other oriented polymers, highly crystalline polymers (e.g. , crystalline polyester or crystalline polyethylene terephthalate), and thermoset films.

[0028] Third layer 46 - E.g. , PVOH and quinone

[0029] It has been found that PVOH is preferred as it acts as a proton donor during oxygen absorption. Examples of other materials that may be used in place of PVOH include but are not limited to: cellulose, hydroxypropyl cellulose (HPC), and hydroxypropyl methylcellulose (HPMC). It should be appreciated that a PVOH layer inherently provides a high passive oxygen barrier, while cellulose, HPC and HPMC are inherently low passive oxygen barriers. It has been found that 85% - 90% (or higher) hydrolyzed PVOH is preferred for the present multilayer structure as PVOH oxygen permeability increases to less acceptable levels as the amount of hydrolysis decreases below 85%.

[0030] Various quinone class organic compounds may be used in the third layer. For example, anthtraquinone, such as anthraquinone-2-sulfonic acid sodium salt (AQ), may be used. Examples of other quinone class compounds which may be used in the present invention include but are not limited to: benzoquinone; and, napthoquinone. It should be appreciated that a "quinone class organic compound" is intended to mean a compound that is derived from aromatic compounds, such as benzene or naphthalene, by conversion of an even number of -CH= groups into -C(=0)- groups with any necessary rearrangement of double bonds resulting in a fully conjugated cyclic dione structure.

[0031] It also should be appreciated that other compounds may be used as a substitute for quinone class organic compounds. The following non-limiting list of compounds may be used as substitutes: phenylglyoxylates, e.g. , methyl benzoylformate; Bis-acyl phosphines, e.g. , phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; and, a-hydroxy ketones, e.g. , 1- hydroxycyclohexyl phenyl ketone or 2-hydroxy-2-methylpropiophenone.

[0032] The foregoing compositions may be applied at a variety of thicknesses and numbers of layers. For example, PVOH in combination with AQ may be applied as a single thick layer or alternatively as multiple thin layers. The drying step discussed below may be performed between each application of a thin layer or after the application of a single thick layer. It has been found that drying a single thick layer requires a longer drying cycle and may result in material irregularities, while each thin layer requires a shorter drying cycle providing a more consistent finished material, although crystallization of the material may occur.

[0033] Fourth layer 48 - sealant layer

[0034] The various embodiments of sealant layers may be ultraviolet transmissive.

However, if sufficient activation of the oxygen absorber occurs by transmission of ultraviolet radiation through one side of the multilayer structure alone, then the sealant layer can be formed from a ultraviolet non-transmissive material on the opposite side of the structure.

[0035] In some embodiments, the sealant layer prevents leaching of material e.g. AQ from internal layers, e.g. , the third layer, thereby preventing contamination of products in contact with the sealant layer, e.g., pharmaceuticals or food. In some circumstances, the present structure will only be suitable for a given use if the structure can pass various extraction protocols, e.g. , protocols set forth in the Code of Regulations (CFR) Title 21.

[0036] In some embodiments the sealant layer is thermoformable thereby providing further structural integrity to formed articles, while in some embodiments the sealant layer is heat sealable to a lid stock thereby providing further functional benefits for the present structure.

[0037] In some embodiments the sealant layer is a passive moisture barrier thereby preventing ingress of moisture through the side of the multilayer structure adjacent to the materials being held by the multilayer structure. [0038] It has been found that polyethylene (PE) and PVDC may be used as suitable sealant layers. However, it is believed that PE should be used in combination with an adhesion layer type surface treatment. It is preferred that the sealant layer is compatible with the lid stock, e.g., foil 49.

[0039] It should be appreciated that for some applications some of the foregoing layers may be non-thermoformable or all of the layers may be non-thermoformable. For example, some layers may be applied via non-thermoforming means, e.g. , spraying, vapor depositing, etc. Such variations fall within the scope of the claims below.

[0040] Methods of forming present structure

[0041] The following is an embodiment of a method of forming a non-metallic oxygen absorbing structure. The methods described herein, including quantities of materials, temperatures, pressures, times, etc. are not intended to be limiting and are included merely as examples of suitable conditions/compositions for use in forming the present structure. However, it is an aspect of an embodiment of the invention that the process conditions do not degrade the UV transmissivity of the various layers to an extent that prevents the quinone from being activated by UV light.

[0042] Oxygen Absorbing Composition

[0043] 440 g of water was heated to 65°C with mechanical stirring present, e.g. , a propeller blade spinning at 950 rotations per minute (RPM). While maintaining the stirring and heating of the water, 7.2 g of anthraquinone-2-sulfonic acid sodium salt (AQ) was added slowly. (Step 50). PVOH was added slowly while continuing to stir the composition and maintaining the temperature at 65°C. (Step 52). In this example, SELVOL™, sold by Sekisui Specialty Chemical America, LLC of Dallas, TX, was used as the source of PVOH. In particular, 24.0 g of SELVOL™ 513 in combination with 26.4 g of SELVOL™ 523 was used as the source of PVOH. Subsequently, the composition was heated to 90°C and stirring was continued for about 15-20 minutes after 90°C was reached. (Step 54). Then, the heat was turned off while continuing to stir the composition. The composition was permitted to cool to a temperature of 40°C or below. (Step 56). Optionally, 2.4 g of glycerin can be added to the composition; however, it is believed that the addition of glycerin is not required. Glycerin is a compatible plasticizer, it prevents perfect crystallization and it may make the overall structure more flexible. Other suitable plasticizers include but are not limited to: ethylene glycol; polyethylene glycol; and, propylene glycol. The stirring element was then stopped and the composition was placed in a closed container for storage in a UV light free environment to prevent the premature activation of the composition. It should be noted that many visible light sources have a UV component.

[0044] Alternatively, the following protocol may be followed for forming an oxygen absorbing composition. 17,600 g of water was heated to 60 - 65°C with mechanical stirring present. While maintaining the stirring and heating of the water, 288 g of AQ was added and stirring continued for 30 - 40 minutes. The water and AQ solution was permitted to cool to ambient room temperature, about 20°C, for a period of at least twelve hours, e.g., overnight. The cooled solution was filtered if necessary, e.g., if undissolved AQ is present. Then, while maintaining stirring, 2016 g of PVOH was added to water and AQ solution. The water, AQ and PVOH solution was then heated to 90 - 95°C with mechanical stirring present. After reaching the desired temperature, stirring continued for 30 - 40 minutes. The resulting solution was then slowly cool to 25°C with mechanical stirring present. While maintaining stirring, 96 g of glycerin was added and stirring continued for 15 minutes. The final solution was stored in a manner to prevent exposure to activation energy, e.g. , within a non-UV transmissive container.

[0045] The foregoing compositions may then be coated on a surface using a variety of coating methods, e.g. , hand coating and machine coating. (Step 58).

[0046] Hand Coating Process

[0047] An APET support layer was subjected to a corona discharge treatment to change the surface energy of the APET, e.g. , atmospheric corona treatment using a charged wire at 1-4 kilowatts. An example corona discharge treatment system is Model No. UCVT106-C sold by Corotec Corporation of Farmington, CT. Alternate methods for surface modification for adhesion enhancement can be used such as etching, flame treatment, plasma treatment, application of other intermediate linking material, or any method for increasing the surface energy or bonding capacity of the coating surface. The oxygen absorbing composition was then coated onto the APET layer using a Mayer Road coater on a vacuum table on a hot plate. An adhesion promoting tie layer can be coated between the treated support and the oxygen absorbing composition if necessary for better adhesion. Mayer Rod coatings were made from wire wound rods from R.D. Specialties, Inc., Webster, NY. The particular rod used depends on the percent solids of solution being coated, desired dry thickness of the coating and the dry coating density. Other coating methods can also be used, for example, a Casting Knife Film Applicator with adjustable knife from Paul N. Gardner Company, Inc., such as model number AP99500601. Other methods are available for applying solutions to plastic films such as rollers and web transfer techniques. The coating was then dried at 65°C for about ten minutes. (Step 60). Similarly, the APET layer was then coated with a sealant layer using a Mayer Road coater. (Step 62). The sealant layer was then dried at 65°C.

[0048] Machine Coating Process

[0049] As opposed to mixing a relatively small quantity of the oxygen absorbing composition as described above, a large batch mixer was used for the mixing and heating steps described above. The time, temperature, and mixing profiles are approximately the same in both arrangements, i.e., small and large batches. Again, the APET layer was subjected to corona discharge treatment prior to coating with the oxygen absorbing composition. The oxygen absorbing composition was then coated on the APET layer using a slot-die coater. (Step 58). As the process is performed using a coating machine, the drying occurs on a moving web. (Step 60). The web speed may be adjusted to optimize the oxygen absorbing composition drying step. One or more drying methods may be used, e.g., infrared (IR) heaters and air-impingement driers. In the present example, IR heaters were used to initially dry the oxygen absorbing layer and then heated air-impingement driers were used to complete the drying process. Subsequently, a sealant layer was coated on the oxygen absorbing layer using either the slot-die coater or a gravure process coater. (Step 62). Alternatively, an extrusion coater may be used if the sealant layer is coated from a melt. As with the hand coated structure described above, the coating process, and in particular, the portions of the process where the oxygen absorbing layer is present are performed in as little UV light as possible, and are protected from UV light exposure as much as possible during transport, during subsequent coating or forming operations and for long term storage.

[0050] It should be appreciated that other methods of coating are also useful in creating the present structure. For example, extrusion coating, water-based emulsion coating and solvent coating techniques may be used. Such variations in the coating processes are within the scope of the claimed invention. Moreover, it has been found that a single thick coating may be applied, or alternatively, multiple thin coatings may be applied, either capable of providing a required percent content of light activatable oxygen absorbing composition.

[0051] Activation Process [0052] Activation may be performed before (Step 64) or after (Step 66) thermoforming or before or after application of a sealant layer. In short, activation may occur before or after any step of the process of forming the present structure; however, once activated, the oxygen absorbing composition will begin absorbing oxygen and expending its useful capacity. In the present example, activation was performed using an ultraviolet source instrument specifically a F300S Ultraviolet Lamp System with a "D" bulb from Fusion UV Systems, Inc. Test pieces were passed through the activation system from 1-10 passes, preferably 2-4 passes at a belt speed of 1-60 feet per minute (fpm), preferably 15-40 fpm. It should be appreciated that the power of a lamp system is typically constant; however, the amount of activation energy reaching the light activatable oxygen absorbing composition may be altered in a variety of ways. For example, an aperture may be increased or decreased to permit more or less energy to pass, a bandpass, cutoff or neutral density filter may be used to limit the amount of energy permitted to pass, and the distance between the lamp and the light activatable oxygen absorbing composition may be changed thereby altering the amount of energy. Other means may also be used and all such means fall within the scope of the claims below. Moreover, the amount of energy permitted to reach the light activatable oxygen absorbing composition may be limited by the multilayer substrate itself. For example, the substrate of substrates may limit the passage of energy or the substrate may only be able to withstand a particular quantity of energy prior to becoming damaged, e.g. , excessive curling of the substrate.

[0053] About 380 nm is a preferred wavelength of illumination when using anthtraquinone; however, it has been found that sufficient activation may occur when using illumination sources ranging between 200 - 420 nm. The web or belt speed of the UV source can be set to ensure proper activation without overheating the present structure. The activation may occur by feeding the present structure through the UV source with either side of the structure closest to the radiation source, the structure may be passed through the UV source multiple times in the same orientation, or the structure may be passed through the UV source multiple times with each time being in a different orientation, i.e. , one side facing the UV source then the other side facing the UV source. Furthermore, a two sided UV source may also be used for the simultaneous activation from both sides. Moreover, it should be appreciated that when using components other than quinone class organic compounds activation may require the use of other wavelengths of light, including but not limited to wavelengths outside of the UV spectrum. For example, an activation wavelength of about 395 nm is required when using methyl benzoylformate, while an activation wavelength of about 370 nm is required when using phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. For a-hydroxy ketone type compounds, an activation wavelength of about 254 nm is required when using 1 -hydroxy cyclohexyl phenyl ketone, and an activation wavelength of about 284 nm is required when using 2-hydroxy-2-methylpropiophenone. Radiation used to activate the present composition must be actinic radiation, i.e., electromagnetic radiation that can produce photochemical reactions.

[0054] Forming Process

[0055] The present structure described above may be formed into a variety of useful articles, e.g. , blister packs for pharmaceuticals, trays for food packaging, etc. (Step 68). Blister pack 20 is depicted in Figures 1 and 2. Blister pack 20 may include a plurality of chambers 22 wherein a pharmaceutical, e.g. , pill 24, is deposited prior to sealing pack 20 with a sealing layer such as a foil (not shown). The structure may be thermoformed, extrusion molded or formed using any other process known in the art. For unactivated forms of the structure, it is preferred to avoid unnecessary exposure to ultraviolet radiation as that would cause the premature activation of the oxygen absorbing material. However, depending on the arrangement of the forming apparatus, it is possible to both form and activate the structure simultaneously or form and activate serially. Packaging the structure in an oxygen impermeable container between activation and use may prevent premature absorption.

[0056] Performance of the Present Structure

[0057] The present structure was tested for performance characteristics under accelerated conditions for a flat film embodiment (equivalent of one year) and a blister pack embodiment (equivalent of three months). The oxygen transmission rate (OTR) tested with essentially zero transmission rate under accelerated conditions, i.e. , one hundred percent (100%) oxygen, at 37.8°C (100°F) and seventy-five percent (75%) relative humidity. This testing was done both on flat films and formed blisters using an Illinois Instruments, Inc. oxygen permeation analyzer for more than 60,000 minutes (1,000 hours) with no measured transmission. It is believed the results of the accelerated testing indicate that over a two year period, the present multilayer structure comprising the above described nonmetallic light activatable oxygen absorbing composition will maintain an oxygen transmission rate of at or about zero transmission in general ambient conditions, e.g. , 20-25°C (68-77°F) and fifty percent (50%) relative humidity.

[0058] It should be appreciated that one benefit of the present structure is that the oxygen absorption characteristics do not require moisture to be introduced to activate the oxygen absorber, as is typically required in metallic oxygen absorbing structures. Moreover, the present structure may be stored, e.g. , in sheet or rolled form, as a stable, inert structure until it is activated by exposure to ultraviolet radiation. The present structure may be thermoformed reliably and uniformly at approximately a 3: 1 area draw ratio.

[0059] Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

Claims

CLAIMS What We Claim Is:

1. A multilayer structure comprising:

a hydroxylated polymer layer having first and second sides, comprising a nonmetallic light activatable oxygen absorbing composition characterized by an activation wavelength range;

a first moisture barrier layer disposed on the first side; and,

a second moisture barrier layer disposed on the second side,

wherein at least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths in the activation wavelength range.

2. The multilayer structure of Claim 1 wherein the hydroxylated polymer layer comprises polyvinyl alcohol (PVOH), cellulose, hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC) or combinations thereof.

3. The multilayer structure of Claim 1 wherein the hydroxylated polymer layer comprises PVOH and the PVOH is at least 85% hydrolyzed PVOH.

4. The multilayer structure of Claim 1 wherein at least one of the first and second moisture barrier layers is a thermoformable layer.

5. The multilayer structure of Claim 1 wherein at least one of the first and second moisture barrier layers is selected from group consisting of: polyethylene (PE); polyvinylidene chloride (PVDC); ethylene vinyl alcohol (EVOH); polychlorotrifluoroethylene (PCTFE); silicon oxide (SiOx); polyvinyl chloride (PVC); polypropylene (PP); polyethylene terephthalate glycol-modified (PETG); polycarbonate; polyolefin; high impact polystyrene (HIPS); acrylonitrile butadiene styrene (ABS); bi-axially oriented polyethylene terephthalate (BOPET); polystyrene; oriented polypropylene (OPP); crystalline polyester; crystalline polyethylene terephthalate; and, combinations thereof.

6. The multilayer structure of Claim 1 wherein at least one of the first and second moisture barrier layers comprises amorphous polyethylene terephthalate (APET).

7. The multilayer structure of Claim 1 wherein the nonmetallic light activatable oxygen absorbing composition comprises a quinone class organic compound.

8. The multilayer structure of Claim 7 wherein the quinone class organic compound is selected from the group consisting of: anthtraquinone; benzoquinone; napthoquinone; and, combinations thereof.

9. The multilayer structure of Claim 7 wherein the quinone class organic compound is anthraquinone-2-sulfonic acid sodium salt (AQ).

10. The multilayer structure of Claim 1 wherein the nonmetallic light activatable oxygen absorbing composition comprises a phenylglyoxylate, a bis-acyl phosphine, or an a-hydroxy ketone.

11. The multilayer structure of Claim 1 wherein the activation wavelength range is between about 200 nm and about 420 nanometers.

12. The multilayer structure of Claim 1 wherein the portion of wavelengths in the activation wavelength range comprises about 380 nm.

13. A multilayer structure article comprising:

a body comprising:

a hydroxylated polymer layer comprising a nonmetallic light activatable oxygen absorbing composition characterized by an activation wavelength range;

a first moisture barrier layer disposed on a first side of the hydroxylated polymer layer; and,

a second moisture barrier layer disposed on a second side of the hydroxylated polymer layer opposite the first side, wherein at least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

14. The multilayer structure article of Claim 13 wherein the hydroxylated polymer layer comprises polyvinyl alcohol (PVOH), cellulose, hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC) or combinations thereof.

15. The multilayer structure article of Claim 13 wherein the hydroxylated polymer layer comprises PVOH and the PVOH is at least 85% hydrolyzed PVOH.

16. The multilayer structure article of Claim 13 wherein at least one of the first and second moisture barrier layers is a thermoformable layer.

17. The multilayer structure article of Claim 13 wherein at least one of the first and second moisture barrier layers is selected from group consisting of: polyethylene (PE); polyvinylidene chloride (PVDC); ethylene vinyl alcohol (EVOH); polychlorotrifluoroethylene (PCTFE); silicon oxide (SiOx); polyvinyl chloride (PVC); polypropylene (PP); polyethylene terephthalate glycol-modified (PETG); polycarbonate; polyolefin; high impact polystyrene (HIPS); acrylonitrile butadiene styrene (ABS); bi-axially oriented polyethylene terephthalate (BOPET); polystyrene; oriented polypropylene (OPP); crystalline polyester; crystalline polyethylene terephthalate; and, combinations thereof.

18. The multilayer structure article of Claim 13 wherein at least one of the first and second moisture barrier layers comprises amorphous polyethylene terephthalate (APET).

19. The multilayer structure article of Claim 13 wherein the nonmetallic light activatable oxygen absorbing composition comprises a quinone class organic compound.

20. The multilayer structure article of Claim 19 wherein the quinone class organic compound is selected from the group consisting of: anthtraquinone; benzoquinone; napthoquinone; and, combinations thereof.

21. The multilayer structure of Claim 19 wherein the quinone class organic compound is anthraquinone-2-sulfonic acid sodium salt (AQ).

22. The multilayer structure of Claim 13 wherein the nonmetallic light activatable oxygen absorbing composition comprises a phenylglyoxylate, a Bis-acyl phosphine, or an a-hydroxy ketone.

23. The multilayer structure article of Claim 13 wherein the activation wavelength range is between about 200 nm and about 420 nanometers.

24. The multilayer structure article of Claim 13 wherein the portion of wavelengths of the activation wavelength range comprises about 380 nm.

25. The multilayer structure article of Claim 13 wherein the article is formed by thermoforming, extrusion molding, or blow molding.

26. A method of forming a nonmetallic oxygen absorbing multilayer structure comprising:

a) dissolving a nonmetallic light activatable oxygen absorbing composition in a quantity of water to form a first composition, wherein the nonmetallic light activatable oxygen absorbing composition comprises an activation wavelength range;

b) adding a hydroxylated polymer into the first composition to form a second composition;

c) heating and mixing the second composition;

d) cooling the second composition;

e) coating the second composition on a first moisture barrier layer;

f) drying the second composition on the first moisture barrier layer; and, g) coating a second moisture barrier layer on the second composition opposite the first moisture barrier layer, wherein at least one of the first and second moisture barrier layers is transmissive to at least a portion of wavelengths of the activation wavelength range.

27. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim

26 further comprising:

h) irradiating the nonmetallic oxygen absorbing multilayer structure with the at least a portion of wavelengths of the activation wavelength range, wherein the nonmetallic oxygen absorbing multilayer structure is activated by exposure to the at least a portion of wavelengths of the activation wavelength range.

28. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim

27 further comprising:

i) forming the multilayer structure of step h) into a molded form.

29. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim

28 wherein the molded form is a blister film.

30. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim 28, wherein the step of forming is performed using a thermoforming apparatus.

31. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim 26 further comprising:

h) forming the structure of step g) into a molded form.

32. The method of forming a nonmetallic oxygen absorbing multilayer structure of Claim 31 wherein the molded form is a blister film.

33. The method of forming a nonmetallic oxygen absorbing structure of Claim 31, wherein the step of forming is performed using a thermoforming apparatus.

34. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein the hydroxylated polymer comprises polyvinyl alcohol (PVOH), cellulose, hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC) or combinations thereof.

35. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein the hydroxylated polymer layer comprises PVOH and the PVOH is at least 85% hydrolyzed PVOH.

36. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein at least one of the first and second moisture barrier layers is selected from group consisting of: polyethylene (PE); polyvinylidene chloride (PVDC); ethylene vinyl alcohol (EVOH); polychlorotrifluoroethylene (PCTFE); silicon oxide (SiOx); polyvinyl chloride (PVC); polypropylene (PP); polyethylene terephthalate glycol-modified (PETG); polycarbonate; polyolefin; high impact polystyrene (HIPS); acrylonitrile butadiene styrene (ABS); bi-axially oriented polyethylene terephthalate (BOPET); polystyrene; oriented polypropylene (OPP); crystalline polyester; crystalline polyethylene terephthalate; and, combinations thereof.

37. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein at least one of the first and second moisture barrier layers comprises amorphous polyethylene terephthalate (APET).

38. The method of forming a nonmetallic oxygen absorbing structure of Claim 37 wherein the step of heating the second composition does not recrystallize the APET.

39. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein the nonmetallic light activatable oxygen absorbing composition comprises a quinone class organic compound.

40. The method of forming a nonmetallic oxygen absorbing structure of Claim 39 wherein the quinone class organic compound is selected from the group consisting of: anthtraquinone; benzoquinone; napthoquinone; and, combinations thereof.

41. The method of forming a nonmetallic oxygen absorbing structure of Claim 39 wherein the quinone class organic compound is anthraquinone-2-sulfonic acid sodium salt (AQ).

42. The method of forming a nonmetallic oxygen absorbing structure of Claim 41 whereinthe step of dissolving AQ comprises heating the quantity of water to about 65°C with mechanical stirring present and slowly adding AQ, the step of adding the hydroxylated polymer comprises maintaining a temperature of about 65°C with mechanical stirring present and slowly adding the hydroxylated polymer, the step of heating and mixing the second composition comprises heating the second composition to 90°C and stirring for about 15-20 minutes after reaching 90°C, and the step of cooling the second composition comprises cooling the second composition to at least 40 °C with mechanical stirring present.

43. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 wherein the nonmetallic light activatable oxygen absorbing composition comprises a phenylglyoxylate, a Bis-acyl phosphine, or an a-hydroxy ketone.

44. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 further comprises the step of:

dl) adding plasticizer to the second composition.

45. The method of forming a nonmetallic oxygen absorbing structure of Claim 44 wherein the plasticizer is selected from the group consisting of: glycerin; ethylene glycol; polyethylene glycol; propylene glycol; and, combinations thereof.

46. The method of forming a nonmetallic oxygen absorbing structure of Claim 26 further comprises the step of:

dl) modifying a surface of the second composition for adhesion enhancement.

47. A container for extending a shelf life of oxygen and moisture degradable pharmaceutical products comprising:

a thermoformable nonmetallic, non-water activatable oxygen absorbing moisture impermeable sealable layer forming a plurality of pill receiving chambers.

48. The container of Claim 47 further comprising:

an oxygen and moisture impermeable lid stock sealed to the sealable layer forming a plurality of moisture free low oxygen chambers.

49. The container of Claim 48 wherein oxygen content within the plurality of moisture free low oxygen chambers is substantially maintained at a constant value for at least two years.