CN1972850A - A support structure for a medicament - Google Patents

Abstract

A drug support structure (1) includes a base plate (2) having at least one cavity (3) for a drug; and a cover (4) for sealing the drug within the cavity (3). Each moisture-permeable area (6) of the structure is protected from moisture ingress by a moisture absorption groove (7) provided between the area and the ambient air outside the structure (1).

Description

drug support structure

technical field

The present invention relates to a medicament support structure in the form of, for example, a blister pack of medicament or an injection molded medicament metering element, as used in an inhalation device. A typical pharmaceutical blister pack is described in WO 01/45777 and a typical pharmaceutical metering element is described in US 5,590,645.

Background technique

For powdered medicaments, there is a need for a packaging/support structure capable of securing the medicament against ingress of moisture, both during storage and when the powdered medicament has been loaded into a delivery device. Similarly, if the drug is in the form of tablets or capsules, it is also necessary to protect the tablets or capsules, which are typically stored in blister packs, from the ingress of moisture. The main disadvantage of a support structure with one or more drug receptacles that seals the base with a cover is the area where the cover is sealed to the base. If the support structure is in the form of a blister pack, the lid and base plate are often made of a material containing an aluminum layer, so that these elements cannot penetrate moisture. Therefore, the only area where moisture can enter the blister pack is through the area where the lid is sealed, which is typically a heat seal. If the base of the blister pack is made of plastic material, moisture will also pass through the base material and into the medication. If the support structure is in the form of an injection molded dosing element, the injection molded base plate will be made of a moisture permeable material and the cover will usually include an aluminum layer making it impermeable to moisture. In this case, moisture can enter through the heat seal between the lid and the base plate and through the base plate material.

The problem of moisture ingress has been overcome to some extent in prior art inhalation device components by using aluminum containing foil material for the lid and base plate and isolating adjacent cavities by approximately 3mm. With this arrangement, moisture in an empty volume does not endanger adjacent volumes which still contain a quantity of medicament. The only weak point is the heat seal between the lid and base plate. A disadvantage of this construction is that there is a certain limit to the number of medicaments that can be arranged in the blister pack/dosing element due to the need for spacing.

Other prior art solutions include providing a desiccant source that is connected or placed into the drug containing chamber. However, this solution is only reactive, and the moisture is eliminated only after entering the passenger cavity instead of preventing the moisture from entering the cavity in advance. Similarly, another option is to use a desiccant cartridge inside an aluminum pack containing multiple pharmaceutical preparations such as tablets, but this form of moisture protection is destroyed when the pack is opened for the first time. Broken and therefore not stable in use. For other prior art solutions see WO 03/61742 and US 6,132,394.

In view of the problems discussed above, the present invention seeks to provide moisture protection of the drug and maximize the amount of formulation placed on the support structure.

Contents of the invention

According to the present invention, there is provided a support structure for medicaments, comprising a bottom plate containing at least one medicament container, and a cover for sealing the medicament in the container, characterized in that each moisture-permeable Areas are protected from the ingress of moisture by providing moisture absorbing slots between the area and the ambient air outside the structure.

Preferably, the trough reduces the relative humidity (RH) of the air passing through it substantially to the level of the relative humidity (RH) of the air within the cavity, thus having minimal diffusion of humidity from the trough to the cavity.

Preferably, each moisture vapor permeable region comprises an inner moisture vapor permeable barrier positioned adjacent the cavity and an outer moisture vapor permeable barrier, the moisture absorbing groove being disposed between the inner and outer barriers.

Preferably, the base and lid are moisture impermeable, with the moisture permeable regions of the structure being located where the cover seals against the base.

Preferably, a moisture absorbing groove located between the lid and the base plate is spaced from the periphery of the cavity, thereby forming an inner moisture-permeable area and an outer moisture-vapor-permeable area, the groove interrupting the passage of moisture ingress , so that there is minimal diffusion of moisture across the interior moisture permeable region to the cavity.

Preferably, the moisture absorption tank comprises a channel in the base plate surrounding the cavity, containing dry air therein.

Preferably, a plurality of cavities are included, each having a channel filled with dry air.

Preferably, each channel is connected to a single desiccant source which dries the air in all channels.

Preferably, the moisture absorbing channel comprises a polymeric ring surrounding the cavity and positioned between the lid and the base plate.

Preferably, a plurality of cavities are included, each cavity having a polymer ring.

Preferably, both the base plate and the lid comprise an aluminum layer for protection against moisture penetration, the lid being heat-sealed to the base plate.

Preferably, the lid is moisture impermeable and the base material is moisture permeable, the moisture permeable areas being located in the base material where the cover is sealed to the base and the walls of the cavity.

Preferably, a first moisture absorbing groove is located between the lid and the bottom plate and spaced from the periphery of the cavity, and a second moisture absorbing groove is positioned in the bottom plate material of the wall of the cavity, thereby forming an interior moisture permeable The barrier and the outer moisture-permeable barrier, the grooves interrupt the ingress passage of moisture so there is minimal moisture diffusion through the inner moisture-permeable barrier to the cavity.

Preferably, the moisture absorption tank comprises a channel containing dry air around the opening of the cavity where the cover is sealed to the floor and through the cavity wall.

Preferably, a plurality of cavities are included, each having a channel for containing dry air.

Preferably, each channel is connected to a single desiccant source which dries the air in all channels.

Preferably the base plate is injection moulded, the lid has an aluminum layer to make moisture impermeable, the cover is heat sealed to the base plate.

Preferably, the base plate comprises mutually cooperating stackable elements, each element comprising a plurality of cavities, and when stacked, the cavities in one element are located between cavities in the other element, through the space between the cooperating elements The interval forms a moisture absorbing groove.

Description of drawings

Preferred embodiments of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of the relative humidity gradient across a barrier for a drug with conventional means of moisture protection;

Figure 2 is a schematic diagram of the relative humidity gradient across a barrier structure having moisture protection in accordance with the present invention;

Figure 3 is a sectional view of a blister of a blister pack with moisture protection according to a preferred embodiment of the present invention;

Figures 4A, 4B and 4C depict a preferred embodiment of a blister pack with multiple chambers with moisture protection;

5 is a plan view of a section of a metering element for an inhalation device having moisture protection measures according to a preferred embodiment of the present invention;

Fig. 6 is a cross-sectional view along the X-X direction of the metering element in Fig. 5;

Figure 7 depicts another preferred embodiment of a metering element with moisture protection;

Figure 8 depicts the underside of the ring 111b in Figure 7; and

FIG. 9 is an enlarged view of a portion of the circle in FIG. 8 .

Detailed ways

Referring now to FIG. 1, this graph depicts the relative humidity (RH) gradient across a moisture vapor permeable barrier. The barrier can be, for example, the material from which the base of the support structure is made or a heat seal between the cover and base of the support structure. The ingress of moisture through the barrier is due to the fact that the relative humidity of the ambient air outside the support structure is typically 70%, while the relative humidity of the air and powdered drug inside the cavity is typically 20%. The ingress of moisture comes both from the ambient air and from adjacent empty volumes. The powdered drug is protected by only one layer of barrier through which moisture is continuously transported due to gradient-driven diffusion. The transfer of moisture continues until the relative humidity in the chamber reaches the ambient level. Moisture protection can only be improved by increasing the thickness of the barrier or improving the properties of the barrier material.

In the present invention, it is proposed to provide a moisture absorbing groove between each moisture permeable area of the support structure and the ambient air. This can be achieved, for example, by dividing one barrier into an outer barrier and an inner barrier and placing a slot between the two barriers. Figure 2 depicts a preferred structure in which the grooves effectively interrupt the entry of moisture. The relative humidity gradient across the outer barrier is large, causing moisture to diffuse as in FIG. 1 . However, any moisture diffusion across the internal barrier will be low when moisture enters the trough with high moisture absorption properties. For example, if you have dry air in the tank, the relative humidity of the air in the tank will drop to 20% (at a similar level as in the cavity), and as a result, the relative humidity gradient across the inner barrier will be low, The ingress channel of moisture is interrupted.

Figure 3 depicts a first preferred embodiment of the invention in which the support structure has the form of a blister pack having a base plate 2 containing at least one receptacle for containing the medicament; is sealed to the base plate 2. Between the outer seal 5 and the inner seal 6 a moisture absorption groove in the form of a channel 7 surrounding the cavity 3 is employed. The channel 7 can accommodate dry air, thereby dehumidifying the area of the cover 4 . The moisture ingress channels M of the support structure will only be through the heat seals 5 and 6, since the bottom panel 2 and lid 4 of the blister pack are typically made of a moisture impermeable material with an aluminum component. The entry of moisture into channel M will result in a relative humidity gradient similar to that described in FIG. 2 . The outer barrier may be a heat seal 5 and the inner barrier may be a heat seal 6 . The drying air in the channel 7 is dried by means of a desiccant. If the dry air reduces the relative humidity in the channel 7 to about 20%, there will be minimal moisture diffusion through the heat seal 6 to the cavity 3, assuming the relative humidity in the cavity 3 is also about 20%.

Referring now to FIGS. 4A , 4B and 4C, three configurations of a blister pack with multiple cavities 3 are described. In FIG. 4A , each cavity 3 is surrounded by a dry air channel 7 . All channels 7 are connected to a desiccant 8 which ensures that the air inside the channels is continuously dried to the required level. Channels and desiccant containers are usually cold formed in the same manufacturing process steps as the cavities. Figure 4B depicts a modification using a rectangular channel structure. FIG. 4C depicts a preferred structure, wherein the moisture absorbing groove of each chamber 3 adopts moisture absorbing material, for example, polymer in the shape of nylon ring 9 . In this case, it is not necessary to use a desiccant, and each chamber 3 has a dedicated nylon ring, located between the bottom plate 2 and the cover 4 of the supporting structure.

In FIG. 5 the drug support structure has the form of an annular drug metering element 101 . This type of metering element is usually placed in an inhaler device and is capable of indexing the drug chambers 103a, 103b, and 103c via a past a mechanism that opens the lid 104 to allow the user to select from each chamber. Inhale drugs. Figure 5 shows a section of an annular metering element 101 comprising three adjacent cavities 103a, 103b and 103c. One of the chambers 103a is empty, while the other two chambers 103b and 103c are still filled with powdered drug. Fig. 6 is a cross-sectional view of the metering element in Fig. 5 along X-X direction.

The base plate 102 of the metering element 101 is typically injection molded and thus moisture permeable. With this construction, moisture protection is required not only when the cover 104 is heat sealed to the base 102, but also within the base material. Channels 107 extend between adjacent pockets and through the floor 102 under each pocket.

All of the channels 107 are connected to a desiccant 108 which dries the air in the channels to reduce the relative humidity to the level in the cavity.

For chamber 103b, an outer heat seal 105 extends around the outer and inner circumference of the annular metering disc. There is also an external moisture barrier 109 on the base plate 102 . Channel 107 creates an internal barrier in the form of internal heat seal 106 and internal moisture barrier 110 in base plate 102 .

When the chamber 103a is emptied, the inner heat seal 106 of the chamber becomes the outer heat seal 105 of the chamber 103b, thus ensuring that the empty chamber 103b cannot form a source of moisture ingress.

FIG. 7 depicts a preferred configuration of the metering element 101 comprising two cooperating rings 111a and 111b stacked one above the other within the containment tray 112 . The space between the rings 111a and 111b forms the channel 107 .

This arrangement allows the distance between each cavity and the adjacent cavity to be as small as 1 mm. In this way, 60 cavities can be arranged on a metering disc 101 with a diameter of 72 mm. A desiccant 108 (not shown) for drying the air in the channel 107 between the parts 111a, 111b and 112 is located below the ring 111b in the channel 113 (see Figures 8 and 9). The lid 104 should be heat sealed to the arrangement shown in FIG. 7 .

The circular ring 111 a has a plurality of cavities 114 , and the circular ring 111 b has a plurality of cavities 115 .

With this arrangement, it is not necessary to injection mold the ring to form the separate channels as shown in FIG. 5 . It is sufficient to injection mold the drug pockets 114 and 115 on a circular ring and stack one on top of the other in the containment disc 112 . The desiccant tank 113 is located below the ring 111b, as shown in FIG. 7 . The space between rings 111a and 111b is sufficient for moisture transfer. The machining process is simpler and there is no need to form narrow channels as described in FIG. 5 . The space between the rings can be increased, for example, by increasing the roughness of the walls, or by employing a grid pattern on the side walls.

Claims (17)

1; a kind of medicine supporting construction; comprise base plate; this base plate comprises at least one drug cavities and medicine is sealed in lid in the cavity volume; the zone of each moisture permeable of this structure all is protected by the moisture absorption groove that is provided with between the ambient air outside this zone and this structure and prevents entering of moisture; it is characterized in that; each moisture permeable region all comprises permeable barriers of inner moisture and the permeable barriers of outside moisture near the cavity volume location; the moisture absorption groove is set between the inside and outside barriers level that is reduced to the relative humidity (RH) of the air in the cavity volume with the relative humidity (RH) of the air that will pass it basically, has minimum humidity diffusion between therefore from the groove to the cavity volume.

2, supporting construction as claimed in claim 1, wherein base plate and lid are that moisture is impermeable, the zone of the moisture permeable of this structure is positioned at the position of sealing of lid to base plate.

3, supporting construction as claimed in claim 2, wherein the moisture absorption groove between lid and base plate and the periphery of cavity volume separate, therefore form permeable zone of inner moisture and the permeable zone of outside moisture, this groove has interrupted the passage that moisture enters, and passes the inner moisture permeable region has minimum to the moisture of cavity volume diffusion thereby make.

4, as each described supporting construction of claim 1 to 3, wherein the moisture absorption groove is included in the base plate around the conduit of this cavity volume, wherein comprises dry air.

5, supporting construction as claimed in claim 4 comprises a plurality of cavity volumes, and each cavity volume all has the conduit that is full of dry air.

6, supporting construction as claimed in claim 5, wherein each conduit all is connected to single desiccant source, the air in dry all conduits in this desiccant source.

7, as each described supporting construction of claim 1 to 3, wherein the moisture absorption groove comprises polymer ring, and this ring is around cavity volume and between lid and base plate.

8, supporting construction as claimed in claim 7 comprises a plurality of cavity volumes, and each cavity volume all has polymer ring.

9, as each described supporting construction of claim 2 to 8, wherein base plate and lid the two all comprise the aluminium lamination that is used to prevent moisture vapor transmission, lid is heat sealed on the base plate.

10, supporting construction as claimed in claim 1, wherein lid is that moisture is impermeable, and baseboard material is a moisture permeable, and the zone of moisture permeable is arranged in lid and is sealed to the place of base plate and the baseboard material of cavity walls.

11, supporting construction as claimed in claim 10, wherein the first moisture absorption groove is between lid and base plate, and it is spaced apart with the periphery of cavity volume, the second moisture absorption groove is arranged in the baseboard material of cavity walls, form in-to-in moisture permeable barriers and exterior moisture permeable barriers thus, described groove interrupts the access passage of moisture, therefore has minimum moisture diffusion by the permeable barriers of inner moisture to cavity volume.

12, as claim 10 or 11 described supporting constructions, wherein the moisture absorption groove comprises the conduit that holds dry air, and this conduit is sealed to the cavity volume opening at base plate place and passes cavity walls around lid.

13, supporting construction as claimed in claim 12 comprises a plurality of cavity volumes, and each cavity volume all has the conduit that holds dry air.

14, supporting construction as claimed in claim 13, wherein each conduit all is connected to single desiccant source, the air in dry all conduits in this desiccant source.

15, as each described supporting construction of claim 10 to 14, wherein base plate is an injection-molded, and lid has aluminium lamination so that moisture porous not, and lid is heat sealed on the base plate.

16, supporting construction as claimed in claim 10, wherein but base plate comprises the overlapped components that cooperatively interacts, each element comprises a plurality of cavity volumes, cavity volume when stacked in element is between the cavity volume in another element, forms a moisture absorption groove by the interval between the element that cooperatively interacts.

17, a kind of medicine supporting construction is basically as here and referring to as described in the accompanying drawing.

Images