Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1999-05-11
2002-06-11
Weiss, John G. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S203120
Reexamination Certificate
active
06401712
ABSTRACT:
The present invention relates to an inhaler, more particularly an inhaler for administering dry powder. It also relates to blister packs containing powder for use with the inhaler and to a method of dispensing powder from a blister.
It is known to provide certain medicaments in the form of a dry powder for inhalation for the treatment of respiratory conditions such as asthma.
It is also known to store individual doses separately in a sealed pack commonly known as a blister pack. The blister pack preferably comprises a series of moulded depressions each containing a dose of powder and sealed by a cover such as a foil. Either the user has manually to peel away the foil from an individual blister or a complex mechanism has to be provided to puncture the foil or cup-shaped part of the blister.
The task of finding the edge of a foil and peeling it away from the blister without spilling any of the contained powder can be difficult for some patients, for instance the young, the elderly or those actually experiencing an asthma attack. On the other hand, mechanisms for automatically opening a blister are complicated and therefore costly to produce. Furthermore, the automatic mechanisms do not peel the foil from the blister, but cut the foil or the cup-shaped portion of the blister itself. In some cases, this can give rise to the danger of parts of the foil or blister themselves becoming detached and joining the inhalation air stream. Furthermore, it has proved extremely difficult to cut the foil or blister in such a way as to ensure that all of the powder is removed from the blister or at least that a consistent proportion of the powder is removed.
According to the present invention there is provided an inhaler for administering dry powder, the inhaler comprising:
an inhaler body extending between two ends;
an outlet at one of said two ends;
a suction tube at the other of said two ends; and
an inhalation channel within said body providing fluid connection between said suction tube and said outlet; wherein
the suction tube is shaped and dimensioned for insertion into a blister containing powder such that inhalation through the inhaler body will draw powder from the blister through the suction tube and inhalation channel and out of the outlet.
There is also provided a method of transferring powder from a blister to the outlet of a device, the device having an inlet connected to the outlet by means of a channel, the method comprising:
inserting the inlet into the blister; and
drawing air out of the outlet so as to form an air stream into the inlet and through the device, the airstream picking up powder from the blister and carrying it through the channel to the outlet.
Thus, there may be provided a device which is relatively simple to construct, of relatively low cost to the user, simple to use and yet extremely effective in removing powder from the blister.
Since the inhaler body is separate from the blister pack, it has the additional advantage of being easily cleaned either at regular intervals or when needed. The inhaler body may be cleaned in any way, including total emersion in water, without any danger of contaminating or interfering with the operation of the inhaler. This is in contrast with previous more complicated inhalation devices, where, even if the powder is sealed in blisters, any powder previously retained in other parts of the inhaler may not be fully removed from the more complicated parts of the inhalation device and may interfere with correct operation of the device by being dampened through a washing operation.
According to the present invention there is also provided an inhaler for administering dry powder from a blister sealed by a thin film cover, the inhaler comprising:
a suction tube having an end for insertion into a blister; the end having:
a channel inlet through which powder may be drawn; and
a cutter around only part of the channel inlet such that, upon insertion into a sealed blister, the cutter cuts the film cover around only part of the channel inlet so as to form a cut film flap.
In this way, the cover foil of the blister is assuredly severed as necessary whilst ensuring that the cut portion of the cover remains attached to the rest of the cover. In this way, the cut cover cannot be inhaled by a user.
Preferably, the cutter comprises a plurality of axially extending blades divided by axially extending gaps.
In this way, it is assured that an air flow path exists from the blister to the channel inlet within the cutter, since air can always flow through the axially extending gaps. Furthermore, by virtue of the relationship between the blades and the gaps, the cover foil will tear to bridge the gaps between the cutters.
Preferably, the blades extend axially beyond the remainder of the end of the suction tube.
In this way, the blades first cut the cover foil, before pushing the cover foil away from the rest of the cover into the blister. The remainder of the end of the suction tube may come into contact with the cut cover foil at the last moments of insertion so as to assist in pushing the flap into the blister.
By using such a cutter, integral with the channel inlet, the blister is only cut when the suction tube is being fitted into the blister. In this way, penetration of the cover foil takes place while the suction tube is being fitted on such that fitting and sealing with the blister lasts throughout the period of use and any losses are avoided.
The present invention also provides an inhaler for administering dry powder from a blister sealed by a thin film cover, the inhaler comprising:
a suction tube having:
an end for insertion into a blister, the end having a channel inlet through which powder may be drawn; and
at least one inlet passage extending between a passage inlet at a position along the length of the suction tube and a passage outlet adjacent said channel inlet, such that, with the end inserted into a blister, the inlet passage provides fluid connection between the blister and a space above the blister.
In this way, powder may be assuredly drawn from a blister, since inlet air channels are provided to the blister. In particular, those inlet air channels may be provided at the outer periphery of the blister so as to assist in ensuring that all of the powder in the blister is removed.
Preferably, the inhaler further comprises a support unit for supporting a blister pack, the support unit including respective guide portions for each blister of a supported blister pack, each guide portion being for guiding said suction tube into a respective blister and supporting the inhaler body with said suction tube so guided.
Alternatively, there may be provided a blister pack comprising at least one blister housing a dose of medicament, the blister comprising:
a cup-shaped portion for holding said powder;
a thin film cover for sealing the powder in the blister; and
an axially elongate passage extending from said cup-shaped portion for guiding a suction tube of an inhaler into the blister.
In this way, it may be ensured that the inhaler body is correctly inserted into the blister. Since the inhaler body is guided into the blister, consecutive uses of the inhaler body will be more consistent. Furthermore, the user has a feeling of greater confidence in using it.
Where the blister pack is formed as a substantially planar surface with a series of depressions forming respective blisters, the support unit may include a guide wall to be positioned adjacent the substantially planar surface and having a series of apertures for alignment with the series of depressions, the guide wall extending away from the substantially planar surface so as to form the guide portions. The support unit may include a housing within which the blister pack may be contained, with the guide wall being a wall of the housing.
In this way, the blister pack is securely held in a housing convenient to the user with its blisters in alignment with the guide portions.
Preferably, the support unit includes a support member having a series of depressions for receiving the series of depressions of
AstraZeneca AB
Farber Martin A.
Mitchell Teena
Weiss John G.
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