Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1999-10-04
2002-07-16
Weiss, John G. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S203150
Reexamination Certificate
active
06418926
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to delivery devices and packaging for medicaments, in particular to delivery devices and packaging for the administration of medicaments by inhalation.
BACKGROUND OF THE INVENTION
The administration of powdered medicaments by inhalation is well-established. One form of delivery device which is employed for this purpose is the pressurised aerosol or metered dose inhaler (MDI). MDI's are, however, not suitable for use by all patients, eg small children, or for the administration of all medicaments. Also, there is concern about environmental damage caused by the propellants employed in MDI's. A widely-used alternative is the so-called dry powder inhaler in which medicament powder is dispensed from an elongate gelatine capsule, by causing the capsule to rotate and/or vibrate, into an airstream which is inhaled by the patient. The capsules are pierced. usually at each end. The piercing is carried out in the device by a suitable puncturing mechanism, and it has also been proposed for the capsules to be supplied in pre-pierced form, in packaging which prevents loss of powder from the capsule and the ingress of moisture.
Gelatine capsules, and known drug delivery devices for inhalation, suffer from numerous disadvantages. Disadvantages of MDI's have been referred to above. So far as dry powder inhalers are concerned, the gelatine capsules are not impervious to moisture. Exposure to the atmosphere can therefore result in absorption of moisture, which in turn may lead to agglomeration of the medicament powder particles. These problems may be particularly acute where as is often the case, the medicament is hygroscopic. As a result, capsules must be packaged in secondary packaging such as a blister package.
Another disadvantage is that the gelatine may be brittle, with the result that the piercing operation may produce shards or fragments which may be inhaled by the patient. This is clearly undesirable. Also, gelatine is a material of biological origin and therefore always contains a certain amount of microbiological organisms, which again is undesirable from the point of view of possible contamination of the medicament.
Removal of the capsule from the secondary packaging and loading it into the device may require a degree of dexterity greater than that possessed by some patients. In addition, the motion of the elongate gelatine capsule within the device may be irregular, leading to incomplete or variable dispensing of the powdered medicament.
Novel drug delivery devices for the administration of medicament by inhalation, and novel forms of packaging for such medicaments, have now been devised, which overcome or substantially mitigate the above-mentioned problems.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a system for the administration of a powdered medicament by inhalation, the system comprising a container containing a unit dose of medicament in powder form, the container having at least one dispensing aperture, and a device having a chamber adapted to receive said container, the device further comprising air inlet means by which air may be drawn into the chamber and mouthpiece means by which air and entrained medicament may be drawn out of the chamber, wherein the chamber is substantially circular or annular in form and, in use, the container follows an orbital path within the chamber.
The system according to the invention is advantageous primarily in that it may provide improved performance in terms of the dispersion of the medicament dispensed from it, ie the proportion of the medicament which is in the form of particles fine enough to penetrate deep into the patient's airways. Loading of the medicament container into the device is easy to perform. Emptying of the medicament container may be better than with other, known devices, leading to accurate and reproducible dosing. The airflow required to generate motion of the container within the device may be relatively low, enabling the device to be used with confidence by patients with weak lung function. In addition, the device is of compact and simple construction, leading to reduced manufacturing cost and longer lifetime. It may also be possible for a wide range of differently sized medicament containers to be utilised in association with the same device.
The air inlet means are preferably arranged such that air enters the chamber substantially tangentially so as to as to facilitate the orbital motion of the container within the chamber. There are preferably provided a plurality of air inlets, most preferably opening into the chamber at substantially equiangularly spaced positions. The air inlets may include narrowed portions to act as venturi and thereby increase the speed of the airflow.
It is particularly preferred that a part of the wall of the chamber into which the air inlets open should be continuous and unbroken. This inhibits any tendency for the movement of the container to be affected by the edges of the air inlet openings. In preferred embodiments, the air inlets open into the peripheral (commonly circular) wall of the chamber, but have a depth which is less than the height of that wall so that at least part of the wall, eg the lower and/or upper part of the wall, forms an uninterrupted annular surface.
The chamber may be provided with a formation which serves to constrain the movement of the container in its orbital path. For example, a spigot or the like may be formed in the centre of the chamber. However, in practice it is commonly found that no such formation is necessary, or merely a vestigial formation, eg a small protrusion in the centre of the base of the chamber, is effective.
According to another aspect of the invention, there is provided a device having a chamber adapted to receive a container containing a unit dose of medicament in powder form, air inlet means by which air may be drawn into the chamber and mouthpiece means by which air and entrained medicament may be drawn out of the chamber., wherein the chamber is substantially circular or annular in form and is provided with one or more formations effective to constrain, in use, the container to an orbital path within the chamber.
Air preferably passes out of the chamber to the mouthpiece through a mesh or grid formed in part of the wall of the chamber. Most preferably. the mesh or grid lies in a plane which is parallel to the plane in which container moves. For example the mesh or grid may be formed in the flat base or roof of the chamber. The mesh or grid may take any suitable form provided that, in use, it serves to retain the container within the chamber whilst permitting air and entrained medicament to pass out of the chamber.
It is particularly preferred that the grid or mesh should extend over only part of the base of the chamber, most preferably the central part of the base, ie the radially outer part of the base is preferably solid. It is found that this arrangement increases the residence time of medicament dispensed from the device within the chamber and this in turn enhances the dispersion of the medicament particles. Most preferably, for a chamber with a circular of substantially circular base, the outermost part of the base forms an annulus having a width corresponding to at least 15% of the radius of the base, more preferably at least 20%.
The mouthpiece is preferably formed at the open end of a passageway or conduit which connects the chamber to the mouthpiece. A particularly compact arrangement is provided if the passageway or conduit is disposed substantially orthogonally to the axis of rotation of the container in the chamber. In other embodiments, the passageway or conduit may be oriented parallel to that axis.
The device may be manufactured from materials conventionally utilised in inhalation drug delivery devices. Examples include plastics materials such as polycarbonate, polyolefins such as polypropylene or polyethylene, and others. Other materials which may be used include metals eg aluminium stainless steel etc. Combinat
Custom Focus Limited
Mitchell Teena
Nixon & Peabody LLP
Weiss John G.
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