Patent Grant
7107988
1. The Field of the Invention
The present invention relates to a powder inhaler, i.e. a device for dispensing a powdered medicament preparation by inhalation. The device is in particular a portable multiple-dose device without propellant gas, equipped with a metering member which dispenses doses from a medicament container. Moreover, the device is based on centripetal force for achieving a more effective pulverization of the powdered inhalation medicament in such a manner that the penetration of the medicament into the lungs of a patient is improved and the adhesion to the upper respiratory passages is reduced for alleviating possible side effects caused thereby.
2. The Relevant Technology
The administering of a powdered medicament preparation by inhalation from an inhaler is commonly known. Multiple-dose type powder inhalers comprising a powder container and a metering member which measures and dispenses a unit dose are also known, for example from patent publications GB 2165159, EP 0 079 478, and EP 0 166 294. In these devices, a series of dosing recesses are notched into the surface of a cylindrical metering member, and the member is disposed in a chamber of precisely the same shape. When the metering member is rotated, the dosing recesses in turn will move first to a position in alignment with the powder container for being filled and thereafter to a position in alignment with an inhalation channel, whereupon a unit dose will fall by gravity from the dosing recess into the inhalation channel. Thereafter the dose of medication is inhaled from the inhalation channel. These devices have the drawback that they make overdosing of the medicament possible by allowing the dispensing of a plurality of doses in succession into the inhalation channel, whereby a multiple dose may be drawn by one inhalation.
Inhalation devices having a metering plate movable between a filling and a dispensing position are described e.g. in patent publications WO 92/10229, U.S. Pat. No. 5,113,855, U.S. Pat. No. 2,587,215, EP 0 546 996, WO 94/04210 and U.S. Pat. No. 5,161,524. A further example of related devices is given in WO 93/03782. However, these devices also suffer from a drawback that they make overdosing possible by allowing the dispensing of a plurality of doses into the inhalation channel.
Attempts have been made to solve this problem by using inhalers or dispensing systems in which the dosing recess will not be emptied into the inhalation channel by gravity but, instead, the dose of medication is inhaled directly from the dosing recess, such recesses having been notched into the surface of a metering member. The metering member may have the shape of a cylinder, a cone or a truncated cone, as disclosed in patent publications WO 92/00771 and WO 92/09322. Furthermore, in these devices, the metering member having the shape of a cylinder, a cone or a truncated cone is disposed in a chamber having precisely the same shape. When the metering member is rotated, the dosing recesses will move first to a position in alignment with the medicament container for filling, and then to the inhalation channel which is shaped so that the respective dosing recess will be emptied under the effect of the air flow being inhaled, and thereafter, having rotated through a full 360°, back to a position in alignment with the medicament container. The lower surface of the chamber wall may also have an emptying aperture from which any powdered medicament possibly left in the dosing recess will fall out during the rotation.
In the rotating dispensing devices described above, the distance from the filling position to the inhalation position is less than 90° of a circle arc. Since the metering member is, for purposes of metering precision, disposed within a chamber of the same shape, and since it has to be rotated through 360°, of which at least 270° are useless for the actual function of the inhaler, in these devices particles will inevitably fall onto the slide surface between the metering member and the chamber. Thereby the rotation of the highly sensitive metering member will be disturbed and may even be completely obstructed. The metering member jamming inside the chamber will hinder the functioning of the whole device. Vigorous shaking or tapping will only increase the jamming as more powder flows into the gap between the chamber and the metering member.
An improvement of the powder inhalers of the related art is suggested in EP 0 758 911. The described powder inhaler comprises a powder container, an air channel through which air is drawn via a mouthpiece, and a metering member equipped with a dosing recess, the metering member being movable in its longitudinal direction between a first position, in which the dosing recess is filled with powder coming from the container, and a second position, in which the filled dosing recess is brought into the air channel, the powder being maintained in the recess by the support of the recess bottom, and the air channel being directed to introduce the air flow into the bottom of the dosing recess during inhalation whereby the powder is released directly from the dosing recess. According to the powder inhaler of this related reference, the metering member is a metering strip which is disposed on a flat surface and moves along the flat surface. When moving between the filling and the inhalation positions, the metering strip travels over an aperture for remnants, at which time any powder possibly remaining between the metering strip and the flat surface will fall out through the aperture. This powder inhaler is still not completely satisfying for the following reasons, e.g. the inhaled air flow is directed longitudinally relative to the metering strip. In this condition both the deaggregation of the powder and the removal of the powdered medicament from the metering strip by the inhaled air flow is not efficient. Moreover, any powder possibly left after the inhalation will remain in the air channel until the metering strip again moves along the flat surface into the air channel during a subsequent inhalation process. This remaining powder could be accidentally inhaled by the patient. Furthermore, the powder remaining inside the air channel may deteriorate due to the friction between the surfaces.
As mentioned above, a further problem with respect to powder inhalers is that a sufficient deaggregation of the powder and the removal of the powdered medicament or drug from the metering member by the inhaled air flow is not satisfactory in the powder inhalers of the related art.
It is generally known that the size of medicament particles should be 1–5 microns, preferably 2–3 microns, for the best possible penetration into their destination, i.e. deep into the lungs. The most common metering device is a so-called inhalation aerosol which is quite readily capable of reaching the optimal particle size. In addition to inhalation aerosols, an increasing number of powder inhalers are presently in use as these offer certain benefits, e.g. there is no need for ozone-destroying propellants. However, a drawback of powder inhalers is that a powdered medicament issuing from the powder inhaler has a too large particle size. Thus, most of the medicine dosage coming out of inhalers is retained in upper respiratory passages which, with certain medicines, can cause serious side effects. The medicine dosages required for different inhalation medicaments vary considerably, the smallest being approximately 0.01 mg and the largest 20 mg. When small amounts of medicine are metered in powdered form, it is generally necessary to use some adjuvant or carrier, so that the sufficiently precise measuring of a dosage would be possible with the present technology. No matter if the dosage comprises just medicine or has a carrier admixed therein, the medicine dosage substantially comprises inter-adhered particles and most of these agglomerates are too large to penetrate into the lungs. As the agglomerates are released in a powder inhaler into an air flow directed into the lungs of a patient, some dispersal of these particle deposits can occur, the dispersal resulting from the formulation of a powdered medicament and the construction of an inhaler. It is known that constructions creating a strong turbulence are capable of more effective pulverization.
In practice, however, no prior known powder inhalator structure and/or medicine formulation has produced results that would be equal to those achieved by an ordinary inhalation aerosol. It has been suggested as a partial solution that inhalation should be effected with as much force as possible, whereby the turbulence and pulverization of particles would accordingly be most effective. However, a quick inhalation is difficult for a person suffering e.g. from serious asthma and, on the other hand, a quick inhalation increases the residue in upper respiratory tracts. According to studies, pulverization of agglomerates is indeed intensified but the overall benefit is marginal. Excellent Pulmonary penetration in relation to the adherence of medicament to the upper respiratory tracts has been achieved by slow inhalation, corresponding to a flow rate of approximately 30 l/min or 0.5 l/sec.
Finnish patent application No. 871000 discloses a powder inhalator which has been designed in an effort to produce a clearly defined turbulence for pulverizing agglomerations of medicine. The centrally directed deflectors inside the device or the helical chute are explained to set the air flow in a spinning motion, whereby the medicine particles entrapped in the air abrade as a result of centrifugal force against the walls of the structure as well as collide with each other with resulting pulverization. The device described in the cited application has been marketed under the trade name Turbohaler® (Draco, Sweden), and the pulverizing structure therein is, as described above, a helical chute or groove. Laboratory tests indicated that this device had a relatively good pulverization of agglomerates of medicine which, however, could still be improved and intensified. In view of the pulverization of agglomerates or accumulations of medicine, there are a few defects in this device. The helical groove has in the centre thereof an open space having less air resistance than inside the groove. Accordingly, the flow rate of air and centrifugal force on the circumference of the groove are less than theoretically possible. Since the particles advance in the groove under a force caused by air resistance and centrifugal force tends to push the particles perpendicularly to the circumferential tangent, the actual force applied to the particles is a resultant of these forces and is applied diagonally relative to the circumferential tangent. Thus, the centrifugal force resulting from the spinning motion cannot be utilized in full extent for the pulverization of accumulations. In all deflector structures according to the cited application, the particles escape from the device within a few thousandths of a second when using conventional inhalation rates of 30–90 l/min, and that is a very short time for an effective pulverization. The residence time can be prolonged, e.g. by increasing the number of helices in groove portions or the number of separate deflector structures or the length of zigzagging air flow channels, but this would complicate manufacturing and cleaning and medicine residues in the actual device would increase. After all, cleaning of the structures disclosed in the cited application is difficult.
EP 0 407 028 shows in its
FR-A-2352556 shows a cylindrical vortex chamber closed at one end, operated by the action of inhalation and having one tangential air-medicament inlet duct, an additional tangential air inlet duct and an axial outlet duct near the same end of the chamber as the inlet duct. The outlet is formed by a tube-like connection extending beyond the zone of the inlet duct and impeding the air flow. Nothing is said again about the diameter of the cylindrical chamber.
Moreover, in the device described in EP 0 477 222 a powdered medicament intended for inhalation is pulverized on the basis of a sufficiently powerful centrifugal force prior to or during inhalation. The centrifugal force is produced by the action of inhalation. A powdered medicament is entrapped in a gas flow and forced in a substantially circular or rotationally symmetrical space to such a powerful rotating motion that an effective splitting of accumulations of medicine is obtained. This is affected in a rotationally symmetrical chamber whose largest internal diameter can be 20 mm. The optimum diameter of the vortex chamber operating by the action of inhalation is 10–20 mm. If the diameter is increased, the pulverization effect deteriorates in a manner that, with a diameter of more than 30 mm, the pulverization effect is no longer significant.
EP 0 865 302, a further powder inhaler is known which comprises a medicament container for storing a dry powdered medicament, a mouthpiece being covered by a removable protective cap, and a movable dosing slide having a dosing cavity to be placed underneath a funnel outlet of the medicament container for filling. With opening of the protective cap, the movable dosing slide with the filled dosing cavity is pushed into a shutter, and the dosing cavity is closed thereby. Upon a sufficient suction force generated by an inhalation process, a valve shield pushes away the shutter, and the dosing cavity is released in order to enable inhalation of the medicament powder. Furthermore, means are provided for enabling the return of the dosing slide only after a correctly completed inhalation process. A recording unit records the number of correctly performed inhalations and blocks the powder inhaler after a predetermined number of inhalations. Between the inlet and the outlet of the mouth-piece a labyrinthine atomiser path for powder deagglomeration is provided.
The technical problem underlying the present invention is to eliminate the above drawbacks of hitherto known powder inhalers and to provide a powder inhaler with an improved functionality. In particular, it is an aspect underlying the present invention to provide a powder inhaler with an improved dosing ability, whereby unintended dosing can be avoided, and to provide a powder inhaler with an optimal pulverization of agglomerates of a medicament to be inhaled, respectively.
This technical problem can be solved by a powder inhaler having the following features a container for storing a powdered medicament, a metering member having a dosing recess, the metering member being moveable between a filling position, in which the dosing recess is in alignment with an opening of the container so as to be filled with a dose of the powdered medicament, and an inhalation position, in which the dosing recess is in alignment with an inhalation channel, and a mouthpiece being in communication with the inhalation channel for enabling inhalation of the dose of the powdered medicament contained in the dosing recess of the metering member when the metering member is in the inhalation position. A protective member can be provided between the metering member and the inhalation channel, the protective member being moveable between a closed position, in which the protective member at least covers the dosing recess of the metering member when the metering member is in the inhalation position, thereby preventing the powdered medicament contained in the dosing recess from entering into the inhalation channel and an open position, in which the protective member does not cover the dosing recess, thereby exposing the dosing recess to the inhalation channel so as to enable inhalation of the dose of the powdered medicament contained in the dosing recess.
Furthermore, a deagglomerator arrangement for deagglomerating a powdered medicament can include a vortex chamber having an opening for the supply of the powdered medicament, at least two air inlets for directing air tangentially into the vortex chamber, and an outlet for outputting air with the deagglomerated powdered medicament. The outlet can be spaced from the air inlets in an axial direction of the deagglomerator arrangement. An outer wall of each air inlet can be connected to the other air inlet by an arched wall portion of the vortex chamber, each arched wall portion being positioned non-concentric to a horizontal circle defining a diameter of the vortex chamber.
In addition, the powder inhaler can include an inhalation channel having a deagglomerator arrangement as described above, which may be incorporated into such a powder inhaler without, however, being limited to this preferred use. These and other aspects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
According to the present invention, a powder inhaler is provided comprising a container or a powder reservoir for storing a powdered medicament, a metering member having a dosing recess to be filled with one dose of the powdered medicament, a mouthpiece being in communication with an inhalation channel, and a protective member being provided between the metering member and the inhalation channel. The metering member is moveable between a filling position, in which the dosing recess is in alignment with an opening of the container so as to be filled with one dose of the powdered medicament, and an inhalation position, in which the dosing recess is in alignment with the inhalation channel. The protective member is moveable between a closed position, in which it at least covers the dosing recess when the metering member is in the inhalation position, thereby preventing the powdered medicament contained in the dosing recess from entering into the inhalation channel, and an open position, in which the protective member does not cover the dosing recess, thereby exposing the dosing recess to the inhalation channel so as to enable inhalation of the dose of the powdered medicament contained in the dosing recess.
The protective member, which is preferably a thin plate sliding on the metering member between its closed position and its open position, prevents the drug or powdered medicament contained in the dosing recess from falling out of the dosing recess, thereby preventing an unintentional loss of the powdered medicament contained in the dosing recess. Although a manual movement of the protective member between its closed position and its open position is conceivable, the protective member is preferably automatically withdrawn and moved from its closed position into its open position upon an inhalation process, thereby enabling the powdered medicament contained in the dosing recess to be released into the inhalation channel. Thus, the powder inhaler can be used in a variety of orientations, even upside down when the user or patient is lying in a bed, for example. This is a distinctive advantage over related art products where the dose can be lost by a poor orientation of the device.
In order to automatically withdraw the protective member from its closed position and move it into its open position upon an inhalation process, an inhalation actuated mechanism may be provided being coupled to the protective member such that, if the protective member is in its closed position, the inhalation actuated mechanism moves the protective member into its open position if the inhalation suction force of the respective user exceeds a predetermined value. Preferably, the inhalation or breath actuated mechanism is constructed such that it automatically returns the protective member into its closed position after the respective inhalation process has properly been completed.
The powder inhaler of the present invention may comprise a casing and an integral cover, the integral cover being rotatably or pivotably coupled to the casing so as to enable opening and closing of the integral cover. The casing may comprise a window or an opening for displaying the number of doses taken or the number of doses left in the container, this number being counted by a dose counting unit. If the cover is closed it covers the mouthpiece being located at the upper side of the casing. The casing may also comprise an opening for a mark, for example in the form of a flap, which shows if a dose is ready for inhalation or not. In particular, this flap may disappear upon completion of an inhalation process, thereby showing that the respective dose has been taken by the user.
The container storing the powdered medicament is preferably divided up into a medicament chamber storing the powdered medicament and a desiccant chamber for storing a desiccant provided for drying out the powdered medicament contained in the medicament chamber, the desiccant chamber being separated from the medicament chamber by a separate permeable membrane. The permeability of the membrane is different from, in particular greater than that between either the desiccant or the medicament and the outside world. This can be achieved, for example, by making the membrane from a different material and/or a thinner material than the main body of the container. Both the medicament chamber and the desiccant chamber may be sealed by foils. The bottom of the medicament chamber may have a dosing opening so that the powdered medicament contained therein can be filled into the dosing recess of the metering member supported by gravity, if the metering member is in its filling position. The filling process is furthermore supported by an appropriate shape of the medicament chamber which should have a cross-section diameter gradually decreasing from its top to its bottom, thereby forming a funnel for the powdered medicament.
The metering member is preferably a slide or a shuttle which is provided within the casing slidingly moveable in the horizontal direction between the filling position and the inhalation position. In the filling position the dosing recess faces the dosing opening of the container, and in the inhalation position the dosing recess faces an inhalation opening of the inhalation channel being in communication with the mouthpiece. The slide is preferably coupled to the cover such that opening of the cover causes the slide to move from the filling position forward to the inhalation position, and closing of the cover causes the slide to move from the inhalation position backward to the filling position. Projections, for example in the form of bolts, may be formed at both longitudinal sides of the slide, these projections engaging with profiled cam tracks being formed at the respective sides of the cover. This allows the fundamental operating sequence of the powder inhaler to include opening the cover, inhaling the dose, and closing the cover. It is the simplest possible operating sequence to reduce training time on the one hand and maximize patient compliance on the other hand.
The coupling between the cover and the metering member is preferably such that opening of the cover by a predetermined first angle from its closed position, preferably by an angle up to about 30°, does not actuate the metering member at all. Within this range of movement of the cover is slack where no mechanism is driven. Furthermore, the coupling between the cover and the metering member is preferably such that the metering member is moved in its inhalation position already a predetermined second angle prior to the cover being fully open. For example, the metering member may be placed in its inhalation position already when the cover has been opened by about 90° from its closed position. Between an opening angle of about 90°–135°, for example, there is free play again. This ensures that, should the user attempt a discrete operation of the device, the drug or the powdered medicament is ready already prior to the mouthpiece becoming exposed to the user.
The dosing recess may be designed to maximize the accuracy of gravitationally filling the dosing recess with the powdered medicament and also to maximize the ease of airborne entrainment of the formulation upon inhalation. Therefore, the dosing recess may be a dosing cup which is circular in profile and has an elliptical cross-section, the diameter being preferably three times the depth thereof. This enables the inhalation airflow to scour the dosing cup effectively. The circular profile and the ratio of depth to top area also combines the lowest variability of filling (primarily associated with deep, narrow receptacles) and scraping upon leaving the container (primarily associated with shallow, wide receptacles).
The flat surface of the metering member may be provided with a slot so that, upon a backward movement of the metering member from its inhalation position to its filling position, any powdered medicament possibly left on the flat surface of the metering member outside the dosing recess is wasted through the slot and can fall into a waste bin being provided underneath the metering member so as to catch this resilient powdered medicament. In this way, even when the dose was not completely inhaled by the user, there is no remaining medicament in the inhalation channel.
The inhalation actuated mechanism may comprise an inhalation actuated means/member, a resilient means/member, and a coupling means/member. The resilient member, which is preferably a spring, has a first end which holds the inhalation actuated member in a first position. In this condition, the aforesaid mark, which is preferably a flag, is visible through the respective opening of the casing, thereby indicating that a dose has not been taken and is ready for inhalation, respectively. The inhalation actuated member is preferably a flap. Upon forward movement of the metering member from its filling position to its inhalation position, the resilient member is charged up or tensioned, thereby releasing the inhalation actuated member. The inhalation actuated member is arranged and constructed such that, in this condition, only a predetermined inhalation suction force of a user, however not blowing, can move the inhalation actuated member out from its first position into a second position. For example, in this case, the inhalation actuated member may pivot or rotate from its first position into its second position. Thereby, the mark of the inhalation actuated member disappears and is no longer visible through the respective opening in the casing, indicating to the user that a dose has been taken and, thus, currently no dose is ready for inhalation. The inhalation actuated member, the resilient member, and the coupling member are also arranged and constructed such that the inhalation actuated member holds the coupling member, which is preferably in the form of a yoke, in a first position. The coupling member is coupled to the protective member, and preferably also to the metering member.
When the inhalation actuated member is moved from its first position to its second position by a sufficient inhalation force effected by a user, the coupling member is released and, by the discharging effect of the resilient member, automatically moved into its second position in which the coupling member automatically moves the protective member from its closed position into its open position, thereby releasing the dose contained in the dosing recess. For example, the coupling member may have an arm which is released upon movement of the inhalation actuated member from its first position into its second position, and the coupling member may also comprise a prolonged projection which, on the one hand, engages an opening of the protective member and, on the other hand, is slidingly moveable within a slid formed in the metering member.
When the cover of the powder inhaler is closed again, the metering member is returned to its filling position, and the aforesaid dose counting unit is actuated and incremented. In particular, this is effected as follows:
The coupling member may comprise a further prolongation, preferably in the form of a cantilever, which, when the metering member causes the coupling member to move back from its second position to its first position, actuates the dose counting unit. In this regard, the dose counting unit may comprise a wheel arrangement having a plurality of wheels being numbered on one side facing the opening of the casing of the powder inhaler and being coupled to each other by a gear arrangement. In particular, the wheel arrangement may comprise a plurality of wheels for displaying the numbers for a different order of magnitude, respectively. For example, the wheel arrangement may comprise a units wheel and a tens wheel being coupled by an idler wheel. On the other side of at least one wheel there may be arranged a plurality of drive teeth being arranged along the circumferential direction of the respective wheel. The above prolongation of the coupling member is moved over one of these drive teeth when the coupling member is moved from its first position to its second position, thereby bringing the prolongation of the coupling member into engagement with the respective drive tooth. On the other hand, when the metering member is moved backward into its filling position (and the resilient member is thus allowed to discharge), the movement of the coupling member from its second position to its first position caused thereby results in the prolongation of the coupling member rotating the respective wheel by one step, thereby decrementing (or alternatively) the dose counting unit. At the same time, the coupling member also moves the protective member back into its closed position, and the resilient member returns the inhalation actuated member to its first position and holds it in this position, so that the mark attached to the inhalation actuated member is visible through the respective opening of the casing again. Furthermore by these movements the coupling member is again brought into engagement with the inhalation actuated member, and in particular in this condition the aforesaid arm of the coupling member is held by the inhalation actuated member again. Thereby, the initial condition of the inhalation actuated mechanism and of the device is resumed again, and the above described operation of the powder inhaler can be repeated.
The above mark or flag has a very useful function. It shows a user if he has already taken a dose, thereby removing the possibility of double dosing. Furthermore, only inhaled doses are displayed by the dose counting unit. This reduces wastage and gives the user a true indication of what has been inhaled. The above described dose counting unit is directly driven by a closing operation of the cover. This is more reliable than using a stored energy. However, the driving of the dose counting unit may well be assisted by the stored energy of the resilient member.
The inhalation channel through which air is inhaled in use is preferably designed to comprise a deagglomerator arrangement comprising a substantially tangential air inlet, a preferably rotationally symmetrical vortex chamber, and an air outlet which is axially aligned with the vortex chamber such that airflow within the vortex chamber leads to a strong velocity gradient. The vortex chamber has a diameter d of 6 mm≦d≦10 mm, preferably 6 mm≦d≦8 mm, in particular about 8 mm, since such a diameter dimension has proven to be most effective for the deagglomeration function. The air outlet of the deagglomerator arrangement has preferably a smaller diameter than the vortex chamber. The base section of the vortex chamber may have a substantially elliptical cross-section, while the air outlet (and the inhalation channel) is preferably circular in cross-section. In addition or alternatively, the outer walls of the vortex chamber have the shape of arcs which are non-concentric to the inner diameter of the vortex chamber so as to achieve improved deagglomerator functionality.
Besides the above described features of the powder inhaler of the present invention, a couple of variants could be incorporated into the powder inhaler as well. For example, a manual override mechanism could be incorporated into the inhalation actuated mechanism for manually moving the protective member and manually actuating the inhalation actuated mechanism. This would allow users who could not generate the required flow rate for actuating the inhalation actuated mechanism to manually release the dose contained in the dosing recess and trigger the dose counting unit. Furthermore, an extra part could be added to override the inhalation actuated dose counting unit. This would especially be of benefit to those people who cannot achieve the required flow rate to operate the inhalation actuated mechanism. Furthermore, a one-way valve could be placed in the inhalation channel, preferably over the inlet to the deagglomerator arrangement (cyclone). This could reduce any moisture blown into the inhaler by about 50%.
Furthermore, another means of delivering a dose upon inhalation could be incorporated. Such a means could comprise a resilient member, in particular in the form of a spring, which is compressed by means of opening the cover. The resilient member would act on the metering member. The metering member would be free to move to a half-way position between the container and the inhalation channel. However, the metering member would be held at this half-way position until an inhalation actuated mechanism releases the metering member to complete its travel to the inhalation channel and, hence, present the dose contained in the dosing recess for inhalation. The half-way position (midpoint position) would have the combined effect of retaining the dose in the dosing recess and protecting it from moisture from user exhalation or discharge.
The device of the present invention delivers consistent respirable dose values to the patient across a wide range of pressure drops. For example, between 30 l/min and 90 l/min the fine particle fraction, a measure of Pulmonary penetration varies by less than 20%. Furthermore, this performance only requires a low work input from the patient with the device being classified as a low to medium resistance device.
To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope.
The powder inhaler shown in
As can be taken from
The structure of the lower shell 1, the integral cover 2 and the mouthpiece 3 can also be taken from
Within the casing and the lower shell 1, respectively, there are two sub-assemblies arranged. The first sub-assembly is a dosing sub-assembly 13 which in particular meters a powdered medicament, while the second sub-assembly is a dose counting sub-assembly 14 which comprises an inhalation actuated mechanism and a dose counting unit for counting the number of doses taken by the user.
As already indicated above, the slide 15 serves as a metering member which can be moved in the horizontal direction from a filling position shown in
As is shown in
The above described integral desiccant system has the following advantages. The desiccant has only to dry out the medicament chamber rather than the whole device. This requires less desiccant reducing product size and cost. Furthermore, the desiccant is always sealed. This means that the desiccant will still be effective even if the cover is left open. The desiccant is stored in the separate sealed desiccant chamber 9. This reduces the risk of incorrect assembly if the desiccant used the same closure as the medicament. Moreover, the integral container 7 comprising both the medicament chamber 8 and the desiccant chamber 9 can be manufactured using a 2-shot moulding. This ensures a good seal between the medicament chamber 8 and the desiccant chamber 9 at low product cost. Finally, the foil sealing provides a tamper-proof means of filling the device with the medicament or drug which has a very low permeability and requires only little product space.
As is shown in
The powder inhaler shown in the drawings solves many technical problems that may occur throughout the life cycle of the powder inhaler. The fundamental operating sequence of the powder inhaler is to open the integral cover 2, inhale the dose of the powdered medicament, and close the integral cover 2.
The cover 2 is gripped by the user and opened. As already described above, the projections 28 formed at both longitudinal sides of the slide 15 (see
When the cover 2 is closed, there are for example 45° of free play before a further closing of the cover 2 moves the slide 15 from the inhalation position to the filling position. Before the cover 2 is completely closed, there may be 15° of free play, for example. It should be noted that the profiled cam tracks 31 shown in the drawings are only exemplary.
As already mentioned before, the dosing recess 18 has the shape of a dosing cup which is designed to maximize the accuracy of gravitationally filling the dosing cup and maximize the ease of airborne entrainment of the formulation upon inhalation. The dosing cup is circular in profile (in top view) with a semi-elliptical cross-section (i.e. the cross-section has the shape of the half of an ellipse); the diameter being three times the depth. This enables the cyclonic airflow in the airway of the deagglomerator arrangement 16 to scour the dosing cup 18 effectively. The circular profile and the above-mentioned ratio of depth to top area also combine the lowest variability of filling and scraping upon leaving the container 7.
During opening the slide 15 is moved from the filling position to the inhalation position as well as after the slide 15 has reached its inhalation position, the dose of the powdered medicament filled in the dosing recess 18 of the slide 15 is prevented from falling out by a protective member, i.e. a dose protector 19. The dose protector 19 is arranged slidingly moveable on the slide 15 between a closed position and an open position. In its closed position, the dose protector 19 at least completely covers the dosing recess 18 when the slide 15 is in the inhalation position; while in its open position the dose protector 19 exposes the dosing recess 18 to the deagglomerator arrangement 16 and the inhalation channel when the slide 15 is in its inhalation position. The dose protector 19 is held in its closed position by an inhalation or breath actuated mechanism which will be described later. This inhalation actuated mechanism is constructed such that the dose protector 19 is moved from its closed position to its open position only if the inhalation suction force affected by the user in the inhalation channel exceeds a predetermined level. Furthermore, the inhalation actuated mechanism is arranged such that only an inhalation suction breath not a blowing breath can actuate the inhalation actuated mechanism and cause a movement from the dose protector from its closed position to its open position.
In the following, the inhalation actuated mechanism in combination with the dose protector and the dose counting unit is described in detail.
In
The functionality of the inhalation actuated mechanism as well as the dosing counting unit is as follows.
As shown in
As shown in
As already described above, when the drive spring 23 is decompressed and discharged, its end 33 exerts a reset force on the portion 41 of the flap 21, thereby holding the flap 21 in its first horizontal position, as shown in
If, however, the slide 15 is pushed forward by opening the cover 2, thereby compressing and charging the drive spring 23, the reset force exerted by the end 33 of the drive spring on the flap 21 is released, and the flap 21 can be rotated from its first horizontal position shown in
In the latter case, the flap 21 is moved by this sufficient high inhalation force from its first position shown in
In
Since the dose protector 19 has been moved out from its closed position into its open position by the yoke 22, the dosing recess 18 of the slide 15 is exposed to the inside 50 of the cyclone, and the dose of the powdered medicament contained in the dosing recess 18 can be inhaled through the cyclone and the inhalation channel 27 as well as the mouthpiece 3. In the cyclone, the drug or the powdered medicament is entrained into a swirling airflow where the active part of the formulation is disaggregated from the carrier (see reference sign 49).
Furthermore, since the flap 21 has been moved from its first horizontal position (see
In the following, the functionality of the dose counting unit is explained in detail. As already mentioned above, the dose counting unit, being provided for counting the number of doses taken (up counter) or, alternatively, the number of doses remaining in the container (down counter), comprises the units wheel 24 and the tens wheel 26 being coupled to one another by the idler wheel 25.
As has been explained above, the coupling between the units wheel 24 and the tens wheel 26 is such that after each ten step-wise rotations of the units wheel 24 the tens wheel 26 is rotated by one step, thereby increasing the combination of tens and hundreds numbers on the outer surface of the units wheel 24. It should be noted that
As described above, when the flap 21 is rotated from its horizontal first position to its second position upon an inhalation process initiated by the user (see
After inhalation, the user closes the cover 2 of the powder inhaler. With the closing of the cover 2, the slide 15 is moved backward from its inhalation position to its filling position by means of the coupling between the projections 28 of the slide 15 and the profiled cam tracks 31 of the cover 2.
As shown in
Furthermore, since the yoke 22 and the drive spring 23 are moved back into their initial positions, the end 33 of the drive spring 23 urges the flap 21 back into its horizontal first position (as shown in
Another advantage associated with the flag 38 is that it may be pushed down by fingers of a user so as to affect a manual override of the inhalation actuated mechanism. This would enable the user to take the dose if the user is not able to generate a sufficient force in order to actuate the inhalation actuated mechanism.
On completely closing the cover 2, there will be an audible click signaling that the cover is closed. Preferably, the powder inhaler will require the cover 2 to be completely closed to function correctly.
Finally, the deagglomerator arrangement 16 (cyclone) of the powder inhaler should be briefly discussed.
The purpose of this deagglomerator arrangement is to produce clearly defined turbulences within the inhalation channel 27 so as to pulverize agglomerations of the medicament. By the swirling airflow within the deagglomerator arrangement 16, the active part of the formulation is disaggregated from the respective carrier.
In principle the deagglomerator arrangement of the present invention comprises a rotationally symmetrical vortex chamber, at least one substantially tangential air inlet, and an outlet or exit for outputting the air with the deagglomerated powdered medicament, the outlet being spaced from the air inlet in the longitudinal axial direction of the vortex chamber. The general structure of the deagglomerator arrangement, for example, can be taken from
In addition, the structure of the deagglomerator arrangement, which is generally not restricted to the usage in powder inhalers as described in connection with the above drawings, will be explained in detail by reference to
As can be taken from
In
Studies have shown that the diameter d of this “base” circle 77 has an important influence on the deagglomerator effect of the cyclone. For example, if the diameter d is too small, the flow resistance is too high. On the other hand, if the diameter d is too large, the flow resistance is too small resulting only in a minor improvement of the efficiency of the deagglomerator arrangement 16.
Comprehensive studies of the geometry of the deagglomerator arrangement 16 in terms of the flow resistance of the device and the quality of the cyclonic flow effected inside the vortex chamber 73 show that a very good efficiency of the device can be obtained if the diameter d is between 6 mm and 10 mm, preferably 6 mm≦d≦8 mm.
For example, if d is 6 mm, a flow rate of 30 l/min at a pressure of 4 kPa can be obtained. The cyclonic flow inside the vortex chamber 73 is of good quality. Nevertheless, the required increase in the width of the air inlets or in the outlet diameter to allow a higher target flow rate (for example 60 l/min at 4 kPa) would presumably result in a degradation of the quality of the cyclone. This is because the dimensions of the air inlets or of the outlet would be too large in comparison to the dimensions of the main section of the cyclone, which are the dimensions of the vortex chamber 73.
Therefore, it may be recommendable to use a larger diameter d of the “base” circle 77. A very compact design of the cyclone 16 and, in addition, the above-mentioned target flow rate in the range of 60 l/min at 4 kPa can be obtained if the diameter d of the “base” circle 77 is in the range of 8 mm. Larger diameters d of the “base” circle 77 do not lead to further significant improvements of the flow pattern inside the vortex chamber 73 over that which can be achieved with a diameter d=8 mm. Therefore, the diameter d=8 mm is considered as a preferred embodiment of the cyclone 16.
As depicted in
The cross-sectional structure of the deagglomerator arrangement 16 is such that a respective semicircle or arc 79, whose centre is on the diameter connecting both air inlets or both end portions of the side walls 78, connects the outer wall of one air inlet 75 with the inner surface of the opposing side wall 78 of the vortex chamber 73 at a place where this side wall 78 intersects with the respective other air inlet. As can be seen from
The structure shown in
The dosing sub-assembly 13 of this embodiment comprises a deagglomerator arrangement (cyclone) 16 similar to that described above. From
As regards the dosing sub-assembly of
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 02016908 | Jul 2002 | EP | regional |
This application is a continuation of the Patent Cooperation Treaty application PCT/EP2003/008432, having an international filing date of Jul. 30, 2003, which claims priority to EP 02016908.2, having a filing date of Jul. 31, 2002, both of which are incorporated herein in their entirety, and to which priority is claimed.
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| Number | Date | Country | |
|---|---|---|---|
| 20050183723 A1 | Aug 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP03/08432 | Jul 2003 | US |
| Child | 11045631 | US |
