Inhaler.

An inhalation. - Inhaleringsanordning.

This invention relates to an inhalation device, namely a device for use in dispensing a dose of a drug or other substance for inhalation into the lungs.

The most common form of inhalation device pushes a dose of drug as a pressurized gas from an aerosol. However, this form of inhaler becomes less popular due to environmental and other considerations. Distribution of some drugs in dry, finely divided form has been shown to have certain medical advantages over other forms of delivery.

Some known proposals for dispensing a drug in fine form cannot be used with one hand. One-handed operation is considered to be an important feature in such an inhaler.

EP 079478, EP 166294 and GB 2165159 all disclose dry powder inhalers that can be operated with one hand. In each of these proposals, the inhalation device includes a drug storage chamber and an inhalation passage through which air is drawn through the mouthpiece. A dispensing member provided with a dispensing recess transfers a dose of drug from the storage chamber and places it in the inhalation chamber. It has been found that the accuracy of such an arrangement can be very poor: on the other hand, by repeatedly indexing the dispensing member, it is possible to place two or more doses of drug in the inhalation channel 25, resulting in the distribution of the drug overdose; on the other hand, because the drug normally falls from the dosing cavity into the inhalation channel under gravity, the drug particles can adhere to the inside of the dosing cavity so that an underdose is delivered.

US 2587215 also discloses dry substance inhalers with the same drawbacks as those mentioned above. However, this document also discloses an embodiment in which the dispensing member directs the drug upwards in an open dispensing cup into a mixing chamber where it is mixed with air before being sucked into the inhalation tube through a nozzle with a narrow opening. The air drawn into the inhaler passes into the inhalation tube either directly or through the nozzle of the mixing chambers. Thus, not all air passes over the dosing cup. If the drug adheres to the surface of the dosing cup but is not sucked from it, an underdose of the drug will be delivered to the user. It has been found that with repeated use of cavities to deliver doses to the inhalation channel, an ever-increasing amount of powder adheres to the bottom of the cavity, leading to progressively reduced dosing to the patient. The tendency of the sticky powder to accumulate has been thought to be a source of inaccurate dosing in many previously proposed inhalation devices. The dispensing member is a rotatably sliding device fitted to a cylindrical pivoting member extending from the bottom of the device body. Such an arrangement tends to jam due to the entry of powder between the cylindrical contact surface of the turning member and the dispensing member.

U.S. Pat. No. 4,274,403 describes an inhalation device having a drug storage chamber and a dispensing head that is movable laterally to collect a dose of drug from the storage chamber and place it in the inhalation channel. This inhaler is said to overcome the problem found in US 2587215 devices, where there is no way to close the drug storage chamber when not in use to prevent moisture contamination.

Another form of inhaler currently available includes a dispensing member that includes a plurality of tapered dispensing recesses that are open at the top and bottom. In use, the finely divided drug from the storage chamber is packed into the recesses, after which the dispensing member is moved to a dispensing position where air can be drawn through the recesses to aspirate the drug out. An example of such a device is described in EP-A-0 069715. This device has been considered to have several significant shortcomings. First, the dispensing recesses tend to become clogged. Second, a large amount of air is needed so that the device is unsuitable for many patients with breathing problems. Third, two hands are needed to operate the device.

It is an object of the present invention to provide an inhaler device form for one-handed operation that is capable of dispensing accurate doses and avoiding the risk of multiple dosing. A further object is to provide an inhalation device which does not require a large amount of suction for efficient operation 5.

The present invention provides an inhalation device for dispensing a substance in a finely divided form, the inhaler comprising a body defining a storage chamber for the substance to be dispensed and further defining an inhalation channel through which air is drawn through the mouthpiece; a dispensing member capable of transferring a volume dose of substance from a storage chamber to an inhalation channel, the dispensing member having a dispensing surface notched to form at least one dispensing cup movable to a first position in which the dispensing cup is directed into the storage chamber to receive a dose of substance; between, known for that in the second position said dispensing cup is open upwards and that the inhaler comprises cup cleaning means, the cup cleaning means comprising means for moving said one or each dispensing cup to a position where, in normal use of the inhaler, any substance remaining in the dispensing cup tends to fall under gravity, out of the cup after the dose of substance has been directed into the inhalation channel in the cup and before this cup is again directed into the storage chamber.

Thus, in normal use of the inhaler, repeated indexing of the dispensing member does not result in multiple layers of substance into the inhalation channel. In addition, the removal of the substance from the dispensing member by the flow of inhaled air rather than by gravity can ensure that the dose is removed more thoroughly.

The cup cleaning means may include an inhalation channel configured such that a dose of the agent directed into the inhalation channel is exposed to a substantially entire flow of air through the inhalation channel as air is drawn through the mouthpiece. Thus, regardless of whether air is drawn into the inhaler through one or more openings, the air flow through the device is such that all the air flows along one channel at the point where the dispensing cup is directed towards the air flow inside this channel.

The cup cleaning means may further comprise flexible sweeping means or include flexible sweeping means for removing any residue from said one or each cup after a dose of substance has been directed into the inhalation channel therein and before that cup is again directed into the storage chamber. The provision of such removal means ensures that the one or each dosing cup in question is cleaned before refilling, and thus prevents the accumulation of adhesive material in repeated refills.

The dispensing member is preferably resiliently brought into contact with the housing and is movable when in contact with the housing. Even more preferably, the dispensing member is rotatable when in contact with the housing.

The dispensing member may comprise a frustoconical side wall containing a dispensing cup or cups. Such a sidewall may include a plurality of spaced distribution cups. The use of a frustoconical shape in the wall of the dispensing member, which includes dispensing cups, allows a good seal to be achieved between the dispensing member and the housing against which the frustoconical wall joins. Thus, either rigid or semi-rigid plastic material can be used, and appropriate shapes can be made with relatively modest tolerances. Other shapes, such as a spherical or cylindrical shape, either require significantly tighter tolerances in order to achieve the required type of seal or flexible materials should be used or, possibly, an additional flexible sealing ring should be included. If the dispensing members have a flat dispensing surface, as in the embodiment of U.S. Patent 25,87215 described above, it is necessary to provide a separate shaft or pin mounted on a portion of the device. Such a separate shaft is prone to jamming due to powder penetration between the contact surfaces associated with the shaft. On the contrary, according to the present invention, the good seal referred to above must be such that the integrity of the stored drug is maintained, for example by preventing any ingress of moisture and / or dirty air into the storage chamber.

The frustoconical shape also makes it possible to form the dispensing member in such a way that it takes up relatively little space so that the inhalation channel can be shorter than in many prior inhalation devices, reducing the amount of suction required from the patient.

The longitudinal axis of the frustoconical wall is located when the inhaler is held in its normal position of use, preferably between an vertical and an angle of 60 ° to its vertical. Even more preferably, this axis is located at an angle of about 45 ° to the vertical.

The body of the inhaler device preferably comprises a housing having an annular contact surface which slides into contact with the dispensing surface, the contact surface being frustoconical in shape to define a seat within which the dispensing member is adapted to rotate between its first and second positions. The inhalation device then preferably comprises means which can flexibly bring the dispensing member into contact with the housing.

Preferably, the inhalation device according to the invention comprises a chamber for holding a moisture absorbing material, with which chamber one or each of the dispensing cups is displaceable after the dose of substance has been directed into the inhalation channel and before this cup is again directed into the storage chamber. In this way, the empty cup can be dried before filling to reduce the adhesion of the surface in the cup. The filled dispensing cup may also align with the same or another chamber for the moisture absorbing material as it moves from the storage chamber to the inhalation channel. This can help prevent moisture from passing from the inhalation channel into the storage chamber.

The inhalation device preferably includes display means that are indexed in cooperation with the dispensing member to display information to the user. The display means may include counting means for counting the number of times the dispensing cup is directed into the inhalation channel and / or the number of remaining doses that are intended to be so directed.

The invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a general perspective view of an inhalation device according to the invention;

Figure 2 is a side view of an inhaler in use:

Figure 3 is a longitudinal section through the inhaler;

Figure 4 is a section IV-IV of Figure 3:

Figures 5 and 6 are perspective exploded views of the inhaler device from opposite ends;

Figures 7a and 7b are perspective exploded views of the calculation mechanism of the inhaler, again illustrated from opposite ends; and

Figures 8a and 8b show the assembled counter mechanism seen from opposite ends.

As shown in the external views of Figures 1 and 2, the inhalation device comprises a housing 1 provided with an air intake 2. The tubular mouthpiece 3 protrudes from the housing.

Referring to Figures 3-6, the housing includes an inner body 4 which, on the side remote from its mouthpiece 3, comprises a recess 5 which forms a housing for a dispensing member 6 rotatable about its axis in the recess. The dispensing member includes a portion having a frustoconical dispensing surface 7 containing a series of circumferentially arranged cup-shaped dispensing recesses.

8. The recess 5 respectively forms a frustoconical housing, the dispensing surface and the angular tolerance and circumferential shape of the housing being carefully controlled during manufacture to ensure close sliding contact between the two mating surfaces.

The opposite side of the body 4 contains a storage chamber 10 for the drug in the form of micronized powder, the chamber 10 being arranged to align with one recess 8. A second, outer chamber 11 surrounds the storage chamber 10 for containing a moisture absorbing material, such as silica gel granules. The second chamber 11 opens into the recesses 8 on either side of the recess which is currently aligned with the storage chamber 10, but the passage of silica gel into the recesses is prevented by the shaped filter film 12. The same side of the body 4 further includes an inhalation channel 15 and a waste container 16, each of which is aligned with one of the recesses 8. The inhalation channel 15 has a flat internal contour and is aligned with both the air inlet 2 and the mouthpiece 3. The air inlet 2 includes a filter membrane 17 to remove any dirty particles that can be sucked into the inlet. The waste chamber 16 includes a brush, a piece of foam rubber or other flexible sweeping element 18 which extends into a corresponding recess 8 to make sweeping contact with the walls of the recess.

Referring to the inhalation channel 15 in more detail, it can be seen from Figure 3 that when the inhaler is in use, the inhalation channel 15 extends in a downward direction without the intake 2, at least to the position where the dispensing cup 8 is directed towards the inhalation channel. The width of the inhalation channel 15 is relatively large in the air intake, relatively small in the area of ​​the dispensing cup and relatively large again in the mouthpiece 3. The inhalation channel includes a first relatively more wearable portion extending substantially downwardly from the air intake 2 to the dispensing cup 8 and a second relatively less wearable portion extending from the dispensing cup 8 to the mouthpiece 3. The dispensing cup 8 is located at the outer edge of the fold connecting the two portions of the inhalation channel. Opposite the dispensing cup, the wall of the inhalation channel bulges across the inhalation channel towards the dispensing cup to form a restricted channel in the region of the dispensing cup. In this area, the shape of the inhalation channel results in both accelerating the air and directing it towards the dispensing cup so that a particularly efficient extraction of material from the cup occurs.

The frustoconical end of the dispensing member 6 is attached to a coaxial circular latch structure 20 followed by a drum 21. A spring washer 22 acts between the end face of the drum 21 and the housing 1 to force the dispensing member 6 against its housing in the recess 5. an indexing finger 26 for gripping the latch structure 20. The spring finger 27, which is also integral with the button 25, projects transversely to the indexing finger 26 to engage the inner body 4 and thus force the button to protrude from the housing 1.

The strip 30 is wound on a roll 31 which is freely rotatable by a pin 32 projecting from inside the housing 1. The leading edge of the strip 30 is attached to a drum 21 to which it is wound from a roll 30 after the dispensing member 6 has been rotated. The tape 30 is routed past a window 33 in the housing 1, through which window a continuous series of numbers or other information on the tape is displayed.

In use, the inhaler is normally supplied as a closed unit with the storage chamber 10 pre-filled with drug or other substance in a dry, finely divided form. With the button 25 at the top, the recess 8, which is aligned with the storage chamber 10, is filled with a fixed volume of drug. With the inhaler held in one hand, the mouthpiece 3 is mounted in the mouth, as shown in Figure 2, and the button 25 is pressed using the index finger so that the indexing element 26 holds rotates the dispensing member 6 one position, thus aligning the next empty recess 8 with the storage chamber 10. At the same time, the filled recess aligns with the inhalation channel 15. Thus, when air is drawn through the inhalation channel 15 through the mouthpiece 3, the internal shape of the inhalation channel causes the air to strike the material still held in the recess 8, causing the powder to mix with the airflow and, after passing through the mouthpiece 3, protrude into the mouth and user airways.

It should be noted that the powder in the recess 8 is exposed to the entire air flow through the inhalation channel 15, from the air intake 2 to the mouthpiece 3, which allows the user to more easily reach the full dose and further contributes substantially to the complete removal of the powder from the recess 8.

As the recess travels around the axis of the dispensing member with successive indexing movements of the button 25, they pass the sweeping element 18 so that any residue of powder remaining in the recess is removed from it to fall into the waste chamber 16. Further movement of the cavity causes it to align with the drying chamber 11 so that the silica gel can absorb all moisture from the cavity before it comes into alignment with the storage chamber 10 for refilling with drug. The filled recesses may also align with the drying chamber 12 to reduce the possibility of moisture transfer from the inhalation channel 15 to the storage chamber 10. This can further ensure that the drug remains dry, thereby ensuring that the vast majority of the drug can be easily removed from the recess into the inhaled air stream.

It is important that the movement of the powder dose to the dispensing position in the inhalation channel 15 is carried out in such a way that a good sealing of the powder in the storage chamber 10 is maintained so that the integrity of the powder is maintained. This is facilitated by providing the dosing surface 7 and the housing for it formed by the recess 5 in a frustoconical shape; such a shape makes it possible to achieve a good seal between the dispensing surface 7 and its housing with less demanding tolerances than is possible with other shapes. Provided that the angular tolerance is maintained (which is relatively simple), the other manufacturing tolerances are adjusted by means of a self-sealing arrangement of the housing provided by the dispensing surface 7 and the recess 5.

In normal use of the inhaler, the repeated indexing of the dosing member 6 does not layer multiple doses of the substance into the inhalation channel. Instead, each dose is simply conveyed around the recess 8 until it is removed to the waste chamber 16.

Each time the dispensing member is indexed, new information is conveyed to the window 33 by the tape 30. This information may simply be a number indicating how many doses have been used or how many are left to be used, or both. The window may also display other information, such as time, as the next dose needs to be taken.

Normally, the device will be discarded as soon as the intended number of doses has been used. However, it is contemplated that the inner body 4 may include a replaceable cartridge containing a stock of fresh drug and possibly also fresh silica gel, new filters 12 and / or 17 and a new strip 31. This strip may be partially wound on a replaceable drum 21 which adheres to a frustoconical dispensing head 6.

The modified counting arrangement is shown in Figures 7 and 8. The housing 1 includes a circular inner recess 36 which receives an outer ring 37 and an inner disc 38 arranged coaxially with the dispensing member 6. The disc 38 contains units from 0 to 9 at 36 ° intervals, while the ring 37 is marked with tens of multiples at regular angular intervals. The tens and units are arranged so that they can both be displayed through the window 39 in the housing 1. The disc 38 is connected to or operated by the dispensing member 6 and includes an integral spring arm 40 which includes a pin 41 to act as a cam lifter. Whenever the disc 38 completes one rotation, the arm 39 engages a cam 44 attached to the inside of the housing 1, which causes the cam lifter 41 to engage one of a series of notches 45 around the outer circumference of the ring 37. This in turn indexes the ring by one angular position with each rotation of the disc 38. The number displayed in window 40 can thus be incremented, for example, from 1 to 200 to count the number of doses used. Instead of a ring surrounding the disc 38, a second transparent disc could be placed behind the disc so that the units are visible through the second disc, which again includes tens of multiples.