Abstract:
An inhaler comprising a reservoir of an inhalable composition with an outlet at one end through which the inhalable composition is discharged. A non-metered breath-activated valve is provided between the one end and the reservoir, the breath-activated valve comprising a flow path extending from the reservoir to the outlet end. At least a portion of the flow path is a deformable tube. A clamping member pinches the deformable tube closed when no suction force is applied to the device and releases the tube to open the flow path when suction is applied at the outlet, to provide uninterrupted flow from the reservoir to the outlet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/389,434, filed Feb. 7, 2012, which is herein incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present invention relates to an inhaler. 
         [0004]    Description of the Related Art 
         [0005]    The invention has been specifically designed for a simulated cigarette device having a generally cigarette-shaped body. However, the invention relates to a development of the outlet valve for such a device which has broader applications in the field of inhalers, for example, medicinal inhalers for oral drug delivery such as asthma inhalers. 
         [0006]    In the field of cigarette replacements, there have been a number of proposals to create a simulated cigarette. Such a device has a number of advantages over traditional nicotine replacement therapies such as patches and gum in that they recreate the physical act of smoking which is psychologically important to a smoker, and also are able to deliver nicotine as a dose which more closely replicates the pharmacokinetic effects of a cigarette that persistent smokers desire. Thus, a smoker is able to obtain the “hit” that is familiar from a cigarette, rather than having to deal with the slow release from a patch or gum which does not produce such a hit which leads to unpredictable dosings and poor craving scores and cessation rates. 
         [0007]    A simulated cigarette has a reservoir of inhalable composition and an outlet valve which can be triggered, for example, by pushing a button or biting on the end of a cigarette. However, a preferred mechanism for opening the valve is to provide a breath-activated valve as this ensures that the cigarette will only dispense when the user sucks on the device in a manner of a normal cigarette. 
         [0008]    WO 02/45783 discloses a drug dispenser having a valve arrangement suitable for dispensing a metered dose. This takes the form of a flexible tube which is wrapped around a valve element and has a pair of kinks. The portion of the tube between the kinks is able to retain a metered dose of the drug to be dispensed. When a user sucks on the dispenser, the valve element moves opening the downstream kink in order to dispense the metered dose. On exhalation, the valve moves in the opposite direction closing the downstream kink and opening the upstream kink to allow the portion of the tube between the kinks to be re-charged with the drug. This arrangement only ever allows a user to inhale one metered dose no matter how long they suck on the device. 
         [0009]    U.S. Pat. No. 4,393,884 discloses one such device which has a large resilient “tongue” with a flow path passing through it. This tongue is biased into a first position in which it is out of alignment with the outlet of the cigarette and can be sucked into a second position in which it aligns with the outlet of the cigarette to provide a flow path from the reservoir to the outlet. Such a device is difficult to seal in the first position. It will also require considerable force in order to suck the tongue to the open position against the action of a retaining spring and the relatively large mass of the tongue means that it will be difficult to return to the closed position meaning that dispensing will continue after the suction has been removed. 
         [0010]    U.S. Pat. No. 6,889,687 discloses a further example of a simulated cigarette with a breath-activated valve. This discloses a number of examples. One of these has a pair of magnets, one of which is retained by a flexible membrane which allows the magnet to moved apart when suction is applied to a device. This opens up a flow path from the reservoir. However, the mechanism is reasonably complex, has a tortuous flow path which is likely to impede delivery of the composition from the reservoir, and is “binary” in nature in the sense that the valve is either open or closed. It does not provide the ability for the user to regulate the amount of flow by varying the degree of suction. A second example is a spring-biased plunger which is moved axially to open up a passageway in a central rod. Such an axially movable plunger is undesirable in practice as it has been found that the level of suction required to overcome the spring biasing force is too high to be usable in practice. Also, the flow path in the open position is out of the rod, into the plunger and back into the rod so that it is again somewhat tortuous. The third example relies on a magnetic interface where the force on which is overcome by a system of vanes which rotate about the axis of the device, thereby moving along a cam surface to pull the magnetic valve element from its seat. Again, this suffers from problems of complexity, lack of control and a tortuous flow path. 
         [0011]    WO 2009/001082 which is our own earlier application discloses two different breath-activated devices. The first of these has a pair of vane systems rotatable about an axis perpendicular to the main axis of the device to align an orifice with the outlet orifice from the reservoir enabling dispensing. The second of these has a pair of hinged flaps which are sucked down against the action of return springs in order to open the flow path. While this solves some of the problems in that it provides a simple mechanism and an axial flow path, the force required as suction to trigger the device is comparatively large and the user, as a result, can exert less control over the system to release a variable dose, small or large according to the inhalation intake. 
         [0012]    The present invention is aimed at providing an improved breath-operated valve for an inhaler and, particularly, a simulated cigarette. 
       SUMMARY OF THE INVENTION 
       [0013]    According to the present invention, there is provided an inhaler comprising: 
         [0014]    a reservoir of an inhalable composition; 
         [0015]    an outlet at one end through which the inhalable composition is discharged; and 
         [0016]    a non-metered breath-activated valve between the one end and the reservoir, the breath-activated valve comprising a flow path extending from the reservoir to the outlet end, at least a portion of the flow path being a deformable tube, and 
         [0017]    a clamping member which pinches the deformable tube closed when no suction force is applied to the device and releases the tube to open the flow path when suction is applied at the outlet, to provide uninterrupted flow from the reservoir to the outlet. 
         [0018]    By clamping a deformable tube, the present invention has a number of advantages. The clamping mechanism is simple as all that is required is a movable component to pinch the tube which need not be complex. Further, as the flow path is along an opened tube, there is no need for a tortuous flow which may otherwise be required to flow around an unseated valve component such as those in U.S. Pat. No. 6,889,687. The non-metered valve which allows uninterrupted flow allows a user to regulate the dose that they receive from the inhaler, as it will continue to dispense for as long as the user sucks. 
         [0019]    The pinched tube arrangement lends itself well to an unmetered dosage. Also, while the device may be provided with the clamping member which effectively “snaps” open to provide a “binary” device which is either open or closed, the pinched deformable tube is well suited to a device in which the degree of opening of the tube is proportional to the strength of the suction. Such an outlet valve which is breath-operable and of varied resistance according to the inhalation profile it is actuated by, allows the user to self-titrate the inhaled dose in a continuous manner. This has applications firstly for smoking cessation inhaler devices where users want to self-titrate their dose of nicotine in a manner that fits their need, but also in other area such a pain management, diabetes, asthma and COPD where self-administered doses are preferable via the oral route. 
         [0020]    The tube could be clamped at several locations but is preferably clamped at a single location as that is all that is necessary to fulfil its function. The flow path is preferably substantially straight to ensure a smooth flow. 
         [0021]    As mentioned above, the inhaler may be a drug delivery inhaler for any inhalable pharmaceutical composition. However, the inhaler is preferably a simulated cigarette device having a generally cigarette-shaped body. In this case, the inhalable composition preferably includes nicotine or a nicotine derivative or salt thereof. On the other hand, it may be a simulated cigarette which replicates the physical act of smoking without requiring nicotine in the composition. Alternatively, the composition may include patient controlled analgesics, anti-inflammatory, bronchodilators, anti-spasmodics, retro-virals or opiates. 
         [0022]    The clamping member may be formed of any suitable device which can release the deformable tube when suction is applied to the outlet. This could, for example, be a combination of an electronic flow sensor and a solenoid to move the clamping member. However, preferably, the clamping member is a mechanical member which is moved by a pressure differential caused when suction is applied at the outlet. 
         [0023]    The mechanical member may take the form of the pair of vanes of the second example of WO 2009/001082 where it is pinched between the vanes in the closed position and is released as the vanes pivot towards the direction of the air through-flow. 
         [0024]    However, preferably, the clamping member is an elongate vane which is pivotally mounted at one end and extends longitudinally within the inhaler, the vane being pivotable between a first position in which the tube is closed and a second position in which it releases the tube to provide the flow path. There may be a single vane which clamps the deformable tube against a fixed part of the inhaler, or there may be a pair of such vanes between which the tube is clamped. 
         [0025]    Preferably, the or each vane is biased into the closed position and the inhaler has a second flow path creating a pressure differential across the vane which overcomes the biasing force. 
         [0026]    The or each vane may be exposed to a through-flow of air such that, as a user sucks on the outlet, the through-flow of air impinges on an outer surface of the vane to move it inwardly. However, preferably, the or each vane is supported by a flexible membrane. This flexible membrane creates a chamber in which the vane is housed and which is open to the outlet, but is otherwise sealed, with the face of the membrane on the opposite side to the vane being open to atmospheric pressure. When a user sucks on the outlet, they create a negative pressure within the chamber to move the vane and the membrane flexes to allow this movement. This provides a very efficient mechanism for conveying the suction force to the vane. 
         [0027]    Preferably, the deformable tube is a nozzle which is also provided integrally with an outlet orifice, which is the narrowest part of the flow path. 
         [0028]    In this case, preferably the nozzle has an outwardly projecting annular flange at its upstream end which fits within a downstream end of the flow path. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    Examples of inhalers in accordance with the present invention will now be described with reference to the accompanying drawings, in which: 
           [0030]      FIG. 1  is a section through a perspective view of a first inhaler in a closed position; 
           [0031]      FIG. 2  is a similar view in the open position; 
           [0032]      FIG. 3  is an exploded perspective view of the inhaler of  FIGS. 1 and 2 ; 
           [0033]      FIG. 4  is a cross-section through a perspective view of a second inhaler in the closed position; 
           [0034]      FIG. 5  is a similar view in the open position; and 
           [0035]      FIG. 6  is a perspective view from the outlet end of the second example shown with the outer housing removed to show the pinch mechanism; and 
           [0036]      FIG. 7  is a cross-section of an alternative arrangement of deformable tubular element. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    The present invention relates to an improvement of the outlet valve for a breath-activated cigarette and only this aspect of the invention will be specifically described here. For details of the construction of the remainder of the cigarette device and its refill mechanism, reference is made to WO 2009/001078. 
         [0038]    The first example of an inhaler in accordance with the present invention is shown in  FIGS. 1 to 3 . 
         [0039]    The device has a housing  1  made up of a main chassis  2  and a closure element  3  as shown in  FIG. 1 . This is held in place by label  4 . Within the housing, there is a reservoir  5  containing the inhalable composition. This is preferably pressurised but could also work with a non-pressurised reservoir in combination with a Venturi nozzle to generate an enhanced suction force on the reservoir, or a non-pressurised reservoir containing a substance that is prone to evaporating at room temperature. It may be refillable as described in WO 2009/001082 through the filling valve  6 , or the device may be a single use device, or may be arranged so that the reservoir  5  is a replaceable component. 
         [0040]    The breath-activated valve  7  is positioned between an outlet end  8  and the reservoir  5 . The breath-activated valve is arranged so that, when a user sucks on the outlet end  8 , the breath-activated valve  7  opens to allow the inhalable composition from the reservoir  5  to be inhaled. 
         [0041]    The housing at the outlet end has two orifices. The first of these is the suction orifice  9  which communicates with a chamber  10  as will be described in greater detail below and the second is an outlet orifice  11  from which the inhalable composition dispensed is also described in more detail below. As is apparent from  FIG. 3 , the outlet orifice  11  is provided on a separate component  12 . 
         [0042]    An outlet path  13  is defined between the reservoir  5  and outlet orifice  11 . 
         [0043]    A portion of the outlet path  13  is provided by deformable tubular element  14 . This tubular element is moved between the closed position shown in  FIG. 1  and the open position shown in  FIG. 2  by a mechanism which will now be described. 
         [0044]    This mechanism comprises a pivotally mounted vane  15  and a membrane  16 . The pivotally mounted vane has a pivot  17  at the end closest to the outlet end  8  and a central reinforcing rib  18  running along its length and tapering away from the outlet end. At around the midpoint, the vane  15  is provided with a recess  19  for receiving a spring  20  which biases it into the closed position shown in  FIG. 1 . Below the recess  19  is a jaw  21  having a triangular cross-section which is configured to apply the force provided from the vane  15  to the deformable tube  14  over a narrow area. The vane  15  is supported by the diaphragm  16  which is sealed to the housing at its ends  22 ,  23 . This seals off the chamber  10  other than to the suction orifice  9 . 
         [0045]    The underside  24  of the membrane  16  is open to atmospheric pressure as a leakage path exists through the housing  1  which is not shown in the drawings as it extends around the outlet path  1  and is therefore not shown in the plane of  FIGS. 1 and 2 . 
         [0046]    When a user sucks on the outlet end  8  with the device in the configuration shown in  FIG. 1 , the suction is communicated by the suction orifice  9  to the chamber  10  through orifices  25  thereby lowering the pressure in this chamber. This causes the vane  15  to be lifted against the action of the spring  20  to the position shown in  FIG. 2  deforming the diaphragm into the configuration shown in  FIG. 2  and lifting the jaw  21  to allow the deformable tube to open, thereby allowing the inhalable composition from the reservoir  5  along outlet path  13  through the deformable tube  14  and out through the outlet orifice  11 . The degree of suction applied by the user will determine the extent to which the vane  15  moves and therefore the amount of composition that the user receives. As soon as a user stops sucking, atmospheric pressure will return to the chamber  10  via the suction orifice  9  and the spring  20  will return the vane to the  FIG. 1  position thereby pinching the tube  14  closed. 
         [0047]    A second example of an inhaler is shown in  FIGS. 4 to 6 . This is also provided with a deformable tube  14 , a reservoir  5  and outlet end  8 , but the mechanism is somewhat different. In the closed position of  FIG. 4 , the deformable tube is pinched between a pair of jaws  30  on a spring clip  31 . This clip  31  is biased into the first position shown in  FIG. 4 . The inhaler has an outlet orifice  32  which completes a flow path from the reservoir  5  via the deformable tube  14  through the outlet orifice  32 , and a plurality of suction orifices  33  which provide suction to an internal chamber  34 . In this example, there are a pair of pivotally mounted vanes  35  extending longitudinally along opposite sides of the device. Each of the vanes is connected to an L-shaped bracket  36 , one of which is shown in  FIG. 6 . This L-shaped bracket extends into the respective jaw  30  and effectively reaches around to the opposite side of the deformable tube  14  for reasons described below. 
         [0048]    The housing  1  is provided with a pair of inlet orifices  37  one for each vane. As a user sucks on the outlet end  8 , the suction force via suction orifices  34  draws air through inlet orifices  37  into chamber  34  thereby applying inward pressure to the vanes  35 . As a result of inward pressure, the vanes pivot inwardly to the position shown in  FIG. 5 . The L-shaped brackets  36  mean that the downward movement of the upper vane  35  moves the lower jaw  30  downwardly and the upward movement of the lower vane  35  moves the upper jaw  30  downwardly, thereby opening the deformable tube  14  as shown in  FIG. 5  to dispense the inhalable composition. When the suction force is removed, the pressure differential across the vanes  35  is removed and the resilience of the spring clip  31  returns the jaws  30  to the position shown in  FIG. 4 . 
         [0049]    An alternative arrangement of a deformable tubular element will now be described with reference to  FIG. 7 . 
         [0050]    The vane  15 , membrane  16  and other components are broadly the same as those described with reference to the previous example. The main difference in this example is the configuration of the deformable tubular element  14 ′ and these differences are all that will be described below. 
         [0051]    Essentially, the orifice  11  which was previously in a separate component has now been integrated into the tubular element  14 ′ as orifice  11 ′. This has some additional benefits. Firstly, by replacing the two components with a single component, the overall space required for the outlet path has been reduced. This allows other elements such as the vane  15  and membrane  16  to be increased in size. This, in turn, increases the sensitivity of the device as it is more efficient at converting small breath forces into a movement which opens the flow path. This is important for users who may have impaired lung function capacity. Secondly, by eliminating the requirement for a seal between the tubular element  14  and the plate with the orifice  11 , the manufacturing of the device can be simplified. In addition, this eliminates the potential for leakage at this interface. Also, the manner in which the orifice plate  14 ′ is sealed to the outlet path  13  at its upstream end has also been modified. At its upstream end, the tubular element  14 ′ is provided with an outwardly projecting annular flange  40 . This fits within the downstream end of the outlet path  13 . This provides a more reliable sealing arrangement than bonding the tubular element  14  in place. As a result, the new nozzle design can contain a pressurised formulation without leakage for a much longer period, and thus increase the stability of the formulation within the device as well as retaining a higher capacity for a longer period. 
         [0052]    The tubular element  14 ′ can be different thicknesses at particular parts. For example, the hoop stresses will be greatest on the walls of the nozzle immediately downstream of the flange  40 . However, for the mid-section of the tubular element  14 ′ where the jaw  21  is sealing the tubular member, the material can be of reduced thickness to allow an easier clamping action. 
         [0053]    Preferably, the tubular element  14 ′ has a shore hardness of between 20 A and 80 A, most preferably 30 A to 40 A. At its thickest part, the wall can be 0.5 mm thick and at its thinnest part can be 0.18 mm thick. In order to deliver the optimum performance for the aerosol to reach the pulmonary system on inhalation, the outlet orifice  11  is preferably between 0.1 mm and 0.5 mm wide, but preferably 0.2 to 0.3 mm and most preferably 0.2 mm wide. The inner channel in the tubular element  14 ′ away from the outlet orifice  11  is preferably between 0.2 mm and 0.6 mm wide, preferably between 0.3 mm and 0.5 mm and most preferably 0.4 mm.