Patent Publication Number: US-2020282159-A1

Title: Inhaler particularly a cannabinoid inhaler and a method of assembling such an inhaler

Description:
The present invention relates to an inhaler particularly a cannabinoid inhaler and method of assembling such an inhaler. 
     Cannabinoids have long been known for their therapeutic potential in pain relief, treatment of seizures, antiemesis et cetera. It is, however, a class of compounds whose usage has been associated with a great deal of debate owing to its psychoactive effects. It was not until the discovery of cannabinoid receptors (CB1 and CB2) and the isolation of individual cannabinoids such as THC (tetrahydrocannabinol), CBD (cannabidiol), CBN (Cannabinol), and THCV (Tetrahydrocannabivarin), that the psychoactive effects could be attributed primarily to compounds (like THC) with high affinities to the receptor CB1. Furthermore, it has been established that individual cannabinoids differ from one another in their affinities to receptors and certain cannabinoids, such as CBD, behave as CB1/CB2 antagonists, thereby blocking some actions of their agonists, such as THC. 
     With on-going research, therapeutic applications of cannabinoids are becoming increasingly evident, resulting in legalisation of these compounds for medical purposes in a number of countries. The primary targets of research in this field are being associated with safe, rapid and/or effective delivery of cannabinoids. 
     A number of ways of delivering cannabinoids are known in the art. 
     For example, US2012/0304990 teaches the use of heating to vaporise a cannabis deposit. One drawback of this system is that there is only a small temperature differential between the temperature at which the cannabis will vaporise (180° c. to 200° c.) and the temperature at which toxins are produced (230° c.). 
     A number of documents (for example WO03/055549, U.S. Pat. No. 6,509,005 and WO2004/000290) disclose the use of a metered dose inhaler. Such inhalers suffer from a number of drawbacks. Firstly, the metering chamber is relatively small, generally less than 100 μl resulting in delivery of fairly concentrated doses. Also, such devices require users to optimally co-ordinate actuation of the outlet valve and inhalation, failing which, dose delivery could be variable. 
     A further common mechanism is the simple spray which is disclosed, for example, in WO02/064109 and US2006/135599 which are designed to provide a sublingual or buccal spray. Such a spray is currently being marketed by GW Pharmaceuticals under the Sativex (™) brand. These sprays suffer from the possibility of non-uniform drug dose delivery owing to the flushing action of saliva. Further, they have a slower onset of action when compared with pulmonary delivery. 
     A development of this idea was disclosed in WO2015/121673. This takes an inhaler which is based on a simulated cigarette and uses it to dispense cannabis. 
     The inhaler is based on a design of simulated cigarette which uses a pressurised reservoir and a breath operated valve. Suction on an inhaling end of the inhaler opens the breath operated valve such that the pressurised reservoir is able to dispense the formulation. 
     The inhaler is primarily designed as a simulated cigarette. Details of the breath operated valve are described in WO2009/001082, WO2010/073018, WO2011/015825, WO2011/015826, WO2014/033438, WO2014/033439, WO2014/155091 and WO2016/005728. 
     Additional details of the inhaler are provided in: WO2011/117580 and WO2014/155093 
     Details of the manner in which the inhaler is tested and assembled are provided in WO2015/087045, WO2014/155095 and WO2016/046567. 
     The inhaler is designed to be refillable via a refill pack which is designed to have the shape and size of a cigarette pack. Details of the refill pack are provided in: WO2009/001078, WO2014/155092, WO2014/155090 and WO2014/155089 
     WO2015/121673 provides details of the composition required to dispense a cannabinoid based product from such an inhaler. 
     The above mentioned references provide a full description of the inhaler internal workings and the composition. 
     The present invention provides modifications of such an inhaler which are suitable for dispensing a cannabinoid product. 
     One issue with the above described inhaler concerns the presence of a spring which is designed to bias closed the breath operated valve. This is inserted into the inhaler before a cap is put in place and welded in position. This is an awkward operation as the cap covers the spring rendering it inaccessible during this part of the assembly process. Further, the metal spring can heat up during the welding process such that the spring can embed itself in the surrounding materials and this will affect the biasing force with which it biases the valve closed. 
     According to the present invention, there is provided an inhaler according to claim  1 . 
     The present invention uses an outer housing. This allows the support for the biasing member to be reconfigured to include a bung to support the biasing member rather than the welded cap as previously. The rigid outer housing then surrounds the inner housing to support the bung. 
     This modification is particularly applicable when the inhaler composition comprises a cannabinoid or a pharmaceutically acceptable derivative or salt thereof as the need for an outer housing is greater in such circumstances. 
     The inhaler preferably further comprises a membrane which is communication with an air flow path through the inhaler leading to the inhaling end, the membrane being configured to be deformable by the air in the air flow path to displace a valve element against the action of the biasing member. This membrane can provide a wide surface area which provides an optimal way of generating a relatively large force to overcome the biasing member in a relatively small space. 
     The inhaler preferably further comprises a cap which forms part of the inner housing adjacent to the biasing member, a hole being provided in the cap to receive the bung. 
     The outer housing can be formed of a number of components which are welded together. In this case, the welded joints can be kept further from the biasing member to avoid the problems with the welding heat set out above. However, preferably, the outer housing is formed of a number of components which are attached in a non-welded manner. Preferably the components are clipped together. In this case, they are preferably irreversibly clipped together such that the outer housing cannot be disassembled without permanently damaging the components. 
     This aspect of the present invention preferably also extends to a method of assembling the inhaler according to claim  5 . 
     A problem with using the inhaler according to WO2015/121673 as a cannabis dispenser is that it is often used by those who have limited dexterity in their fingers. The inhaler of WO2015/121673 is designed to be held in the finger tips and pressed against the refill nozzle in order to refill the inhaler. 
     According to a second aspect of the present invention there is provided an inhaler according to claim  6 . 
     By providing a much larger inhaler with a relatively flat body, it is much easier for those with a limited dexterity to refill it as it can be held more easily between the thumb, the index finger and palm of the hand. 
     In order to enhance this, the flattened shape comprises opposing flat surfaces, wherein at least one of the flat surface comprises a recess which extends for at least one third (preferably at least one half) of the length of the inhaler and at least one third (preferably at least one half) of the width of the inhaler. The edges of this relatively large recess provide additional surface which makes it easier for a user to manipulate the inhaler. In particular, the depth of the recesses is preferably greater than 10% of the depth of the inhaler. The relatively deep recess provides a surface towards the inhaling end of the inhaler against which a user can push when mating the device with the refill pack. Whilst there may only be a recess on one side of inhaler, preferably each of the flat surfaces comprises a respective recess. 
     In view of the nature of the composition being dispensed, the inhaler should be capable of being stored in a child-resistant manner. No such child-resistant storage is provided in WO2015/121673. 
     According to a third aspect of the present invention there is provided a combination of an inhaler and a refill pack as defined in claim  12 . 
     By providing latches at each end of the housing, which are spaced at least 80 mm (preferably 90 mm) apart, the refill pack cannot readily be operated by accident by a child holding the refill pack in one hand as their hand will not be able to reach both latches at the same time. They can, of course, still open the container using both hands, but this requires a great deal more dexterity and coordination and is far less likely to happen accidently. At the same time, given that the refill is intended to be used by those with a limited dexterity, the fact that it can still be opened simply by depressing two latches at opposite ends of the housing provides a mechanism which is easy to use. The mechanism can also readily be accommodated in the refill pack without unduly affecting its aesthetics. 
     Also, in view of the nature of the composition, it is desirable that a user is not able to dispense the composition directly from the refill canister. This can be dealt within the refill canister itself by recessing the refill nozzle while inside the refill pack housing. In accordance with a fourth aspect of the present invention, there is provided a combination of a cannabinoid inhaler and a refill pack according to claim  14 . 
     Because the only way to obtain access to the pressurised canister is to destroy the refill pack housing, this will deter any casual attempts to do this. Whilst it is still possible to destroy the housing, this is by no means straightforward and risk damaging the pressurised canister. As such, it is unlikely that this will be attempted by the casual user and therefore offers a greater degree of protection than WO2015/121673. The parts of the refill pack may, for example, be clipped together in an irreversible manner such that they cannot easily be separated and such that separating them will then inevitably result in permanently damaging the housing. Preferably, however, the at least two parts are welded together, for example, by sonic welding. 
     According to a fifth aspect of the present invention there is provided a combination of a cannabinoid inhaler and refill pack according to claim  16 . By making the refill pack housing have a curved cross section which is wider at the containing the pressurised canister, this provides ergonomic advantages. This shape naturally encourages the user to grip the refill pack housing at the wider end which is the end at which they will insert the inhaler in order to carry out the refill operation. Because they are holding this end, this provides a stable base from which to press the inhaler against the refill pack. 
     Preferably the housing is provided with a transparent window in the vicinity of an outlet from the pressurised refill canister. This allows the user to have a visual guide of the mating between the inhaler and the outlet from the pressurised refill canister. 
     Preferably the refill end of the inhaler is configured to fit closely into a recess in the vicinity of an outlet from the pressurised refill canister. This helps guide the inhaler into the refill position, potentially aided by the presence of the transparent window. 
    
    
     
       Examples of the various aspects of the present invention will now be described with reference to the accompanying drawings, in which: 
         FIGS. 1A to 1F  are a front, left, top, right, bottom and back views respectively of the inhaler; 
         FIGS. 2A to 2D  are a top back perspective, top front perspective, bottom back perspective and bottom front perspective views respectively of the inhaler; 
         FIG. 3  is a top view of the inhaler; 
         FIG. 3A  is a cross section through line A-A in  FIG. 3 ; and 
         FIG. 3B  is an enlarged cross section of the part within the ring B in  FIG. 3A ; 
         FIGS. 4A and 4B  are a top perspective and bottom perspective view respectively of the internal core; 
         FIGS. 5A to 5F  are top, back, left, front, right and bottom views respectively of the refill pack; 
         FIGS. 6A to 6D  are top back perspective, top front perspective, bottom back perspective and bottom front perspective views respectively of the refill pack; and 
         FIGS. 7A and 7B  are perspective views of the refill with the door opened, with the inhaler shown in place in  FIG. 7A  and removed in  FIG. 7B . 
     
    
    
     The present invention comprises an inhaler device  1  shown in  FIGS. 1-4 and 7A  and a refill pack  2  shown in  FIGS. 5 to 7 . 
     The internal workings of the inhaler device  1  are based on an inhaler I which is described in all of the PCT publications referred to above. This forms the inner core of the present invention. The modification provided by the present invention is, in broad terms, to surround this inner core I with an outer housing  3  as described below. 
     In general terms, the workings of the inhaler I have not been modified and this will therefore not be described in great detail here. 
     In broad terms, the inhaler core comprises a reservoir  4  and a breath operated valve mechanism  5  which has a spring loaded member valve member  6  (see  FIG. 3B ) which pinches a deformable tube  7  closed to close off access to the reservoir. The valve element  6  is biased closed by a spring  8 . A membrane  9  is in communication with an air flow path such that suction on the outlet end  10  causes a change of pressure on the membrane which will lift the valve element  6  against the action of the spring  8 . Further details of this are given in the above references. 
     The inhaler core also has a dip tube  11  which is held by a fixture  12  adjacent to a refill valve  13 . This allows the inhaler I to be refilled at the refill end  14 . Again, further details can be found in the above mentioned references. 
     One modification to the inhaler I is illustrated in  FIG. 3B . The inhaler I is closed in the vicinity of the membrane  9  by a cap  15  which in the above mentioned references directly support the spring  8 . In the present case, however, a further component in the form of a bung  16  is inserted through an opening  17  in the cap and is sealed by an O ring  18 . This allows the cap  15  to be welded in place before the spring  8  is put in place and then retained by the bung  16 . 
     As is apparent, for example, from  FIGS. 1 and 2 , the outer housing  3  is made up of three separate portions, namely a mouthpiece casing  20 , a top casing  21  and a bottom casing  22  which are clipped together to form the outer housing. As can be seen in  FIG. 3B , an O-ring  23  seals a flange  24  on the inhaler core to the mouthpiece casing  20 . This flange  24  represents a further modification of the inhaler I. A similar flange  24 A is present at the opposite end to the outer housing  3 .The mouthpiece casing  20  is also provided with a number of ribs  25  (only one of which is visible in  FIG. 3B ) to prevent the bung  16  from being dislodged. 
     The inhaler core I is also held in place within the outer housing  3  by the presence of an elongate rib  26  which extends along a significant portion of the length of the inhaler I and engages with a corresponding slot in the outer housing  3  to retain the inhaler I in place. 
     As shown particularly in  FIGS. 1 and 2 , the outer housing  3  is provided with a number of ergonomic features to enhance the usability of the inhaler device  1  particularly for those with limited manual dexterity. 
     Thus, the outer housing  3  is provided with a significantly larger size than the inhaler core as can be seen, for example, from  FIG. 3A  as well as  FIGS. 1A and 1F  in which the inhaler I is visible at the inhaling  10  and refill  14  ends. The inhaler is approximately 26 mm across in its widest position and is preferably approximately 20 mm deep at its widest position. This provides the relatively flat elongate configuration apparent from  FIGS. 1A and 1F . Recesses  30  are provided in the top and bottom surfaces of the outer housing  3  as seen in many of the figures. This makes the inhaler device  1  easier to grip both during the inhaling process and as it is refilled. During inhaling, the user will grip the inhaler by placing their fingers on the top recess and their thumb against the bottom recess. The inhaler can be used either way up, but it is provided with an indica in the form of an arrow  31  marking the top of the inhaler to encourage the inhaler always to be used in the same orientation with the arrow uppermost. In this orientation, the composition outlet  32  (see  FIGS. 1F and 3B ) is uppermost. This provides a more uniform dosage pattern, although the inhaler will still operate in any orientation. 
     When the inhaler device  1  needs to be refilled, the refill end  33  is inserted into the refill pack  2  as described below. The recesses  30  provide a pair of surfaces  34  that can readily be gripped by a user and which are oriented such that a user can readily exert a pushing force urging the refill end  33  into the refill pack as described below. 
     The refill pack  2  will now be described with reference to  FIGS. 5 to 7 . 
     The refill pack  2  has a housing  40  with an openable door  41  as shown in  FIGS. 7A and 7B , the refill pack  2  is essentially separated into two compartments namely a device storage compartment  42  located behind the door  41  and a compartment for the storage of a pressurised refill canister  43  depicted in  FIG. 6A . This is a standard pressurised cylinder design and contains the composition defined in WO2015/121673. The canister  43  has a nozzle  44  which is depressed into the canister  43  by the inhaler device  1  in order to refill the inhaler device  1  as described in the above listed references directed to the refill pack. 
     The body of the housing  40  other than the door  41  is provided by two parts  45 ,  46  which are welded (eg. by sonic welding) along line  47  to encapsulate the canister  43 . The canister  43  can therefore not be removed without destroying the housing  40 . The parts can alternatively be clipped together in an irreversible manner. 
     A window  48  is provided in the housing  40  on both sides of the nozzle  44  so that a user can see when the refill end  33  of the inhaler device  1  is inserted into a recess  49  surrounding the nozzle  44 . The recess  49  has a shape which is complimentary to the shape of the refill end  33  such that, not only can the user see the refill end being guided onto the refill nozzle  44 , this is also guided by the interaction of the refill end  33  and the recess  49 . 
     The door  41  is attached to the main body of the housing  40  by a pair of hinges  50  to allow the door  41  to be hinged between the closed position shown in  FIGS. 5 and 6  and the open position shown in  FIG. 7 . As is apparent from  FIG. 7B , the housing is provided with a recess  51  which is complimentary to the shape of inhaler device  1  in order to retain the inhaler device  1  in the place shown in  FIG. 7A . A pair of clips  52  securely hold the retainer device  1  in place so that it does not fall out when the door  41  is opened but can then be easily removed. 
     A pair of latches  53  are provided one at each end of the door  41 . Each comprises a hook  54  which is resiliently deformable to engage in a respective aperture  55  in the casing  40  and a release component  56  clearly marked with a visible arrow which has textured surface to allow the user to readily locate an engage with the release component  56 . A notch  57  is provided in the door  40  in the vicinity of the release component  56  such that the release component  56  is deflectable inwardly of the housing to release the hook  54  from the aperture  55  thereby allowing the door to be opened. The latches  53  are deliberately positioned one at each end of the device, which has a length of approximately 100 mm such that they spaced apart by a distance which cannot be opened by a child holding the device in a single hand. They can, however, readily be opened by an adult sized hand. 
     As will be apparent from  FIGS. 5A and 5F , the housing  40  has a curved profile which is slightly wider at the end with the refill canister  43  than at the opposite end. This means that the user will naturally tend to grip the housing  40  around the wider end which provides a more stable arrangement as they insert the refill end  33  of the inhaler device  1  into the recess  49 . 
     While certain claims specify a cannabinoid inhaler and require an inhalable composition comprising a cannabinoid, all aspects of the invention can be used with any inhalable pharmaceutical composition.