Mouthpiece of pulmonary delivery device having warm and cold chambers

Abstract

A pulmonary delivery device (300) with a first chamber (206) adapted to thermally vaporise a quantity of a first fluid to form a relatively warm first vapour and a second chamber (208) adapted to atomize a quantity of a second fluid without heating of the second fluid to form a mist of a relatively cold, second vapour, the device further comprising an outlet via which, in use, a user can inhale a mixture of the first and second vapours. The second chamber is in the form of a passive atomiser wherein the second chamber is selectively or continuously in fluid communication with air, the second chamber including at least one flavouring or aroma wherein the flavour is inhaled by drawing air through the chamber.

Claims

1. A mouthpiece for a pulmonary delivery device, the mouthpiece having a first inlet end and a second outlet end and comprising: a first chamber adapted for receipt within a main body of the pulmonary delivery device at the inlet end of the mouthpiece and a second chamber at least partially surrounding the first chamber, the second chamber being adapted for receipt of at least one flavour or aroma, and having at least one air inlet at the inlet end whereby the second chamber is selectively or continuously in fluid communication with air and wherein the first chamber of the mouthpiece extends beyond the end of the second chamber at the inlet end of the mouthpiece and the first and second chambers are substantially co-terminus at the outlet end of the mouthpiece.

2. The mouthpiece of claim 1 in combination with the pulmonary delivery device incorporating the mouthpiece, the pulmonary delivery device comprising: the main body having a chamber adapted to thermally vaporise a quantity of a first fluid to form a relatively warm, wet first vapour, and the mouthpiece is received within the chamber of the main body, the first chamber of the mouthpiece providing an extension to the chamber of the main body, the second chamber of the mouthpiece being adapted to atomize a quantity of a second fluid without heating of the second fluid to form a mist of a relatively cold, second vapour, wherein the second chamber is in the form of a passive atomiser.

3. The mouthpiece as claimed in claim 2, wherein the flavour is provided in a solid or semi-solid form within the second chamber.

4. The mouthpiece as claimed in claim 2, wherein the extension to the chamber of the main body comprises a central cylindrical tube concentrically surrounded by the second chamber, the central cylindrical tube is dimensioned for receipt within the chamber of the main body provided in the pulmonary delivery device that produces the heated or warm vapour.

5. The mouthpiece as claimed in claim 2, wherein the extension to the chamber of the main body comprises a central cylindrical tube concentrically surrounded by the second chamber, the second chamber terminating in a flange having the at least one air inlet wherein the flange is received on a top surface of the chamber of the first body of the pulmonary delivery device.

6. The mouthpiece as claimed in claim 2, wherein multiple air inlets are provided into the second chamber of the mouthpiece and the mouthpiece includes means for selectively opening and closing the multiple air inlets.

7. The mouthpiece as claimed in claim 2, wherein multiple air inlets are provided into the second chamber of the mouthpiece and entry of air through the air inlets is adjustable, wherein the mouthpiece comprises two parts, one part forming the extension to the chamber of the main body, at least a portion of the extension including air inlets in fluid communication with the second chamber formed by the second part surrounding the first part and wherein the first part and second part are at least partially rotatable with respect to each other to effect closing or opening of one or multiple air inlets provided in the first part.

8. The mouthpiece as claimed in claim 1, wherein the inlet end of the second chamber is provided with an annular flange extending substantially perpendicularly from the second chamber, the flange having at least one air inlet in fluid communication with the second chamber.

9. The mouthpiece as claimed in claim 1, wherein the inlet end of the second chamber is provided with an annular flange extending substantially perpendicularly from the second chamber, the flange having at least one air inlet in fluid communication with the second chamber, a portion of the first chamber extends beyond the flange for receipt within the chamber of the main body of the pulmonary delivery device and the flange is adapted to rest or engage with sides of the main body, whereby the at least one air inlet of the second chamber is positioned beyond the sides of the main body.

10. The mouthpiece as claimed in claim 1, wherein multiple air inlets are provided at the inlet end of the second chamber, the multiple air inlets being spaced equidistant apart around a perimeter of the second chamber and the second chamber concentrically surrounds the first chamber.

11. The mouthpiece as claimed in claim 1, wherein the mouthpiece includes means for selectively opening and closing the at least one air inlet to the second chamber.

12. The mouthpiece as claimed in claim 11, wherein the second chamber is formed by a cylindrical wall which is at least partially rotatable with respect to the first chamber to selectively open and close the at least one air inlet.

13. The mouthpiece as claimed in claim 1, wherein the flavour comprises two half sections, each half section being of a different flavour, and the mouthpiece is provided with means for opening only the at least one air inlet adjacent one of the half sections.

14. The mouthpiece as claimed in claim 1, wherein the second chamber has multiple air inlets and wherein the mouthpiece includes means for selectively closing a portion of the multiple air inlets simultaneously.

15. The mouthpiece as claimed in claim 1, wherein the mouthpiece comprises two parts, a first part forming the first chamber and a second part forming the second chamber, at least a portion of the first part including one or multiple air inlets in fluid communication with the second chamber wherein the first part and second part are at least partially rotatable with respect to each other to effect closing or opening of one or multiple air inlets provided in the first part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective view of a pulmonary delivery device according to the prior art;

(3) FIG. 2 is an exploded view of the pulmonary delivery device of FIG. 1;

(4) FIG. 3A is a plan view of the pulmonary delivery device of FIG. 1;

(5) FIG. 3B is a close up view of part of FIG. 3A;

(6) FIG. 4 is a plan view of another pulmonary delivery device that forms part of the state of the art;

(7) FIG. 5 is a schematic view of a pulmonary delivery device and user interface;

(8) FIG. 6A is a cross-section through a mouthpiece according to an embodiment of the present invention for attachment to a pulmonary delivery device;

(9) FIG. 6B is a perspective view of the mouthpiece shown in FIG. 6A with a flavour block fully inserted into the second chamber;

(10) FIG. 6C is a perspective view of the mouthpiece shown in FIG. 6A with a flavour block partially inserted into the second chamber;

(11) FIG. 6D is a perspective view of the mouthpiece of FIG. 6A illustrating the air inlets of the second chamber;

(12) FIG. 6E is a partially exploded perspective view of an alternate embodiment of the mouthpiece of FIG. 6A having a slidable shutter;

(13) FIG. 7 is perspective view of a prior art pulmonary delivery device and mouthpiece according to the present invention; and

(14) FIGS. 8A, 8B and 8C are respectively a perspective view, a partial cross-sectional view and a top view of a mouthpiece according to another embodiment of the present invention for attachment to a pulmonary delivery device.

(15) FIG. 8D is a perspective view of an alternate embodiment of the mouthpiece of FIG. 8B.

DETAILED DESCRIPTION

(16) Referring to FIGS. 1, 2 and 3A to 3B of the accompanying drawings, a prior art pulmonary delivery device 10 comprises a generally cylindrical main body portion 12 adapted to resemble a cigarette. The main body portion 12 comprises a tubular filter chamber 14 encasing first and second vaporiser chambers 15, 16 and a tubular battery chamber 18 encasing a rechargeable battery 20. The tip 22 of the main body 12 is closed off by a translucent end cap 24, behind which sits an (light emitting diode (LED) indicator light 26 that illuminates when the device 10 is in use. A control circuit 28 is contained within the body 12, which comprises a programmable circuit for controlling the operation of the device 10, in use.

(17) Turning to FIGS. 2 and 3, the device 10 comprises a first pressure sensor (not visible) located within the filter chamber 14, which has an outlet 30 therein through which, in use, vapour generated by the device 10 can be inhaled by a user. When the user draws on the filter chamber 14, the pressure sensor (not visible) activates the first and/or second vaporiser chambers 15, 16 to form a mixed vapour comprising the first and/or second liquids, to be inhaled.

(18) The first and second vaporiser chambers 15, 16 comprise a pair of separate reservoirs containing first and second liquids respectively. A first vaporiser chamber 15 contains a first liquid and comprises a capillary wick 31, which absorbs the liquid, and whose end touches a heater element 35 in the form of a pyramid-shaped, super-hydrophilic foil, which is wetted by the first liquid, in use (see, in particular, FIG. 3B). The heater element 35 could alternatively comprise a resistive heating coil, which is wrapped around the wick 31. In any event, the heater element 35 is connected to the battery 20 under the control of the control circuit 28.

(19) The second vaporiser chamber 16 contains a second liquid that is held under pressure within the chamber and includes a pressure release valve or flow control valve (not shown). When the user draws on the filter chamber, the pressure sensor activates the valve to propel the second liquid out of the second chamber as a fine mist or vapour. The absence of any heating element results in a cold vapour being released from the second chamber.

(20) Thus, when the heater element 35 is switched on, the first vaporiser chamber acts as a “warm vapour chamber” with the first liquid being evaporated and forming a warm vapour B within the interior of the filter chamber 14. Simultaneously, cold vapour A is released into the interior of the filter chamber 14 from the second vaporiser chamber (the “cold vapour chamber”) thus allowing the warm and cold vapours B, A to mix in the hollow space of the filter chamber, before being inhaled by the user, via the outlet 30 of the device.

(21) The first liquid comprises a mixture of glycerol and water and the second liquid comprises nicotine and a suitable propellant. Preferably, the particles forming the mist of the second liquid are less than 10 μm in diameter, more preferably less than 5 μm. In this manner, nicotine (or other active molecule provided in the second liquid) is delivered deep into the lungs to allow for its quick absorption into the bloodstream via the lungs. However, the simultaneous delivery of a warm, wet vapour in the form of the vaporised first liquid provides the user with a sensation that more closely resembles that experienced during the smoking of a conventional tobacco cigarette. The active molecule is not in direct contact with the heater element, reducing the potential for its thermal degradation which may have resulted in the user inhaling harmful by-products. In contrast, only glycerol and water are in contact with the heater element which do not result in the production of harmful by-products upon their thermal degradation.

(22) The device may also be provided with a suitable control circuit 28 that may control the delivery of the first and/or second vapours from their respective chambers. The ability to deliver nicotine from a pressurized chamber without heating allows for more accurate nicotine dosing using the device of the present invention than the delivery of nicotine using the heated vapour method. It is to be appreciated that the delivery of the wet warm vapour and the cold vapour may be controlled and the content of the mixed vapour may be adjusted as required.

(23) For example, the control of the delivery of heated vapour may be achieved using a resistance sensor operatively connected to the heater element 35 which measures the heater's resistance, and infers from that, the heater temperature. The control circuit 28 additionally comprises a current limiting circuit for limiting the current to the heater element 35 and is programmed to heat it according to a predetermined, time-dependent heating/cooling profile.

(24) When a user draws on the filter chamber 14, the pressure switch (not visible) triggers the control circuit 28 to heat the heater element 35. The control circuit 28 thereby connects the battery 20 to the heater element 35 in a controlled and reproducible manner. As such, the time, and time-at-temperature of the heater element 35 is thus controlled, thereby regulating the vaporisation of the first liquid from the wick 31.

(25) The control circuit 28 may also be operatively connected to a second pressure sensor 39 (FIG. 2), which measures the ambient air pressure. The control circuit 28 is configured to switch on the heater element 35 only when the first pressure switch is triggered, as described hereinabove.

(26) A vapour is thereby formed adjacent the heater element within a hollow interior space (a mixing chamber) located towards the tip of the filter chamber 14, i.e. the space between the first vaporiser chamber 15 and the outlet 30, when the device 10 is assembled.

(27) The outlet from the “cold vapour chamber” or second vaporiser chamber is sufficiently small as to control (mass-limit) the amount of the second liquid that can escape in each dispensation, and is selectively closed and/or opened by a control valve (not shown). The control valve is connected to the control circuit 28 enabling it to be controlled independently of the heater element. The control circuit 28 can thus be configured to open the valve a given number of times, per actuation, thereby incrementally controlling the dose of liquid dispensed (the dose per actuation being constant due to the size of the outlet aperture). Thus, the device is able to accurately control the ratio of the first and second liquids dispensed in each actuation, and hence the dose of a particular medicament or mixture of medicaments in the first and second liquids. The ratio may be adjusted by the control circuit 28, in accordance with a pre-programmed dosing regimen.

(28) While the afore-mentioned device may accurately control the dose provided by each chamber, if the active molecule or medicament is only included in the “cold vapour” chamber then it is possible to only accurately control dosing provided by this chamber. This allows for simpler control of dosing than when the active molecule or medicament is dispensed in the warm vapour.

(29) FIG. 4 shows an alternative pulmonary delivery device forming part of the state of the art. In FIG. 4, the first and second vaporiser chambers are not in a side-by-side arrangement but instead arranged along the longitudinal axis of the device, in an end-to-end arrangement, thereby providing a slim-line device. Features that are identical to those described in FIGS. 1 to 3 are given the same reference numerals, for the sake of simplicity. The first and second vaporiser chambers 15, 16 are provided in a hollow cylindrical pressure vessel comprising a dual ended aerosol container having an aerosol outlet at each end, the container being surrounded by housing having outlet 30. The second vapour chamber 16 is provided in the intended top end of the aerosol container near to the outlet 30 and the first vapour chamber 15 extends from the base of the chamber 16 in the bottom end of the aerosol container. A heating element 35 is provided in line with the base of the aerosol container. The second liquid containing the active molecule is dispensed from the upper chamber (as cold vapour designated by reference character A) and the first liquid is dispensed from the lower chamber on to the heating element 35 (warm vapour designated by reference character B). This warms up the second vapour which then passes up the passage (warm vapour B) between the housing and container to the outlet 30, thereby enabling mixing of the hot and cold vapours (B, A) prior to their exit through the outlet and inhalation by the user.

(30) In this example, the control circuit may be programmed to activate vapourisation of the first liquid in the warm vapour chamber a few milliseconds before release of vapour from the cold vapour chamber thereby ensuring that warm vapour is released simultaneously with the cold vapour.

(31) It is to be appreciated that alternative arrangements may be provided for the warm and cold vaporiser chambers in the device. For example, the device may include a dual chamber having a hollow cylindrical pressure vessel comprising a central divider thus dividing the interior thereof into two separate reservoirs for first and second liquids. A pressurised propellant gas occupies the remaining space of one reservoir and a heater element and wick is provided in the other reservoir, with outlet apertures provided to enable the liquids to escape from their respective reservoirs under the actions of the pressurised propellant and heater element.

(32) A ceramic heater may be used for heating the first liquid in the first chamber. This reduces the potential for harmful metal residues from metallic heating elements to be inhaled by the user.

(33) An alternative type of “cold vapour” chamber may comprise a spring-loaded syringe comprising a tubular body portion forming a reservoir for retaining the second liquid. A piston is slideably moveable within the body and is sealed thereto by an O-ring seal. A superelastic spring cooperates between the rear face of the piston and an end cap of the body to push the piston along the body and thus eject the liquid contained therein through an outlet aperture. An outlet flow control valve is also provided to open and close the outlet aperture. The super elastic spring is compressed within its super elastic range and, provided the superelastic spring is operated within this range, the pressure of the liquid remains constant, thereby accurately regulating the amount of liquid dispended during each actuation of the valve.

(34) A device incorporating this type of “cold vapour” vaporiser would, of course, also include a “warm vapour” chamber with a heating element for releasing a warm vapour, and, optionally, a control circuit 28 to control the delivery of the liquids.

(35) A dose control system 100 is shown in FIG. 5 of the drawings. In FIG. 5, a pulmonary delivery device 10 such as that shown in in FIGS. 1 to 3B, FIG. 4 or FIGS. 6A to 7 is wirelessly connected 102 to a user's smartphone, tablet computer or PC 104 and to the internet 106, via a Wi-Fi access point 108, such as a broadband router. Internet connected computers 110, 112 (local or remote) can thus connect to the device 10 wirelessly, as can the user him or herself. The wireless connection is provided via a Wi-Fi and/or Bluetooth® interface of the control circuit 28, thereby providing a graphical user interface (GUI) 120 on any of the devices 104, 110, 112 for interacting with the device 10.

(36) The GUI 120 has a secure login-in system 122 to prevent unauthorised re-configuration of the device 10 and allows a user to select between three main modes of operation, namely a “wean” mode 124 whereby the dose 126 of a given medicament can be reduced over time 128, as shown on a dose-time graph 130 of the GUI. The graph has draggable handles 132 that enable the shape of the curve to be adjusted to change the weaning profile, i.e. the severity, duration, delay etc. of the weaning process.

(37) Another option from the drop-down menu is to select a control program 134, which ensures that a desired quantity of medicament is administered over a period of time. The dose-per-puff is thus controlled to ensure, on average, a relatively even administration of the medicament over the time period.

(38) A third option is to set an upper limit, which may be useful in analgesic applications. This program prevents a maximum dose per unit time from being delivered, but allows for under-administration.

(39) The GUI 120 comprises a configuration settings menu 138, which enables a user to configure the GUI in accordance with the liquids 140, 142 in the device. A history table 144 is also provided, which provides a summary of the number of administrations 146, the amount of medicament delivered 147 and a running total 148. These data are shown on a historic 150, actual 152 and a target 154 basis to facilitate monitoring of the drug delivery to the user.

(40) The device is not restricted to the details of the foregoing examples. For example, the shape and configuration of the device can be changed, the materials of manufacture, the combinations of vaporiser technology used, the combinations of heaters used, the additional features, such as the on/off switch, control valves etc. can be varied.

(41) For example, the first “warm vapour” chamber containing an inert liquid, such as a water-glycol mixture, which forms an inhalable vapour may be consumed without restriction by a user. The device has a pressure switch located within the filter chamber 14, which detects when a user inhales on the device. The pressure switch is connected to the control circuit 28, and the control circuit is adapted to switch on a current, from the battery 20, to a resistive heating coil wrapped around an end of the wick, which evaporates the first liquid to form a vapour that can be drawn from the device, via the vaporiser outlet and the device's outlet 30.

(42) The device may additionally comprise a push switch that is accessible from the exterior of the device, which a user can depress, in use, to actuate the valve of the “cold vapour” second vaporiser chamber. Thus, a user can use the device at will, and can choose when to administer a dose of a medicament or active ingredient, such as nicotine, which is contained in the second chamber, by pressing on the button during inhalation.

(43) The afore-mentioned device provides many potential advantages over earlier pulmonary delivery devices. The active ingredient, such as nicotine or a cannabinoid, is inhaled as small particles (<10 μm) resulting in it being delivered deep into the lungs of a user enabling its fast absorption into the bloodstream. The simultaneous delivery of a warm inert vapour enhances the flavour and sensation of the inhalation. The active ingredient is not subject to thermal degradation, leading to a reduction in any harmful by-products and increasing the accuracy and reproducibility of the dosage.

(44) A device according to embodiments of the present invention is illustrated in FIGS. 6A-6D, FIG. 7 and FIGS. 8A to 8C of the accompanying drawings. The device is an adaptation of the devices hereinbefore described and addresses the problems associated with flavourings, such as oils, being delivered in a hot wet vapour and the contamination of a pulmonary delivery device by said flavourings.

(45) The invention overcomes significant regulatory burden of inhalation toxicology for various flavour compounds where inhalation data is not known or where the risk of inhalation is significantly greater than oral deposition.

(46) The invention provides delivery of the flavor or aroma in a “cold” atomized vapour. This is in contrast to the devices of the prior art that deliver the flavor or aroma with the carrier liquid (such as water, or a water-glycol mixture) from a heated chamber. Thus, in the pulmonary delivery device shown in FIGS. 1 and 4 the aroma or flavour would be provided in the second chamber, optionally with the active molecule, rather than the first chamber that provides a relatively warm vapour relative to the second chamber. This ensures that the flavour is delivered to the mouth and prevents degradation of the flavour to harmful by-products that may occur on heating.

(47) The provision of flavours in the warm vapour according to the prior art also causes contamination or carryover in the tank/chamber system of the device. An embodiment of the present invention enables the flavour of an electronic nicotine delivery system (ENDS) to be changed without contamination or carryover in to the tank system. Coffee, tobacco, mint and fruit flavours are often difficult to alternate due to their characteristic aromas. The invention as described in FIGS. 6A to 6D, 7 and 8A to 8C enables the use of a flavour block in the aerosolising chamber to reduce or eliminate cross-contamination of flavour from use to use with simple changeover. Currently the flavours are integral part of the propylene glycol/water in devices available.

(48) The embodiment shown in FIGS. 6A to 6D is a mouthpiece 200 for attachment to a conventional pulmonary delivery device, such as a pulmonary delivery device 300 shown in FIG. 7. The mouthpiece has a first inlet end 202 and a second outlet end 204 with a first central chamber 206 consisting of a cylindrical tube which is adapted for receipt within a main body of the pulmonary delivery device 300 at the inlet end 202 of the mouthpiece. A second chamber 208 concentrically surrounds the first chamber, the second chamber being adapted for receipt of at least one flavour block 210 and having at least one air inlet 212 at the inlet end.

(49) The first central chamber 206 of the mouthpiece extends beyond the inlet end of the second chamber. The outlet ends 204 of the chambers are substantially co-terminus. The inlet end of the second chamber is provided with an annular flange 220 extending perpendicularly from the second chamber, the flange having the at least one air inlet 212 in fluid communication with the second chamber. A portion 202a of the first chamber extends beyond the flange for receipt within a main body of a pulmonary delivery device and the flange is adapted to rest or engage with the sides of the main body, whereby the air inlets of the second chamber are positioned beyond the sides of the main body. A filter tip 302 may also be received at the outlet end 204 of the mouthpiece (see FIG. 7).

(50) It is to be appreciated that multiple air inlets 212 may be provided at the inlet end of the second chamber, preferably being spaced equidistant apart around the perimeter of the second chamber to optimize air flow into the second chamber. Ideally, the air inlets 212 lie adjacent the portion of the first chamber that extends beyond the flange.

(51) Any desired flavour block 210 may be provided within the second chamber 208. In this manner, when the mouthpiece 200 is attached to the pulmonary delivery device and a user inhales with the mouthpiece, warm wet vapour from the main body of the device enters the first chamber 206 of the mouthpiece.

(52) Simultaneously, air is able to enter the second chamber through air inlets 212 to atomise the flavour in the flavour block. This results in the user having a mixture of warm wet vapour with a cold vapour that contains the flavour, addressing the cold sensation of delivery of some nicotine products or other active agents without the potential of harmful ingredients of flavourings being orally deposited.

(53) This arrangement is not only less detrimental to health because the flavouring, such as an oil, is not subjected to heat, but also enables the mouthpiece to be easily changed for a mouthpiece having a different flavor block, without any contamination of the main pulmonary delivery device.

(54) Ideally, but not essentially, the nicotine or other active agent is also delivered via the cold chamber. Combination of this unheated gas with a heated aerosol (typically flavourless) is thought to increase customer satisfaction and is likely to result in a product more akin to customer expectations of a nicotine-containing product.

(55) The embodiment shown in FIGS. 6A to 6D and 7 is preferably formed from a simple two piece construction. The mouthpiece may be disposed of after use and replaced with a new mouthpiece or may have the flavor block removed, be cleaned and a new flavor block inserted. Thus, this provides an easy mechanism for a user to change the flavor or their device, for example from cherry to menthol.

(56) Another embodiment of a mouthpiece according to the present invention is shown in FIGS. 8A to 8A. The mouthpiece 400 is similar to mouthpiece shown in FIGS. 6A to 6D having outlet end 404 and inlet end 402 but the annular flange 420 is formed as part of the moulding forming the first mouthpiece chamber 406 and a cylindrical sleeve 408a rests on the flange to form the second chamber 408. Air inlets 412 are provided through the flange and the portion of the first mouthpiece chamber 402a that extends beyond the inlet end 402 of the second chamber is threaded for engagement with the heated chamber of a pulmonary delivery device (not shown). The sleeve is preferably of a more malleable material than the rest of the mouthpiece to increase user comfort.

(57) In a preferred embodiment of the present invention, the number of air inlets that are open to the second chamber are selectively adjustable to vary the flow of air through this chamber. This enables a user to select the amount of flavour that is inhaled and mixed with the hot vapour. Alternatively, or additionally, more than one type of flavour may be provided in the second chamber with the user being able to select which air inlets to open dependent upon which flavour is to be inhaled.

(58) For example, the mouthpiece may have means for opening and closing the air inlets to the second chamber thereby enabling the volume of air entering the second chamber to be adjusted (not shown). For example, the second chamber may be at least partially rotatable (see arrow of FIG. 8D) with respect to the first chamber to open and close the air inlets or vice versa. The walls of the cylinder forming the second chamber may be provided with spaced apart protruberances or tabs 409 (see FIG. 8D) that can extend over and close the air inlets depending upon the degree of rotation of the second cylinder with respect of the first chamber.

(59) In another embodiment, the second chamber is provided with multiple flavour blocks and the air inlets may be opened to allow flavour from only the desired flavour of the block. For example, the flavour block may comprise two half sections, each being of a different flavour, and the mouthpiece is provided with means for opening only the air inlets adjacent one of the half sections, such as by the provision of a rotatable or slidable shutter 205 (see e.g., FIG. 6E). In another example, the flavours may be provided in inner and outer concentric rings within the second chamber having air inlets provided in a corresponding arrangement of inner and outer concentric rings, wherein the mouthpiece is provided with means for selective opening and closing of the air inlets of inner or outer concentric rings. This would enable a user to easily select a particular flavour without having to change the mouthpiece. This is desirable as many users get used to a flavour very quickly and may wish to alternate flavours, such as cherry and mint, throughout the day.