WO2021181119A1

WO2021181119A1 - Aerosol generating assembly

Info

Publication number: WO2021181119A1
Application number: PCT/GB2021/050634
Authority: WO
Inventors: Biniam TESFATSION; Ugurhan Yilmaz; Tatiana BETSON; Jennifer CROSS
Original assignee: Nicoventures Trading Limited
Priority date: 2020-03-13
Filing date: 2021-03-12
Publication date: 2021-09-16
Also published as: GB202003675D0; JP2023508751A; CA3170779A1; US20230157359A1; EP4117461A1; KR20220152313A; MX2022011355A

Abstract

The present invention relates to an assembly for generating an inhalable medium, a cartridge for use in an assembly for generating an inhalable medium, a method of generating an inhalable medium, a kit, a liquid pod, and a nicotine-containing pod.

Description

AEROSOL GENERATING ASSEMBLY

Technical Field

The present invention relates, without limitation, to an assembly for generating an inhalable medium, a cartridge for use in an assembly for generating an inhalable medium, a method of generating an inhalable medium, a kit, a liquid pod, and a nicotine-containing pod.

Background

Smoking articles such as cigarettes, cigars and the like bum tobacco during use to create tobacco smoke. Alternatives to these types of articles, release compounds without burning to form an inhalable medium.

Examples of such products are heating devices, including e-cigarette / heat-not-bum hybrid devices, also known as electronic tobacco hybrid devices. These hybrid devices contain a liquid that is vaporised by heating to produce an inhalable vapour and/or aerosol. The liquid may contain flavourings and/or aerosol-generating substances, such as glycerol and in some instances, nicotine. The vapour and/or aerosol passes through a substrate in the device and entrains one or more constituents of the substrate to produce the inhaled medium. The substrate material may be, for example, tobacco, other non tobacco products or a combination, such as a blended mix, that may or may not contain nicotine.

Summary

According to a first aspect of the present invention, there is provided an aerosol generating assembly comprising: a solid, nicotine-containing material having a pH of at least 7; an aerosolisable liquid comprising an acid, and having a pH of at least 2 and less than 7; and wherein the assembly is configured to heat the aerosolisable liquid to form a vapour and/or an aerosol, wherein the vapour/aerosol is contacted with the solid, nicotine-containing material to entrain one or more components thereof, and thus forming an inhalable medium.

The assembly may be referred to as an electronic tobacco hybrid device. In some cases, the solid, nicotine-containing material comprises a tobacco material. In some cases, the solid, nicotine-containing material is tobacco material. In some cases, the assembly is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

In some cases, the pH of the solid, nicotine-containing material is of from 8 to 9.5 of from 8.5 to 9. In some cases, the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8. In some cases, the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight. In some cases, the acid has a pKa greater than 0.5, greater than 1, greater than 1.5, greater than 2, greater than 2.5 or greater than 3, suitably, of from 3.7 to 4.3.

According to a second aspect of the present invention, there is provided an aerosol generating assembly comprising: a solid, nicotine-containing material having a pH of at least 7; an aerosolisable liquid comprising an acid, the acid with a pKa greater than 0.5; and wherein the assembly is configured to heat the aerosolisable liquid to form a vapour and/or an aerosol, wherein the vapour/aerosol is contacted with the solid, nicotine-containing material to entrain one or more components thereof, and thus forming an inhalable medium.

In some cases, the pKa of the acid is greater than 3 or from 3.7 to 4.3. In some cases, the pH of the solid, nicotine-containing material is of from 8 to 9.5 or from 8.5 to 9. In some cases, the aerosolisable liquid has a pH of at least 2 and less than 7, or from 4 to 5, suitably from 4.3 to 4.8. In some cases, the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

According to a further aspect of the present invention, there is provided a cartridge for use in an assembly for generating an inhalable medium, the cartridge comprising an aerosolisable liquid comprising an acid in a first chamber, the aerosolisable liquid having a pH of at least 2 and less than 7, and a solid, nicotine-containing material having a pH of at least 7 in a second chamber. In some cases, the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8. In some cases, the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a pKa greater than 0.5 or greater than 3, suitably, of from 3.7 to 4.3. In some cases, the solid, nicotine-containing material has a pH of from 8 to 9.5 or from 8.5 to 9. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

The cartridge may be for use in an assembly that may be referred to as an electronic tobacco hybrid device. In some cases, the solid, nicotine-containing material comprises a tobacco material. In some cases, the solid, nicotine-containing material is tobacco material. In some cases, the cartridge is for use in an assembly that is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol. According to a further aspect of the present invention, there is provided a cartridge for use in an assembly for generating an inhalable medium, the cartridge comprising an aerosolisable liquid comprising an acid in a first chamber, the acid having a pKa greater than 0.5, and a solid, nicotine-containing material having a pH of at least 7 in a second chamber. In some cases, the acid has a pKa of greater than 3 or from 3.7 to 4.3. In some cases, the aerosolisable liquid has a pH of less than 7, or of from 4 to 5, suitably from 4.3 to 4.8. In some cases, the solid, nicotine-containing material has a pH of from 8 to 9.5 or from 8.5 to 9. In some cases, the difference between the pH of the solid nicotine- containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

The cartridge may be for use in an assembly that may be referred to as an electronic tobacco hybrid device. In some cases, the solid, nicotine-containing material comprises a tobacco material. In some cases, the solid, nicotine-containing material is tobacco material. In some cases, the cartridge is for use in an assembly that is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

According to a further aspect of the present invention, there is provided a method of generating an inhalable medium using an assembly comprising an aerosolisable liquid comprising an acid, the aerosolisable liquid having a pH of at least 2 and less than 7, and a solid, nicotine-containing material having a pH of at least 7, the method comprising: heating the aerosolisable liquid to form a vapour and/or an aerosol; forming an inhalable medium, by contacting the aerosolisable liquid in the form of a vapour and/or an aerosol with the solid, nicotine-containing material to entrain one or more components thereof. In some cases, the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8. In some cases, the acid has a pKa greater than 0.5 or greater than 3, suitably, of from 3.7 to 4.3. In some cases, the solid, nicotine-containing material has a pH of from 8 to 9.5 or from 8.5 to 9. In some cases, the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

In some cases, the solid, nicotine-containing material comprises a tobacco material. In some cases, the solid, nicotine-containing material is a tobacco material. In some cases, the assembly is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

According to a further aspect of the present invention, there is provided a method of generating an inhalable medium using an assembly comprising an aerosolisable liquid comprising an acid, the acid with a pKa greater than 0.5, and a solid, nicotine- containing material having a pH of at least 7, the method comprising: heating the aerosolisable liquid to form a vapour and/or an aerosol; forming an inhalable medium, by contacting the aerosolisable liquid in the form of a vapour and/or an aerosol with the solid, nicotine-containing material to entrain one or more components thereof. In some cases, the acid has a pKa of greater than 3 or from 3.7 to 4.3. In some cases, the aerosolisable liquid has a pH of at least 2 and less than 7, or from 4 to 5, suitably from 4.3 to 4.8. In some cases, the solid, nicotine-containing material has a pH of from 8 to 9.5 or from 8.5 to 9. In some cases, the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

The assembly may be referred to as an electronic tobacco hybrid device. In some cases, the solid, nicotine-containing material comprises a tobacco material. In some cases, the solid, nicotine-containing material is a tobacco material. In some cases, the assembly is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

According to a fifth aspect of the present invention, a use is provided for an acidic vapour and/or aerosol to extract nicotine from a solid, nicotine-containing material having a pH of at least 7, wherein the rate of nicotine extraction exceeds the rate of nicotine- salt formation in the solid, thereby providing an increased nicotine content in the vapour and/or aerosol as compared to using a neutral vapour and/or aerosol.

According to a further aspect of the present invention, there is provided a kit comprising:

(i) a liquid pod containing an aerosolisable liquid comprising an acid, the aerosolisable liquid having a pH of at least 2 and less than 7; and

(ii) a nicotine-containing pod, containing a solid, nicotine-containing material having a pH of at least 7; wherein the liquid and nicotine-containing pod are configured for use in an assembly for use in generating an inhalable medium, the assembly being such that in use, an inhalable medium is generated by contacting the aerosolisable liquid in the form of a vapour and/or an aerosol with the solid, nicotine-containing material to entrain one or more components thereof.

The liquid and nicotine-containing pod may be for use in an assembly that may be referred to as an electronic tobacco hybrid device. In some cases, the solid, nicotine- containing material comprises a tobacco material. In some cases, the solid, nicotine- containing material is a tobacco material. In some cases, the liquid and nicotine- containing pod are configured for use in an assembly that is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

In some cases, the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8. In some cases, the pKa of the acid is greater than 0.5 or greater than 3, suitably of from 3.7 to 4.3. In some cases, the vapour pressure of the acid at 25 °C is of from 0.1 Pa to 2.5 kPa. In some cases, the pH of the solid, nicotine-containing material is of from 8 to 9.5 or from 8.5 to 9. In some cases, the difference between the pH of the solid nicotine- containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5. In some cases, the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight. According to a further aspect of the present invention, there is provided a kit comprising:

(i) a liquid pod containing an aerosolisable liquid comprising an acid, the acid with a pKa greater than 0.5; and

To the extent that they are compatible, features described in relation to one aspect of the invention are explicitly disclosed in combination with each and every other aspect. For instance, features described in relation to the assembly, cartridge, nicotine-containing pod, liquid pod or kit are explicitly disclosed in combination with the each of the others of the assembly, cartridge, nicotine-containing pod, liquid pod and kit. Specifically, features of the solid, nicotine-containing material and aerosolisable liquid comprising an acid as described herein are explicitly disclosed in combination with the assembly, cartridge, nicotine-containing pod, liquid pod, and kit embodiments of the invention. Similarly, features described in relation to apparatus are explicitly disclosed in combination with method and use aspects of the invention, and vice versa.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Examples of assemblies and cartridges for generating an inhalable medium according to the invention are described below with reference to the accompanying drawings, in which:

Figure 1 shows a schematic longitudinal cross-sectional view of an example of an assembly for generating an inhalable medium;

Figure 2 shows a schematic longitudinal cross-sectional view of another example of an assembly for generating an inhalable medium;

Figure 3 shows a schematic longitudinal cross-sectional view of another example of an assembly for generating an inhalable medium;

Figure 4 shows a schematic longitudinal cross-sectional view of an example of a cartridge having a liquid chamber and an integral chamber for solid material;

Figure 5 shows a schematic longitudinal cross-sectional view of an example of a cartridge having a liquid chamber and a detachable chamber for solid material; Figure 6 shows nicotine delivery from assemblies according to embodiments of the invention, and a comparative assembly.

Detailed Description

The present invention relates to improving the taste of an inhalable aerosol, and increasing the amount of nicotine delivery in an assembly for use in a hybrid device, where the nicotine has been pH-treated to raise its pH.

At its most general, the assembly described herein volatilises an aerosolisable liquid to form a vapour and/or an aerosol that passes through a solid nicotine-containing material so as to produce an inhalable medium that contains one or more constituents, such as nicotine, derived from the solid.

In some assemblies, base-treated nicotine may be included in the solid, nicotine- containing material. The nicotine reacts with the base; this reaction deprotonates nicotine, increasing its volatility and releasing it from its bound state to provide nicotine in its deprotonated basic form (herein referred to as “deprotonated nicotine” or simply “free nicotine”). As a result, base-treated nicotine will be more readily volatilised upon heating. The present inventors have found, however, that inhalable aerosols (sometimes referred to herein as “inhalable medium”) containing free nicotine have a less desirable taste, in comparison to those containing nicotine salts.

In some embodiments, the inhalable aerosol of the assembly may have improved sensory qualities, such as taste. In some embodiments, the inhalable aerosol may have a higher amount of nicotine delivery, and may promote the extraction of nicotine from a nicotine source, where the nicotine source has been treated with base to raise its pH, in comparison to other inhalable aerosols.

The inventors have determined that by including an acid in the aerosolisable liquid, better tasting inhalable aerosols are produced. The acid in the vapour/aerosol - produced by heating the aerosolisable liquid - reacts with the free nicotine from the solid, nicotine-containing material to provide nicotine in its better tasting, salt form. That is, the acid and free nicotine undergo an acid-base salt formation to produce nicotine salts in the vapour/aerosol.

It was thought that whilst the use of an acidic aerosol/vapour would improve the taste, it was expected that some reduction in the overall nicotine delivery would be observed as less volatile nicotine salts would form in the solid, nicotine-containing material, upon contact with the acidic vapour/aerosol.

Surprisingly, the inventors found that including an acid in the aerosolisable liquid of an assembly actually increases the overall nicotine delivery during use, in comparison to a neutral aerosolisable liquid. Without being limited by theory, it is thought that the affinity between the free nicotine and the acid in the vapour/aerosol may draw or extract the nicotine out of the solid, nicotine-containing material. It is thought that this extraction occurs at a rate that is faster than the rate of formation of nicotine salt in the solid. Hence, an inhalable aerosol with improved taste and higher nicotine content may be provided. Using an acidic vapour/aerosol may also allow for a higher overall amount of nicotine to be extracted from the solid.

Solid, nicotine-containing material

In some cases, the invention provides an assembly for generating an inhalable medium or a cartridge for use in an assembly for generating an inhalable medium, wherein the assembly or cartridge includes a solid, nicotine-containing material (herein referred to as “nicotine source” or simply “solid”).

The nicotine source has a pH of at least 7. In some cases, the nicotine source has a pH of from 8 to 9.5, of 8.2 to 9.3, of 8.3 to 9.2, of 8.4 to 9.1. Suitably, the pH may be of from 8.5 to 9, or may be 8.5. This allows for the nicotine in the solid, nicotine-containing material to be provided in its deprotonated basic form (as free nicotine), thereby increasing the volatility of the nicotine so that it is more readily volatilised on heating.

In some cases, the pH of the nicotine source is selected such that there is a difference between the pH of the nicotine source and the pH of the aerosolisable liquid of from 3 to 5.5, of 3.5 to 5, of 3.7 to 4.8, suitably from 4.1 to 4.2, suitably from 3.6 to 3.8. Without being limited by theory, it is thought that a larger pH difference will result in higher affinity between the acidic vapour/aerosol and the free nicotine, thereby increasing the rate of extraction, to provide a higher amount of nicotine delivery in the inhalable medium.

The nicotine source may have been treated to raise its pH - the pH measured according to the CORESTA protocol for measuring the pH of tobacco, CORESTA Recommended Method No. 69 (CRM-69). An example method of pH-treatment may comprise the addition of a solution of base to the nicotine source. The solution of base may, in some cases, comprise an aqueous solution of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydrogen carbonate, sodium carbonate, potassium carbonate, calcium carbonate or mixtures thereof, or other GRAS water-soluble bases, for example.

In some cases, the nicotine source comprises tobacco material. In some cases, the nicotine source is tobacco material. This may provide the inhalable medium with tobacco flavours.

As used herein, the term “tobacco material” refers to any material comprising tobacco or derivatives thereof. The term “tobacco material” may include one or more of tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes. The tobacco material may comprise one or more of ground tobacco, tobacco fibre, cut tobacco, extruded tobacco, tobacco stem, reconstituted tobacco, agglomerated tobacco, spheronised tobacco and/or tobacco extract.

The tobacco used to produce tobacco material may be any suitable tobacco, such as single grades or blends, cut rag or whole leaf, including Virginia and/or Burley and/or Oriental. It may also be tobacco particle ‘fines’ or dust, expanded tobacco, stems, expanded stems, and other processed stem materials, such as cut rolled stems. The tobacco material may be a ground tobacco or a reconstituted tobacco material. The reconstituted tobacco material may comprise tobacco fibres, and may be formed by casting, a Fourdrinier-based paper making-type approach with back addition of tobacco extract, or by extrusion.

In some cases, the nicotine source may be porous, such that an aerosol and/or vapour can pass through the solid nicotine source. This provides a high contact area for the nicotine source to contact the aerosol and/or vapour. Thus, components of the nicotine source are efficiently entrained in the aerosol/vapour.

The nicotine source may additionally comprise flavourings and/or aerosol generating agents. As used herein, the terms "flavour" and "flavourant" refer to materials that, where local regulations permit, may be used to create a desired taste or aroma in a product for adult consumers.

In some cases, the nicotine source may be provided in one of two chambers of a cartridge as described herein.

In some cases, the nicotine source may be provided in a nicotine-containing pod, configured for use in an assembly for use in generating an inhalable medium, as part of a kit as described herein.

Aerosolisable liquid

In some cases, the invention provides an assembly for generating an inhalable medium or a cartridge for use in an assembly for generating an inhalable medium, wherein the assembly or cartridge includes an aerosolisable liquid (sometimes herein referred to as simply “liquid”).

The aerosolisable liquid may, in some cases, comprise a gel and/or liquid. Suitably, the aerosolisable liquid comprises, substantially consists of, or consists of a liquid.

The aerosolisable liquid may comprise liquids that are conventionally used in e-cigarette or Hybrid assemblies. In some cases, the aerosolisable liquid may comprise flavourings and/or aerosol-generating agents, including but not limited to propylene glycol and/or glycerol. The aerosolisable liquid is typically volatilised at around 100-300°C, suitably at around 150-250°C. In some cases, the aerosolisable liquid does not contain nicotine.

The aerosolisable liquid comprises an acid, such that the aerosolisable liquid may have a pH of from at least 2 to 7, or from about 2.5 to about 5. In some embodiments, the pH of the aerosolisable liquid is from 4 to 5. In some cases, the liquid has a pH of from 4.1 to 4.9, of 4.2 to 4.8, suitably of from 4.3 to 4.8, suitably 4.37, suitably 4.8.

In some cases, the liquid has a pH of from 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3,

3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or from 4 and of up to 6.9, 6.8, 6.7, 6.6, 6.5, 6.4, 6.3, 6.2, 6.1, 6, 5.9, 5.8, 5.7, 5.6, 5.5, 5.4, 5.3, 5.2, 5.1, 5, 4.9, 4.8, 4.7, 4.6, 4.5, 4.4, 4.3,

4.2, 4.1 or up to 4. Without being limited by theory, it is thought that this results in an affinity between the free nicotine from the nicotine source and the acid in the vapour/aerosol; the affinity is such that the vapour/aerosol may draw or extract the nicotine out of the nicotine source. It is thought that a lower pH of the aerosolisable liquid will result in a higher affinity between the free nicotine and the aerosolisable liquid, and thus may increase the extraction rate.

The pH of the aerosolisable liquid is dependent upon various properties, such as pKa or concentration of the acid, and the acidity or basicity of any other components in the aerosolisable liquid.

In some cases, the pH of the aerosolisable liquid is selected such that there is a difference between the pH of the nicotine source and the pH of the aerosolisable liquid of from 3 to 5.5, of 3.5 to 5, of 3.7 to 4.8, suitably from 4.1 to 4.2, suitably from 3.6 to 3.8. Without being limited by theory, it is thought that a larger pH difference will result in higher affinity between the acidic vapour/aerosol and the free nicotine, thereby increasing the extraction rate to provide a higher amount of nicotine delivery in the inhalable medium.

In some cases, any characteristic of the aerosolisable liquid may be altered or selected in order to increase affinity of the liquid with the free “deprotonated” nicotine in the nicotine source, including but not limited to dipole moment, polarity, and vapour pressure. For example, a higher dipole moment, polarity or vapour pressure may increase affinity of the liquid with the free “deprotonated” nicotine in the nicotine source. The addition of an acid may alter the polarity and vapour pressure characteristics of the aerosolisable liquid, which are important for the desired effect in this invention. Further, a non-acid substance that can alter polarity (increasing more positive dipole in the liquid), this may lead to similar effect like addition of acid.

Acid

Any acid that is suitable for the protonation of nicotine may be used in the aerosolisable liquid. Examples of acids include, but are not limited to, inorganic acids such as hydrochloric, hydrobromic, or sulfuric acid, and organic acids including saturated and unsaturated aliphatic acids, saturated and unsaturated alicyclic acids, aromatic acids (including heterocyclic aromatic), polycarboxylic acids, hydroxy, alkoxy, keto, and oxo acids, thioacids, amino acids, and each of the preceding optionally substituted with one or more heteroatoms, including but not limited to halogens. In some cases, the acid is a carboxylic acid, suitably benzoic acid. In some cases, the carboxylic acid is a hydroxy acid, suitably lactic acid. In some cases, the acid is selected from the group consisting of benzoic acid, lactic acid, and combinations thereof. The selected acid may protonate the free nicotine, and promote acid-base salt formation upon contact of the aerosol/vapour with the nicotine source, thereby providing nicotine salts. This promotes extraction of the nicotine from the nicotine source to increase nicotine delivery of the assembly, and improves the taste of nicotine in the inhalable medium.

In some cases, the acid selected has a pKa greater than 0.5, 1, 1.5, 2, 2.5, 3, or greater than 3.5, or suitably of from 3.7 to 4.3. Without being limited by theory, it is thought that this promotes the acid-base salt formation of free nicotine to improve the flavour and the amount of nicotine delivery by the inhalable medium; a lower pKa, or a stronger acid, for the same pH of a nicotine source, will increase the affinity between the aerosolisable liquid and the free nicotine, and may promote extraction of nicotine from the nicotine source to provide a higher nicotine delivery in the inhalable medium during use. In some cases, the acid has a pKa of greater than 3, or of from 3.7 to 4.3, and provides an aerosolisable liquid with a pH of from 4 to 5, of 4.1 to 4.9, of 4.2 to 4.8, suitably from 4.3 to 4.8, suitably 4.37, suitably 4.8. Thus, in some embodiments, this promotes the acid-base salt formation of free nicotine to provide improved flavour and increase the amount of nicotine delivery by the inhalable medium during use.

In some cases, the aerosolisable liquid comprises an acid with a vapour pressure at 25 °C of from 0.05 Pa to 3 kPa, from 0.1 Pa to 2.5 kPa, from 0.1 Pa to 2 kPa, from 0.1 Pa to 1.5 kPa, from 0.1 Pa to 1 kPa, from 0.1 Pa to 750 Pa, from 0.1 to 500 Pa, from 0.1 to 250 Pa, from 0.1 to 100 Pa, from 0.1 to 90 Pa, from 0.1 to 80 Pa, from 0.1 to 70 Pa, from 0.1 to 60 Pa, from 0.1 to 50 Pa, from 0.1 to 40 Pa, from 0.1 to 30 Pa, from 0.1 to 20 Pa, from 0.1 to 11 Pa, suitably from 0.1 to 0.2, suitably from 9 to 11 Pa. An acid with a higher vapour pressure at 25 °C will be more volatile. Thus, more acid may be present in the aerosol/vapour and this may further increase the rate of extraction of free nicotine from the nicotine source during use.

In some cases, the aerosolisable liquid comprises an acid in an amount of from 0.001 to 5% by weight. In some embodiments, the aerosolisable liquid comprises an acid in an amount of at least 0.01%, 0.1%. 0.5%, 0.6%, 0.7%, 0.8% 0.9% or at least 1 % acid. In some embodiments, the aerosolisable liquid comprises as acid in an amount of up to 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, 0.1% or up to 0.01 % by weight. Including the acid in the aerosolisable liquid at higher concentrations will increase the acidity and lower the pH of the aerosolisable liquid. Without being limited by theory, it is thought that a higher acidity of the aerosolisable liquid may result in it having a higher affinity to the free nicotine in the nicotine source, thereby facilitating the extraction of nicotine to increase the amount of nicotine delivery by the inhalable medium during use.

In some cases, the aerosolisable liquid comprising an acid may be provided in one of two chambers of a cartridge as described herein. In some cases, the aerosolisable liquid comprising an acid may be provided in a liquid pod, configured for use in an assembly for use in generating an inhalable medium, as part of a kit as described herein.

In some cases, the acid may be selected such that the conjugate acid-base salt formed upon reaction with the free nicotine in the aerosol/vapour has a high volatility (i.e. has a high vapour pressure). This may further increase the amount of nicotine delivery in the inhalable medium.

In some embodiments, the conjugate acid-base will have a vapour pressure similar to or slightly less than that of the acid used. Conjugate acid-base formation is one mechanism of elevating vapour pressure.

Assembly

The assembly according to some examples of the invention may be configured such that in use, liquid volatilised by the heater passes, in the form of at least one of a vapour and an aerosol, through the solid nicotine source to thereby entrain one or more components from the nicotine source to produce the inhalable medium. In some cases, the inhalable medium passes out of an outlet.

The assembly may comprise components such as a first chamber (referred to herein as the “liquid chamber”) for housing the aerosolisable liquid, and a second chamber (referred to herein as the “solid chamber”) for housing the solid, nicotine-containing material. The assembly may further comprise an outlet, and a flow path between the chambers and the outlet.

When the vapour/aerosol passes through the nicotine source, it is contacted with the nicotine source to entrain one or more components thereof. Once entrained in the vapour/aerosol, the one or more components from the nicotine source may undergo reactions with components in the vapour/aerosol. For example, acid-base salt formation reactions may occur. Without being bound by theory, it is thought that the acid-base salt formation reaction in the vapour/aerosol occurs at a higher rate than the acid-base salt formation reaction in the solid. The use of an acidic vapour/aerosol may result in a higher amount of nicotine to be extracted or drawn out of the tobacco, when compared to a vapour/aerosol with a neutral pH.

In some embodiments, the assembly heats the nicotine source in use, encouraging release of components thereof into the inhaled medium. In other embodiments, the assembly heats both the nicotine source and the aerosolisable liquid. Suitably, the assembly may be configured such that the heater only heats the aerosolisable liquid directly and the nicotine source is heated by warmth carried in the vapour/aerosol formed from the aerosolisable liquid (thereby volatilising components of the nicotine source that are then entrained in the vapour/aerosol flow). That is, the assembly is configured such that it directly heats the aerosolisable liquid, but does not directly heat the solid, nicotine-containing material.

In some cases, the invention provides a cartridge for use in an assembly for generating an inhalable medium, the cartridge comprising an aerosolisable liquid comprising an acid in a first chamber, the liquid corresponding to the liquid as described hereinabove, and a solid, nicotine-containing material in a second chamber, the solid, nicotine- containing material corresponding to the nicotine source described hereinabove. The cartridge is configured such that in use, a vapour and/or an aerosol generated from the aerosolisable liquid passes through the second chamber containing the nicotine source and entrains one or more constituents of the nicotine source. Suitably, the cartridge may be adapted for use in the assembly for generating an inhalable medium described herein.

In some embodiments, the assembly comprises a cooler or cooling zone downstream of the heater and upstream of the second chamber containing a nicotine source, the cooler or cooling zone being arranged to cool vaporised material to form an aerosol of liquid droplets that, in use, pass through the nicotine source in the second chamber. In some embodiments, the cooler may be arranged in effect to act as a heat exchanger, allowing for recovery of heat from the vapour and/or aerosol. The recovered heat may be used, for example, to pre-heat the nicotine source and/or to assist in heating the aerosolisable liquid. In an embodiment, the assembly is battery-operated.

In an embodiment, the or each heater is an electrically resistive heater.

In an embodiment, the heater is puff actuated. That is, the assembly includes a puff- detector and only heats the aerosolisable liquid on detection of a puff. This means that vapour/aerosol forms in the assembly only during puffs.

In an embodiment, the first and/or second chamber is removable. The first and/or second chamber may be in the form of a pot or the like (that in some embodiments may be annular for example), and/or an absorbent wadding or the like. The first and/or second chamber may in effect be a disposable item that is replaced as a whole after use. As an alternative, the arrangement may be such that the user removes the first and/or second chamber from the assembly, replaces used material or tops up the material in the first and/or second chamber, and then places it back in the assembly.

In some cases, the first and/or second chamber may be non-removable from the assembly. In such an embodiment, the user may just replace used material or top up material in a chamber after use as necessary.

In some cases, the first and second chamber are an integral unit. In some cases, the integral unit is a cartridge that can be removed from the assembly.

In some cases, the first and/or second chamber is removable from the assembly. The first and/or second chamber may be, for example, in the form of a cartridge or the like which contains the nicotine source before use. The second chamber containing the nicotine source may in effect be a disposable item which is replaced as a whole after use. As an alternative, the arrangement may be such that the user removes the second chamber from the assembly, replaces used material in the second chamber, and then places the second chamber back in the assembly. The invention also provides a kit comprising an aerosol-generating assembly according to embodiments of the invention. The kit comprises (i) a liquid pod containing an aerosolisable liquid according to the embodiments described herein, (ii) a nicotine- containing pod containing a solid, nicotine-containing material according to the embodiments described herein. Features described hereinabove in relation to the assembly are explicitly disclosed in combination with the kit aspect of the invention. Thus, for example, the assembly may include one or more puff actuators, a cooling element or cooling zone, actuation means such as a button, further heaters, a pump for the wetting agent, and so on.

The invention also provides the use of an acidic vapour and/or aerosol to extract nicotine from a solid, nicotine-containing material having a pH of more than 7, wherein the rate of nicotine extraction exceeds the rate of nicotine-salt formation in the solid, nicotine-containing material, thereby providing an increased nicotine content in the vapour and/or aerosol as compared to using a neutral vapour and/or aerosol.

Examples of cartridges, liquid pods, nicotine-containing pods and assemblies for generating an inhalable medium according to some embodiments of the invention will now be described, with reference to the accompanying drawings.

Referring to Figure 1, there is shown an example of an assembly 1 for generating an inhalable medium. In broad outline, the assembly 1 volatilises an aerosolisable liquid to form a vapour and/or an aerosol which passes through a nicotine source so as to produce an inhalable medium that contains one or more components derived from the nicotine source.

In this respect, first it may be noted that, in general, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that for example the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature. On the other hand, in general, an aerosol is a colloid of fine solid particles or liquid droplets, in air or another gas. A “colloid” is a substance in which microscopically dispersed insoluble particles are suspended throughout another substance.

Returning to Figure 1, the assembly 1 of this example has a generally hollow cylindrical outer housing 2. The housing 2 has an open end 3. In this example, a tubular mouthpiece 4 is provided in the open end 3. The mouthpiece 4 in this example is removable by a user from the housing 2. An O-ring or other seal 5 assists in sealing the mouthpiece 4 in the housing 2. At or towards the other end 6 of the housing 2 is a battery 7 for powering various components of the assembly 1, as will be discussed further below. The battery 7 may be a rechargeable battery or a disposable battery. A controller 8 is also provided in the housing 2 for controlling the operation of various components of the assembly 1, as will be discussed further below.

The housing 2 has a chamber 9 (sometimes referred to herein as “liquid chamber”) for holding or containing an aerosolisable liquid (sometimes referred to herein as simply “liquid”) 10. The liquid 10 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example. Various different forms for the liquid chamber 9 may be used. In the example of Figure 1, the liquid chamber 9 is in the form of an annular chamber 9 provided in the housing 2 between the open end 3 and the other end 6. In this particular example, the housing 2 is in two parts, a first part 2a being towards the open end 3 and a second part 2b towards the other end 6. The first and second parts 2a, 2b of the housing 2 may connect to each other via a screw thread, a bayonet fitting or the like. In use, a user can separate the first and second parts 2a, 2b of the housing 2 to allow the aerosolisable liquid 10 to be replenished or replaced as necessary. Alternatively, the mouthpiece 4 can be removed to provide access to the liquid chamber 9. It will be understood however that other arrangements are possible. For example, the liquid 10 may be provided in a discrete annular pot-like liquid chamber which can be removed as a whole from the housing 2. Such a discrete liquid chamber may be disposable so that the user replaces the liquid 10 by fitting a new liquid chamber with liquid 10 in the housing 2. Alternatively, such a chamber may be reusable. In such a case, the user may replenish or replace liquid 10 in the liquid chamber whilst it has been removed from the housing 2 and then replace the refilled liquid chamber in the housing 2. It will be understood that the housing 2 need not be in two parts and that other arrangements enabling access for the user may be provided, for example, to enable refilling in situ.

A heater 11 is provided generally centrally of the housing 2, that is, centrally along the length and width of the housing 2 in this example. In this example, the heater 11 is powered by the battery 7 and is therefore electrically connected to the battery 7. The heater 11 may be an electrically resistive heater, including for example a nichrome resistive heater, a ceramic heater, etc. The heater 11 may be for example a wire, which may for example be in the form of a coil, a plate (which may be a multi-layer plate of two or more different materials, one or more of which may be electrically conductive and one or more of which may be electrically non-conductive), a mesh (which may be woven or non- woven for example, and which again may be similarly multi-layer), a film heater, etc. Other heating arrangements may be used, including non-electrical heating arrangements.

This heater 11 is provided for volatilising the liquid 10. In the example shown, an annular wick 12 surrounds the heater 11 and is in (thermal) contact with the heater 11. The outermost surface of the annular wick 12 is in contact with liquid 10 contained in the liquid chamber 9. The wick 12 is generally absorbent and acts to draw in liquid 10 from the liquid chamber 9 by capillary action. The wick 12 is preferably non-woven and may be for example a cotton or wool material or the like, or a synthetic material, including for example polyester, nylon, viscose, polypropylene or the like. Whilst this will be described more fully below, it may be noted here that in use, liquid 10 drawn into the wick 12 is heated by the heater 11. The liquid 10 may be volatilised so as to produce an aerosol of liquid droplets or sufficiently heated to produce a vapour. The aerosol and/or vapour so produced exits the wick 12 and passes towards the mouthpiece 4 as shown by the arrows A under the action of the user drawing on the mouthpiece 4. The heater 11 and wick 12 may be provided as a single, effectively integral item, sometimes referred to as an “atomiser”, such that the heating and wicking is effectively carried out by a single unit. The housing 2 further contains a chamber (sometimes referred to herein as “solid chamber”) 13 which holds or contains a solid, nicotine- containing material (referred to herein as “nicotine source”) 14 in the assembly 1. The nicotine source 14 corresponds to the nicotine source described hereinabove, is base-treated, and may have a pH of from 8 to 9.5, for example. In use, a user can access the solid chamber 13 to replace or replenish the nicotine source 14 through the open end 3 of the housing 2 by removing the mouthpiece 4 and/or by separating the two parts 2a, 2b of the housing 2. Various different forms for the solid chamber 13 may be used. For example, the solid chamber 13 may be a tube which is completely open at both ends and which contains the nicotine source 14. As another example, the solid chamber 13 may be a tube which has one or more end walls which have through holes through which a vapour and/or aerosol can pass. The solid chamber 13 may remain in situ within the housing 2 whilst the user removes and replaces the nicotine source 14. Alternatively, the solid chamber 13 containing the nicotine source 14 may be a discrete item which in use is inserted into and removed from the housing 2 as a whole. A removable solid chamber 13 of this type may be disposable so that the user replaces the nicotine source 14 by fitting a new solid chamber 13 containing a fresh nicotine source 14 into the housing 2. As an alternative, the solid chamber 13 may be reusable. In such a case, the user may replace the nicotine source 14 in the solid chamber 13 whilst the solid chamber 13 has been removed from the housing 2 and then replace the refilled solid chamber 13 in the housing 2. In yet another example, the solid chamber 13 may comprise clips or the like provided internally of the housing 2 and which retain the nicotine source 14 in position. In some examples, the nicotine source 14 could simply fit snugly within the solid chamber 13. As another alternative, the chamber 9 for containing the liquid 10 may itself be arranged to support or carry the nicotine source 14. For example, the liquid chamber 9 may have one or more clips or a tube or the like for receiving and holding the nicotine source 14 in position. Such a dual function liquid chamber 9/solid chamber 13 for both containing the liquid 10 and receiving the nicotine source 14 may be in the form of a cartridge or the like and may be a disposable item or may be re-useable, with the liquid 10 and nicotine source 14 being replaced or topped up by the user as required. In some cases, it may be that the user only needs to top up or replace the nicotine source 14 from time to time, with sufficient liquid 10 being provided for several uses. Once the liquid 10 has been consumed, the user disposes of the dual function liquid chamber 9/solid chamber 13 and uses a new one. Likewise, it may be that the user only needs to top up or replace the liquid 10 from time to time, with sufficient nicotine source 14 being provided for several uses. Once the nicotine source 14 has been consumed, the user disposes of the dual function liquid chamber 9/solid chamber 13 and uses a new one. Specific examples of dual function liquid chambers/solid chambers are discussed further below.

The nicotine source 14 is located in the housing 2 downstream of the location where the aerosol and/or vapour is produced from the liquid 10 and upstream of the open end 3 of the housing 2 and the mouthpiece 4. In this particular example, the nicotine source 14 is effectively provided in the same portion or chamber of the housing 2 as the wick 12. The aerosol and/or vapour produced from the liquid 10 exits the wick 12 and passes as shown by the arrows A towards the nicotine source 14 under the action of the user drawing on the mouthpiece 4. In particular embodiments, the nicotine source 14 is porous so that the aerosol and/or vapour passes through the nicotine source 14 and then through the open end 3 of the housing 2 and the mouthpiece 4.

In some embodiments, the nicotine source 14 and/or its chamber 13 are arranged so that there is no air gap between the nicotine source 14/solid chamber 13 and the interior of the housing 2 so that the aerosol and/or vapour flows entirely through the nicotine source 14.

The liquid 10 is suitably a liquid that is volatilisable at reasonable temperatures, preferably of from 100-300°C or more particularly around 150-250°C, as that helps to keen down the power consumption of the assembly 1. Suitable materials include those conventionally used in e-cigarette assemblies, including for example propylene glycol and glycerol (also known as glycerine). The liquid 10 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example.

The nicotine source 14 imparts a flavour to the aerosol and/or vapour produced from the liquid 10 as the aerosol and/or vapour passes through the nicotine source 14. As the acidic aerosol and/or vapour passes through and over the nicotine source 14, the hot aerosol and/or vapour entrains organic and other compounds or constituents from the nicotine source 14 that lend the nicotine source its organoleptic properties, thus imparting the flavour to the aerosol and/or vapour as it passes to the mouthpiece 4. In particular, the free “deprotonated” nicotine in the nicotine source 14 undergoes acid- base salt formation with the acidic vapour and/or aerosol from the liquid 10. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 14 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 14, nicotine is provided in its better tasting, salt form.

The assembly 1 provides nicotine for the user. The nicotine is obtained from the nicotine source 14, or it may be provided as a coating or the like on the nicotine source 14, or a combination of these. Likewise, flavourings may be added to the nicotine source 14 and/or to the liquid 10.

In the example shown in Figure 1, the only heat source for heating the nicotine source 14 in the assembly 1, which is required so as to generate the organic and other compounds or constituents from the nicotine source 14, is the hot aerosol and/or vapour produced from heating the liquid 10.

Referring now to Figure 2, there is shown another example of an assembly for generating an inhalable medium. In the following description and in Figure 2, components and features that are the same as or similar to the corresponding components and features of the example described with reference to Figure 1 have the same reference numeral but increased by 200. For the sake of brevity, the description of those components and features will not be repeated in its entirety here. It will be understood that the arrangements and alternatives, etc. described above in relation to the example of Figure 1 are also applicable to the example of Figure 2. Again, in broad outline, the assembly 201 of Figure 2 heats a liquid to form a vapour and/or an aerosol which passes through a nicotine source 214 so as to produce an inhalable medium that contains one or more components derived from the nicotine source 214. The assembly 201 of this example has a generally hollow cylindrical outer housing 202 with an open end 203 and a tubular mouthpiece 204. The mouthpiece 204 in this example is removable by a user from the housing 202 and an O-ring or other seal 205 assists in sealing the mouthpiece 204 in the housing 202. A battery 207 for powering various components of the assembly 201 and a controller 208 are provided at or towards the other end 206 of the housing 202. The housing 202 of this example is in two parts, a first part 202a being towards the open end 203 and a second part 202b towards the other end 206.

The housing 202 has a chamber (sometimes referred to herein as “liquid chamber”) 209 for holding or containing an aerosolisable liquid (sometimes referred to herein as simply “liquid”) 210. The liquid 210 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example. The liquid chamber 209 may be of any of the types described above in relation to the example of Figure 1. A heater 211 is provided generally centrally (lengthwise and widthwise) of the housing 202 for volatilising the liquid 210. In this example, the heater 211 is powered by the battery 207 and is therefore electrically connected to the battery 207. The heater 211 may be an electrically resistive heater, a ceramic heater, etc. The heater 211 may be for example a wire, which may for example be in the form of a coil, a plate (which may be a multi-layer plate of two or more different materials, one or more of which may be electrically conductive and one or more of which may be electrically non-conductive), a mesh (which may be woven or non- woven for example, and which again may be similarly multi-layer), a film heater, etc. Other heating arrangements may be used, including inductive heating arrangements or non-electrical heating arrangements. An annular wick 212 surrounds the heater 211 and is in (thermal) contact with the heater 211. The outermost surface of the annular wick 212 is in contact with liquid 210 contained in the liquid chamber 209. The liquid 210 may be heated so as to produce an aerosol of liquid droplets or sufficiently heated to produce a vapour. The aerosol and/or vapour so produced exits the wick 212 and passes towards the mouthpiece 204 as shown by the arrows A under the action of the user drawing on the mouthpiece 204. The heater 211 and wick 212 may be provided as a single, effectively integral item such that the heating and wicking is effectively carried out by a single unit.

The housing 202 further contains a chamber (sometimes referred to herein as “solid chamber) 213 which holds or contains a nicotine source 214 in the assembly 201. The nicotine source 214 corresponds to the nicotine source described hereinabove, is base- treated, and may have a pH of from 8 to 9.5, for example. The solid chamber 213 may be of any of the types described above in relation to the example of Figure 1. The nicotine source 214 is located in the housing 202 downstream of the location where the aerosol and/or vapour is produced from the liquid 210 and upstream of the open end 203 of the housing 202 and the mouthpiece 204. In this particular example, the nicotine source 214 is effectively provided in the same portion or chamber of the housing 202 as the wick 212. The aerosol and/or vapour produced from the liquid 210 exits the wick 212 and passes as shown by the arrows A towards the nicotine source 214 under the action of the user drawing on the mouthpiece 204. In particular embodiments, the nicotine source 214 is porous so that the aerosol and/or vapour passes through the nicotine source 214 and then through the open end 203 of the housing 202 and the mouthpiece 204.

In some embodiments, the nicotine source 214 and/or its chamber 213 are arranged so that there is no air gap between the nicotine source 214/chamber 213 and the interior of the housing 202 so that the aerosol and/or vapour flows entirely through the nicotine source 214. As the aerosol and/or vapour passes through and over the nicotine source 214, the hot aerosol and/or vapour entrains organic and other compounds or constituents from the nicotine source 214 that lend the nicotine source its organoleptic properties, thus imparting the flavour to the aerosol and/or vapour as is passes to the mouthpiece 204. In particular, the free “deprotonated” nicotine in the nicotine source 214 undergoes acid-base salt formation with the acidic vapour and/or aerosol from the liquid 210. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 214 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 214, nicotine is provided in its better tasting, salt form. The liquid chamber 209 for containing the liquid 210 may itself be arranged to support or carry the nicotine source 214. For example, the liquid chamber 209 may have one or more clips or a tube or the like for receiving and holding the nicotine source 214 in position. Such a dual function liquid chamber 209/solid chamber or receptacle 213 for both containing the liquid 210 and receiving the nicotine source 214 may be in the form of a cartridge or the like and may be a disposable item or may be re-useable, with the liquid 210 and nicotine source 214 being replaced or topped up by the user as required. In some cases, it may be that the user only needs to top up or replace the nicotine source 214 from time to time, with sufficient liquid 210 being provided for several uses. Once the liquid 210 has been consumed, the user disposes of the dual function liquid chamber 209/solid chamber 213 and uses a new one. Likewise, it may be that the user only needs to top up or replace the liquid 210 from time to time, with sufficient nicotine source 214 being provided for several uses. Once the nicotine source 214 has been consumed, the user disposes of the dual function liquid chamber 209/solid chamber 213 and uses a new one.

In the example assembly 201 of Figure 2, a second heater 215, such as an oven heater, is provided in thermal contact with the nicotine source 214 to pre-heat the nicotine source 214 and/or provide additional heat to the nicotine source 214 throughout use of the assembly 201. This encourages release of constituents from the nicotine source 214 as the vapour and/or aerosol passes through the nicotine source 214 in use. The amount of heated liquid 210 to achieve desirable heating of the nicotine source 214 may be reduced. The second heater 215 may be an electrically resistive heater, a ceramic heater, etc., powered by for example the battery 207. The second heater 215 may be for example a wire, which may for example be in the form of a coil, a plate (which may be a multi-layer plate of two or more different materials, one or more of which may be electrically conductive and one or more of which may be electrically non-conductive), a mesh (which may be woven or non-woven for example, and which again may be similarly multi-layer), a film heater, etc. The second heater 215 may be an inductive heater powered by for example the battery 207. Nicotine source 214 may include materials susceptible to inductive heating. Other heating arrangements may be used for the second heater 215, including non-electrical heating arrangements.

In the example assembly 201 of Figure 2, the heater 215 for heating the nicotine source

214 is provided externally of the nicotine source 214 and heats the nicotine source 214 by heat conduction from the exterior of the nicotine source 214. The heater 215 in this example is generally cylindrical. The heater 215 may in effect be an integral part of the assembly 201 and be provided as part of the housing 202. As an alternative, the heater

215 may be provided integrally with the solid chamber 213 which holds or contains the nicotine source 214. In this alternative, in the case that the solid chamber 213 is disposable, the heater 215 will be replaced when a new solid chamber 213 with fresh nicotine source is loaded into the assembly 201 by the user.

Referring now to Figure 3, there is shown another example of an assembly for generating an inhalable medium. In the following description and in Figure 3, components and features that are the same as or similar to the corresponding components and features of the example described with reference to Figure 1 have the same reference numeral but increased by 300. For the sake of brevity, the description of those components and features will not be repeated in its entirety here. It will be understood that the arrangements and alternatives, etc. described above in relation to the examples of Figure 1 and Figure 2 are also applicable to the example of Figure 3. Again, in broad outline, the assembly 301 of Figure 3 heats a liquid to form a vapour and/or an aerosol which passes through a nicotine source 314 so as to produce an inhalable medium that contains one or more constituents derived from the nicotine source 314.

The assembly 301 of this example again has a generally hollow cylindrical outer housing 302 with an open end 303 and a tubular mouthpiece 304, which is removable by a user from the housing 302. O-ring or other seal 305 assists in sealing the mouthpiece 304 in the housing 302. A battery 307 for powering various components of the assembly 301 and a controller 308 are provided at or towards the other end 306 of the housing 302. The housing 302 of this example is again in two parts, a first part 302a being towards the open end 303 and a second part 302b towards the other end 306.

The housing 302 has a chamber (sometimes referred to herein as “liquid chamber”) 309 for holding or containing an aerosolisable liquid (sometimes referred to herein as simply “liquid”) 310. The liquid 310 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example. The liquid chamber 309 may be of any of the types described above in relation to the examples of Figures 1 and 2. A heater 311 is provided generally centrally of the housing 302 for heating the liquid 310. The heater 311 may be any of the types described above. In this example, the heater 311 is powered by the battery 307 and is therefore electrically connected to the battery 307. An annular wick 312 surrounds the heater 311 and is in (thermal) contact with the heater 311. The outermost surface of the annular wick 312 is in contact with liquid 310 contained in the liquid chamber 309. The liquid 310 may be heated so as to produce an aerosol of liquid droplets or sufficiently heated to produce a vapour. The aerosol and/or vapour so produced exits the wick 312 and passes towards the mouthpiece 304 as shown by the arrows A under the action of the user drawing on the mouthpiece 304. The heater 311 and wick 312 may be provided as a single, effectively integral item such that the heating and wicking is effectively carried out by a single unit.

The housing 302 further contains a chamber (sometimes referred to herein as “solid chamber”) 313 which holds or contains a nicotine source 314 in the assembly 301. The nicotine source 314 corresponds to the nicotine source described hereinabove, is base- treated, and may have a pH of from 8 to 9.5, for example. The solid chamber 313 may be of any of the types described above in relation to the examples of Figures 1 and 2. (In the example shown in Figure 3, the solid chamber 313 is in the form of a tube which has end walls 316 which have through holes 317 through which a vapour and/or aerosol can pass, which was mentioned as an option above.) The nicotine source 314 is located in the housing 302 downstream of the location where the aerosol and/or vapour is produced from the liquid 310 and upstream of the open end 303 of the housing 302 and the mouthpiece 304. In this particular example, again, the nicotine source 314 is effectively provided in the same portion or chamber of the housing 302 as the wick 312. The aerosol and/or vapour produced from the liquid 310 exits the wick 312 and passes as shown by the arrows A towards the nicotine source 314 under the action of the user drawing on the mouthpiece 304. In particular embodiments, the nicotine source 314 is porous so that the aerosol and/or vapour passes through the nicotine source 314 and then through the open end 303 of the housing 302 and the mouthpiece 304.

In some embodiments, the nicotine source 314 and/or its chamber 313 are arranged so that there is no air gap between the nicotine source 314/chamber 313 and the interior of the housing 302 so that the aerosol and/or vapour flows entirely through the nicotine source 314. As the aerosol and/or vapour passes through and over the nicotine source 314, the hot aerosol and/or vapour entrains organic and other compounds or constituents from the nicotine source 314, thus imparting flavour to the aerosol and/or vapour as is passes to the mouthpiece 304. In particular, the free “deprotonated” nicotine in the nicotine source 314 may undergo acid-base salt formation with the acidic vapour and/or aerosol from the liquid 310. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 314 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 314, nicotine may be provided in its better tasting, salt form.

The chamber 309 for containing the liquid 310 may itself be arranged to support or carry the nicotine source 314. For example, the liquid chamber 309 may have one or more clips or a tube or the like for receiving and holding the nicotine source 314 in position. Such a dual function liquid chamber 309/solid chamber or receptacle 313 for both containing the liquid 310 and receiving the nicotine source 314 may be in the form of a cartridge or the like and may be a disposable item or may be re-useable, with the liquid 310 and nicotine source 314 being replaced or topped up by the user as required. In some cases, it may be that the user only needs to top up or replace the nicotine source 314 from time to time, with sufficient liquid 310 being provided for several uses. Once the liquid 310 has been consumed, the user disposes of the dual function liquid chamber 309/solid chamber 313 and uses a new one. Likewise, it may be that the user only needs to top up or replace the liquid 310 from time to time, with sufficient nicotine source 314 being provided for several uses. Once the nicotine source 314 has been consumed, the user disposes of the dual function liquid chamber 309/solid chamber 313 and uses a new one.

In the example assembly 301 of Figure 3, a second heater 318 is again provided in thermal contact with the nicotine source 314 to heat the nicotine source 314 to encourage release of constituents from the nicotine source 314 as the vapour and/or aerosol passes through the nicotine source 314 in use. The second heater 318 may be an electrically resistive heater, a ceramic heater, etc., powered by for example the battery 307. Other heating arrangements may be used for the second heater 318, including non electrical heating arrangements.

In the example assembly 301 of Figure 3, the heater 318 for heating the nicotine source 314 is provided internally of the nicotine source 314 and heats the nicotine source 314 by heat conduction from the interior of the nicotine source 314. The heater 318 in this example is generally in the form of a cylindrical rod located along the central longitudinal axis of the nicotine source 314. In other arrangements, the heater 318 may be a wire, which may for example be in the form of a coil, a plate (which may be a multi-layer plate of two or more different materials, one or more of which may be electrically conductive and one or more of which may be electrically non-conductive), a mesh (which may be woven or non-woven for example, and which again may be similarly multi-layer), a film heater, etc. The nicotine source 314 in this case is generally tubular or otherwise has an internal aperture for receiving the heater 318. The heater 318 may in effect be an integral part of the assembly 301 and be provided as part of the housing 302. In this case, as the nicotine source 314 is loaded into the assembly 301 (for example, as the solid chamber 313 containing the nicotine source 314 is loaded into the assembly 301), the nicotine source 314 surrounds the second heater 318. As an alternative, the heater 318 may be provided integrally with the solid chamber 313 which holds or contains the nicotine source 314. In this alternative, in the case that the solid chamber 313 is disposable, the heater 318 will be replaced when a new solid chamber 313 with a fresh nicotine source is loaded into the assembly 301 by the user. In another example, plural internal heaters 318 may be provided, so as to provide for more efficient heating of the nicotine source 314. In another example, the nicotine source 314 may be heated by both one or more external heaters (like the second heater 215 of the example of Figure 2) and by one or more internal heaters (like the second heater 318 of the example of Figure 3).

Referring now to Figure 4, there is shown a schematic longitudinal cross-sectional view of an example of a cartridge 600 having a liquid chamber 601 for containing aerosolisable liquid 602, and a receptacle or chamber (sometimes referred to herein as “solid chamber”) 603 for a nicotine source 604. The liquid 602 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example. The nicotine source 604 corresponds to the nicotine source described hereinabove, is base-treated, and may have a pH of from 8 to 9.5, for example. In this example, the liquid chamber 601 and the nicotine source chamber 603 are provided as one integral component, either by being formed integrally initially or being formed initially of two parts which are then assembled in a substantially permanent fashion. The cartridge 600 is arranged so that as the liquid 602 is volatilised so as to produce an aerosol of liquid droplets or sufficiently heated to produce a vapour, at least some and preferably all or substantially all of the aerosol and/or vapour passes through the nicotine source 604 to pick up flavour from the nicotine source 604. In particular, the free “deprotonated” nicotine in the nicotine source 604 may undergo acid-base salt formation with the acidic vapour and/or aerosol from the liquid 602. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 604 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 604, nicotine may be provided in its better tasting, salt form.

In the example of Figure 4, the liquid chamber 601 is provided generally centrally of the cartridge 600. The liquid chamber 601 in the example shown is frustoconical in shape, but may have a different shape, such as conical, cylindrical, etc. The liquid chamber 601 is surrounded by an outer shell 605 which defines an annular channel 606 around the outside of the length of the liquid chamber 601 and which extends from one end of the liquid chamber 601 to the other. The outer shell 605 extends beyond a first end wall 607 of the liquid chamber 601 to define a chamber 608 beyond the first end wall 607 of the liquid chamber 601. In the example shown, both the chamber 608 and the annular channel 606 contain the nicotine source 604 and so can be regarded as together providing the solid chamber 603 for the nicotine source 604. In other examples, the nicotine source 604 may be provided only in the chamber 608, which therefore defines the solid chamber 603 for the nicotine source 604, and the annular channel 606 is empty. The chamber 608 is closed off by an end wall 609 which is spaced from the end wall 607 of the liquid chamber 601. The end wall 609 may be part of the outer shell 605 or may be a separate plastics or rubber cap or the like. In yet other examples, the annular channel 606 contains the nicotine source 604 and there is no material in the chamber 608, and indeed the chamber 608 may be omitted and the channel 606 effectively terminates at the end wall 609. The channel 606 and/or chamber 608 may be entirely filled with nicotine source 604 or may only contain a portion or plug of nicotine source 604. The end wall 609 is porous and/or has one or more through holes 610 to enable the aerosol and/or vapour to exit the cartridge 600 to be inhaled by a user. The liquid chamber 601 and the solid chamber 603 may each be formed of rigid, watertight and airtight materials, such as metal, suitable plastics, etc.

The example cartridge 600 shown in Figure 4 is provided with a heater 611 and a wick 612 in (thermal) contact with the heater 611. In this example, the heater 611 and the wick 612 are provided as a single unit, often referred to as an “atomiser”. In this case, where the cartridge 600 includes an atomiser, such a cartridge is often referred to as a “cartomiser”. The orientation of the heater 611 is shown schematically and for example the heater 611 may be a coil having its longitudinal axis perpendicular to the longitudinal axis of the cartridge 600 rather than parallel as shown in Figure 4.

The wick 612 is in contact with the liquid 602. This may be achieved by for example the wick 612 being inserted through a through hole (not shown) in the second end wall 613 of the liquid chamber 601. Alternatively or additionally, the second end wall 613 may be a porous member (shown schematically in Figure 4 by dashed lines) which allows liquid to pass through from the liquid chamber 601, and the wick 612 may be in contact with the porous second end wall 613. The second end wall 613 may be for example in the form of a porous ceramic disk. A porous second end wall 613 of this type helps to regulate the flow of liquid onto the wick 612. The wick 612 is generally absorbent and acts to draw in liquid 602 from the liquid chamber 601 by capillary action. The wick 612 is preferably non- woven and may be for example a cotton or wool material or the like, or a synthetic material, including for example polyester, nylon, viscose, polypropylene or the like.

In use, the cartridge 600 is connected by the user to a battery section of an assembly (not shown) to enable the heater 611 to be powered. When the heater 611 of the atomiser is powered (which may be instigated for example by the user operating a button of the overall assembly or by a puff detector of the overall assembly, as is known per se), liquid 602 drawn in from the liquid chamber 601 by the wick 612 is heated by the heater 611 to volatilise or vaporise the liquid. As the user draws on a mouthpiece of the overall assembly, the vapour and/or aerosol passes into the annular channel 606 around the outside of the length of the liquid chamber 601 and into the chamber 608 as shown by the arrows A. The vapour and/or aerosol picks up flavour from the nicotine source 604 and entrains one or more components thereof. When the vapour/aerosol contacts the nicotine source 604, the free “deprotonated” nicotine in the nicotine source 604 may undergo acid-base salt formation with the acidic vapour and/or aerosol from the liquid 602. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 604 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 604, nicotine may be provided in its better tasting, salt form. The vapour and/or aerosol can then exit the cartridge 600 through the end wall 609 as shown by the arrow B. Optionally, a one way valve 614 may be provided inside the end wall 609 so that the vapour and/or aerosol can only exit the cartridge 600 and cannot back- flow to the heater 611 or the electronics of the assembly as a whole.

Referring now to Figure 5, there is shown a schematic longitudinal cross-sectional view of another example of a cartridge 700 having a chamber (sometimes referred to herein as “liquid chamber”) 701 for containing aerosolisable liquid (sometimes referred to herein as simply “liquid”) 702 and a chamber (sometimes referred to herein as “solid chamber”) 703 which defines a chamber 708 for containing a nicotine source 704. The liquid 702 corresponds to the liquid described hereinabove and may have a pH of from 4 to 5, and/or may comprise an acid with a pKa greater than 3, for example. The nicotine source 704 corresponds to the nicotine source described hereinabove, is base-treated, and may have a pH of from 8 to 9.5, for example. In the following description and in Figure 5, components and features that are the same as or similar to the corresponding components and features of the example described with reference to Figure 4 have the same reference numeral but increased by 100. For the sake of brevity, the description of those components and features will not be repeated in its entirety here.

In this example, the liquid chamber 701 and the solid chamber 703 of the cartridge 700 are provided as separate components, which are detachably connected to each other in use. The liquid chamber 701 and the solid chamber 703 may for example be clipped or otherwise detachably fixed to each other, or for example the solid chamber 703 may simply rest on or be a tight friction fit on the liquid chamber 701. The cartridge 700 is arranged so that as the liquid 702 is volatilised so as to produce an aerosol of liquid droplets or sufficiently heated to produce a vapour, at least some and preferably all or substantially all of the aerosol and/or vapour passes through the nicotine source 704 to pick up flavour from the nicotine source 704 and entrains one or more components thereof. When the vapour/aerosol contacts the nicotine source 704, the free “deprotonated” nicotine in the nicotine source 704 may undergo acid-base salt formation with the acidic vapour and/or aerosol from the liquid 702. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 704 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 704, nicotine may be provided in its better tasting, salt form.

In this example, the liquid chamber 701 is surrounded by an outer shell 705 which defines an annular channel 706 around the outside of the length of the liquid chamber 701 and which extends from one end of the liquid chamber 701 to the other. The outer shell 705 extends beyond a first end wall 707 of the liquid chamber 701 and terminates in an end wall 709. The end wall 709 may be a separate plastics or rubber cap or the like. The end wall 709 is porous and/or has one or more through holes 710 to enable the aerosol and/or vapour to exit the annular channel 706. A one way valve 714 may be provided inside the end wall 709 so that the vapour and/or aerosol can only exit the annular channel 706 at the end remote from the heater 711 and wick 712 and cannot back- flow to the heater 711 or the electronics of the assembly as a whole. The nicotine source chamber 703 is located in use over the end wall 709 so that vapour and/or aerosol exiting through the end wall 709 passed into the solid chamber 703. The solid chamber 703 has an exit aperture and/or or a porous end wall 715 to enable the aerosol and/or vapour to exit the cartridge 700 to be inhaled by a user.

In use, the cartridge 700 is connected by the user to a battery section of an assembly (not shown) to enable the heater 711 to be powered. When the heater 711 of the atomiser is powered (which may be instigated for example by the user operating a button of the overall assembly or by a puff detector of the overall assembly as is known per se), liquid 702 drawn in from the liquid chamber 701 through the end wall 713 by the wick 712 is heated by the heater 711 to volatilise or vaporise the liquid. As the user draws on a mouthpiece of the overall assembly, the vapour and/or aerosol passes into the annular channel 706 around the outside of the length of the liquid chamber 701 towards the end wall 709 of the outer shell 705 as shown by the arrows A. The vapour and/or aerosol then passes through the end wall 709 (via the one-way valve 714 if present) and into the solid chamber 703 where it picks up flavour from the nicotine source 704 contained in the solid chamber 703, and entrains one or more components of the nicotine source 704. When the vapour/aerosol contacts the nicotine source 704, the free “deprotonated” nicotine in the nicotine source 704 may undergo acid-base salt formation with the acidic vapour and/or aerosol from the liquid 702. In this way, nicotine may be drawn out or extracted by the acidic vapour and/or aerosol from the nicotine source 704 to increase the amount of nicotine delivery in the inhalable medium. Furthermore, by passing the acidic vapour/aerosol through and over the nicotine source 704, nicotine may be provided in its better tasting, salt form. The vapour and/or aerosol can then exit the cartridge 700 through the end wall 715 of the solid chamber 703 as shown by the arrow B.

The examples shown in Figures 4 and 5 are particularly suitable for use with so-called modular or “e-go” products, in which the cartomiser is fitted to a battery section (not shown), typically by a screw thread, a bayonet fitting or the like. The cartomiser as a whole is typically discarded after use and a new, replacement cartomiser used. As an alternative, it may be possible for the user to re-use the cartridge by refilling the liquid and/or replacing the solid material from time to time as necessary.

The examples shown in Figures 4 and 5 may easily be adapted for use with other types of an electronic tobacco hybrid device, which are known per se. There are for example so-called “look alike e-cigarette” or “cig-alike” assemblies which are generally small and have a form and appearance similar to a conventional cigarette. In such assemblies, the liquid chamber typically includes some wadding material, of for example cotton or the like, for holding the liquid. The cartridge or cartomiser in such known assemblies is typically disposable as a whole, but it may be possible to refill the liquid and/or replace the sold material in examples that use an embodiment of the present invention. As another example, there are so-called tank assemblies or personal vaporisers which generally have large liquid chambers for holding relatively large volumes of liquid and also provide for advanced functions that allow users to control a number of aspects of the assembly.

As an alternative to any of the cartomiser arrangements discussed above, the atomiser (i.e. the heater and the wick) for the liquid may be provided separately of the liquid and solid chambers. The atomiser may for example be provided as part of the battery section of the overall assembly to which the cartridge is detachably fitted by the user in use.

In any of the examples described above in relation to Figures 4 and 5, there may also be provided a heater for the nicotine source so as to “pre-heat” it. This heater may be provided as part of the cartridge or as part of the battery section of the assembly to which the cartridge is fitted in use. EXAMPLES

Several experiments were tested to evaluate the effects of using an acidic vapour and/or aerosol on nicotine extraction from a nicotine source to provide an enhanced amount of nicotine delivery in an inhalable medium.

In this example, the objective was to test whether using an acidic aerosolisable liquid would extract nicotine from pH-treated tobacco to increase the amount of nicotine delivery in the inhalable medium. Three aerosolisable liquids were prepared for the experiments:

1-C, a control sample an e-liquid composition of glycerol (17% w/w), propylene glycol (71% w/w) and water (12% w/w);

1-BA, a sample containing 0.04% by weight benzoic acid and the e-liquid; and 1-LA, a sample containing 0.04% by weight lactic acid and the e-liquid.

The solid, nicotine containing material used was a tobacco blend, treated with base to have a pH of 8.5. The materials were loaded onto a standard test system as pods and the liquid was heated; the heater element had a power of 7.5 W. The vapour/aerosol formed from the liquid was then passed through or over the pH-treated tobacco composition, entraining one or more components thereof to provide an inhalable medium, which passes to a detector through an outlet.

During one experiment the system performed 60 puffs in total per pod, formed of three 20 puff blocks, measuring the nicotine delivery at each 20-puff interval. The puffing was done using a 55/3/30 regime (55 ml puff of 3 second duration every 30 seconds). The measurements were repeated four times for each sample. A summary of the results is shown in the tables below.

Puff block = 20

Puff block = 40

Puff block = 60

Referring to Figure 6, a graph of the results from the experiments described above are shown, and demonstrates examples of nicotine delivery from assemblies according to embodiments of the invention, as well as a comparative assembly.

For the 1-20 puff block measurement on each sample, the nicotine delivery has increased for the acidified liquids. For benzoic acid containing liquids, the nicotine delivery has increased from 67.2 pg/puff (control, 1-C) to 79 pg/puff (1-BA). For lactic acid containing liquids, the nicotine delivery has increased from 67.2 pg/puff (control, 1-C) to 100 pg/puff (1-LA). Accordingly, the results of the experiments show that the use of an acidic vapour/aerosol (such as one formed from a liquid containing benzoic acid or lactic acid in 1-BA or 1-LA, respectively) increases the amount of nicotine delivered to the user, compared to a neutral vapour/aerosol (such as the liquid used in 1-C). Furthermore, the above results show that the total nicotine content removed from the solid tobacco is higher when an acidic vapour/aerosol is used. That is, a higher amount of nicotine is extracted from the tobacco when using an acidic vapour/aerosol (1-BA, 1- LA) compared to a neutral vapour/aerosol (1-C). Thus, in some embodiments the assembly allows for the rate of nicotine extraction to be increased, as well as the total amount of nicotine that is available to be extracted from the nicotine source to be increased.

As used herein, “aerosol generating agent” refers to a compound or mixture that promotes the generation of an aerosol. An aerosol generating agent may promote the generation of an aerosol by promoting an initial vaporisation and/or the condensation of a gas to an inhalable solid and/or liquid aerosol.

In general, any suitable aerosol generating agent or agents may be included in the aerosolisable liquid or nicotine source. Suitable aerosol generating agents include, but are not limited to: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, high boiling point hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacetin, triacetin, triethylene glycol diacetate, triethyl citrate or myristates including ethyl myristate and isopropyl myristate and aliphatic carboxylic acid esters such as methyl stearate, dimethyl dodecanedioate and dimethyl tetradecanedioate.

As used herein, the terms "flavour" and "flavouring" refer to materials which, where local regulations permit, may be used to create a desired taste or aroma in a product for adult consumers. They may include extracts (e.g., liquorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint, peppermint, lavender, cardamom, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger, anise, coriander, coffee, or a mint oil from any species of the genus Mentha), flavour enhancers, bitterness receptor site blockers, sensorial receptor site activators or stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame potassium, aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose, sorbitol, or mannitol), and other additives such as charcoal, chlorophyll, minerals, botanicals, or breath freshening agents. They may be imitation, synthetic or natural ingredients or blends thereof. They may be in any suitable form, for example, oil, liquid, or powder. For the avoidance of doubt, where in this specification the term “comprises” is used in defining the invention or features of the invention, embodiments are also disclosed in which the invention or feature can be defined using the terms “consists essentially of’ or “consists of’ in place of “comprises”.

As used herein, the term pH is used as a reference to the pH measured at room temperature, i.e. at 20-22°C. In some embodiments, room temperature is 20°C.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

1. An aerosol generating assembly comprising: a solid, nicotine-containing material having a pH of at least 7; an aerosolisable liquid comprising an acid, and having a pH of at least 2 and less than 7; and wherein the assembly is configured to heat the aerosolisable liquid to form a vapour and/or an aerosol, wherein the vapour/aerosol is contacted with the solid, nicotine- containing material to entrain one or more components thereof, and thus forming an inhalable medium.

2. An aerosol generating assembly according to claim 1, wherein the solid, nicotine-containing material comprises a tobacco material.

3. An aerosol generating assembly according to claim 1 or 2, wherein the pH of the solid, nicotine-containing material is of from 8 to 9.5 or from 8.5 to 9.

4. An aerosol generating assembly according to any of claims 1-3, wherein the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8.

5. An aerosol generating assembly according to any of claims 1-4, wherein the difference between the pH of the solid nicotine-containing material and the pH of the aerosolisable liquid is of from 3.0 and 5.5.

6. An aerosol generating assembly according to any of claims 1-5, wherein the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa.

7. An aerosol generating assembly according to any of claims 1-6, wherein the aerosolisable liquid has an amount of acid of from 0.001 to 5 % by weight.

8. An aerosol generating assembly according to any of claim 1-7, wherein the assembly is configured such that the solid, nicotine-containing material is heated only by the vapour/aerosol.

9. An aerosol generating assembly comprising: a solid, nicotine-containing material having a pH of at least 7; an aerosolisable liquid comprising an acid, the acid with a pKa greater than 0.5; and wherein the assembly is configured to heat the aerosolisable liquid to form a vapour and/or an aerosol, wherein the vapour/aerosol is contacted with the solid, nicotine-containing material to entrain one or more components thereof, and thus forming an inhalable medium.

10. An aerosol generating assembly according to claim 9, wherein the pKa of the acid is greater than 3, or is from 3.7 to 4.3.

11. An aerosol generating assembly according to claim 9 or 10, wherein the pH of the solid, nicotine-containing material is of from 8 to 9.5 or from 8.5 to 9.

12. A cartridge for use in an assembly for generating an inhalable medium, the cartridge comprising an aerosolisable liquid comprising an acid in a first chamber, the aerosolisable liquid having a pH of at least 2 and less than 7, and a solid, nicotine- containing material in a second chamber, the solid, nicotine-containing material having a pH of at least 7.

13. A cartridge according to claim 12, wherein the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8.

14. A cartridge according to claim 12 or 13, wherein the solid, nicotine-containing material has a pH of from 8 to 9.5 or from 8.5 to 9.

15. A cartridge according to any of claims 12-14, wherein the acid has a vapour pressure at 25 °C of from 0.1 Pa to 2.5 kPa.

16. A method of generating an inhalable medium using an assembly comprising an aerosolisable liquid comprising an acid, the aerosolisable liquid having a pH of at least 2 and less than 7, and a solid, nicotine-containing material having a pH of at least 7, the method comprising: heating the aerosolisable liquid to form a vapour and/or an aerosol; forming an inhalable medium, by contacting the aerosolisable liquid in the form of a vapour and/or an aerosol with the solid, nicotine-containing material to entrain one or more components thereof.

17. A method according to claim 16, wherein the aerosolisable liquid has a pH of from 4 to 5 or from 4.3 to 4.8.

18. A method according to claim 16 or 17, wherein the vapour pressure of the acid at 25 °C is of from 0.1 Pa to 2.5 kPa.

19. Use of an acidic vapour and/or aerosol to extract nicotine from a solid, nicotine- containing material having a pH of more than 7, wherein the rate of nicotine extraction exceeds the rate of nicotine-salt formation in the solid, thereby providing an increased nicotine content in the vapour and/or aerosol as compared to using a neutral vapour and/or aerosol.

20. A kit comprising:

(i) a liquid pod containing an aerosolisable liquid comprising an acid, the aerosolisable liquid having a pH of from at least 2 and less than 7; and