Field

[0001] The invention relates to a herbal extract, in particular to a herbal extract for use in vaporising systems, and to methods of preparing and delivering the extract. Background

[0002] It can often be difficult to deliver a herbal extract in a therapeutic amount. One reason for this is the often low bioavailability of such extracts when taken orally, requiring high dosages to be taken to achieve the therapeutic effect. For instance, herbal extracts can require up to a gram of the extract to be ingested before any benefits are observed. [0003] Alternative forms of delivery are known. These include inhalation techniques, such as nebulisation. However, these have not been widely used as it can be difficult to nebulise many herbal extracts because of the ethanol bases that are typically used.

[0004] Independently, in the pursuit of less harmful methods of delivering nicotine to the body, e-cigarettes and "vaping" have become popular in recent years. Such products can be flavoured, but do not contain herbal extracts. This is because herbal extracts are generally ethanol extracts, thus making them unsuitable for use in vaping systems. Furthermore, such e-cigarette products generally use harsh chemicals, which do not interact well with herbal extracts, and this therefore precludes the offering of a "natural" product. [0005] In view of the above, it would be desirable to provide a method of delivering herbal extracts, such that less extract needs to be delivered to the patient than with oral dosage forms, and such that a wider range of extracts can be delivered than is possible with nebulisation techniques. In particular, it would be desirable to provide a herbal extract which can be delivered to the body using a vaping system.

[0006] The invention is intended to overcome or ameliorate at least some aspects of this problem. Summary

[0007] Accordingly, in a first aspect of the invention there is provided a herbal extract comprising a herbal active and a carrier comprising glycerine, wherein the extract is delivered in a therapeutic dose upon vaporisation of, typically, in the range 0.1 - 0.6 ml of the herbal extract.

[0008] The inventors have found that using vaporisation delivery methods, the bioavailability of the herbal extract can be increased dramatically, reducing the amount of extract that must be ingested relative to when provided in oral form. This is partly as the active remains intact and is not damaged during vaporisation, and partly as contact with stomach acid is avoided. However, vaporisation methods are inappropriate for use with traditional herbal extracts as these are either water or ethanol based. Water extracts are unsuitable for vaporisation, due to the energy required to vaporise the water. This is particularly the case if e-cigarette technology is to be used (as used herein references to "vaping" and "e-cigarette" technology are used interchangeably). Further, ethanol extracts, although easy to vaporise, and usable with vaping technology, are considered harmful, as they can cause lung damage. For this reason, the use of ethanol extracts is illegal in some parts of the world. The invention addresses both of these problems through the use of medically benign carriers with low volatility. Further, it is intended that the carriers used in the invention be naturally occurring substances where possible, allowing a product to be offered which includes only naturally occurring products, and is free of synthetic chemicals. This is beneficial as many of the users of herbal extracts are attracted to products which can be branded as "natural".

[0009] The herbal extracts used herein are generally undiluted extracts, vaporised "neat". Although the extracts are described with reference to an active and a carrier, this is within the context of standard extraction methodology and is not intended to imply that the herbal extracts have been formulated, or are e-cigarette formulations as would be understood by the skilled reader. An e-cigarette formulation with a herbal flavour would comprise a base, generally also nicotine, and have added to this either synthetic flavouring or low levels of a herbal extract in which the carrier is water or ethanol. In the present invention, no base is required, because the carrier for the herbal active (the solvent into which the herbal active was extracted) comprises glycerine. No additional formulation is required. This means that the herbal extract can be vaporised directly, in its undiluted form. This allows the herbal extract to be delivered in therapeutically active amounts, which would be impossible with a flavoured e-cigarette formulation. As such, the herbal extracts of the invention are distinct from e-cigarette formulations, as not only are they nicotine free, but the nature of the vaporised fluid is entirely different.

[0010] Further, the purpose of the vaporisation is different. E-cigarette formulations support the smoking habit, or provide a pleasant tasting experience, whereas in the present invention the herbal extract is delivered primarily to offer a therapeutic benefit from a natural source, although a pleasant taste experience is also desirable. As such, whilst vaping technology can be used to vaporise the herbal extract of the invention, there is a clear distinction between the current extract and e-cigarette formulations.

[0011] The therapeutic dose will be dependent upon the herbal extract selected, and is within the capability of the skilled person to determine. In the invention, a therapeutic dose can be available from a single, typical 0.5 to 1.5 ml total e-cigarette charge. Preferably the charge is 1 ml and often a lower volume of extract can be used, such as from in the range of 0.1 - 0.6 ml , or in the range of 0.2 - 0.4 ml. Vaporisation may deliver the whole therapeutic dose in a single dosage, or through multiple small doses during the day. Where multiple small doses are desired, delivery through vaping can be particularly desirable as this can be less intrusive to the user. As vaping technology is designed to provide for multiple "puffs" of liquid, in this case herbal extract, during the day, the therapeutic dose may be provided cumulatively through the course of the day such that the level of herbal extract in the body builds up over time. The therapeutic dose may therefore be provided in one or more smaller doses, for instance in multiple doses (such as in the range of 1 - 200, 50 - 150, 75 - 125 or 10 - 60 doses). [0012] Any herbal extract which provides a therapeutic effect may be used. Preferably, the herbal active is selected from Echinacea, ginseng, ginger, and combinations thereof. Any species of Echinacea may be used. Preferably the species of Echinacea is Echinacea purpurea or Echinacea angustifolia, more preferably Echinacea purpurea. Preferably the ginseng is Siberian ginseng. [0013] As noted above, the carriers intended for use in the invention are naturally occurring substances. These may be synthetic equivalents of the natural substance, or the substance sourced from nature. Often the carrier will be a plant or animal extract. Often the carrier will be a plant extract as plant extracts are acceptable to the vegetarian community. Often, the carrier comprises water. The water will generally be present at low levels so as not to inhibit vaping, such as at a ratio relative to the other components of the carrier of 100: 1 - 30: 1.

The carrier may comprise glycerine alone, such that it consists of glycerine. Alternatively, the carrier may consist of glycerine and water. [0014] As noted above, it is desirable to avoid the use of ethanol as extracts in ethanol can cause lung damage. However, whilst an ethanol-free product would be desirable (0 wt% or in the range 0 - 0.01 wt% ethanol), small amounts of ethanol may be present as residues from earlier extractions of the herbal active. In such cases, the extract may comprise ethanol in the range of 0 - 5 wt%, often in the range of 0 - 2 wt% and preferably in the range of 0.0001 - 1 wt%, or less.

[0015] Often, the extract comprises a ratio of the herbal active: carrier in the range 1 : 1 - 1 : 100. The ratio will depend upon the solubility of the active in the carrier, and may be higher for less soluble herbs, such as woody herbs, or bark extracts. For many herbal extracts, the ratio will be in the range 1 : 1 - 1 : 100, often 1 : 1 - 1 :50, 1 : 1 - 1 : 10 or 1 : 1 - 1 :5. In some cases the ratio will be in the range 1 : 1 - 1 :2. A low ratio is desirable to maximise the dosage of active delivered during vaporisation. At these levels, a therapeutic dose of the herbal extract can be provided in up to 0.6 ml of herbal extract.

[0016] Often, the herbal active and carrier are selected from Echinacea and glycerine; ginseng and glycerine; and ginger and glycerine or mixtures thereof. It may be that the extract comprises a ratio of the Echinacea active: glycerine or ginseng active: glycerine which may be in the range 1 : 1 - 1 : 10. Alternatively, a ratio of the ginger active: glycerine may be in the range of 1 : 1 - 1 : 10 or 1 : 10 - 1 :50. Preferably the ratio of Echinacea active or ginseng active to glycerine is 1 : 1 and the ratio of ginger active to glycerine is 1 :2. At these ratios, stable, high concentration extracts are provided which can offer a therapeutic dose of the example herbs through vaporisation in a small volume of extract. [0017] Preferably, the extract does not comprise any synthetic, or synthetically prepared, chemicals. This means that the extract does not comprise any substances, made by chemical synthesis, which are designed to imitate a natural product.

[0018] In a second aspect of the invention there is provided a vaporising system for receiving a herbal extract according to the first aspect of the invention, the system comprising: a storage portion for storing the herbal extract; herbal extract stored in the storage portion; a heater comprising at least one heating element for vaporising the herbal extract; and a mouthpiece for delivery of the vaporised herbal extract to a user. Providing the vaporising system can perform the function of vaporising the herbal extract, any vaporising system may be used. The vaporising system described will generally be a conventional e-cigarette product as is well known in the art, the exact design of the vaporising system being secondary to the herbal extract stored and delivered using the system. E-cigarette vaporisers offer the benefit of being readily available, easy to use, and portable. [0019] In a third aspect of the invention there is provided a method for delivery of a herbal extract comprising vaporising the herbal extract in a vaporising system according to the second aspect of the invention.

[0020] In a fourth aspect of the invention there is provided a method for preparing a herbal extract according to the first aspect of the invention for use with a vaporising system, the method comprising vacuum evaporating a herbal extract in solvent in the presence of a carrier comprising glycerine. The use of vacuum evaporation allows the integrity of the extract to be maintained as the solvent is removed. The presence of glycerine allows the herbal extract to be easily dissolved during the extraction process. Preferably the solvent is an alcohol and more preferably the solvent is ethanol. [0021] In a fifth aspect of the invention there is provided a herbal extract according to the first aspect of the invention for use as a medicament, and in a sixth aspect of the invention a herbal extract according to the first aspect of the invention for use in the treatment of the common cold, the immune system, fatigue, stomach upsets, pain and/or inflammation. Preferably the herbal extract is vaporised. [0022] Unless otherwise stated, each of the integers described may be used in combination with any other integer as would be understood by the person skilled in the art. Further, although all aspects of the invention preferably "comprise" the features described in relation to that aspect, it is specifically envisaged that they may "consist" or "consist essentially" of those features outlined in the claims. In addition, all terms, unless specifically defined herein, are intended to be given their commonly understood meaning in the art.

[0023] Further, in the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, is to be construed as an implied statement that each intermediate value of said parameter, lying between the smaller and greater of the alternatives, is itself also disclosed as a possible value for the parameter.

[0024] In addition, unless otherwise stated, all numerical values appearing in this application are to be understood as being modified by the term "about".

Examples

Echinacea Extract

[0025] An extract of Echinacea purpurea (1 :2) in glycerine was prepared as follows:

1) 100 kg of Echinacea purpurea was loaded into a standard digester. 2) The Echinacea was covered in 45% ethanol v/v. 3) The mixture was left to macerate for 16 hours. 4) The liquid was drained into a suitable receiving vessel. 5) Steps 2) to 3) were repeated 5 times. 6) The extracted liquor was distilled until the alcohol was fully recovered. 7) The distilled liquor was transferred to an evaporation vessel and evaporated to 55 litres. 8) The liquor was allowed to cool before transferring it to a suitable mixing vessel. 9) 40 litres of ethanol was added to the product and it was allowed to stand for 48 hours. 10) The alcohol extract was drawn off.

[0026] The resulting extract was mixed with glycerine in equal volume to the alcohol in the mixture and placed in a vacuum extraction unit at 50°C and 7kPa. The alcohol was drawn off, allowing the herbal active to pass into the glycerine base. The final product was tested for the level of herbal active and the absence of alcohol was tested for using wet chemistry titration techniques known to one skilled in the art.

[0027] The resulting extract comprised 1 : 1 Echinacea active: glycerine and the alcohol was tested to the limit of detection using wet chemistry titration.

[0028] Echinacea was tested for using HPLC with the conditions as outlined in Table 1 below.

[0029] Table 1

[0030] The extract was found to be appropriate for direct vaporisation using e-cigarette technology. Therapeutic benefits can be observed at a dosage of 0.1 to 0.6 ml with inhalation delivery, this equates to 10 to 60 puffs of an e-cigarette (the average puff being 10 μΐ), and can be delivered over a period of several hours. Ginseng Extract and Ginger Extract

[0031] An extract of either Siberian ginseng or ginger in glycerine and water was prepared using a hot maceration system. Such techniques are well known to one skilled in the art. [0032] The resulting ginseng extract comprised 1 : 1 ginseng active: glycerine and the resulting ginger extract comprised 1 :2 ginger active:glycerine.

[0033] Ginseng and ginger can be tested for by thin-layer chromatography in accordance with the European Pharmacopoeia protocol known to one skilled in the art. The absence of alcohol was tested for using wet chemistry titration techniques known to one skilled in the art.

[0034] The extracts were found to be appropriate for direct vaporisation using e-cigarette technology. Therapeutic benefits can be observed at a dosage of 0.1 to 0.6 ml with inhalation delivery, this equates to 10 to 60 puffs of an e-cigarette (the average puff being 10 μΐ), and can be delivered over a period of several hours. [0035] It should be appreciated that the extracts and methods of the invention are capable of being implemented in a variety of ways, only a few of which have been illustrated and described above.