GB2590494A

GB2590494A - A dispensing device

Info

Publication number: GB2590494A
Application number: GB1918944.8A
Authority: GB
Inventors: Maguire Kevin
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2021-06-30
Also published as: WO2021123333A1; GB201918944D0

Abstract

This invention relates to a dispensing device for repeatedly and accurately dispensing micro- doses of a compound such as cannabidiol (CBD) or tetrahydrocannabinol (THC). The dispensing device comprises a body having a cartridge 5 and a drive mechanism 7. The cartridge has a reservoir 31 containing the compound, a discharge outlet 15, a seal nut 37 configured to be advanced along the cartridge towards the discharge outlet, and a leadscrew 33 having a helical thread engaging the seal nut. The drive mechanism comprises a push button 11, a helical drive cam 25, a helical drive cam coupling 21 connecting the cam to the button, and a drive shaft 29 coupled between the helical drive cam and the leadscrew. Depression of the push button will cause the helical drive cam to rotate the drive shaft, which in turn will rotate the leadscrew by a predetermined revolution amount, which in tum will advance the seal nut towards the discharge outlet. The same predetermined amount of compound is thus discharged from the outlet each time.

Description

"A dispensing device"

Introduction

This invention relates to a dispensing device. More particularly, the present invention relates to a dispensing device for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active therapeutic ingredient. In particular, the present invention is particularly suited for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active therapeutic ingredient of cannabidiol (CBD).

CBD products are becoming increasingly popular in many parts of the world. These products are used both as an alternative to, and in conjunction with, more traditional medicines. Various studies have argued that CBD products have a range of health benefits for a range of disparate ailments. For example, it is known for people to use CBD products to treat the symptoms of chronic pain, anxiety, depression, epilepsy and multiple sclerosis to name but a few.

Mainstream CBD products come in a number of forms of which perhaps the most well-known to date is CBD oil. More recently, CBD pastes have been gaining in popularity.

The CBD paste is dispensed from a dispenser and is usually taken sublingually. More specifically, a small amount of CBD paste is dispensed from a container onto an individual's finger and the CBD paste is then placed underneath the recipient's tongue where the CBD paste is gradually absorbed.

There is however a significant problem with CBD paste products. Although CBD pastes generally consist of an excipient with an even distribution of the active ingredient therein, and therefore a predictable amount of active ingredient by weight of compound, the amount of compound required per dose is usually relatively small and it is very difficult to dispense the small amounts of paste compound with any real degree of consistency and accuracy. Due to the fact that it is difficult to accurately dispense CBD paste products, it is difficult for the user to know precisely how much they are taking each time. Underdosing and overcompensating are quite common. Furthermore, the dosage regimens tend to vary from person to person and are a very individual thing. Once a -2 -person finds a dosage that works for them and their condition, it is very difficult for the person to replicate that dosage consistently which leads to frustration.

Various dispensers have been proposed to accurately dispense micro-doses of compounds containing viscous excipients such as CBD paste however these have proven unpopular. The known devices include syringe-like dispensing devices that are able to repeatedly, accurately dispense CBD paste. However, these devices have negative connotations, can attract unwanted attention and are therefore generally not used in public. Other devices are often difficult to manipulate and require a high level of manual dexterity, which may be absent. As a result, uptake of CBD paste products has been inhibited.

It is an object of the present invention to provide a dispensing device for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active ingredient of cannabidiol (CBD) that overcomes at least some of the above-identified problems. It is a further object of the present invention to provide a useful alternative choice for the consumer.

Statements of Invention

According to the invention there is provided a dispensing device for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active therapeutic ingredient, the dispensing device comprising: a body having a cartridge and a drive mechanism; the cartridge having a reservoir containing the compound, a discharge outlet for discharge of the compound from the cartridge, a seal nut mounted in the cartridge and configured to be advanced along the cartridge towards the discharge outlet, a leadscrew having a helical thread engaging the seal nut for advancing the seal nut along the cartridge towards the discharge outlet by a predetermined distance per revolution of the leadscrew; and -3 -the drive mechanism comprising a push button, a helical drive cam, a helical drive cam coupling for coupling the push button and the helical drive cam together, and a drive shaft coupled to the helical drive cam and the leadscrew so that depression of the push button WIl cause the helical drive cam to rotate the drive shaft, which in turn will rotate the leadscrew by a predetermined revolution amount, which in turn will advance the seal nut by a predetermined distance towards the discharge outlet.

By having such a dispensing device, it will be possible to repeatedly, accurately dispense micro-doses of an excipient containing a therapeutic ingredient such as a CBD paste and like compounds with relative ease. In order to actuate the device, the user simply has a push button that they depress. Once depressed, the push button will, through various inter-engaged components, cause a leadscrew to be rotated by a predictable angular amount. This in turn will push a seal nut along the cartridge by a predictable distance, displacing a predictable amount of CBD paste from the cartridge. In this way, the user is certain that the same amount of CBD paste is being dispensed each time they depress the push button. They can reproduce the amount required by them for their condition, time after time, with ease. Underdosing and overcompensating will be avoided and there will as a result be a better user experience. Furthermore, it is not necessary for the device to take on the appearance of a syringe and therefore the device will be more discrete and can be used in public without fear of negative perceptions.

In one embodiment of the invention there is provided a dispensing device in which the body is a two-part body, with the cartridge and the drive mechanism being housed separately and in which there is provided means to releasably couple the cartridge and the drive mechanism together. For example, one of the cartridge and the drive mechanism body may be provided with one or more bosses and the other of the cartridge and the drive mechanism body may be provided with one or more complementary dimples to provide a "click-in, click-out" engagement between the two parts. This is seen as a useful aspect of the present invention. By having a two-part body, replaceable cartridges can be used and cartridges with different concentrations of active ingredients and different volumes of compound may be interchanged with one drive mechanism. This can also reduce the amount of waste produced and the cost of the product over time to the consumer. -4 -

In one embodiment of the invention there is provided a dispensing device in which the leadscrew and the drive shaft are releasably couplable together. This is seen as a particularly useful way of allowing the dispenser to be provided in two parts, as the engagement between the drive shaft and leadscrew will be relatively simple to form and will be reliable in operation.

In one embodiment of the invention there is provided a dispensing device in which the drive mechanism comprises an end cap through which the drive shaft protrudes, and in which outer end of the drive shaft is configured for engagement of the leadscrew. By having an end cap, the entire drive mechanism can be housed compactly together without fear of one or more components being mislaid.

In one embodiment of the invention there is provided a dispensing device in which the cartridge comprises a cartridge collar through which the leadscrew protrudes, and in which the outer end of the leadscrew is configured for engagement of the drive shaft. Again, this will provide a compact configuration of device that may be assembled with ease.

In one embodiment of the invention there is provided a dispensing device in which one of the cartridge and the drive mechanism comprise a socket portion and the other of the cartridge and the drive mechanism comprise a complementary plug portion for complementary engagement of the cartridge and the drive mechanism. This will be a simple intuitive construction of device that will be relatively simple for even those with dexterity difficulties to put together.

In one embodiment of the invention there is provided a dispensing device in which there are provided a plurality of interchangeable cartridges for engagement of the drive mechanism, each with a different reservoir capacity.

In one embodiment of the invention there is provided a dispensing device in which the leadscrew and the drive shaft are formed integrally with each other. This is seen as a useful alternative construction, with fewer parts, lower cost and easier to use. In essence, the entire unit will be built in a unitary fashion and the device will either be -5 -disposable or the reservoir may be refillable. This will ensure that the amount dispensed is practically identical over time.

In one embodiment of the invention there is provided a dispensing device in which the push button is configured to permit accurate dispensing of fractional amounts of the micro-dose amount. In this way, the user can for example dispense half doses, quarter doses or other fractional amounts of the micro-dose amount to suit their specific requirements.

In one embodiment of the invention there is provided a dispensing device in which there are provided indicia on the push button to indicate fractional amounts of the micro-dose amount. In this way, there will be a clear indicator to the user how much they are dispensing and it allows them greater freedom to determine and reproduce the required dose.

In one embodiment of the invention there is provided a dispensing device in which there is provided one of a boss or a dimple on the push button to provide hapfic feedback to the operator upon a fractional amount of the micro-dose amount being dispensed. This will enable the user to replicate their desired dosage with accuracy each time.

Alternatively or in addition, in another embodiment, there could be provided a button on the body that would co-operate with the push button and that can be moved to select: lock, 25%, 50%, 75%, 100% dosages. This would work by limiting the movement of the push button from 0% stroke (i.e. to prevent inadvertent dispensing of the compound) to full 100% stroke (i.e. 100% of dosage amount). Other dosage amounts are also envisaged if preferred, for example it may be preferred to provide the option of 33% and 67%, dosages or to only provide an option of either a 0%, 50% or 100% dose.

In one embodiment of the invention there is provided a dispensing device in which there is provided a removable end cap for the cartridge for releasably sealing the discharge outlet.

In one embodiment of the invention there is provided a dispensing device in which there is provided a spring to urge the push button away from the helical drive cam and helical drive cam coupling. This is seen as a particularly useful aspect of the present invention. -6 -

the spring will urge the push button back to the starting operation so that the device is easier to use. Furthermore, it is envisaged that this will simplify the dispensing of fractional doses as well.

In one embodiment of the invention there is provided a dispensing device in which the spring comprises a helical spring.

In one embodiment of the invention there is provided a dispensing device in which the interior of the cartridge and the seal nut are configured to prevent rotation of the seal nut in the cartridge. By configuring the interior of the cartridge and the seal nut in this way, it is possible to ensure that the seal nut is progressed along the cartridge as the leadscrew is rotated. This will also make the manufacture of the device easier and more cost effective.

In one embodiment of the invention there is provided a dispensing device in which the interior of the cartridge is substantially elliptical in cross section and the seal nut is substantially elliptically shaped to prevent rotation of the seal nut in the cartridge. This is seen as a particularly simple configuration that is inexpensive to produce and simple to manufacture.

In one embodiment of the invention there is provided a dispensing device in which there is provided a viewing window in the cartridge.

In one embodiment of the invention there is provided a dispensing device in which there is provided a nozzle on the discharge outlet dimensioned to restrict inadvertent flow of compound out of the discharge outlet. In this way, by using an appropriate nozzle, more viscous compounds including creams and the like may be dispensed with ease from the dispensing device.

In one embodiment of the invention there is provided a dispensing device in which the drive cam coupling is partially inserted into the push button and in which there is provided a seat in the push button against which the drive cam coupling rests. This is seen as a simple yet robust construction that will be inexpensive to manufacture. -7 -

In one embodiment of the invention there is provided a dispensing device in which one of the drive cam coupling and the drive cam are provided with an annular groove and the other of the drive cam coupling and the drive cam are provided with an annular collar seated in the annular groove.

In one embodiment of the invention there is provided a dispensing device in which the annular collar forms a loose fit in the annular groove so that the push button may be depressed by a given amount prior to the drive cam coupling pushing against the drive cam. In this way, there will be a little "play" before any compound is dispensed and this will ensure that compound is not wasted. Furthermore, by having this configuration, the drive cam can rotate relative to the drive cam coupling as the pressure is removed from the push button and the spring moves the button out of the dispenser once more.

In one embodiment of the invention there is provided a dispensing device in which the compound comprising a viscous excipient is a CBD paste.

Detailed Description of the Invention

The invention will now be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying drawings, in which:-Figure 1 is a perspective view of the dispensing device according to the invention; Figure 2 is a partially exploded view of the dispensing device of Figure 1; Figure 3 is another perspective view of the dispensing device of Figure 1, Figure 4 is a perspective view of the dispensing device with the end cap removed; Figure 5 is a perspective view of the dispensing device with the end cap removed dispensing some compound; -8 -Figure 6 is an exploded view of the dispensing device of Figure 1; Figure 7 is an exploded view of the dispensing device of Figure 1, similar to Figure 6 but taken from the other end of the dispensing device; Figure 8 is a front view of the dispensing device; Figures 9(a) to 9(e) are side cross-sectional views along the lines A-A of Figure 8 of the dispending device, showing sequential operation of the device; Figure 10 is an exploded view of a second embodiment of dispensing device according to the invention, Figure 11 is an exploded view of the second embodiment of dispensing device, similar to Figure 10 but taken from the other end of the dispensing device; and Figure 12 is a perspective view of a third embodiment of dispensing device with alternative nozzle.

Referring to Figure 1, there is shown a dispensing device for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active ingredient of cannabidiol (CBD), indicated generally by the reference numeral 1. The dispensing device comprises a body 3 having a cartridge 5 and a drive mechanism 7. The cartridge has an end cap 9 covering a discharge outlet (not shown) and the drive mechanism 7 comprises a spring-loaded push button 11.

Referring to Figures 2 and 3, it can be seen that the body 3 is a two-part body (3(a) and 3(b)) with the cartridge 5 forming one part of the body and the drive mechanism forming the other part of the body. One end of the cartridge 5 forms a plug 13 for entry in and retention by a socket (not shown) in the end of the drive mechanism 7.

Referring now to Figures 4 and 5, in order to dispense a predictable quantity of CBD paste from the dispensing device, the end cap 9 is removed, thereby exposing a -9 -discharge outlet 15. The push button is then depressed (as illustrated in Figure 5) and a small, predictable amount of compound 17 is discharged out of the discharge outlet. Once the button is released, the push button will be moved back to the start position by the spring as shown in Figure 4. The operator can then push the button again if more CBD paste is required.

Referring now to Figures 6 and 7, there is shown a pair of exploded views of the dispensing device according to the invention, a dashed line is used to denote the separation between the cartridge 5 and the drive mechanism 7. Referring first of all to the drive mechanism part, the drive mechanism part comprises the push button 11 but also comprises a casing 19, a drive cam coupling 21, a helical spring 23, a helical drive cam 25, a body cap 27 and a drive shaft 29. Referring now to the cartridge part, in addition to the end cap 9 and the dispensing nozzle 15, the cartridge part 5 comprises a reservoir 31 containing the compound, a cartridge leadscrew 33, a cartridge collar 35 and a seal nut 37. It can be seen from Figures 6 and 7 that the ends of the cartridge leadscrew 33 and the drive shaft 29 are dimensioned to couple together so that when the drive shaft rotates, this will cause the cartridge leadscrew to also rotate.

The interaction of the components will now be more comprehensively described with reference to Figures 8 and 9(a) to 9(e) inclusive. Referring initially to Figure 8, there is shown a front view of the device with the end cap 9 removed, before the push button 11 has been depressed. Referring now to Figures 9(a) to 9(e), there are shown cross sectional views of the dispensing device taken along the lines A-A of Figure 8.

Referring specifically to Figure 9(a), it can be seen that before the push button 11 is depressed, the drive cam coupling 21 is not engaging the helical drive cam 25. There is an annular collar 39 on the drive cam coupling that sits in an annular groove 41 in the drive cam 25 however the drive cam is free to rotate relative to the drive cam coupling. The drive shaft 29 sits in the helical drive cam 25. The end of the drive shaft 29 is coupled to the end of the cartridge leadscrew 33. The helical thread of the leadscrew passes through a threaded bore of the seal nut 37.

Referring now to Figure 9(b), the push button 11 has been depressed slightly so that the annular collar 39 on the drive cam coupling 21 sitting in the annular groove 41 in the -10 -drive cam 25 abuts against the end of the drive cam 25. The drive cam 25 is no longer free to rotate relative to the drive cam coupling 21. This little amount of play will also prevent inadvertent discharge of compound.

Referring now to Figure 9(c), the push button 11 has now been depressed further, fully into the casing 19, as far as it will travel. Helical spring 23 is compressed. The drive cam coupling 21 will push the helical drive cam 25 inwardly into the casing in a direction towards the discharge outlet. As the helical drive cam 25 is pushed inwardly, the drive shaft 29, which is unable to move inwardly as it is held in position relative to the casing by the body cap 27, is caused to rotate (there is a cam on the drive shaft 29 that co-operates with the helical drive cam 25). As the drive shaft 29 rotates, it will cause the cartridge leadscrew 33 to also rotate as they are coupled together. As the cartridge leadscrew 33 rotates, the seal nut 37, which is unable to rotate in the reservoir 31, will instead move along the cartridge leadscrew 33 in the direction towards the discharge outlet 15. It can be seen that previously, in Figures 9(a) and 9(b), the seal nut 37 sat against the cartridge collar 35 however in Figure 9(c), after the push button has been depressed and the cartridge leadscrew has rotated, a gap 43 opens up between the seal nut 37 and the end of the cartridge collar 35. As the seal nut 37 moves towards the discharge outlet, an amount of CBD paste/compound in the reservoir 31 is displaced by the seal nut 37 and the CBD paste is expelled out of the discharge outlet 15.

Referring now to Figure 9(d), once the CBD paste has been discharged from the reservoir 31, the push button 11 is released. It can be seen that the helical spring 23 acts on the push button 11 and the drive cam coupling 21 to push them out of the casing 19. As this happens, the drive cam coupling 21 disengages from the helical drive cam 25 and the helical drive cam 25 is free to rotate in the casing. The helical drive cam 25 is dragged along the casing 19 in a direction away from the discharge outlet 15 by the helical spring 23 and the drive cam coupling 21 as the helical drive cam 25 and the drive cam coupling 21 are still connected to each other by way of the annular collar 39 sitting in the annular groove 41. As the helical drive cam 25 rotates as it travels along the casing 19, it does not cause the drive shaft 29 and in turn the cartridge leadscrew 33 to counterrotate. This is due to the viscous nature of the CBD paste providing friction against rotation of the cartridge leadscrew 33 and the drive shaft 29. As a consequence, the seal nut 37 will be ready to act upon the compound in the reservoir the next time that the push button 11 is depressed.

In Figure 9(e), the push button, helical drive cam 25, drive cam coupling 21 and the spring 23 have all returned to their initial positions as shown in Figure 9(a).

Referring now to Figures 10 and 11, there is shown a second embodiment of dispensing device, indicated generally by the reference numeral 51, where like parts have been given the same reference numeral as before. The dispensing device 51 differs from the dispensing device 1 in that the drive shaft and the cartridge leadscrew have been amalgamated into a single driveshaft leadscrew 53 component. Furthermore, the body cap 27 has been omitted as it is superfluous. The device may be constructed as a unitary device and the cartridge reservoir 31, cartridge collar 35 and casing 19 can be bonded permanently together. In this way, the cartridges will not be interchangeable or replaceable and the device will effectively be a disposable device.

Referring finally to Figure 12, there is shown a third embodiment of dispensing device, indicated generally by the reference numeral 61, where like parts have been given the same reference numeral as before. The dispensing device 61 comprises a new nozzle 63 that is configured to prevent inadvertent flow of compound out of the nozzle. This configuration may be useful for less viscous compounds.

In the present invention, reference is made to dispensing a "viscous" compound and viscous excipient. It will be understood that CBD pastes are quite viscous in nature.

Typically, the present invention will be intended for use with compounds and excipients having a "high" viscosity (at 20°C) of the order of 2,000 centipoise (cp) or higher, up to of the order of 250,000 cp. For other embodiments where the present invention is provided with an adapted nozzle for use with less viscous products such as oils and creams, the device will be intended for use with compounds and excipients with a "medium" viscosity in the range of the order of 100 cp up to less than 2,000 cp.

It will be understood from the foregoing that the components may be configured and dimensioned to dispense a desired amount of compound each time. For example, when the button is fully depressed, the helical cam drive and cam on the drive shaft may be -12 -configured to rotate the drive shaft one full revolution. This in turn could be used to rotate the cartridge leadscrew one full revolution. The rotation of the cartridge leadscrew by one full revolution could in turn cause the seal nut to move down the reservoir by a distance so that 0.05m1 of compound will be dispensed from the discharge outlet. In a compound with 5m1 in the container and 1000mg of active ingredient, 0.05m1 would equate to 10mg of active ingredient being discharged, per button push.

For example, in one embodiment of the invention, the pitch of the leadscrew thread is 1 mm and the seal nut also has an internal thread with a 1mm pitch. The helical drive cam turns 90 degrees (effectively a 1/4 turn) when the push button is fully pressed. In this way, the drive shaft will turn 90 degrees (1/4 turn) when the push button is fully pressed, and this in turn will cause the leadscrew to rotate one quarter rotation and the seal nut to advance 0.25mm when the push button is fully pressed.

The components are preferably dimensioned so that, in one embodiment, the paste volume is 5m1 when the cartridge is full (it is envisaged that the cartridge may be provided in 2m1, 10m1 and other quantities if desired). If 5m1 of paste were dispensed all in one string it would result in a string of paste 25mm long. The cross-sectional area of the seal nut front end is 200mm2. The front face of the seal nut will displace the paste by 0.25mm for each full push button depression and therefore the seal nut will displace 0.05m1 of paste for a full push button depression. If the paste has 20% CBD content, there will be 0.01m1 of CBD content per press of the push button.

The invention is intended to dispense micro-doses and these will be understood to be doses of the order of 50mg or less in a volume of compound of the order of 0.05m1 or less.

Throughout the specification, reference is made to dispensing of cannabidiols (CBD) however it will be understood that the active therapeutic ingredient could be other than or in addition to CBD. For example, the active ingredient could be tetrahydrocannabinol (THC), as found for example in medicinal marijuana and/or terpenes. Although the invention has been described in terms of dispensing a CBD paste, it extends also to other medicinal pastes, medicinal oils, medicinal waxes, and medicinal resins. It will be -13 -understood that the CBD paste is typically mixed with either bee's wax or coconut oil or other component of the excipient.

In this specification the terms "comprise, comprises, comprised and comprising" and the term "include, includes, included and including" are all deemed interchangeable and should be afforded the widest possible interpretation.

The invention is not solely limited to the embodiments hereinbefore described but may be varied in both construction and detail within the scope of the appended claims.

Claims

-14 -Claims: (1) A dispensing device for repeatedly, accurately dispensing micro-doses of a compound consisting of a viscous excipient containing an active therapeutic ingredient, the dispensing device comprising: a body having a cartridge and a drive mechanism; the cartridge having a reservoir containing the compound, a discharge outlet for discharge of the compound from the cartridge, a seal nut mounted in the cartridge and configured to be advanced along the cartridge towards the discharge outlet, a leadscrew having a helical thread engaging the seal nut for advancing the seal nut along the cartridge towards the discharge outlet by a predetermined distance per revolution of the leadscrew; and the drive mechanism comprising a push button, a helical drive cam, a helical drive cam coupling for coupling the push button and the helical drive cam together, and a drive shaft coupled to the helical drive cam and the leadscrew so that depression of the push button will cause the helical drive cam to rotate the drive shaft, which in turn will rotate the leadscrew by a predetermined revolution amount, which in turn will advance the seal nut by a predetermined distance towards the discharge outlet.(2) A dispensing device as claimed in claim 1 in which the body is a two-part body, with the cartridge and the drive mechanism being housed separately and in which there is provided means to releasably couple the cartridge and the drive mechanism together.(3) A dispensing device as claimed in claim 2 in which the leadscrew and the drive shaft are releasably couplable together.(4) A dispensing device as claimed in claim 2 or 3 in which the drive mechanism comprises an end cap through which the drive shaft protrudes, and in which outer end of the drive shaft is configured for engagement of the leadscrew.-15 - (5) A dispensing device as claimed in any one of claims 2 to 4 in which the cartridge comprises a cartridge collar through which the leadscrew protrudes, and in which the outer end of the leadscrew is configured for engagement of the drive shaft. 5 (6) A dispensing device as claimed in any one of claims 2 to 5 in which one of the cartridge and the drive mechanism comprise a socket portion and the other of the cartridge and the drive mechanism comprise a complementary plug portion for complementary engagement of the cartridge and the drive mechanism.(7) A dispensing device as claimed in any of claims 2 to 6 in which there are provided a plurality of interchangeable cartridges for engagement of the drive mechanism, each with a different reservoir capacity.(8) A dispensing device as claimed in claim 1 in which the leadscrew and the drive shaft are formed integrally with each other.(9) A dispensing device as claimed in any preceding claim in which the push button is configured to permit accurate dispensing of fractional amounts of the micro-dose amount.(10) A dispensing device as claimed in claim 8 in which there are provided indicia on the push button to indicate fractional amounts of the micro-dose amount.(11) A dispensing device as claimed in claim 9 or 10 in which there is provided one of a boss or a dimple on the push button to provide haptic feedback to the operator upon a fractional amount of the micro-dose amount being dispensed (12) A dispensing device as claimed in any preceding claim in which there is provided a removable end cap for the cartridge for releasably sealing the discharge outlet.(13) A dispensing device as claimed in any preceding claim in which there is provided a spring to urge the push button away from the helical drive cam and helical drive cam coupling.-16 - (14) A dispensing device as claimed in claim 13 in which the spring comprises a helical spring.(15) A dispensing device as claimed in any preceding claim in which the interior of the cartridge and the seal nut are configured to prevent rotation of the seal nut in the cartridge.(16) A dispensing device as claimed in claim 15 in which the interior of the cartridge is substantially elliptical in cross section and the seal nut is substantially elliptically shaped to prevent rotation of the seal nut in the cartridge.(17) A dispensing device as claimed in any preceding claim in which there is provided a viewing window in the cartridge.(18) A dispensing device as claimed in any preceding claim in which there is provided a nozzle on the discharge outlet dimensioned to restrict inadvertent flow of compound out of the discharge outlet.(19) A dispensing device as claimed in any preceding claim in which the drive cam coupling is partially inserted into the push button and in which there is provided a seat in the push button against which the drive cam coupling rests.(20) A dispensing device as claimed in any preceding claim in which one of the drive cam coupling and the drive cam are provided with an annular groove and the other of the drive cam coupling and the drive cam are provided with an annular collar seated in the annular groove.(21) A dispensing device as claimed in claim 20 in which the annular collar forms a loose fit in the annular groove so that the push button may be depressed by a given amount prior to the drive cam coupling pushing against the drive cam.(22) A dispensing device as claimed in any preceding claim in which the compound comprising a viscous excipient is a CBD paste.