Screw pump delivery device for solid medicaments

Abstract

A screw pump for dispensing a solid dosage form (e.g., a drug or medicament) is configured to transport units of the solid dosage form for dispensing. The screw pump comprises a screw comprising a helical channel. A surface defining the helical channel has a profile at a position along the helical path of the helical channel, the profile being defined in a plane extending along a rotational axis of the screw pump and presenting a concavity.

Description

[0001] SCREW PUMP DELIVERY DEVICE FOR SOLID MEDICAMENTS

[0002] FIELD

[0003] The present invention relates generally to delivery devices for medication, in particular solid dosage form.

[0004] BACKGROUND

[0005] Medications can be manufactured as a solid dosage form, e.g., tablets or pellets. These could contain different substances where the main ingredient(s) is / are the active pharmaceutical ingredient (“API”). Dispensing mechanisms for various forms of solid dosage form are known, and can range from blister-pack type devices, wherein individual tablets can be retained within pockets and retained therein by the use of foil, to dispensing bottles. Various more complicated mechanisms are also known, in particular for other types of drug formulation.

[0006] It is desired to improve the reliability of mechanisms by which solid dosage form is dispensed, to ensure that an accurate and correct dose is dispensed.

[0007] Various methods have been used to dispense accurate doses of solid dosage form, but the mechanics of such devices can be tricky to optimize. The Applicant has developed a device which is highly effective at dispensing medication contained within a cartridge using a screw pump mechanism. When developing this technology further, the Applicant has found that there can be challenges associated with solid dosage form becoming jammed or interlocked within the screw pump when being dispensed, causing a degree of unpredictability in the amount of solid oral dosage form being dispensed. It is desired, therefore, to further improve the mechanics of a device for dispensing medication to avoid such issues. It is against this background that the present invention was devised.

[0008] SUMMARY

[0009] According to a first aspect of the invention, there is provided a screw pump for dispensing a solid dosage form (e.g., a drug or medicament), wherein the screw pump is configured to transport units of the solid dosage form for dispensing. The screw pump comprises a screw comprising one or more helical channels, wherein a surface defining the helical channel(s) has a profile at a position along the helical path thereof, the profile being defined in a plane extending along a rotational axis of the screw pump and presenting a concavity.

[0010] The concavity, which may be defined as an outline or surface that curves inwards like the interior of a circle or sphere, helps to avoid jamming of solid dosage form within the channel when the screw pump is rotating. This is at least because a unit of solid dosage form adjacent to the concavity will tend to roll around the concavity upon compression being applied thereto. This helps to avoid jamming or interlocking of solid dosage form within the channel. The channel of the screw is therefore configured to avoid jamming of the solid dosage form.

[0011] Further optional specifications of the screw pump include:

[0012] The profile may correspond to a cross-section of the surface and / or screw, for example forming a two-dimensional line formed by the surface when the surface is cut along the plane.

[0013] The cross-section may be taken along the plane, which may be parallel to the rotational axis of the screw pump and extending in a radial direction therefrom (the radial direction defined relative to the rotational axis).

[0014] The surface may form part of the helical channel (e.g., the path thereof), which may be bound by the surface.

[0015] The helical channel may be a helical groove forming a surface of the screw facing radially outwards with respect to the rotational axis of the screw pump.

[0016] The concavity may form a concave and / or curved surface of the helical channel.

[0017] The profile as defined herein is intended to refer to the general profile of the surface, such that minor imperfections and the like do not affect the profile. Hence, reference is made herein to "substantially" continuous curves, etc.

[0018] Unless otherwise specified, references to "radial", "axial" and the like are relative to the rotational axis of the screw pump.

[0019] The screw may have multiple screw starts, and therefore multiple helical channels, and the concavity may be present in one or more of these helical channels as appropriate. For brevity, the following description will refer to the screw as though there is a single screw start, and single helical channel, but it will be appreciated that this does not exclude the presence of more screw starts and helical channels, any or all of which may also have the same features.

[0020] According to a particularly advantageous embodiment, the entirety of the profile may present a concavity (at least at the position defined above, but perhaps along a majority or even all of the screw), which thereby forms a substantially continuous curve. In other words, the cross- section as defined above may present a substantially continuous curve. This profile is particularly effective at avoiding jamming of solid dosage form within the channel, since sharp corner are eliminated and the solid dosage form can easily roll around the entire concavity.

[0021] In this embodiment, the largest radius of curvature of the profile may be at the radially innermost point along the profile. The radius of curvature may become progressively smaller moving away from the radially innermost point of the profile. This helps further to avoid jamming, because the largest radius of curvature is located at the point along the profile where jamming may be most likely to occur.

[0022] Various embodiments do not require the entire profile to present the concavity, and this is not essential to the broadest aspects of the present invention. More broadly, therefore, the helical channel (at least at the position defined above, but perhaps along a majority or even all of the screw) may comprise two radially extending surfaces and a central portion therebetween, with the concavity presented at least in the central portion. This remains effective at avoiding jamming of solid dosage form within the screw pump, because the concavity is still located where jamming is most likely to occur. The use of radially extending surfaces can help to provide a more compact screw. In a particularly advantageous arrangement which further reduces jamming within the channel, the central portion may merge continuously into the lower and upper portions such that sharp corners at this transition are avoided.

[0023] Generally, the helical channel and solid dosage form should be sized such that the units of the solid dosage form are able to contact the concavity as they travel through the screw thread (excluding, therefore, a very small filleted corner that could not contact larger units of the dosage form). For example, the concavity has a radius of curvature which is always (for example around the whole profile at the position along the helical path) greater than two times a maximum dimension of each unit of solid dosage form (for example an average maximum dimension of the solid dosage form). This allows the solid dosage form to freely rotate around the concavity, thereby reducing the chance of solid dosage form from becoming jammed in the helical channel. This applies to all of the aspects and embodiments described herein.

[0024] Specifying some of the features in more detail, the central portion may form a radially inner portion of the helical surface, such that it includes the radially innermost point along the profile thereof.

[0025] The radially extending surfaces could extend from the ends of the concavity, optionally to the radially outermost part of the screw. This provides a channel which is simple in configuration, compact, whilst remaining effective at avoiding jamming. The radially extending surfaces themselves may be straight i.e. they form a straight line in cross-section through the rotational axis of the screw pump, wherein the radially extending surfaces extend from the concavity to respective edges of the helical channel, although this is not essential. For example, the radially extending surfaces may be parallel to each other. This minimises the height of the screw and leads to a particularly compact arrangement. Alternatively, the radially extending surfaces may be angled relative to each other such that the radially extending surfaces diverge in a radially outward direction. This can help prevent jamming since the solid dosage will be encouraged to roll along the angled surface.

[0026] The concavity may define a curved fillet that interconnects at least one of the radially extending surfaces and the central portion. The solid dosage form can roll around the fillet to help prevent it from becoming jammed in the screw pump. In this arrangement the concavity may be present only between one of the radially extending surfaces and the central portion. The other radially extending surface may interconnect with the central portion via a relatively sharp corner, for example. In such scenarios it is most advantageous to provide the concavity in the lower radially extending surface (towards an outlet of the screw), since the pellets are most likely to rest on this surface in use (e.g., due to gravity). At least one of the two radially extending surfaces may be straight i.e. they form a straight line in cross-section through the rotational axis of the screw pump. This allows the solid dosage form to easily roll along the surfaces and provides an arrangement which is simple to manufacture.

[0027] Substantially the entire length (or at least the majority) of the helical channel within the screw pump may have the profile, to help prevent the solid dosage form from becoming jammed at any point along the length of the helical channel.

[0028] The use of a fillet that interconnects at least one of the radially extending surfaces and the central portion may be advantageous even if the fillet does not present a concavity. As such, from another aspect the present invention includes a screw thread as defined above, but instead of a concavity in the profile, the profile includes at least one mitre fillet (i.e. a fillet with a straight rather than concave cross-sectional profile).

[0029] In a particularly advantageous arrangement, the profile comprises a lower portion, the lower portion including a radially outermost point of the profile and extending radially inwards from the radially outermost point, wherein the lower portion is angled relative to a radial direction, for example such that the lower portion slopes upwards as the lower portion transitions radially inwards from the radially outermost point of the lower portion. The radially outermost point of the lower portion may form an axially lowest point of the profile. This arrangement helps to prevent jamming of solid dosage form within the channel, whilst simultaneously helping to direct the solid dosage form towards a lower portion of the channel, thus urging the solid dosage form down towards an outlet of the device. This helps to ensure that the solid dosage form flows effectively out of the device when the screw is rotated during a dispensing operation.

[0030] In a further advantageous arrangement, a tangent to the lower portion at the radially outermost point forms a non-zero angle with the radial direction. This further contributes to a reduction in the chance of jamming of solid dosage form within the channel, and also enables better flow of the solid dosage form. This is because a perpendicular angle between surfaces in this portion is avoided (it has been found that a corner with, for example, a 90 degree angle can lead to difficulties in dispensing solid dosage form due to jamming and or poor flow). An angle of between 5 and 45 degrees, and more preferably is between 10 and 25 degrees, has been found to be particularly effective at reducing jamming. In such an arrangement, the lower portion may be generally straight or can be continuously curved.

[0031] In the above arrangements, “lower” may be defined in relation to the device when held in a vertical orientation (with an outlet of the device towards the lower end of the device, the vertical direction being generally aligned with a rotational axis of the screw).

[0032] In the above arrangement, the profile may also comprise an upper portion opposite to the lower portion, the upper portion including a radially outermost point of the profile and extending radially inwards from the radially outermost point, wherein the upper portion may be angled relative to the radial direction, for example such that the upper portion slopes downwards as the upper portion transitions radially inwards from the radially outermost point of the lower portion. This helps to reduce the chance of jamming from occurring in the upper portion of the channel, and generally allows the solid dosage form to move freely around the surfaces of the channel. Similarly to above with the lower portion, the radially outermost point of the upper portion may form an axially highest point of the profile, and a tangent to the upper portion at the radially outermost point may form an angle with the radial direction, wherein the angle may advantageously be between 5 and 45 degrees, and more advantageously between 10 and 25 degrees. These features each help to contribute to smooth flowing of solid dosage form within the channel, such that solid dosage form does not become jammed within the channel and thus inhibit effective dispensing of the solid dosage form when the screw is rotated. The radially outermost point of the lower portion may advantageously be radially aligned with the radially outermost point of the upper portion.

[0033] In the above arrangements, the concavity may form a central portion of the screw and extend between the lower and upper portions. This helps to allow units of solid dosage form within the channel to freely flow around the profile, to again help to prevent units of solid dosage form from becoming jammed between surfaces of the channel during a dispensing step. The central portion may merge continuously into the lower and upper portions, such that the profile is devoid of sharp corners, which further helps the solid dosage form to move freely around the profile. The profile may also advantageously have a maximum radius of curvature at a radially innermost point of the profile. The radius of curvature of the profile may gradually reduce as the profile transitions radially outwardly from the radially innermost point to a or the radially outermost points of the profile.

[0034] In an embodiment of any of the above, the profile may be shaped such that a tangent to any point on the profile has a non-zero angle relative to a or the radial direction. This helps to prevent parallel surfaces within the channel, and to allow the solid dosage form to roll around the channel of the profile.

[0035] In an embodiment of any of the above, the channel may extend circumferentially around a or the longitudinal axis of the screw by less than or equal to one and a half turns, optionally by less than or equal to 1 turn. This has been found to be effective at dispensing solid dosage form, particularly in the form of pellets, whilst reducing the complexity of the device and the time needed to dispense the solid dosage form.

[0036] In a further embodiment of any of the above, the channel profile may have a maximum width in a radial direction which is at least two times the average width of the solid dosage form being dispensed, which helps to reduce the likelihood of two adjacent units of solid dosage form from being jammed between surfaces of the channel.

[0037] In any of the aspects and embodiments described herein, the surface of the screw defining the helical channel may be devoid of indentations or protrusions. In other words, the surface may be smooth. This can help to allow the solid dosage form to effectively move within and flow along the channel during dispensing. This is not essential. Also, we reiterate that the "profile" of the surface as defined herein relates to the general profile around the screw thread, which would be unaffected, for example, by minor indentations / protrusions and the like. The helical channel may comprise an outlet at the end of the screw pump for dispensing units of the dosage form. The channel may also have an outlet portion which corresponds to the end of the channel and which extends to the outlet.

[0038] The path forming the helical channel may follow a generally helical path forming the screw thread (in the conventional manner), but may then bend towards the axial direction of the screw pump in the outlet portion. This has been found to help the units flow effectively to the outlet. Without wishing to be bound by theory, it is thought that the bend exerts a higher amount of friction to the units of solid dosage form, slowing them down and reducing their pressure and density as they flow towards the outlet. The path may correspond to a longitudinal axis of the helical channel. The path may bend / curve further towards the longitudinal axis of the screw pump at the bend, and moving towards the outlet. A width, for example the largest width, of the helical channel may increase progressively towards the outlet. This has been found to help the solid dosage form to flow freely and effectively towards and through the outlet. The width may be the largest distance perpendicular to and extending through a longitudinal axis of the helical channel.

[0039] The screw may be configured such that the whole of the screw thread is located within the exit tube and such that there is a gap between a top of the exit tube (the top being at the opposite end of the exit tube to the outlet of the screw pump) and a top of the screw thread of the screw. It has been found that providing a gap between the top of the exit tube and the top of the screw thread allows the solid dosage form to flow into the screw thread whilst avoiding crushing and jamming of the solid dosage form between the screw thread and the top of the exit tube.

[0040] The screw thread may also have a variable pitch. The pitch may decrease progressively as the screw thread moves towards the outlet. This contributes to providing a constant density of solid dosage form (for example pellets) and also contributes to avoiding jamming and crushing of the solid dosage form during dispensing. This is because the pellets will enter the screw pitch with varied bulk density due to the randomness of the feed, then along the decreasing pitch the bulk density of the solid dosage form will stabilize.

[0041] The screw thread may also have a helix angle of between 1 to 60 degrees and optimally between 10 to 25 degrees for solid dosage form, for example in the form of powder or pellets, and more particularly for solid dosage form with high flowability. However, the optimal angle range may vary depending on the flowability characteristics of the solid dosage form. It has been found that a screw pump with a helix angle between these values is particularly effective at dispensing solid dosage form, and especially small units of a solid dosage form, for example in the form of mini- tablets or pellets. These helix angles are relatively shallow, which contributes towards avoiding jamming and crushing of solid dosage form, because the solid dosage form is moved relatively slowly or gradually in an axial direction by the screw pump. The helix angle also helps to provide more accurate dosing, because it helps to avoid solid dosage form from flowing out the screw pump too quickly. As such, it is easier to dispense solid dosage form from the screw pump in a controlled manner. Although advantageous in their own right, the above features of the screw pump cooperate to allow the screw pump to dispense solid dosage form in a manner which is efficient, accurate, and helps to prevent crushing and jamming of solid dosage form as it is being dispensed. In this way a variable dose of solid dosage form can be dispensed to a high degree of accuracy, which is of particular importance in the context of medication where an incorrect dose may have significant health or safety implications.

[0042] In an embodiment of any of the above, the screw may be formed as a single piece. This helps to provide a robust and air-tight arrangement.

[0043] According to an aspect of the invention, there is provided a device comprising the screw pump according to any of the above aspects or embodiments thereof. The device may be for dispensing the solid dosage form. The screw pump defined herein is suitable for dispensing various type of solid dosage form, using any suitable device. As such the invention is not limited to using the screw pump to dispense a specific type of medication, or within a specific type of device.

[0044] The device may comprise a plurality of medicament pellets, for example having the dimensions defined below. Medicament in the form of pellets allows for highly individualised doses of medicament to be dispensed, because the relatively small size of the pellets means that the dose can be fine-tuned depending on the patient’s needs. However, medicament pellets can be challenging to dispense accurately, and can be prone to becoming over-compacted / jammed within devices. The above device serves to mitigate these risks, and is particularly well suited to dispensing medicament in this form.

[0045] In a non-limiting embodiment, therefore, the device may comprise a tube, which is configured to cooperate with the screw to form the screw pump for dispensing the solid dosage form. Such an arrangement allows flexible and accurate dosing.

[0046] More specifically, a radially outer surface of the screw may be shaped to fit within a radially inner surface of the tube such that the screw and tube cooperate to form a closed channel for transporting the solid dosage form out of the device. The screw may be configured to rotate within the exit tube to form the screw pump. A radially outer surface of the screw may substantially contact a radially inner surface of the exit tube. The outer surface of the screw and the radially inner surface of the exit tube may substantially contact each other or abut, but not to the extent that they have an interference or friction fit relative to each other, to ensure that they can move smoothly past each another and ensure reliable dispensing as the radially outer surface of the screw rotates past the radially inner surface of the exit tube. A small tolerance or gap may be present between the outer surface of the screw and the inner surface of the exit tube.

[0047] Generally, the device may comprise an actuator configured to rotate the screw pump, so that a dose of solid dosage form can be dispensed automatically (and accurately). This can allow dispensing of a particular dose without the user needing to count or calculate the number of rotations of the screw necessary to achieve a particular dose. The actuator may be a motor. The device may further comprise a removable / replaceable cartridge that is configured to attach to the actuator, the cartridge containing the solid dosage form, as well as the screw pump for dispensing thereof. This means that the cartridge can be replaced (instead of, e.g., the whole device). The cartridge may comprise a receptacle for storing a plurality of the solid dosage form, and the screw pump may be configured to dispense the solid dosage form from the receptacle.

[0048] The cartridge may further comprise a tapered portion adjacent to the exit tube and configured to guide or direct solid dosage form contained within the receptacle into the screw thread of the screw pump. The tapered portion may be provided by a surface of the cartridge forming an end of the receptacle, where the surface is angled such that it is not perpendicular to a longitudinal axis A of the screw pump or cartridge. The tapered portion helps to encourage the solid dosage form to flow into the exit tube and helps to avoid solid dosage form from becoming jammed or crushed against the surface.

[0049] In any of the aspects and embodiments described herein, the device may comprise means configured to vibrate the screw pump. Vibrating the units of the solid dosage form in the screw pump improves how they move through it, and ultimately improves reliability and accuracy. The use of a concavity as part of the screw (as described herein) combines with this vibration feature to achieve a technical effect that is greater than the sum of the effects of each feature separately. This is because the vibration causes the units interact with the concavity more than they would otherwise. For example, the vibration encourages the units of the solid dosage form to roll around the concavity as described, in a manner not achievable without the vibration. The vibration means may be placed adjacent to the cartridge and / or screw pump. The vibration means may comprise a motor.

[0050] Vibration may be applied before a dispensing step. This can help to aid in distributing the solid dosage form within the receptacle, for example those units of the solid dosage form that may have become jammed or highly compacted, and thereby help the solid dosage form to flow consistently and reliably into the screw pump during dispensing. Vibration may also be applied to the solid dosage form during a dispensing step. This can help to avoid solid dosage form from becoming jammed within the screw pump, and can help to provide smooth movement of the solid dosage form through the device. This helps to ensure that an accurate dose of solid dosage form is dispensed from the device. The vibration may occur throughout the whole of the dispensing step.

[0051] In any of the aspects and embodiments described above and herein, the helical channel may be formed in (e.g., cut away from) an otherwise cylindrical outer surface of the screw (otherwise known as the screw crest). The screw may include a single (i.e., only one) screw start, helical channel, and outlet, which allows greater control over the dispensing of the oral dosage form.

[0052] The screw crest may have a height (defined in a direction parallel to a longitudinal axis of the screw) which is at least 50% of the height of the helical channel profile, for example at least 75%, at least 100% or at least 125% of the height of the helical channel profile. The height of the channel profile may be defined as the maximum height of the channel profile, which is usually at the radially outer part of the channel profile (adjacent to the crest). The screw crest may have a height which is always at least 50% (or 75%, 100% or 125%) of the height of the profile of the channel regardless of the position of the profile along the helical path of the channel (excluding the outlet of the channel). This feature helps to provide a robust and stable screw pump which will retain its shape throughout use. Providing a crest of significant height (as defined above) also contributes to allowing smooth rotation of the screw pump throughout a dispensing step, because any potential contact between the crest and the inner surface of the exit tube will be distributed over a greater area than if a crest of smaller height were used. Overall, such a configuration has been found to contribute towards providing reliability when dispensing solid dosage form, and particularly solid dosage form in the form of mini-tablets or pellets, as defined below.

[0053] The helical channel may have a depth that is less than 90% of the radius of the screw, the radius defined relative to the rotational axis of the screw (the depth being defined in the radial direction). The helical channel may have a depth that is less than 75%, or even less than 50% of the radius of the helical screw. Such a screw may be easier to produce than other screw configurations, because it may be easier to produce a screw with a channel with a specific desired profile. For example, it may make it easier to achieve specific channel dimensions or a screw with specific features, for example a variable pitch. Channels with the above depth to radius ratios also allow the channel to be dimensioned optimally for dispensing solid dosage form, and in particular relatively small solid dosage form, for example pellets or mini-tablets. Such geometry allows a straight vertical parting line in injection moulding tooling, As such, the residuals of the parting line (known as “split lines”) will be easier to control and there will thus be a smoother surface with fewer obstacles for the solid dosage form to pass over when being dispensed. The outer surface of the screw may be a radially facing surface which follows a cylindrical envelope. The outer surface of the screw may be sized to cooperate with, and optionally be in sliding contact with, an inner surface of an exit tube of the screw pump.

[0054] Herewith will be described various aspects and embodiments of a screw for use with a dispensing device, and a dispensing device that may be used in the present invention, and in relation to any of the aspects and embodiments of the invention described herein insofar as they are suitable therefor.

[0055] Definitions

[0056] Solid dosage form - a medicament, drug or medication in solid form. This includes (but is not limited to) tablets, mini-tablets, pellets. Solid dosage for may comprise multiple units of medicament, drug or medication in solid form. The units may be generally uniform in size, or may include a range of unit sizes.

[0057] Solid oral dosage form - a solid dosage form which is designed or intended to be consumed by a patient orally.

[0058] Mini-tablet - a solid dosage form (e.g., a medicament, drug, medication, etc.) in the form of a tablet, each with a dimension smaller than that of conventional medicament tablets, optionally having a maximum dimension (e.g., a diameter, if the solid dosage form has a circular cross-section) of between about 1 mm and 7 mm, optionally between about 1 mm and 5 mm, optionally between about 1 mm and 4 mm, optionally between about 2 mm to 5 mm, optionally between about 2 mm and 4 mm, optionally between about 1 mm and 3 mm, optionally between about 3 mm and 4 mm. A height (which is a dimension of the tablet perpendicular to the width) of the mini-tablet may be between about 1 mm and 7 mm, optionally between about 1 mm and 5 mm, optionally between about 2 mm to 5 mm, optionally between about 2 mm and 4 mm, optionally between about 1 mm and 3 mm, optionally between about 3 mm and 4 mm. The width to height ratio may be between 0.8 and 1 .2. By “diameter” it is meant that the mini-tablets are assumed to be roughly spherical, although they could be irregular shaped. For example, the mini-tablets may have an ovoid shape. Each mini-tablet may typically be shaped as a cylinder with domed caps. The diameter or width / dimension could correspond to a largest width of the mini-tablets. Mini-tablets may or may not have a surface coating. Mini-tablets may be manufactured by a die stamping process.

[0059] Pellet - A single granule of a solid oral dosage form (e.g., a medicament, drug, medication, etc.), optionally having a dimension (e.g., width, diameter or largest dimension) of less than 2000 pm, optionally having a dimension (e.g., a largest dimension, width or diameter) between about 150 pm and about 1200 pm (or even about 1500 pm, optionally between about 200 pm and about 300 pm, between about 300 pm and about 900 pm, between about 500 pm and about 700 pm, between about 50 pm and 2000 pm, or between about 250 pm and 1000 pm). By “diameter” it is meant that the pellets are assumed to be roughly spherical, although they could be irregular shaped. The diameter could correspond to a largest width of the pellets, if they are not assumed to be spherical. Pellets may or may not have a surface coating. Where a surface coating is provided, the dimensions provided herein correspond to the pellets with any surface coating.

[0060] In various embodiments the pellets may have a dimension (e.g., a largest dimension, width or diameter) within one or more of the following ranges: 150-300 pm; 150-400 pm; 200-400 pm; 200-500 pm; 300-500 pm; 400-600 pm; 300-700 pm 500-700 pm; 200-800 pm; 600-800 pm; 700- 900 pm; 700-1200 pm; 800-1000 pm; 800-1100 pm; 900-1100 pm; 900-1200 pm; and 1000-1200 pm.

[0061] Dose - A single measurement (e.g., volume or weight) of solid dosage form, for example totalling between about 0.0.01 ml to about 5 ml (such as about 0.1 ml to about 0.6 ml) by volume, for example about 0.3 ml by volume (although sometimes such solid dosage form is measured by weight).

[0062] Dispensing Mechanism - A system, e.g., an electromechanical system that converts a user’s action into the dispensing of a dose.

[0063] Cartridge - A component, e.g., a replaceable component used to store and dispense solid dosage form, optionally containing features of the device such as a rotating member in the form of, e.g., a central threaded bar, a moving plunger and the pellets.

[0064] Plunger - A component that can ensure the solid dosage form stay packed together toward the dispensing end of the cartridge. It will be appreciated that references to “a” drug or medicament as referred to herein may be taken as “one or more” drugs or medicaments. For example, the solid dosage form could comprise several drugs or medicaments. This could be achieved by mixing solid dosage form, each comprising a different drug or medicament, and / or mixing drugs or medicaments.

[0065] BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0067] Fig. 1 shows a cutaway view of a device capable of dispensing a drug or medicament (e.g., an oral dosage form) in pellet form;

[0068] Fig. 2 shows a cutaway view of the screw pump of the device shown in Fig. 1 ;

[0069] Fig. 3 schematically illustrates a cross-sectional view of a screw and an exit tube suitable for use in the device shown in Figures 1 and 2;

[0070] Fig. 4 schematically illustrates a cross-sectional view of a cavity of the screw shown in Figure 3 with two units of solid dosage form located in the cavity;

[0071] Fig. 5 illustrates a side view of another screw suitable for use in the device shown in Figure 1 and 2;

[0072] Fig. 6 schematically illustrates a cross-sectional view of a cavity of the screw shown in Figure 5 with two units of solid dosage form located in the cavity;

[0073] Fig. 7 illustrates a side view of an exit portion of the screw shown in Figure 5;

[0074] Fig. 8 schematically illustrates a cross-sectional view of another screw and exit tube suitable for use in the device shown in Figure 1 and 2;

[0075] Fig. 9 schematically illustrates a cross-sectional view of another screw and exit tube suitable for use in the device shown in Figure 1 and 2;

[0076] Fig. 10 schematically illustrates a cross-sectional view of a cavity of the screw shown in Figure 9 with two units of solid dosage form located in the cavity;

[0077] Fig. 11 shows a cutaway view of another device capable of dispensing a drug or medicament (e.g., an oral dosage form) in pellet form; and

[0078] Fig. 12 schematically illustrates a side view of another screw suitable for use in the device shown in Figure 1 , 2 and 11 .

[0079] DETAILED DESCRIPTION Fig. 1 shows a schematic cutaway view of a device 100, which is a delivery device capable of dispensing a solid dosage form. The device 100 has the aim of making the dispensing of dosages of solid dosage form more reliable and efficient.

[0080] The device 100 comprises a first end 102 for connecting to an actuator or other driving mechanism (e.g., a motor), and a second end 104 (opposite the first end 102) that comprises the dispensing end of the device 100. In use, the medication will be dispensed out of the second end 104 as a result of the operation of the driving mechanism (e.g., motor).

[0081] The device 100 comprises a cartridge 200 that is configured to attach to the actuator or driving mechanism (e.g., motor) at the first end 102 of the device 100.

[0082] The device 100 comprises a rotating member 250 extending through the cartridge 200. As described in more detail below, at the first end 102 of the device 100 the rotating member 250 connects to the actuator or driving mechanism (e.g., motor), which is configured to rotate the rotating member 250 so as to cause solid dosage form to be dispensed from the second end 104 of the device 100.

[0083] The device 100 comprises an exit tube 212 at the second end 104 thereof, through which solid dosage form (drug, medicament, etc.) is dispensed.

[0084] The cartridge 200 is hollow and comprises a chamber 220 for holding a plurality of units of a solid dosage form (e.g., solid oral dosage form), and through which the rotating member 250 extends from the first end 102 of the device 100 to the second end 104 of the device 100.

[0085] The chamber 220 and / or the cartridge 200 may be substantially hermetically sealed (e.g., with the exception of the passage through which solid dosage form is dispensed). For example, at the first end 102 the connection between the rotating member 250 and the cartridge 200 may comprise a seal, for example an elastomeric gasket or valve (not shown). Similarly, at the second, dispensing end 104 of the device 100 a suitable seal (not shown) may be provided between the rotating member 250 and exit tube 212. For example, a packaging seal may be provided that covers and seals the outlet of the device (e.g., the exit tube 212), which a user can remove (e.g., peel off) when they wish to begin use. Additionally, or alternatively a valve may be used to at least partly seal the second, dispensing end of the device 100. These features can help prevent air and / or moisture from entering the chamber 220 and interacting with the units of the solid oral dosage form undesirably.

[0086] The rotating member 250 extends into the exit tube 212 at the second end 104 of the device 100, and comprises a screw 240. Together, the exit tube 212 and screw 240 form a type of screw pump configured to dispense solid dosage form from the second end 104 of the device 100. That is, solid dosage form will enter a helical channel 233 defined by a screw thread 242 of the screw 240 and, upon rotation of the rotating member 250, will be forced out of the exit tube 212 via the channel 233 and be dispensed from the device 100.

[0087] The rotating member 250 and the cartridge 200 may have a common longitudinal axis, which may also be the axis of rotation of the rotating member 250. However, in various embodiments the longitudinal axis of the cartridge 200 may be offset from that of the rotating member 250 and / or the axis of rotation of the rotating member 250.

[0088] Fig. 1 shows the cartridge 200 having an oblong shape. This shape may have advantages in terms of ergonomics, however this shape is not essential, and the cartridge 200 could have any suitable shape.

[0089] The device 100 may further comprise a plunger 230 (as shown in Fig. 1) that is configured to move along the rotating member automatically or as a result of the rotation of the rotating member.

[0090] Each cartridge 200 holds solid dosage form within the chamber 220 thereof, as described above. In embodiments involving a plunger 230, the volume of the chamber 220 varies during operation of the device 100 and throughout its lifetime by the action of the plunger 230, which will be described in more detail below.

[0091] At one end, the chamber 220 is enclosed at least in part by the plunger 230, and more specifically a radially extending surface 232 of the plunger 230 that faces the chamber 220. The other end of the chamber 220 is enclosed at least in part by a surface 210 of the cartridge 200. The rotating member 250 extends through the chamber 220 along the longitudinal axis A of the cartridge 200. As the rotating member 250 is rotated in use, the plunger 230 rests on top of the solid dosage form (not shown) located within the chamber 220.

[0092] The plunger may act by gravity, to move solid dosage form contained within the chamber towards the screw pump. For example, the plunger may be a weight configured to rest on top of solid dosage form contained within the chamber 220 when the device is in an orientation that permits dispensing of solid dosage form.

[0093] The plunger 230 may be configured to move along the rotating member 250 automatically or as a result of the rotation of the rotating member 250. For example, a portion of the rotating member 250 within the chamber 220 may comprise a screw thread (e.g., a plunger screw thread, which may be distinct from any screw thread of the screw pump) that is configured to cooperate with a corresponding screw thread 233 on the plunger 230, and the plunger 230 may form a nut around the rotating member 250 that is configured to travel along the screw thread of the rotating member 250 in use, such that, as the rotating member 250 rotates, the plunger 230 moves towards the screw pump so as to force solid dosage form contained within the chamber 220 towards the screw pump. The plunger 230 may be configured to abut and / or contact an inner surface of the cartridge 200 and / or chamber 220, and a friction fit may exist between the plunger 230 and the inner surface of the cartridge 200 and / or chamber 220, to help prevent the plunger 230 rotating with the rotating member 250.

[0094] In this manner, as the plunger 230 translates along the rotating member 250, the volume of the chamber 220 gradually decreases. Furthermore, solid dosage form contained within the chamber 220 will be forced towards the second end 104 of the cartridge 200 by the plunger 230 throughout the operation and lifetime of the device 100. The device 100 may include certain features that provide a driving force to the plunger 230 that acts in a direction towards solid dosage form located within the chamber 220, for example other than relying on the weight of the plunger 230 as described above. For example, a ratchet mechanism may be used, or a resilient member (e.g., a spring) may be provided to force the plunger 230 towards the solid dosage form located within the chamber 220.

[0095] In use, the radially extending surface 232 of the plunger 230 presses onto the solid dosage form and forces it towards the second, dispensing end 104 of the device 100, which assists in packing the solid dosage form tightly within the chamber 220.

[0096] The plunger 230 may be configured to fill the gap between the rotating member 250 and the walls of the container 200, such that solid dosage form contained within the chamber 220 cannot move past the plunger 230 as it moves down the rotating member 250 in use.

[0097] In other embodiments, there may not be a plunger present, and the solid dosage form may be contained within the chamber 220 by an end surface of the cartridge. In such an embodiment, gravity may be relied upon to ensure that the solid dosage form stays at the bottom of the device to feed into the screw pump during dispensing.

[0098] Fig. 2 schematically shows the second, dispensing end 104 of the cartridge 200 in more detail, at which end there is located the exit tube 212, with the screw 240 of the rotating member 250 extending through the exit tube 212 as discussed above.

[0099] A radially outer surface 241 of the screw 240 may substantially contact (and / or abut) a radially inner surface 214 of the exit tube 212. The outer surface 241 of the screw 240 and the radially inner surface 214 of the exit tube 212 may substantially contact each other or abut (e.g., continuously or intermittently), but not to the extent that they have an interference or friction fit relative to each other, to ensure that they can move smoothly past each another and ensure reliable dispensing as the radially outer surface 241 of the screw 240 rotates past the radially inner surface of the exit tube 212. If the surfaces are configured to contact each other (e.g., continuously or intermittently), the surfaces may be manufactured from low friction materials (e.g., a non-stick coating). In various embodiments, a tolerance or gap between the outer surface 241 of the screw 240 and the inner surface 214 of the exit tube 212 may be present, and may be large enough to allow free rotation of the shaft 250, but small enough to prevent any solid dosage form (and / or pellet debris) from sliding between the gap, adding friction and inhibiting the free rotation.

[0100] The screw 240 defines at least one helical channel 233 defined by the screw thread 242. The screw 240 is configured to receive units of solid dosage form contained within the chamber 220 and transport them, upon rotation of the rotating member 250, along the channel 233 to be dispensed out of the exit tube 212. The screw thread 242 defines one or more channel starts, each channel 233 forming a continuous helix that the solid dosage form fills during operation of the device 100, for example due (at least in part) to the action of the plunger 230 (when present) pressing on the solid dosage form within the chamber 220, which forces them into the channel 233. The screw 240 contacts or cooperates with the inner radial surface of the exit tube 212 so as to form a screw pump (e.g., an “Archimedes” screw) with the exit tube 212 of the cartridge 200. That is, as the rotating member 250 rotates, the screw 240 will also rotate, causing solid dosage form contained within the chamber 220 to enter the channel 233 of the screw 240, travel down the channel 233 of the screw thread 242 and exit the cartridge 200. The screw pump may comprise an outlet 243 through which solid dosage form is dispensed.

[0101] The actuator or driving mechanism (e.g., an electric motor) may be configured to rotate the rotating member 250, and may be connected to the rotating member 250 at the first end 102 of the device, as described above. The actuator may be configured to provide a rotary force to the rotating member 250, and, in turn, to the screw thread(s) 242, 252 of the rotating member 250. The actuator may be either mechanical (e.g., manually operated) or electromechanical (e.g., electrically operated, for example an electric motor). The actuator (or a control unit comprising the actuator) may be detachable from the cartridge 200, so that different cartridges could be connected to the same actuator or control unit.

[0102] In order to dispense the solid dosage form from the cartridge 200, the actuator 300 may rotate the rotating member 250. This causes (in relevant embodiments) the plunger 230 to move down the screw thread 252 of the rotating member 250, and / or the screw 240 to rotate, causing the solid dosage form to be dispensed via the screw pump.

[0103] The device 100 may include a control system (e.g., as part of the actuator or control unit), which may be configured to control rotation of the screw to dispense a dose of the solid dosage form. An actuating signal of the control system may be initiated, for example, by a user pressing a suitable button or other input mechanism located on the control unit, in order to initiate dispensing. The control system may be provided in the form of a computer, processor, processing device or microcontroller, e.g., on a PCB, which may be located within the housing of the device 100 of within the actuator or control unit.

[0104] By using an electromechanical actuating mechanism, the device 100 may be able to dispense a precise amount of solid dosage form repeatedly. The motors, and the control system may be powered by an integrated battery (which may be user replaceable), which may be held within the housing of the actuator.

[0105] The cartridge 200 may be made from a rigid material, for example polycarbonate or polyamide, although any suitable material may be used. The inner diameter of the cartridge 200 (i.e. , forming the chamber 220) may be between about 5 mm to about 200 mm, optionally between about 10 mm to about 30 mm, optionally about 10 mm to about 20 mm. The cartridge 200 may have a length (corresponding to its longest dimension) of between about 90 mm and about 120 mm, a width (transverse to its length) between about 33 mm and about 43 mm, and a height (transverse to its width) of between about 15 mm and about 25 mm.

[0106] The exit tube 212 may have an internal diameter that substantially equals the diameter of the rotating member 250, and specifically the screw 240 thereof. This internal diameter may be less than 10 mm, for example less than about 6 mm. The length of the exit tube 212 along the longitudinal axis A of the device 100 may be less than about 20 mm (such as about 15 mm or about 10 mm).

[0107] The volume of the chamber 220 (i.e., prior to operation or a maximum volume) may be less than about 75 ml, for example less than 20 ml or approximately 14 ml.

[0108] The cartridge 200 comprises a tapered portion 210 at the second end 104 of the device 100. The tapered portion 210 is configured to guide or direct solid dosage form contained within the chamber 220 into the screw threads 242 of the screw 240. In other words, the surface 210 may be tapered or angled such that it is not perpendicular to the longitudinal axis A, but is oriented at an angle with respect thereto, for example an angle of about 30°, 60° or more. The tapered portion 210 helps to encourage the solid dosage form to flow into the exit tube 212 and helps to avoid solid dosage form from becoming jammed or crushed against the surface 210. This can be particularly important if a plunger 230 is present, as the tapered portion 210 helps to avoid the solid dosage form from becoming over compacted between the surface 210 and the plunger 230, especially when the plunger 230 is near the second end 104 of the device 100. In embodiments, the tapered portion is omitted and the second end 104 of the cartridge 200 may be perpendicular to the longitudinal axis A.

[0109] The outer surface 241 of the screw 240 may be made from a low friction material, for example nylon, polyethylene (“PE”), polyethylene terephthalate (“PET”), PBT optionally containing friction reducing additives. The cartridge 200 and portions thereof that abut, oppose or contact the screw 240, plunger 230 (when present) or other moving parts of the device 100 may also be made from a low friction material.

[0110] In the embodiment of Figs. 1 and 2, the screw 240 is configured such that the whole of the screw thread 242 is located within the exit tube 212. In this embodiment, there is a gap 211 between a top of the exit tube 212 (the top being where the exit tube 212 meets the surface 210 of the cartridge) and a top of the screw thread 242 of the screw 240. It has been found that providing a gap 211 between the top of the exit tube 212 and the top of the screw thread 242 allows the solid dosage form to flow into the screw thread 242 whilst avoiding crushing of the solid dosage form between the screw thread 242 and the top of the exit tube 212. However, whilst advantageous this feature is not essential for operation, and in other embodiments the screw thread 242 may extend to or above the top of the exit tube 212.

[0111] As best illustrated in Fig. 2, the screw thread 242 has a variable pitch. The screw thread 242 illustrated has a pitch which decreases as the screw thread 242 moves towards the outlet 243. The pitch may decrease gradually towards the outlet 243. This contributes to providing a constant density of solid dosage form (for example powder / pellets) and also contributes to avoiding jamming and crushing of the solid dosage form during dispensing. This is because the solid dosage form will enter the screw pitch with varied bulk density due to the randomness of the feed, then along the decreasing pitch the bulk density of the solid dosage form will stabilize. However, whilst advantageous this feature is not essential for operation, and in other embodiments the screw thread 242 may have a constant pitch or a variable pitch that varies differently to that shown.

[0112] The screw thread 242 may have a helix angle of between 1 to 60 degrees and optimally between 10 to 25 degrees. It has been found that a screw pump with a helix angle between these values is particularly effective at dispensing solid dosage form, and especially small units of a solid dosage form, for example in the form of mini-tablets or pellets. However, the optimal angle range may vary depending on the flowability characteristics of the solid dosage form. It has been found that a screw pump with a helix angle between these values is particularly effective at dispensing solid dosage form, and especially small units of a solid dosage form, for example in the form of mini- tablets or pellets. These helix angles are relatively shallow, which contributes towards avoiding jamming and crushing of solid dosage form, because the solid dosage form is moved relatively slowly or gradually in an axial direction by the screw pump. The helix angle also helps to provide more accurate dosing, because it helps to avoid solid dosage form from flowing out the screw pump too quickly. As such, it is easier to dispense solid dosage form from the screw pump in a controlled manner.

[0113] The exit tube 212 may have a length of between about 5 mm and about 20 mm (optionally between about 10 mm and about 15 mm), wherein the length of the screw thread 242 in a direction along the longitudinal axis A of the cartridge 200 may be at least the length of the exit tube 212 in the same direction, for example between about 1 to about 5 times the length of the exit tube 212, for example about 1 .2, 1 .3, 1 .4, 1 .5 or 2 times the length of the exit tube 212.

[0114] The rotating member 250 may comprise a high stiffness and / or rigid material, for example polycarbonate or polyamide. The diameter of the rotating member 250 can vary from about 3 mm to about 10 mm, for example about 3 mm to about 6 mm. The diameter of the rotating member 250 may be equal to the diameter of the outer surface 241 of the screw 240, e.g., along its entire length (along the longitudinal axis A).

[0115] The actuator, if provided with an electromechanical motor, may be configured to rotate the rotating member 250 at a rate of between about 0 rpm and about 1000 rpm, optionally between about 50 rpm and about 500 rpm, optionally between about 90 rpm and about 150 rpm.

[0116] Generally, the apparatus and devices disclosed herein may be aimed at providing an accurate dose of medication by weight, and also providing a simple mechanism by which to administer a dose.

[0117] Figure 3 illustrates a schematic cross-sectional view of a portion of a conventional screw 340 for use in a dispensing device for dispensing solid dosage form, such as the device 100 described above, as well as a section of an exit tube 312 as described above. The screw 340 and the exit tube 312 cooperate to form a screw pump, such as the screw pump described above in relation to Figures 1 and 2.

[0118] As shown in Figure 3, the screw 340 has at least one helical screw thread 342 which has a rectangular cross-sectional shape (the cross-sectional shape being radial, that is defined in a plane coinciding with a longitudinal axis A of the screw 340). The helical screw thread 342 surrounds a central core of the screw 340. A radially outer surface 341 of the helical screw thread 342 fits snugly within (and may be in contact with) a cylindrical radially inner surface 343 of the exit tube 312, as described above.

[0119] A helical channel 333 is defined along the at least one screw thread 342. The helical channel 333 has a rectangular cross-sectional shape. When the screw 340 is taken in isolation of the exit tube 312, the helical channel 333 is an open channel 333 defined by an axially extending (or “radially inner”) surface 350, with two surfaces 351 , 352 extending radially therefrom. The axially extending inner surface 350 of the screw 340 is perpendicular to each of the parallel surfaces 351 , 352. Accordingly, the helical channel 333 has a radial cross-section in the shape of a ‘U’ with right- angled edges.

[0120] When the screw 340 is located in the exit tube 312, a channel 333 with a rectangular cross- sectional shape is formed, as shown in Figure 3.

[0121] As explained in relation to Figures 1 and 2, the exit tube 312 and the screw 340 together form a screw pump configured to dispense solid dosage form from the device 100. Solid dosage form will enter the channel 333 and, upon rotation of the screw 340, will be forced out of the exit tube 312 via the channel 333 and dispensed from the device 100.

[0122] It has been found that the screw 340 illustrated in Figure 3, although having certain advantages generally, may cause interlocking of solid dosage form when the screw pump is rotating. This is illustrated schematically in Figure 4, which shows two units of solid dosage form 360 interlocked or jammed within the channel 333 when the screw 340 is located in the exit tube 312. As can be seen, the units of solid dosage form 360 are being pushed towards each other by the radially inner surface 350 of the screw 340 and the radially inner surface 343 of the exit tube 312. Because the radially inner surface 343 of the exit tube 312 and the radially inner surface 350 of the screw 340 are parallel, these surfaces exert parallel reaction forces on the solid dosage form 360, causing them to become jammed between these surfaces. The reaction forces are illustrated by arrows.

[0123] This is exacerbated in this instance by the combined diameter of the solid dosage form 360 being approximately equal to the distance between the radially inner surface 343 of the exit tube 312 and the radially inner surface 350 of the screw 340. This can inhibit the solid dosage form from being able to freely and effectively flow down the channel 333 to be dispensed from the device, because the pellets stick and are unable to flow or move freely within the channel 333.

[0124] Another problem has been identified with the screw 340 illustrated in Figures 3 and 4. This is due to the radially inner surface 350 of the screw 340 being generally perpendicular to each of the parallel surfaces 351 , 352. This, combined with a sharp corner between the two parallel surfaces 351 , 352 and the radially inner surface 350 of the screw 340, means that once interlocking or jamming of the solid dosage form has occurred, the solid dosage form can become stuck in the corner defined between an axially facing surface 351 , 352 and the radially inner surface 350 of the screw 340 and cannot escape.

[0125] The interlocking of solid dosage form in the screw pump can inhibit effective dispensing of solid dosage form from the device, which can result in unpredictable fluctuations in the number of units of solid dosage form being dispensed from the device for a certain number of rotations of the screw thread 342. This is of course problematic for a device aimed at dispensing a drug or medicament, where accurate and predictable dispensing of the drug or medicament can be of critical importance. For example, an incorrect dose may have significant health or safety implications.

[0126] Figure 5 illustrates a side view of an embodiment of the invention, which includes an advantageous screw 440. The screw 440 shown in Figure 5 is suitable for use in the device described in relation to Figures 1 and 2, as well as any other dispensing devices that incorporate a screw thread to form a screw pump.

[0127] Similarly to the screw 340 shown in Figure 3, the screw 440 shown in Figure 5 has at least one helical screw thread 442. The helical screw thread 442 extends around a central core of the screw 440.

[0128] As shown, the screw thread 442 defines a helical radially outer surface 441 . The radially outer surface 441 of the screw thread 442 is shaped to fit snugly within (and may be in contact with) a cylindrical surface of the screw pump (for example, radially inner surface 443 of an exit tube 412, as described above). A tolerance gap may be present between the outer surface 441 and the cylindrical surface of the screw pump.

[0129] A helical channel 433 is defined along the screw thread 422. As shown in Figures 5 and 6, when the screw 440 is taken in isolation of the exit tube 412 the helical channel 433 is an open channel 433 defined at least in part by a concavity, so as to form, in the illustrated example, a substantially curved cross-sectional profile 450 of the channel.

[0130] Locating the screw 440 in a screw pump (e.g., the exit tube 412) substantially closes the channel 433, as shown in Figure 6. This shows a schematic cross-sectional view of one level of the channel 433 at a position along the helical path thereof and an inner surface 443 of the screw pump (e.g., the exit tube 412 shown in Figures 1 and 2). The cross-sectional profile shown in Figure 6 (and referred to elsewhere herein) is defined in a plane coinciding with a longitudinal axis A of the screw 440.

[0131] As explained in relation to Figures 1 and 2, the exit tube 412 and the screw 440 may together form a screw pump configured to dispense solid dosage form from the device. Solid dosage form will enter the channel 433 and, upon rotation of the screw 440, will be forced out of the screw pump via the channel 433 to be dispensed from the device.

[0132] The cross-sectional profile 450 of the channel shown in Figure 6 has a ‘U’-shape and is devoid of sharp corners. The profile 450 can be considered to include a lower portion 451 , an upper portion 453 and a central portion 455 joining the lower and upper portions 451 , 453. The lower and upper portions 451 , 453 extend generally radially (relative to a longitudinal axis of the screw) from opposite ends of the central portion 455 to respective radially outermost points 459, 461 of the channel profile 450.

[0133] As illustrated in Figure 6, the central portion 455 is continuously curved and extends continuously to the lower and upper portions 451 , 453 such that there is no sharp corner where the central portion 455 meets the lower and upper portions 451 , 453. In the disclosed embodiment, the radius of curvature of the profile 450 along central portion 455 is greater than the radius of curvature of the profile 450 along the lower and upper portions 451 , 453. The central portion 455 forms a radially inner portion of the profile 450.

[0134] In this embodiment, the central portion 455 has a radius of curvature along its profile which is greater than the radius of curvature along the lower and upper portions 451 , 453 such that the central portion 455 follows a profile which is more tightly curved than the lower and upper portions 451 , 453. In this embodiment, the radius of curvature of the central portion 455 has a maximum value at a radially innermost point 463 of the central portion 455. The radius of curvature along the central portion 455 then reduces gradually as the central portion 455 transitions radially outwardly towards the lower and upper portions 451 , 453.

[0135] The lower portion 451 has a radius of curvature which reduces gradually as the lower portion 451 transitions radially outwardly from the central portion 455 to the radially outermost point 459. In this embodiment, the lower portion 451 is continuously curved along its whole length, but in other embodiments the lower portion 451 may be substantially straight adjacent to the radially outmost point 459, and may transition gradually into a curve to meet the central portion 455.

[0136] As mentioned above, the lower portion 451 extends generally radially from the central portion 455 to a radially outermost point 459 of the profile 450. As illustrated in Figure 6, a tangent to the lower portion 451 at the radially outermost point 459 defines an angle 457 relative to the radial direction. The angle 457 is greater than zero, and may advantageously be between 5 and 45 degrees.

[0137] Providing the angle 457 within this range helps to avoid jamming of solid dosage form 460 in the channel, because the non-zero angle 457 helps to urge solid dosage form around the profile 450 and prevents solid dosage form from becoming stuck between the radially outermost point 459 and the exit tube 412. The non-zero angle 457, and more advantageously the angle 457 of between 5 and 45 degrees, also acts to make the screw pump more reliable at dispensing solid dosage form. This is at least in part because the angle 457 means that the screw pump can still effectively dispense solid dosage form even if the screw pump is not held perfectly vertically. This is because the angle helps to avoid a situation where the channel profile 450 essentially forms a vertically facing “cup” ( i.e. where the lower portion 451 of the profile 450 extends in a upward rather than downward direction as it transitions radially outwardly from the central portion 455), which would hinder movement of the solid dosage form down the screw as the screw rotates. An angle 457 of between 5 and 25 degrees can ensure that the screw thread is not too large (using an angle above 25 degrees, whilst beneficial for avoiding jamming, would require the screw thread to be very large in order to contain a sufficient number of units). Similarly, an angle of between 10 and 45 degrees (or between 10 and 25 degrees) can ensure optimum results for avoiding jamming, due to the increased lower limit.

[0138] In this embodiment, the upper portion 453 is symmetrical to the lower portion 451 about a radial line extending through the centre of the profile. This may not be the case and the upper portion 453 may be different. It will be appreciated that the most important surface is the one upon which the units of medicament will rest in use, that is the lower portion 451 . However, providing the same features in the upper portion 453 also helps.

[0139] As illustrated in Figure 6, the curved profile 450 helps to avoid jamming of solid dosage form 460 within the channel 433 when the screw pump is rotating, because a unit of solid dosage form 460 adjacent to the surface 450 will tend to roll around the surface 450 upon compression being applied thereto (as illustrated by arrows in Figure 6 which illustrate the direction of movement of the solid dosage form within the channel). This helps to avoid jamming or interlocking of solid dosage form. It will be appreciated that the schematic drawing in Figure 6 is for illustrative purposes only, and the pellet to channel size ratio may vary to that shown, for example the solid dosage form may be smaller than those illustrated. In other words, the invention is applicable to any solid dosage form, and / or size of the solid dosage form.

[0140] In addition to the avoidance of jamming, providing the angled lower portion 451 also helps to improve movement of units through the screw pump when the device is oriented at an angle relative to vertical (which, it will be appreciated, is highly likely for a device dispensing medicament). This is in contrast to a device with a non-angled or horizontal lower portion, which will point upwards when the device is oriented in this way.

[0141] The surfaces defining the channel 433 may benefit from having a relatively high surface roughness. It has been found that having a channel 433 with a surface roughness of between about 20 and 40 VDI, more preferably 25 to 30 VDI, and even more preferably about 27 VDI (defined using the “Verein Deutscher Ingenieure” standard) is particularly advantageous, because this causes the solid dosage form to predominantly roll along the surface rather than slide along it. This has been found to cause the solid dosage form to flow through the channel 433 more consistently and effectively, and can help to avoid jamming of solid dosage form within the channel 433. Although described in relation to the screw 440 shown in Figures 5 and 6, the surface roughness can be applied to any of the aspects and embodiments described herein, including for example those described in relation to Figures 8 to 10.

[0142] Figure 7 illustrates an outlet portion 432 of a screw according to an embodiment, which may be a screw 440 as illustrated in Figures 5 and 6. The outlet portion 432 is suitable for use in the device described in relation to Figures 1 and 2, as well as any other dispensing devices that incorporate a screw thread As shown, the outlet portion 432 corresponds to the end of the channel 433, and bends towards the rotational axis of the screw pump. The channel 433 ends at an outlet 434 such that the solid dosage form exits the outlet 434 in more of an axial direction (i.e., a longitudinal axis of the channel 433 bends towards the rotational axis of the screw pump). This has been found to assist in dispending of solid dosage form through the outlet 434.

[0143] The longitudinal axis of the channel 433 at the outlet portion 432 may have a substantially constant radius of curvature. In this embodiment, the channel 433 turns through an angle of over 80 degrees (the angle may be slightly greater or lesser than this). Without wishing to be bound by theory, it is thought that the walls of the channel 433 exert a higher amount of friction to the units of solid dosage form, slowing them down, which reduces the pressure and density of the units of solid dosage form within the channel 433 as they flow towards the outlet 434. The result is that the solid dosage form flows more easily through the outlet 434.

[0144] Furthermore, as also shown, the helical channel 433 can increase in width towards the outlet. The helical channel 433 may transition from the generally helical path to bend towards the axial direction, as described above. The outlet portion 432 may include a progressively increasing width, as illustrated by arrows in Figure 7. The width may eb defined as the largest distance perpendicular to and extending through a longitudinal axis of the helical channel 433. This also helps to reduce the density of units of solid dosage form and pressure within the channel 433 towards the outlet 434. Although illustrated in relation to the screw 440 shown in Figures 5 and 6, the outlet portion 432 can be applied to any of the aspects and embodiments described herein, for example those described below in relation to Figures 8 to 10.

[0145] Figure 8 is a schematic cross-sectional view of an embodiment, in which a screw 540 is provided and is suitable for use in the device described in relation to Figures 1 and 2, as well as any other dispensing devices that incorporate a screw pump.

[0146] This screw 540 in this embodiment includes a cross-sectional profile of the channel 533 that is defined by two radially extending surfaces 551 , 552 that form straight lines in cross-section through the rotational axis of the screw pump, and a curved central portion 550 (i.e., the central portion 550 forms a curve in cross-section through the rotational axis of the screw pump). The central portion 550 forms a radially inner surface 550 of the screw 540, and interconnects the two radially extending surfaces 551 , 552. The radially extending surfaces 551 , 552 may be parallel.

[0147] The radially extending surfaces 551 , 552 may each meet the central portion 550 at a junction (i.e., the point at which these surfaces meet). The angle between each radially extending surface 551 , 552 and the central portion 550 at the junction may be greater than 90 degrees (obtuse). Thus, this arrangement still provides a concavity, which helps to avoid jamming of solid dosage form in the channel, as well as a gradual transition between the side surfaces 551 , 552 and the central portion 550 (e.g., as compared to the screw 540 of Figures 3 and 4). Figure 9 is a schematic cross-sectional view of an embodiment, in which a screw 640 is suitable for use in the device described in relation to Figures 1 to 2, as well as any other dispensing devices that incorporate a screw pump.

[0148] This screw 640 differs from that shown in Figures 5 and 6 in that a fillet 653 is provided between the bottom (the top and bottom defined in relation to the orientation of the screw pump when in use) axially facing surface 652 and the radially inner surface 650 of the screw 640. As shown in Figure 10, which illustrates a cross-section of the fillet 653 and two units of solid dosage form 660, the fillet 653 helps to reduce the probability of jamming of solid dosage form, because the fillet 653 will avoid a sharp corner and prevent jamming of the solid dosage form. Although one fillet 653 is shown, in other embodiments there may also be a fillet 653 between the top axially facing surface 651 and the radially inner surface 650. The fillet 653 illustrated is in the form of a mitre fillet. However, in other embodiments the fillet may be a concave fillet, which may further aid in reducing the chance of jamming of pellets, since a concave fillet helps to avoid sharp corners.

[0149] The screws illustrated in Figures 5 to 10 provide a screw pump for a device for dispensing solid dosage form which aids in avoiding the solid dosage form jamming or interlocking within the channel of the screw pump during dispensing. As explained, this results in a device which is highly accurate and effective at dispensing a particular dose of the solid dosage form. As also explained, the screw pump provides simple and effective means for dispensing the solid dosage form. The number of rotations of the screw pump dictates how much of the solid oral dosage form is dispensed, and a particular dose (which can be individualised to a patient) can be dispensed from the device, where the same device can easily dispense different doses by changing the amount of rotation of the screw pump. The described screw profile helps to ensure that the dose dispensed by the device accurately correlates with the number of rotations of the screw pump.

[0150] Figure 11 illustrates a perspective cutaway view of a device 700 for dispensing solid dosage form comprising a screw pump 741 with a screw 740 as defined above. The device 700 comprises the screw pump 741 at a second end 722 thereof. The device 700 may comprise a vibration device 731 , as described below. The device 700 is similar to the device shown in Figures 1 and 2 and features of the device described in relation to Figures 1 and 2 can also be applied to the device shown in Figure 11 .

[0151] The device 700 comprises a cartridge 701 and a control assembly 703. The cartridge 701 is configured to mate with the control assembly 703 and the cartridge 701 is attachable to and removable from the control assembly 703.

[0152] The control assembly 703 comprises an actuator or driving mechanism 705, for example an electric motor.

[0153] The control assembly 703 extends from a first end 720 to a second end 722. The control assembly 703 may comprise a first portion 710 located towards the first end 720, and a second portion 720 located towards the second end 722. The first portion 710 may comprise a pocket or cavity 721 shaped to receive and hold the cartridge 701 . The first portion 710 may further comprise a battery 707 and optionally a vibration device 731 . The second portion 720 is configured to contain various control electronics and the actuator 705 to control the dispensing of medication from the cartridge 701 . The second portion 720 may be relatively thick and / or bulky, with the first portion 710 forming an elongate extension from the second portion 720, which overlies a majority of the cartridge 701 . This can help to distribute the weight of the device 700 evenly and make it more comfortable to hold and / or easier to operate. In other embodiments, the components may be distributed differently.

[0154] The control assembly 703 may comprise an interface 732 at a junction between the first portion 710 and the second portion 720, wherein the interface 732 is configured to mate with the cartridge 701 . When the cartridge 701 is received in the control assembly 703, an end of the rotating member 750 of the cartridge 701 mates with a rotating member 751 of the actuator 705 of the control assembly 703 located at the interface 732, such that when the rotating member 751 of the actuator 705 rotates, this causes rotation of the rotating member 750 of the cartridge 701 to dispense the drug or medicament from the cartridge 701 , as described further below. The mating may be achieved in any suitable manner, for example using complementary teeth which engage with each other.

[0155] The first portion 710 of the control assembly 703 may further comprise means 731 for vibrating the solid dosage form within the cartridge 701 . This may be any suitable device that causes vibration. The vibration device 731 may be a motor, such as an eccentric rotating mass (“ERM”) or linear resonant actuator (“LRA”) motor. The vibration device 731 may be placed adjacent to or close to the cartridge 701 such that the vibration motor 731 is configured to vibrate the units of the solid dosage form within the cartridge 701 .

[0156] In the illustrated embodiment, the vibration motor 731 is located at the first end 720 of the first portion 710 of the control assembly 703 such that the vibration motor 731 is close to the screw pump 741 of the cartridge 701. In other embodiments, the vibration device 731 may be placed in another portion of the device 700, for example in the second portion 720 of the control assembly 703.

[0157] The vibration device 731 is configured to vibrate the units of the dosage form within the screw pump 741 . Vibrating the units of the solid dosage form in a screw pump 741 , especially with the new screw designs as described above, results in a device which is particularly reliable and accurate. This is because the new screw design and the vibration both contribute towards avoiding jamming of solid dosage form within the screw pump 741 during dispensing. The vibration generated encourages movement of solid dosage form within the screw of the screw pump 741 if it starts to become jammed, further preventing jamming from occurring.

[0158] Figure 12 illustrates a side view of another embodiment an advantageous screw 840. The screw 840 shown in Figure 12 is suitable for use in the devices described in relation to Figures 1 , 2 and 11 (and is hereby disclosed in combination with these devices), as well as any other dispensing devices that incorporate a screw thread to form a screw pump. The screw 840 shown in Figure 12 is similar to the screw shown in Figure 5 (and has equivalent features), except that the channel 833 of the screw illustrated in Figure 12 extends circumferentially by one half turn (180 degrees) about the longitudinal axis of the screw. It has been found that a screw thread with a channel 833 with one and a half full turns or less, especially but not necessarily with the channel profile shown in Figure 6, is highly effective at dispensing medication (in particular pellet medication) whilst allowing the device to be more compact, and can even more effectively dispense pellet medication accurately whilst avoiding jamming of pellets in the screw.

[0159] The use of a device with a screw pump comprising a screw according to any of the above embodiments (and optionally a vibration device) is advantageous when used to dispense any type of solid dosage form. However, the screw pump may be particularly advantageous when used to dispense small units of a solid dosage form, such as in the form of pellets (as defined herein). The screw pump has been found to be particularly accurate at dispensing a dose of pellet medication. The screw pump is also able to provide accurate dose adjustments (by varying the number of turns of the screw pump during dispensing) so that the dose can be easily and continuously varied using the same dispensing device. This means that an individualised dose can be applied and dispensed more easily, and depending on an individual user’s needs. Another advantage is that the pellets could be easy to swallow by patients having difficulty swallowing, who might alternatively crush tablets in order to swallow. Variable dosing of pellets allows for a more exact tuning of a dose than what may be achieved using larger dosage forms such as tablets or capsules (which can typically only be cut along predetermined lines of weakness). Pellets have been found to be particularly prone to becoming jammed in the screw, however, and the screw designs according to the invention aid in preventing such jamming so that accurate doses of pellets can be dispensed.

[0160] As explained, the use of a screw pump according to the invention is particularly advantageous when used in a device configured to dispense small units of a solid dosage form. This is equally applicable to mini-tablets (as defined herein). Mini-tablets are smaller than conventionally sized tablets. Use of a medication formulated as mini-tablets can also support accurate dose adjustment and help with difficulties with swallowing. The use of vibration in a device for dispensing mini-tablets can also help to ensure that the density of the mini-tablets within the cartridge is consistent. Mini-tablets can also be prone to becoming jammed, and the new screw design and vibration means can also help to avoid such jamming.

[0161] It will be appreciated that the screw design could be used in any device for dispensing drugs in solid oral dosage form with a screw pump, and is not limited to use in the device shown in Figures 1 and 2.

[0162] The device defined herein may combine medical knowledge with digital capabilities. The control unit may be reusable, and may be combined with various different cartridges that are prefilled with a prescribed medication. For ADHD, for example, a cartridge could be prefilled with the relevant medication for use over a one-month period. The cartridges could be filled with solid oral dosage form. The solid oral dosage form could be taken with liquid or soft foods supporting swallowing of the medicine. Although the device has a particular use with ADHD, the technology disclosed herein is applicable to many other treatments and especially for paediatric use or for use in psychiatry, neurology, cardio-metabolic disorders or oral cancer treatments.

[0163] Example treatments that may be associated with the apparatus described herein are Attention Deficit Hyperactivity Disorder (“ADHD” - wherein the medication used in the device could include amphetamines and / or methylphenidate), general pain (wherein the medication could include one or more of fentanyl, methadone, meperidine, tramadol, morphine, codeine, thebaine, oxymorphone, hydrocodone, oxycodone, hydromorphone, naltrexone, buprenorphine and methadone), immunosuppression post organ transplant (wherein the medication could include one or more of tacrolimus, sirolimus, everolimus, corticosteroids, cyclosporine, mycophenolate and azathioprine), diabetes (wherein the medication could include one or more of sitagliptin, vildagliptin, saxagliptin, linagliptin, metformin, canagliflozin, Dapagliflozin, empagliflozin and semaglutide), heart failure (wherein the medication could include one or more of carvedilol, metoprolol, bisoprolol and diurethics), Parkinson's disease (“PD” - wherein the medication could include levodopa and / or carbidopa ), epilepsy (wherein the medication could include one or more of sodium valproate, carbamazepine, lamotrigine, levetiracetam, oxcarbazepine, ethosuximide and topiramate), depression (wherein the medication could include one or more of Citalopram, bupropion, paroxetine, milnacipran, fluoxetine, duloxetine, fluvoxamine and reboxetine), schizophrenia (wherein the medication could include one or more of aripiprazole, asenapine, brexpiprazole, cariprazine, clozapine, iloperidone, lurasidone and olanzapine), cancer, animal health, oncology (substances mercaptopurine, methotrexate, temozolomide, isotretinoin, imatinib). For example, the device may be combined with medication (e.g., in pellet form) that is aimed or associated with the aforementioned treatments, for example any or all of those described above.

[0164] Use of a medication formulated as pellets or mini-tablets can support accurate dose adjustment and help paediatrics with swallowing issues. Developments for paediatric medicines have generally included different formulations or devices which go toward solving one or two of the challenges faced with this patient population. By combining the medication with a digital capability with the handheld apparatus disclosed herein, leads to improvements in dose setting, titration, ease of use, swallow-ability and compliance. The technology can be tailored to different treatment regimens for paediatric populations including combination therapy. Other areas for treatment using the device disclosed herein could be epilepsy and general pain alleviation. The dispensing technology could also be developed for infectious diseases, for example in children, for example the medication used with the apparatus (e.g., in pellet form) could include amoxicillin and / or penicillin.

[0165] The control unit (in any of the aspects or embodiments described herein) may include an input device or user interface, which may include one or more buttons for operating the apparatus, for example the dispensing mechanisms therein.

[0166] The control unit may comprise a or the control system configured to operate the various electrical and mechanical parts of the apparatus, for example a user interface, display and dispensing mechanisms. A prefilled cartridge (e.g., for ADHD, with a one-month prescription) may have an integrated circuit board trip that communicates relevant information to the control unit. The control unit may set the dosage, prevent taking more than a maximum dosage, allow titration, and ensure notification of tampering. The control system may record dispensing of medication, for example over a defined period (e.g., the one-month prescription).

[0167] Although the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.

Claims

Claims1 . A screw pump for dispensing a solid dosage form (e.g., a drug or medicament), the screw pump configured to transport units of the solid dosage form for dispensing, wherein the screw pump comprises a screw comprising a helical channel, wherein a surface defining the helical channel has a profile at a position along the helical path of the helical channel, the profile being defined in a plane extending along a rotational axis of the screw pump and presenting a concavity.

2. The screw pump as defined in claim 1 , wherein the entirety of the profile is presented by the concavity.

3. The screw pump as defined in claim 1 , wherein the helical channel includes two radially extending surfaces and a central portion therebetween at the position of the profile, with the concavity presented in the central portion, wherein the radially extending surfaces form a straight line in cross-section through the rotational axis of the screw pump, wherein the radially extending surfaces extend from the concavity to respective edges of the helical channel.

4. The screw pump as defined in claim 3, wherein the radially extending surfaces are angled relative to each other such that the radially extending surfaces diverge in a radially outward direction.

5. The screw pump of claim 1 , wherein the profile comprises a lower portion, the lower portion including a radially outermost point of the profile and extending radially inwards from the radially outermost point, wherein the lower portion is angled relative to a radial direction.

6. The screw pump of claim 5, wherein the radially outermost point of the lower portion forms an axially lowest point of the profile.

7. The screw pump of claim 5 or 6, wherein a tangent to the lower portion at the radially outermost point forms a non-zero angle with the radial direction.

8. The screw pump of claim 7, wherein the angle is between 5 and 45 degrees, and optionally the angle is between 10 and 25 degrees.

9. The screw pump of any of claims 5 to 8, wherein the lower portion is generally straight.

10. The screw pump of any of claims 5 to 8, wherein the lower portion is continuously curved.11 . The screw pump of any of claims 5 to 10, wherein the profile comprises an upper portion opposite to the lower portion, the upper portion including a radially outermost point of the profile and extending radially inwards from the radially outermost point, wherein the upper portion is angled relative to the radial direction.

12. The screw pump of claim 11 , wherein the radially outermost point of the upper portion forms an axially highest point of the profile.

13. The screw pump of claim 11 or 12, wherein a tangent to the upper portion at the radially outermost point forms an angle with the radial direction.

14. The screw pump of claim 13, wherein the angle is between 5 and 45 degrees, and optionally the angle is between 10 and 25 degrees.

15. The screw pump of any of claims 11 to 14, wherein the upper portion is generally straight.

16. The screw pump of any of claims 11 to 14, wherein the upper portion is continuously curved.

17. The screw pump of any of claims 11 to 16, wherein the concavity forms a central portion of the screw and extends between the lower and upper portions.

18. The screw pump of any of claim 17, wherein the central portion merges continuously into the lower and upper portions, such that the profile is devoid of sharp corners.

19. The screw pump of any of any preceding claim, wherein the profile has a maximum radius of curvature at a radially innermost point of the profile.

20. The screw pump of claim 19, wherein the radius of curvature of the profile gradually reduces as the profile transitions radially outwardly from the radially innermost point to a or the radially outermost points of the profile.21 . The screw pump of claim 1 , wherein: the profile consists of a lower portion, an upper portion and a central portion interconnecting the lower portion and the upper portion; the lower portion includes a first, lower radially outermost point of the profile and extends radially inwards from the first radially outermost point, wherein the lower portion is angled relative to a radial direction; the first radially outermost point forms an axially lowest point of the profile; a tangent to the lower portion at the first radially outermost point forms an angle with the radial direction of between 5 and 45 degrees; the profile has a maximum radius of curvature at a radially innermost point of the profile; and the radius of curvature of the profile gradually reduces as the profile transitions radially outwardly from the radially innermost point to radially outermost points of the upper and lower portions.

22. The screw pump of claim 21 , wherein the upper portion includes a second, upper radially outermost point of the profile and extends radially inwards from the second radially outermost point, wherein the upper portion is angled relative to a radial direction, the second radially outermost point forms an axially highest point of the profile, and a tangent to the upper portion at the radially outermost point forms an angle with the radial direction of between 5 and 45 degrees.

23. The screw pump of any preceding claim, wherein the profile is shaped such that a tangent to any point on the profile has a non-zero angle relative to a or the radial direction.

24. The screw pump of any preceding claim, wherein the channel extends circumferentially around a or the longitudinal axis of the screw by less than or equal to one and a half turns, optionally by less than or equal to 1 turn.

25. The screw pump of any preceding claim, wherein the channel profile has a maximum width in a radial direction which is at least two times the average width of the solid dosage form.

26. The screw pump as defined in any preceding claim, wherein substantially the entire length of the helical channel within the screw pump has the profile, optionally at least 70% of the length of the helical channel has the profile.

27. The screw pump as define in any preceding claim, wherein the surface of the screw defining the helical channel is devoid of indentations or protrusions.

28. The screw pump as defined in any preceding claim, wherein the helical channel comprises an outlet, wherein the path forming the helical channel follows a generally helical path forming the screw thread, and then bends towards the axial direction of the screw pump at the outlet.

29. The screw pump as defined in claim 28, wherein a width of the helical channel increases progressively towards the outlet of the screw pump.

30. The screw pump as defined in any preceding claim, wherein the screw has a screw crest with a height defined in a direction parallel to the rotational axis of the screw which is at least 50% of a height of the helical channel profile defined in a direction parallel to the rotational axis of the screw.31 . The screw pump as defined in any preceding claim, wherein the helical channel has a depth defined in a radial direction that is less than 90% of the radius of the screw, optionally less than 75%.

32. The screw pump as defined in any preceding claim, wherein the screw is formed as a single piece.

33. A device comprising the screw pump as defined in any preceding claim.

34. The device of claim 33, further comprising solid dosage form comprising a plurality of medicament pellets.

35. The device of claim 33 or 34, wherein the device is for dispensing a or the solid dosage form and further comprises a tube configured to dispense the solid dosage form, the tube and the screw cooperating to form the screw pump.

36. The device as defined in claim 35, wherein a radially outer surface of the screw is shaped to fit within a radially inner surface of the tube such that the screw and tube cooperate to form a closed channel for transporting the solid dosage form out of the device.

37. The device as defined in any of claims 33 to 36, further comprising an actuator configured to rotate the screw pump.

38. The device as defined in claim 37, further comprising a cartridge that is configured to attach to the actuator, the cartridge containing the screw pump.

39. The device as defined in claim 38, wherein the cartridge comprises a receptacle for storing a plurality of the solid dosage form, wherein the screw pump is configured to dispense the solid dosage form from the receptacle.

40. The device as defined in any of claims 33 to 39, wherein the device further comprises vibration means configured to vibrate solid dosage form within the screw pump. 41 . The device as defined in claim 40, wherein the vibration means comprises a motor disposed adjacent to the screw pump.

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