WO2015067950A1

WO2015067950A1 - Injector device and base station

Info

Publication number: WO2015067950A1
Application number: PCT/GB2014/053305
Authority: WO
Inventors: George Mcgee Perkins; Timothy Duncan Wooller; Eugene Johannes VAN WYK
Original assignee: Cambridge Consultants Limited
Priority date: 2013-11-05
Filing date: 2014-11-05
Publication date: 2015-05-14
Also published as: GB201319528D0; GB2520008A

Abstract

An injector device (200) for use with a syringe (150) holding a medicament is disclosed. The syringe has a housing for accommodating the syringe and a heater (221) for heating the fluid held by the syringe whilst housed in the housing. Control logic (600) is provided for controlling the heating based on an error. The control logic accumulates an integral term when the error > 0 and disables accumulation of the integral term when the error < 0 and the integral of the error > 0. A vibrator (700) is provided for vibrating the syringe to mix the fluid.

Description

Injector Device and Base Station

Technical Field

The present invention relates to injector devices and, in particular, automatic injector devices. The invention has particular relevance to injector devices that house and discharge a syringe, allowing drugs to be delivered by the syringe to a delivery area. In particular, the present invention relates to such devices which are reusable and adapted for self-administration of drugs.

Background

Self-administration of drugs can be awkward, intimidating (particularly to needle-phobics) and potentially hazardous if not executed correctly. Auto-injector delivery devices address these issues, to a certain extent, by providing assemblies which are easier to hold and operate than a syringe, particularly if the injection site is in an awkward position.

However, patients still encounter problems with these injector devices. For example, patients with rheumatoid arthritis may find it difficult to hold and operate both syringes and injector devices due to the impairment of dexterity caused by this condition. Furthermore, conditions such as rheumatoid arthritis and psoriasis are increasingly being treated by self-injection of biologic drugs. These drugs include genetically engineered proteins derived from human genes, which are designed to inhibit the parts of the immune system that fuel inflammation. However, many of these medicinal products have a relatively high viscosity, so injecting them with a traditional syringe can be slow and painful because of their thick consistency. Furthermore, such drugs often need to be refrigerated before use, and as a result it takes time to safely warm them to room temperature before injection.

Whilst self-injection devices can be configured to help alleviate some of these issues they are often cumbersome and inconvenient to set up and use, especially for those with reduced dexterity or motor control, for example those suffering from arthritis and/or Parkinson's disease.

These problems, along with the psychological issues some patients encounter when self-injecting, can reduce patient compliance with treatment programs. The present invention seeks to overcome or at least partially alleviate one or more of the above issues.

According to an aspect of the present invention there is provided an injector device for use with a syringe holding a medicament to be injected, said injector device comprising: a housing for receiving the syringe; means for heating the fluid held by the syringe whilst housed in said housing, wherein said means for heating comprises control logic for controlling said heating based on an error representing the difference between a temperature setpoint and a measured temperature, wherein said heating is controlled based on a proportional term that is proportional to said error and an integral term representing an integral of said error over time; and means for operating the syringe, whilst housed in said housing, to expel fluid held by the syringe that has been heated by the heating means; wherein said control logic is operable to disable accumulation of said integral term when measured temperature is greater than said temperature setpoint (error < 0). The control logic may be operable to disable accumulation of said integral term when measured temperature is greater than said temperature setpoint (error < 0) and the integral of the error < 0. The control logic may be operable to accumulate said integral term when said measured temperature is less than said temperature setpoint (error > 0).

The injector device may further comprise means for vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe. The injector device may further comprise a syringe holder, for holding a syringe, movably mounted within the housing and wherein said means for vibrating said syringe is coupled to said syringe holder whereby vibration of said syringe holder causes said vibration of said syringe, while heating is progressing. The means for vibrating may comprise a vibration motor (e.g. one of a brushless coin or button vibration motor and a cylinder type vibration motor).

The device may further comprise means for heating the fluid held by the syringe when whilst housed said housing. The heating means may comprise a heater element, said heating element arranged to be located proximate to a barrel of said syringe when the syringe is housed in said housing. The heater element may comprise at least one of a resistive heater and a dielectric heater. The heater element may be configured to surround substantially an entire perimeter of the barrel of the syringe when the syringe is housed in said housing. The heater element may be configured to be in contact with the barrel of the syringe when the syringe is housed in said housing. The heating means may be configured to heat the fluid held by the syringe, whilst the syringe is housed in said housing, to a predetermined temperature. The device may further comprise means for inhibiting heat generated by said heating means propagating away from the barrel of the syringe when the syringe is housed in said housing. The inhibiting may comprise an insulating layer surrounding at least a portion of the barrel of the syringe, whilst the syringe is housed in said housing. The device may further comprise means for transferring power from an external source of power to said heating means to drive said heating means. The device and power transferring means may be configured such that power is transferred from said external source of power to the heating means when the device is connected to a docking device. The power transferred from the external source of power to the device may be electrical power. The power may be transferred from the external source of power to the device via a direct electrical connection. The power may be transferred from the external source of power to the device via an inductive connection. According to an aspect of the present invention there is provided an injector device for use with a syringe holding a medicament to be injected, said injector device comprising: a housing for receiving the syringe; means for heating the fluid held by the syringe whilst housed in said housing; means for vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe; and means for operating the syringe, whilst housed in said housing, to expel fluid held by the syringe that has been heated by the heating means.

The housing may further comprise a syringe holder, for holding a syringe, movably mounted within the housing and wherein said means for vibrating said syringe is coupled to said syringe holder whereby vibration of said syringe holder causes said vibration of said syringe, while heating is progressing.

According to an aspect of the present invention there is provided a method of preparing an injector device according to another aspect for performing an injection using a syringe holding a medicament, said method comprising: receiving the syringe comprising said medicament; heating the fluid held by the syringe whilst housed in said housing; wherein said heating comprises controlling said heating based on an error representing the difference between a temperature setpoint and a measured temperature, wherein said heating is controlled based on a proportional term that is proportional to said error and an integral term representing an integral of said error over time, and accumulation of said integral term is disabled when measured temperature is greater than said temperature setpoint (error < 0). According to an aspect of the present invention there is provided a method of preparing an injector device for performing an injection using a syringe holding a medicament, said method comprising: receiving the syringe comprising said medicament; heating the fluid held by the syringe whilst housed in said housing; and vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe. According to an aspect of the present invention there is provided an injector device for use with a syringe holding a medicament to be injected via advancement of a plunger of the syringe, said injector device comprising: a housing for accommodating the syringe; means for advancing the plunger of the syringe, when accommodated in the housing, to expel the medicament held by the syringe; means for storing mechanical energy for driving said plunger advancing means; means for transferring mechanical energy from a source external to said injector device to said energy storing means to store said energy for driving said plunger advancing means; means for triggering said advancing means to drive said plunger of the syringe, when accommodated in the housing, to expel the medicament held by the syringe using said energy stored in said storing means. The housing may comprise a first portion and a second portion, the first and second portions being movable relative to one another. The first portion may be movable, relative to the second portion, between and open configuration and a closed configuration. In the open configuration, the first portion may be configured to receive the syringe and in the closed configuration, the first portion may be configured to at least partially enclose the syringe within the housing. The housing may further comprise means for biasing the first portion into the open configuration, means for securing the first portion in the closed configuration, and/or means for releasing the securing means when the first portion is secured in the closed position to allow the first portion to move from the closed configuration to the open configuration under the influence of the biasing means. The mechanical energy transferring means may be adapted to trigger said release means to release the securing means. The mechanical energy transferring means may be adapted to trigger said release when the mechanical energy storing means has stored at least enough energy to drive said plunger advancing means to expel the medicament held by the syringe. The mechanical energy transferring means may be adapted to trigger release while the mechanical energy storing means is in a process of storing energy for driving said plunger advancing means.

The plunger advancing means may be movable, under a force provided from the energy storing means, from a primed position in which it is primed for driving the plunger of the syringe when accommodated in the housing, to a discharge position. Movement of the plunger advancing means from its primed position to its discharge position may thus cause the plunger advancing means to engage with and advance the plunger of the syringe, when accommodated in the housing, to expel any medicament held by the syringe. The plunger advancing means may be operable to engage with the mechanical energy storing means when it is moved from its discharge position to its primed position to cause the mechanical energy storing means to store energy for driving said plunger advancing means. The mechanical energy storing means may comprise a spring. Movement of the plunger advancing means from its discharge position to its primed position may cause the spring to be compressed thereby storing said mechanical energy for driving said plunger advancing means.

The mechanical energy transferring means may be adapted to drive the plunger advancing means from its discharge position to its primed position thereby transferring energy to the mechanical energy storing means for driving said plunger advancing means. The mechanical energy transferring means may comprise a rotatable element and may be adapted to convert rotational energy from the rotatable element into energy for storing by said mechanical energy storing means whereby mechanical energy comprising rotary motion can potentially be transferred from the external energy source to the injector device. The mechanical energy transferring means may further comprise a reciprocating element. A rotatable element of the mechanical energy transferring means may be coupled to the reciprocating element. The coupling may be configured to convert rotary motion of the rotatable element into linear motion of the reciprocating element whereby to convert said rotational energy from the rotatable element into energy for storing by said mechanical energy storing means. The reciprocating element of the mechanical energy transferring means may be coupled to the plunger advancing means. The reciprocating element may comprise a cord or wire. The coupling between the rotatable element and the reciprocating element may comprise a spindle adapted to wind up the cord or wire.

The housing may further comprise a syringe holder for holding a syringe in said housing. The syringe holder may be movably mounted within the housing in order to allow the syringe, when held in the holder, to move between: a home position in which a needle of the syringe may be located within the injector device such that a user is inhibited from touching the needle; and an advanced position in which the needle may be located outside the injector device such that the needle can be inserted into a user's skin. The syringe holder may form part of the first portion of the housing.

The syringe holder may form at least part of the plunger advancing means. The syringe holder may comprise means for guiding said syringe into position in said syringe holder. The guiding means may be adapted to engage with a complementary handling element fitted to said syringe whereby to assist said guiding of said syringe into position in said syringe holder.

According to an aspect of the present invention there is provided an injector device, according to an above aspect, for use with a syringe holding a medicament for the treatment of rheumatoid arthritis.

According to an aspect of the present invention there is provided an injector device, according to an above aspect, for use with a syringe holding a medicament for the treatment of psoriasis.

According to an aspect of the present invention there is provided an injector device, according to the above aspect, for use with a syringe holding a medicament for the treatment of cancer.

According to an aspect of the present invention there is provided a base station for the injector device of any of the above aspects said base station comprising: a source of mechanical energy; means for engaging with said mechanical energy transferring means of said injector device whereby to transfer mechanical energy from said source of mechanical energy to said energy storing means of said injector device.

According to an aspect of the present invention there is provided a handling element for use with a syringe in the injector device, the handling element comprising means for fitting said handling element to said syringe. The fitting means may be adapted to engage with a finger flange of said syringe whereby to fit said handling element to said syringe (e.g. using a snap-fit). According to an aspect of the present invention there is provided a kit comprising the injector device and the base station. The kit may further comprise the handling element and/or a syringe.

According to an aspect of the present invention there is provided a method of preparing the injector device for performing an injection using a syringe holding a medicament, said method comprising: engaging the injector device with the base station; transferring mechanical energy for advancing the plunger of the syringe, from the source of mechanical energy of said base station, to said energy storing means of said injector device, using said energy transferring means; and accommodating the syringe in said housing in a configuration ready for triggering said advancing means of said injector device to drive said plunger of the syringe to expel the medicament held by the syringe using said energy stored in said storing means.

The present invention will now be described, by way of example only, with reference to the attached figures, in which:

Figures la and lb illustrate a simplified depiction of an exemplary syringe assembly for use with the injector device described herein; Figures 2a and 2b respectively show a top view and a side view of an embodiment of an injector device for use with the syringe illustrated in Figures la and lb;

Figure 3 is an isometric view of the injector device illustrated in Figures 2a and 2b;

Figure 4 is an exploded view of the injector device illustrated in Figure 3;

Figure 5 is cut-away view of a first portion of the injector device illustrated in Figure 3; Figure 6 is a cut-away view of a second portion of the injector device illustrated in Figure 3;

Figure 7 is a cut-away view of the injector device of Figure 3, where the injector device is fully assembled with the first portion attached to the second portion;

Figures 8a and 8b illustrate a top view and a side view respectively of a base station for use with the injector device of Figure 2; Figure 9 is an isometric view of the base station illustrated in Figures 8a and 8b;

Figure 10 is a cut-away view of the base station illustrated in Figures 8a and 8b;

Figure 11 is cut-away view of the injector device docked with the base station;

Figures 12a and 12b are side views of the injector device, illustrating loading of the syringe assembly into the injector device; Figure 13 is a flow chart illustrating a method, performed by a user, of administering an injection using the injector device;

Figure 14 is a simplified schematic illustrating possible heating control logic used by the injector device; and Figure 15 illustrates a possible enhancement to the injector device. Overview

Referring to Figures la and lb, which illustrate a simplified depiction of an exemplary syringe assembly 150, the syringe assembly 150 includes a syringe body, or "barrel" portion 105 in which a bore 107 is disposed and to which a hollow needle 110 is coupled. An opening 109 is provided in the syringe body 105 to provide a fluid connection between the bore 107 and the needle 110.

A plunger 113 is slidable within the bore 107 between an extended position, as illustrated in Figure la, in which the cavity defined by the bore 107 can accommodate a medicament or other substance, and an enclosed position, as illustrated in Figure lb, in which the plunger 113 abuts an end of the bore proximate to the syringe opening 109 (essentially filling, or at least partially filling, the cavity). The bore 107 can hold a medicament such as a drug for treating rheumatoid arthritis.

Advancing the plunger 113 towards the opening 109 causes discharge of the medicament held within the syringe assembly 150, via the needle 110. Discharge will continue until the plunger 113 has fully advanced towards the syringe opening 109 and is in its enclosed position.

The plunger 113 maintains a substantially sealed contact with the inner surface of the bore 107 as it moves along the bore 107, which helps to ensure that all of the contents of the syringe held within the bore 107 is expelled from the syringe assembly via the syringe opening 109 and the needle 110.

The syringe body 105 also includes a finger flange 106 disposed at its rear end, which helps a user to grip the syringe body 105 while advancing the plunger 1 13, in particular allowing a user to discharge the syringe one-handed. The syringe 150 also includes an extended needle shield 101 which is removably attached to the syringe body 105, preferably in a snap-fit arrangement. The extended needle shield 101 surrounds the needle 110 when attached to the syringe body 105, preventing user contact with the needle and thereby preventing associated needle stick injuries.

Figures 2a and 2b respectively show top and side views of an injector device 200 adapted to receive and operate the syringe 150 illustrated in Figures la and lb. As illustrated, the injector device 200 is made up of a main body 204 which is generally cylindrical in shape and is configured to hold and discharge the syringe assembly 150, and a handle 271 which is mounted to the main body 204 and extends along a substantial length of the main body 204. As generally indicated in Figures 2a and 2b, the injector device 200 has a front end 290 and a rear end 291. The front end 290 is also known as the injection end, as this end is the end which is placed immediately adjacent to or on a user's skin during use of the injector device 200 in the administration of a medicament to the user. It is from this front end that at least part of the needle 110 of the syringe assembly 150 protrudes while the medicament is being injected into the user by the injector device 200, although between loading of a syringe assembly and injection the syringe assembly and needle remain encapsulated within the injector device 200 for safety. The rear end 291 opposes the front end of the injector device 200. The handle 271 extends between the rear end 291 and an intermediate point on the main body 204 between the rear end 291 and the front end 290.

On the main body 204 of the injector device 200 there is disposed, adjacent to or at the rear end, a trigger button 253 which is used to trigger commencement of the injection procedure.

When the injector device 200 has been primed and the syringe assembly 150 has been loaded into the injector device 200, depression of the trigger button 253 triggers a piston inside the injector device 200 to be advanced towards the front end of the device, the piston powered by a power spring. The piston moves the syringe assembly 150 held inside the main body 204 until at least part of the needle 110 of the syringe assembly 150 is protruding from the front end of the injector device. Subsequently, the piston causes the plunger 113 of the syringe assembly 150 to advance towards the syringe opening 109, moving from its extended position to its enclosed position and therefore causing a medicament held within the bore 107 of the syringe assembly 150 to be discharged via the needle 118.

The priming of the injector device 200, involving retracting the piston, is done mechanically via engagement between the injector device and a base station, where mechanical energy in the form of rotational motion is transferred from the base station to the injector device via a drive shaft. Advantageously, there is no electrical energy stored on board or delivered to the injector device 200 once it is undocked from the base station.

Furthermore, the injector device is configured to warm the contents of the syringe assembly 150 prior to delivery of the drug into a patient. Heating the drug immediately prior to delivery can be seen to provide a number of benefits over a room temperature delivery. This is particularly advantageous for the intramuscular administration of drugs with a higher viscosity than typical intramuscular administered drugs. As an example, drugs for treating rheumatoid arthritis and psoriasis are often biologic drugs which have a relatively high viscosity, so injecting them with a traditional syringe can be slow and painful because of their thick consistency. Heating the drug contained in a syringe prior to delivery of the drug leads to a lower viscosity and therefore lower resistance during delivery and increased delivery speed, which minimises user discomfort. It has been found, for example, that pre- warming of such drugs can result in approximately a 30% reduction in injection duration.

Furthermore, this has advantages over conventional drug delivery, where drugs need to be refrigerated before use and the drug used in the injector device 200 has to be warmed - at least to room temperature - resulting in a significant delay associated with the time to safely warm the drugs up to room temperature before injection.

The automatic priming mechanism, combined with a particularly ergonomic design of the handle, body and trigger mechanism assembly, has significant advantages in terms of ease of use especially for those with reduced dexterity or motor control, for example those suffering from arthritis and/or Parkinson's disease.

Injector Device

The injector device 200 will now be described with reference to Figures 3 to 7.

Figure 3 is an isometric view of the injector device 200 as illustrated in Figures 2a and 2b. In Figure 3, the syringe assembly 150 is housed within the injector device 200 and the syringe assembly 150 occupies its home position, where the only part of the syringe assembly 150 protruding from the front end 290 of the injector device 200 is the extended needle safety shield (where present).

Figure 4 is an exploded view of the injector device illustrated in Figure 3. As generally indicated in Figure 4, the injector device includes two main portions: a first portion (or 'syringe receiving assembly') 200a which, when the injector device is assembled, forms part of the main body 204 and a second portion (or "control assembly") 200b which includes the rest of the main body 204 and handle 371.

The syringe receiving assembly 200a is configured to receive and hold the syringe 150, while the control assembly 200b is configured to control an injection using the syringe 150 by controlling the insertion of the needle 110 of the syringe into the user and subsequently advancing the plunger 113 in order to discharge a medicament from the syringe assembly 150.

The syringe receiving assembly 200a of the injector device 200 includes an outer chassis 205 which, when the injector device is assembled, is pivotally connected to the control assembly 200b by engagement between projections 211 (only one of which is visible in Figure 4) disposed near the front end of the outer chassis 205 and complementary recesses 210 (only one of which is visible in Figure 4) disposed on the control assembly 200b, which are configured to receive the projections 211.

This pivotal connection between the syringe receiving assembly 200a and the control assembly 200b allows the syringe receiving assembly 200a to swing between an open position and a closed position relative to the control assembly 200b. In the open position, the syringe 150 can be loaded into and unloaded from the injector device 200. This ability of the syringe receiving assembly 200a to swing between the open and the closed position allows easy loading of the syringe assembly 150 into the injector device 200. The outer chassis 205 is also configured to slidably receive a syringe cage 281, which is configured to hold the syringe assembly 150. The slidable connection between the outer chassis 205 and the cage 281 allows the cage to slidably translate within the injector device 200 in a longitudinal direction of the injector device (i.e. a direction parallel to an axis of the injector device, running between the front end and the rear end, and parallel to the longitudinal axis of the syringe when loaded). The ability of the cage to slidably translate within the syringe receiving assembly 200a, and hence the main body 240, allows translation of the syringe assembly 150, whilst the syringe assembly is held within the injector device 200 in the closed configuration, such that the needle of the syringe assembly 150 can move between an advanced or 'extended' position in which it projects from the injector device 200 and a home position in which it is encapsulated/shielded within the injector device 200. The slidable connection is provided for by a tubular portion 207 of the outer chassis 205 which slidably receives a front portion 381 of the syringe cage 281.

When the injector device 200 is disposed in the closed configuration, the outer chassis 205 encloses the syringe cage 281 within the main body 204 thereby protecting the movable syringe cage 281 and the components of the control assembly 200b. The outer chassis 205 includes an outer chassis opening 231 through which part of the syringe assembly 150 can extend. In particular, the opening 231 is sized to allow the extended needle shield 101 to extend through the opening 231. Therefore, at the point of being loaded into the injector device 200, the extended needle shield 101 may be retained, attached to the syringe body 105. This beneficially protects the user from coming into contact with the needle 110 whilst loading the syringe assembly 150 into the injector device 200.

In this example, as seen in Figure 4, the syringe assembly 150 is provided with an additional handling element 125 which can be attached (preferably with a snap-fit or the like) to the finger flange 106 of the syringe assembly 150. The additional handling element 125 has a pair of guide portions 125a arranged for symmetrical location on either side of the syringe when fitted to it. The guide portions 125a have gripping or 'friction' surfaces and extend beyond the rear end of the syringe body 105 when fitted to it. Hence, a user can beneficially hold the syringe assembly by the gripping surface(s) when loading or unloading the syringe assembly into the injector device without the user intentionally or accidentally gripping the plunger 113. Figure 5 is a cutaway view of the injector device, showing the syringe 150 present within the syringe receiving assembly 200a, where the syringe receiving assembly 200a is in its closed position with respect to the control assembly 200b and the syringe cage 281 is in its home position. As seen, in Figure 5, in the home position the syringe cage 281 is at or near the limit of its range of movement towards the rear end 291 of the injector device 200. In the advanced position, the syringe cage 281 is at or near the limit of its range of motion towards the front end 290 of the injector device 200. When the syringe cage 281 is in its home position, the needle 110 of the syringe assembly 150 is held within the main body of the injector device 200, but in the advanced position the needle protrudes from the front end of the injector device 200. When the cage 281 is in its home position, the only part of the syringe assembly 150 which protrudes out of the injector device 200 from the opening of 231 is the extended needle shield 101 (when present). The cage 281 is biased towards its home position by a first spring (not shown in Figure 5) held within a first spring cavity 451 extending between the front end of the outer chassis 205 and the front end of the cage 281.

In order to assist the slidable mounting of the syringe cage 281 to the outer chassis 205, and to prevent relative rotation of the cage 281 and outer chassis 205 about the longitudinal axis of the syringe receiving assembly 200a, longitudinal grooves/apertures and co-operating projections are provided on the tubular portion 207 of the outer chassis 205 and the front portion 381 of the syringe cage 281. For example, the outer chassis tubular portion 207 includes a lower groove/aperture 407 extending in the longitudinal direction of the syringe receiving assembly 200a. The lower groove/aperture 407 is located on the bottom side of the tubular portion 207. The front portion 381 of the syringe cage 281 has a co-operating projection 411 which is received by the groove/aperture 407

Also, as can be seen in Figure 4, the front portion 381 of the syringe cage 281 has two side grooves/apertures 408 located on opposing side faces of the front portion 381. One of these side grooves/apertures is visible in Figure 4. These side grooves/apertures 408 receive complementary projections protruding from inner side faces of the tubular portion 207.

In Figure 5, the syringe 150 is ready for use, with a medicament held in the cavity of the bore 107, the plunger 113 in its extended state, and with the extended needle shield 101 attached to the syringe body 105. The syringe cage 281 includes a cavity in which the syringe assembly 150 can be held, and in which heating and insulation elements are disposed. The syringe cage 281 also includes an insulation layer 285 which is disposed within the syringe cage cavity. The insulation layer 285 is generally tubular in shape and extends around the outer of the cavity. The insulation layer 285 extends along at least the majority of the length of the syringe body. At a rear end of the insulation layer 285, the insulation layer forms a lip 485 running around the circumference of the insulation layer 285 and extending radially outwards. The lip 485 allows the insulation layer 285 to be securely held within the syringe cage 281. In this embodiment, the insulation layer lip 485 is held by a complementary lip 483 of the syringe cage 281. The insulation layer lip 485 facilitates smooth insertion of the prefilled syringe by mitigating the risk of snagging during loading. In this embodiment, the insulaton layer 285 is made from a foam-like material which includes a large number of small air pockets, giving the insulation layer 219 good thermal insulating properties. The syringe cage 281 beneficially includes a heating element 221 which is arranged to heat the contents of the syringe 150 to a desired temperature, before the contents of the syringe 150 is expelled. The auto injector device 200, of the present embodiment, is adapted for use on human patients, and therefore the heating element 221 is configured to heat the contents of the syringe 150 to an average human body temperature - approximately 38°C (although it will be appreciated that any appropriate temperature setpoint may be used).

The heater element 221 is disposed around the inner surface of the insulation layer 285. The heater element, in this embodiment, is a flexi-heater including a resistance wire arranged in a relatively widely-spaced pattern, and held between two layers of capton tape. The flexibility of the heating element 221 allows it to conform to the curved inner surface of the insulating layer 285, and to help accommodate the syringe and encourage close contact between the heating element 221 and the syringe body 105.

The heater element 471 is disposed around the inner surface of the insulation layer 285, and is arranged to contact the material of the syringe barrel, in order to ensure optimal thermal conduction between the heater element and the syringe body 105. Thus, when the syringe 150 is in place the heating element 221 substantially surrounds the syringe body 105 and the heating element 221 is sandwiched between the syringe body 105 and the insulating layer 285. The insulation layer 285 thereby inhibits heat from the heater element 221 from conducting towards the outside of the injector device and thus maximises the heat energy transferred, from the heating element 221, through the syringe body 105, and to the contents of the syringe bore 107, causing the contents of the syringe to increase in temperature efficiently.

The syringe cage 281 includes a moveable needle safety sheath 201, which is generally tubular in shape and is slidably mounted to the syringe cage 281. The needle safety sheath 230 can move between a sheath home position, illustrated in Figure 5, in which the sheath 201 is extended from the syringe cage 281, and a retracted position in which it is retracted into the syringe cage 281. In the home position, the needle safety sheath 201 surrounds the needle 110 of the syringe assembly 150, preventing user contact with the needle 110. In order to provide a sliding connection, the needle safety sheath 201 is received by a complimentary groove 531 in the syringe cage which is annular in cross-section. A second spring (not shown in Figure 5) is disposed within a second spring cavity 453 formed within the needle safety sheath 201, which biases the needle safety sheath 201 into the illustrated home position with respect to the syringe cage 281. The needle safety sheath 201 is prevented from being extended further by virtue of engagement between an inner lip of the needle safety sheath projecting inwardly around the rear end of the needle safety sheath and a complimentary lip extending outwardly from around the syringe cage 281.

The needle safety sheath 201 includes a user contact portion 215, for placing adjacent or in contact with a user's skin during an injection, which is formed as an annular surface disposed at the injection end of the needle safety sheath 201. The user contact portion 215 is thicker than the rest of the needle safety sheath 201 , in order to provide a reinforced area. At the centre of the user contact portion 215 the annular shape of this portion defines a safety sheath opening 216 through which both the needle 110 and the extended needle shield 101 can pass. The user contact portion 215 also includes a groove having an annular cross-section which is disposed on the rear side of the user contact portion 215. This groove receives and holds the second spring.

The cage 281 includes a loading aperture 405 which allows the syringe assembly 150 to be inserted into the cavity of the syringe cage 281. The loading aperture 405 includes an opening at the rear end of the cage 281 and two side (or 'guide') openings which extend longitudinally along either side of part of the cage 281. The side openings are configured to receive the guide portions 125a of the handling element 125, when fitted, in order to assist guiding the syringe assembly 150 into position during loading. The inclusion of the end opening and the two longitudinal side openings can be seen, therefore, to provide improved access to the loading aperture 405, which is particularly beneficial to allow users with reduced dexterity to load the syringe 150 into the injector device 200. The syringe cage 281 also includes a syringe receiving orifice 287 which connects the cavity of the cage 281 to the loading aperture 405. The syringe receiving orifice 287 has a generally frustoconical shape, narrowing in cross sectional diameter in the forward direction, in order to guide the syringe assembly 150 into the cavity of the cage 281.

Figure 6 is a cut-away view of the control assembly 200b where the illustrated cut is made along the central axis of the control assembly 200b. The handle 271 defines a void 272 which is sized to accommodate the user's fingers when the user is gripping either the handle 271 or the main body 204 of the injector device 200 itself. Preferably, the void 272 can accommodate all five fingers on a user's hand when either of these parts are being gripped by the user. The handle 271 defines the void 272 to be substantially an elliptical shape which improves user comfort when gripping the injector device 200.

The control assembly 200b includes a U-shaped channel 509 which has openings at the injection end of the control assembly 200b and along the top of the control assembly 200b. The U-shaped channel 509 is sized to receive the syringe receiving assembly 200a, as illustrated in Figure 7. Adjacent to the injection end 290 of the U-shaped channel, following its U-shaped internal contour, there is disposed an outer chassis receiving groove 501 which runs between the recesses 210 disposed on opposing internal sides of the U-shaped channel 509. The outer chassis receiving groove 501 is shaped to receive a lower front edge of the outer chassis 205. This outer chassis receiving groove 501 allows the syringe receiving assembly 200a to pivot from its closed configuration to its open configuration about projections 211 without contact between the lower front edge of the outer chassis 205 and the lower part of the channel 509 which might otherwise inhibit movement of the syringe receiving assembly 200a. The control assembly 200b includes a plunger piston 255 which is disposed near the rear of the injector device 200 and is configured to engage with the plunger 113 of the syringe assembly 150 and to advance the plunger and/or the syringe assembly 150 towards the front end 290 of the injector device 200. The plunger piston 255 is driven by a power spring 251, the power spring 251 biasing the plunger piston 255 towards the front of the injector device 200. In this embodiment, the power spring is a 20N power spring (although any appropriate biasing means may be used). The plunger piston 255 is guided by two guide rails 265 provided along sides of the control assembly 200b. The plunger piston 255 can move between a plunger home position (also referred to as its primed position), which is illustrated in Figure 6, where the plunger piston 255 is located near the limit of its longitudinal range of travel towards the rear of the injector device 200 and the power spring 251 is compressed. The plunger piston 255 can travel a short distance rearward beyond its illustrated primed position when being pulled by a winding mechanism (later described).

When the plunger piston 255 is pulled rearward to occupy, or just surpass, its primed position, a trigger latch is configured to engage with the plunger piston 255. Thereafter, engagement of the trigger latch with the plunger piston 255 prevents forward travel of the plunger piston 255. This has the effect of storing mechanical energy in the power spring 251, the energy being sufficient to drive the needle 110 into a user's skin and to drive the plunger 113 into the syringe body to deliver the medicament. The trigger latch can be disengaged from the plunger piston 255 via depression of the trigger button 253 by a user, thereby releasing the plunger piston 255 which is driven towards the front end 290 by the power spring 251. Furthermore, when the plunger piston 255 is pulled rearward to occupy, or just surpass, its primed position, it is configured to affect the release of a latch 259 that holds the syringe receiving assembly 200a in its closed position. Specifically, when the plunger piston 255 moves rearwards beyond the primed position, the latch 259 which is configured to hold the syringe receiving assembly 200a in the closed position, is forced to disengage with the syringe receiving assembly 200a and therefore release the syringe receiving assembly allowing it to swing into its open position. Biasing means 544, in the form of a leaf spring (or the like) biases the syringe receiving assembly towards the open position such that when the latch 259 disengages the syringe receiving assembly automatically moves into the open position. This beneficially avoids the potentially fiddly operation of a user having to manually open the syringe receiving assembly. When the plunger piston 255 is released by the trigger latch , the plunger piston advances towards the front end 290, driven by the power spring 251, and engages with the plunger 113. Upon engagement, continued advancement of the plunger piston 255 has the effect of driving the whole of the syringe cage 281 forwards, along with the syringe assembly 150 itself. The cage 281 and syringe assembly 150 are driven forward until the cage 281 reaches the limit of its range, at which point the needle 110 is projecting outwards from the front of the injector device 200 by a predefined distance, in order to deliver the drug at a controlled depth. In order for the plunger piston 255 to be able to drive the cage 281 forward, the power spring 251 must store enough energy to overcome the skin resistance to needle insertion and to overcome the biasing springs in the cavities 451 and 453. Thereafter, continued advancement of the plunger piston 255 has the effect of advancing the plunger 113 forwards within the syringe body, causing the medicament held in the bore 107 to be expelled via the needle 110.

The control assembly 200b also includes the drive shaft channel 547 which is, in this embodiment, a recess provided on the front end of the handle 271 approximately at the point at which the handle 271 adjoins the main body 204. The drive shaft channel 547 is sized to accommodate a keyed drive shaft which projects from a base station provided for use with the injector device 200 (the base station is described later with reference to Figures 8 to 11). The drive shaft channel 547 provides access to a keyed drive recess 545 which is in turn connected, in a unitary manner, to a priming spindle 543. The keyed drive recess 545 is generally tubular and is sized and shaped to receive the drive shaft of the base station in a complementary fashion. When the keyed drive shaft of the base station is inserted into the complimentary keyed drive recess 545, any rotation of the drive shaft will in turn rotate the keyed drive recess 545 and in turn the primary spindle 543 will be rotated, winding up a steel cable which is strung between the priming spindle 543 and the plunger piston 255. Winding up of the steel cable onto the priming spindle 543 causes the plunger piston 255 to retract into its primed position where the power spring 251 is compressed and therefore exerting a force on the plunger piston 255. The path of the steel wire between the priming spindle and the plunger piston 255 follows a steel wire channel 261 which runs along the lower part of the main body 204 and in turn the steel wire extends around a steel wire pulley 263 which is provided behind the plunger piston 255. The steel wire pulley is used, effectively, to reverse the direction of the force provided by the priming spindle winding up the steel wire. It will be appreciated that whilst the base station is described as having a keyed drive shaft and the injector device the complementary keyed drive recess the base station may be provided with the keyed drive recess and the injector device a complementary keyed drive shaft. As can be seen in Figure 7, the second portion 200a also includes injector device electronics 541 which receive power from a base station, via sprung electrical contacts 542 disposed on the bottom of the main body 204 adjacent the front end 290.

A sensor is also provided for detecting the presence of the syringe assembly 150 within the cage 281. Furthermore, the injector device 200 includes a plurality of independent temperature sensors, each connected to the injector device electronics 541. The use of multiple individual temperature sensors advantageously provides redundancy, so that the injector device is fault tolerant, being able to accurately measure the temperature of the syringe body even if one temperature sensor malfunctions. The sensors are embedded into the flexible heater element which is, itself, in contact with the material (typically glass) of the syringe barrel. The sensors in this embodiment are thermocouples or thermistors but could be any suitable temperature sensor.

Base Station

The base station 900 will now be described with reference to Figures 8 to 11.

Figures 8a and 8b show respective top and side views of a base station 900 for use with the injector device 200 described in relation to Figures 2 to 7. Figure 9 is an isometric view of the base station illustrated Figures 8a and 8b. The base station 900 includes an injector front end receiving cavity 909 disposed on the top of the base station 900. The injector front end receiving cavity 909 is partially covered by a hood 903 which defines an enclosed portion of the injector front receiving cavity 909 for helping to securely hold the injector device 200 at its front end and also to enclose and protect the front end of the injector device, in particular inhibiting premature accidental removal of the extended needle shield 101.

Disposed within the injector front end receiving cavity 909 there is disposed a number of electrical contacts 905 for engaging with complementary electrical contacts 542 disposed on the bottom side of the injector device 200. The electrical contacts 905 allow electrical signals and/or power to be transmitted between the base station 900 and the injector device 200.

The base station 900 also includes a handle receiving cavity 907 which is disposed on base station 900. Within the handle receiving cavity 907 there is disposed a keyed drive shaft 951 which extends upwardly in order to enter into the drive shaft receiving channel 547 of the injector device, and to engage with the keyed drive recess 645, when the injector device 200 is docked on the base station 900.

The base station 900 also includes a first button 921 and a second button 923 disposed proximate to opposing sides of the base station 900 and on the top of the base station 900, where, in this embodiment, the first button 921 is a power button for powering up the base station 900, and the second button 923 is a warming button which triggers the initiation of a warming sequence, warming the contents of the syringe body 105 via the heater element 221 of the injector device 200, the power for heating provided to the heater element 221 by the base station 900 via the electrical contact 905.

The base station 900 also includes a display 913 disposed near the front end 931 of the base station 900, for displaying information, for example the measured temperature of the contents of the syringe assemble 150. The display 913 is controlled by control electronics, which are provided in the base station and are configured to communicate with the injector device electronics 541 via the electrical contacts.

As illustrated in Figure 10, which is a cut-away view of the base station 900, the cut-away being made along a central longitudinal axis. As shown, the base station 900 includes a worm drive 1020 which drives the keyed drive shaft 951. The worm drive 1020 is in turn driven by an electrical motor 1010 which is powered by an external power source, preferably a mains power supply, and is controlled by the control electronics.

The worm drive 1020 is used to convert the high RPM, low torque output of the motor 1010 to a low RPM, high torque rotation of the keyed drive shaft 951 which is required to compress the power spring 251 via winding up of the steel wire onto the priming spindle 543 of the injector device 200.

Figure 11 is a cut-away view showing the injector device 200 docked on the base station 900.

Operation

Figures 12a and 12b are side views of the injector device 200 showing the device in its open and closed configurations respectively.

In Figure 12a, the syringe receiving assembly 200a is in its open position with respect to the control assembly 200b. In this configuration, the syringe 150 can be loaded or unloaded into the injector device 200.

Figure 13 is a flow chart illustrating the steps undertaken in an exemplary injection method using the injector device 200 to administer a dosage of drug, either by one user administering the drug to a second user, such as a doctor on a patient, or more particularly where one user is administering the drug themselves.

At step 1301, the method starts.

At step 1303, the injector device 200 is docked in the base station. The base station 900 and injector device 200 are powered up, by user activation of a first button 921 (or "power" button). This allows electrical current and signals to be passed between the base station 900 and the injector device 200 via the sprung electrical contacts 542 of the injector device 200 and the corresponding electrical contacts 905 of the base station 900. The control electronics are configured to check for the presence of the injector device 200 by monitoring whether there is contact between the respective electrical contacts 542, 905 of the injector device and base station. At step 1305, the user presses the second button 923, and at step 1306 the user waits for the plunger piston 255 to retract and syringe receiving assembly 200a to open.

The control electronics are configured to await receipt of a prime command via the second button 923 (also referred to as the priming or warming button), and upon receipt of the command at step 1305 the control electronics are configured to activate and control the supply of electrical power to the motor 1010. The motor 1010 drives the worm drive 1020 with high RPM rotation motion, and the worm drive 1020 in turn drives the keyed drive shaft 951 at a lower RPM but with increased torque. The drive shaft 951 will in turn rotate the keyed drive recess 545, rotating the primary spindle 543. The spindle converts the rotary motion into linear motion by winding up the steel cable which is strung between the priming spindle 543 and the plunger piston 255. The retraction of the steel cable by the spindle 543 draws the plunger piston 255 rearwards within the injection device until it is beyond its primed position, which allows the receiver release latch 259 to engage with the plunger piston 255 to release the syringe receiving assembly 200a, such that it swings upwards and open, ready to receive a syringe. Alternatively, an intermediate trigger latch may act between the plunger piston 255 and the receiver release latch 259 to release the syringe receiving assembly 200a. As the plunger piston 255 is retracted, the power spring 251 is compressed. On reaching the limit of its travel the control electronics will detect a spike in current being utilised by the motor 1010 and turn off the supply of electrical power to the motor 1010. The absence of torque acting on the plunger piston 255 by the steel wire will cause the plunger piston 255 to move forward due to the force applied by the now compressed power spring 251, but the forward travel of the plunger piston 255 will be limited by the trigger latch.

At step 1307 the user loads a syringe into the syringe receiving assembly 200a. The extended needle shield 101 is still in place at this point.

At step 1309 the user closes the syringe receiving assembly 200a, which is held in its closed position by engagement with the receiver release latch 259. At step 1311, the user presses the warming button 923. The injector device electronics 541 control the power supplied from the base station 900 to the heater element 221 in order to minimise the time taken for the syringe body 105 to reach 37 Celsius (body temperature). Once the syringe body 105 has reached body temperature, the injector device electronics 541 control the power supplied to the heater element 221 to maintain this temperature for a fixed period of time, for example 5 minutes. After the fixed period of time has elapsed while the injection device remains docked, the injector device electronics 541 are configured to disconnect the power supplied to the heater element 221 and optionally control the power down of the base station. In more detail, the temperature sensors are connected to a monitoring circuit, of the injector device electronics 541, which monitors the temperature of the syringe body 105 and therefore obtains an indication of the temperature of the syringe contents. The monitoring circuit 903 controls a heating circuit which is configured to supply power to the heating element 221, in turn heating the contents of the syringe 150 to a desired temperature. The action of placing the injector device 200 in the docking station 900 initiates the control circuitry to activate the heater and commence the heating operation.

The monitoring circuit monitors the temperature of the syringe body 105 until a target temperature is achieved (preferably human body temperature, approximately 38C). At this point the monitoring circuit continues to monitor the temperature of the syringe body 105 and controls the heating circuit to only apply power to the heating element 221 in order to maintain the target temperature. Once at body temperature, the injector device electronics 541 are configured to indicate to the user that the device is ready to use. In this embodiment, this is done via a visual indication provided on a display 913 disposed near the front end 931 of the base station 900. Preferably, the display 913 indicates the current temperature of the syringe body 105. In order for this information to be displayed, heating information is exchanged between the injector device electronics 541 and the control electronics.

If the injection device is undocked prematurely, the control electronics are configured to warn the user to re-dock the injection device, for example via a visual indication on the display 913 or output of an audio message using a speaker (not illustrated). Also, if injector device electronics 541 detect a temperature in excess of 37 Celsius the injector device electronics 541 will disconnect the power supply to the heater element 221 and optionally control a shut down of the base station 900 for safety.

At step 1315, the user undocks the injector device 200 from the base station 900. Advantageously, there is no electrical energy stored on board or delivered to the injector device 200 once it is undocked.

At step 1317, the user removes the extended needle shield 101 (if present) and positions the injector device 200 at the injection site for delivery, with the injection end of the injector device 200 placed in contact with the user's skin. By pushing the front of the injector device into the skin, a small movement of the needle safety sheath occurs, this movement releases an internal interlock within the injection device, effectively arming the trigger mechanism. The device requires compression of both the safety sheath and trigger button in order to fire. The interlock, in this example, comprises a mechanical linkage (not shown) between the needle sheath and trigger mechanism that prevents triggering without movement of the needle safety sheath first.

At step 1319, the user presses the trigger button 253, and at step 1321, the user waits for delivery of the medicament. As the trigger button is depressed, the trigger latch releases the plunger piston 255. The plunger piston 255 is pushed towards the syringe plunger 113 by the power spring. As the plunger piston 255 begins to exert force on the plunger, the syringe assembly 150 is pushed forward along with the syringe cage 281 within the injector device. This forward motion inserts the needle 110 into the user's skin to a controlled depth. Once the needle is fully inserted, subsequent forward motion of the plunger piston 255 will advance the syringe plunger 113 within the syringe barrel, expelling the medicament into the user through the needle 113.

At step 1323, the user lifts the injector device away from the skin. As the needle 110 is removed from the skin, the needle safety sheath 201 will extend, driven forwards by the spring in the second spring cavity 453. The needle safety sheath 201 encloses the needle 113, preventing accidental needle stick injury.

At step 1325, the user re-docks the injector device 200. If the user wishes to immediately dispose of the spent syringe, they can push the 'prime' button 923 to re-prime the injector device 200 and open the syringe receiving assembly 200a to facilitate disposal. Doing so will allow the syringe cage 281 and the needle safety sheath 201 to automatically reset to their home positions. The injector device 200 is then ready for re-use or storage.

At step 1327, the method ends.

Heating Control

A particularly beneficial method of controlling the heating applied to the syringe body 105 will now be described, by way of example only, with reference to Figure 14 which shows control logic 600 applied for controlling the heating of the syringe and its contents.

As seen in Figure 14 the control logic 600 comprises proportional-integral (PI) control logic in which an error 601, representing the difference between a temperature setpoint (SP) 602 and a measured temperature 603 fed back via a feedback loop, is calculated at node 604.

The error 601 is multiplied by a proportional term 'Κ_Ρ' in a proportional branch 606 of the control logic 600 and is integrated over time and multiplied by an integral multiplier '¾' in an integral branch 608 of the control logic 600. The output of the proportional branch 606 and the output of the integral branch 608 are summed at node 610 and the resulting output applied to a heater controller 612 which is operable to control the heater element in dependence on the output from the control logic.

The control logic 600 is advantageously configured to disable the integral branch 608, as shown illustratively by switch 616, when the error drops below zero (measured temperature exceeds temperature setpoint), and the integral of the error < 0, thereby preventing the error from accumulating when the input hits this constraint. This has the benefit of reducing recovery time significantly.

Specifically, because the active heat flow is always positive, if the integral term were not disabled, then the magnitude of the integral term in the integral branch 608 could become very large if cooling is required (i.e. the actual measured temperature exceeds the setpoint or, in other terms the error < 0). This is because the temperature gradient between the ambient external temperature and actual temperature at the syringe body required to provide this cooling is uncontrolled. Moreover, this is compounded because the insulation layer slows cooling in the event of such a temperature overshoot. The presence of the second condition (i.e. integral of the error < 0) in conjunction with the first (i.e. error < 0) is beneficial because it helps to ensure that the control error decays to 0.

Thus, if the integral term were not disabled, then when the error exceeds zero again (the measured temperature drops below the setpoint), it could take a long time for the accumulated error to be reduced enough to ensure that the overall controller output enables the heater to turn on. This has the potential to introduce significant delays and could potentially degrade controller performance. Further Heating related Improvements

Even with the beneficial heater control logic. The need to heat the contents of the syringe can result in: significant delays before the contents of the syringe can be administered; a significant temperature gradient from the wall of the syringe, where the heating is applied, to the centre of the syringe; and potentially the formation of hot spots. These potential issues are further alleviated in a particularly beneficial embodiment of the invention, as shown in Figure 15, in which hot and cold layers of the solution are mixed during the heating process in order to mitigate against the formation of hot spots and reduce the heat-up time. In the case of a perfectly mixed fluid the heat-up time is limited by the resulting thermal stress of the glass wall of the syringe, i.e. breaking the syringe by large temperature gradient. In order to facilitate this, in this embodiment, the sliding syringe cage 281 is provided with a vibrator 700, which in this example comprises a vibration motor of the sort typically used to provide vibrating call alerts in mobile (cellular) telephones. The vibration motor, in this example, comprises a 'coin' or 'button' type vibration motor such as a brushless coin vibration motor but may comprise any suitable motor including, for example, a cylinder type vibration motor. The vibration motor, in this example, is powered via the flexi circuit utilised to power the heating element. It will be appreciated that, whilst the vibrator 700 is shown at a particular location, the vibrator 700 may be provided at any location suitable for causing vibration of the syringe and agitation of any liquid within it. Thus, in operation, the vibrator 700 is used to automatically vibrate the syringe cage 281, and hence the syringe within it, when the heater is in operation, thereby causing mixing of any liquid within the syringe and a more uniform heating process.

Modifications & Alternatives

Detailed embodiments have been described above. As those skilled in the art will appreciate, a number of modifications and alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein.

A visual indication may be provided to indicate to the user that the injector device is ready to be triggered, which in one embodiment is provided by movement of a mechanical flag provided behind a window 203 (illustrated in Figures 2a and 2b) provided on the main body 204, such that a different coloured part of the mechanical flag is visible through the window. Preferably, the mechanical flag is configured to move when the front of the injector device 200 has been pressed against the user's skin with a predetermined amount of force, causing a small movement of the needle safety sheath 201, this movement releasing an internal interlock within the injection device, effectively arming the trigger mechanism. Advantageously, in this embodiment the device requires compression of both the safety sheath and trigger button in order to fire, and provides a visual indication of when the device is "armed" and ready to fire.

The heater element may be controlled to heat the contents of the syringe to any desired temperature. For example, if medicaments are refrigerated, the heater element may be controlled to heat the contained medicament to room temperature (e.g. 21 Celsius). In some embodiments, the injector device electronics can be programmed by a user, using the buttons 921, 932 on the base station 900 (or alternative means), to heat the syringe contents to a chosen temperature, optionally within a range from room temperature to body temperature.

The syringe receiving assembly 200a and the control assembly 200b may be pivotally connected together using any suitable means. In Figure 4 and Figure 6 the needle safety shield 201 is shown with its end passing through the opening 231, wherein this end is the injection end of the needle safety sheath 201, however in other configurations during the injection process a larger portion of the needle safety sheath 201 can protrude outward from the opening 231. Furthermore, in alternative embodiments, the needle safety sheath 201 may be moveable to reside entirely within the outer chassis 205, with no part of the needle safety sheath 201 extending through the opening 231.

The heating element 221 may comprise a resistive heater, a dielectric heater or any other heating means.

The injector device electronics 541 may include or be replaced by any electronics which control the operation of the injector device 200 and/or base station 900.

The injector device electronics 541 and/or the control electronics in the base station 900 may comprise, for example, a printed circuit board (PCB).

While the control electronics are preferably provided in the base station and communicate with the injector device electronics 541, they may be located in the injector device separately or combined with the injector device electronics 541.

In alternative embodiments, the needle safety sheath 201 may not be included in the injector device 200.

The injector device electronics 541 may be configured to detect whether a syringe assembly 150 is present within the cage 281 via measurement obtained from the biasing means 544.

It will be appreciated that while several springs have been disclosed any appropriate resilient means may be used for example leaf springs, compressible/stretchable rubber or the like.

The plunger piston 255 is described with power spring which exerts a force on the plunger piston 255. However, it will be appreciated that the power spring may be replaced with other means suitable for exerting a force on the plunger piston 255.

It will be appreciated that the priming spindle 543 and/or the keyed drive recess 545 may be located at a different point in the injector device 200. In particular, the priming spindle 543 may be disposed near the rear end 291 of the injector device 200, in which case the steel wire pulley 263 may be removed or replaced with alternative wire guiding means.

It will also be appreciated that although the mechanical priming arrangement for retracting the plunger piston 255 into its primed position as described includes a steel wire, a steel wire pulley, a priming spindle and a keyed drive recess, another suitable mechanical arrangement may be used, for example an arrangement employing a crankshaft and/or an arrangement employing a rack and pinion.

In alternative embodiments the heating element 221 and the insulation layer 285 may extend radially around the whole of the loading aperture. The insulation layer 285 may extend only partially around the loading aperture. The temperature sensors may be in contact with the syringe body or may be located in close proximity to the syringe body.

Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Claims

1. An injector device for use with a syringe holding a medicament to be injected, said injector device comprising:

a housing for receiving the syringe;

means for heating the fluid held by the syringe whilst housed in said housing, wherein said means for heating comprises control logic for controlling said heating based on an error representing the difference between a temperature setpoint and a measured temperature, wherein said heating is controlled based on a proportional term that is proportional to said error and an integral term representing an integral of said error over time; and

means for operating the syringe, whilst housed in said housing, to expel fluid held by the syringe that has been heated by the heating means;

wherein said control logic is operable to disable accumulation of said integral term when measured temperature is greater than said temperature setpoint (error < 0).

A injector device according to claim 1, wherein said control logic is operable to disable accumulation of said integral term when measured temperature is greater than said temperature setpoint (error < 0) and the integral of the error < 0.

A injector device according to claim 1 or 2, wherein said control logic is operable to accumulate said integral term when said measured temperature is less than said temperature setpoint (error > 0).

A injector device according to any preceding claim, further comprising means for vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe.

An injector device according to claim 4, wherein the housing further comprises a syringe holder, for holding a syringe, movably mounted within the housing and wherein said means for vibrating said syringe is coupled to said syringe holder whereby vibration of said syringe holder causes said vibration of said syringe, while heating is progressing.

An injector device according to claim 4 or 5, wherein the means for vibrating comprises a vibration motor (e.g. one of a brushless coin or button vibration motor and a cylinder type vibration motor).

7. A injector device according to any preceding claim wherein the heating means comprises a heater element, said heating element arranged to be located proximate to a barrel of said syringe when the syringe is housed in said housing.

A injector device according to claim 4, wherein said heater element comprises at least a resistive heater and a dielectric heater.

9. A injector device according to any of claims 4 to 8, wherein said heater element is configured to surround substantially an entire perimeter of the barrel of the syringe when the syringe is housed in said housing.

10. A injector device according to any of claims 4 to 9, wherein said heater element is configured to be in contact with the barrel of the syringe when the syringe is housed in said housing.

11. A injector device according to any of claims 4 to 10, wherein said heating means is configured to heat the fluid held by the syringe, whilst the syringe is housed in said housing, to a predetermined temperature.

12. A injector device according to any of claims 4 to 11, further comprising means for inhibiting heat generated by said heating means propagating away from the barrel of the syringe when the syringe is housed in said housing.

13. A injector device according to claim 12, wherein said inhibiting means comprises an insulating layer surrounding at least a portion of the barrel of the syringe, whilst the syringe is housed in said housing.

14. A injector device according to any of claims 4 to 13, further comprising means for transferring power from an external source of power to said heating means to drive said heating means.

15. A injector device according to claim 14, wherein the device and power transferring means are configured such that power is transferred from said external source of power to the heating means when the device is connected to a docking device.

16. A injector device according to claim 14 or 15, wherein the power transferred from the external source of power to the device is electrical power.

17. A injector device according to claim 16, wherein the power is transferred from the external source of power to the device via a direct electrical connection.

18. A injector device according to claim 16, wherein the power is transferred from the external source of power to the device via an inductive connection.

19. An injector device according to any preceding claim, for use with a syringe holding a medicament for the treatment of rheumatoid arthritis.

20. An injector device according to any preceding claim, for use with a syringe holding a medicament for the treatment of psoriasis.

21. An injector device according to any preceding claim, for use with a syringe holding a medicament for the treatment of cancer.

22. An injector device as claimed in any preceding claim, said injector device further comprising:

means for advancing a plunger of the syringe, when accommodated in the housing, to expel the medicament held by the syringe;

means for storing mechanical energy for driving said plunger advancing means; means for transferring mechanical energy from a source external to said injector device to said energy storing means to store said energy for driving said plunger advancing means;

means for triggering said advancing means to drive said plunger of the syringe, when accommodated in the housing, to expel the medicament held by the syringe using said energy stored in said storing means.

23. An injector device according to claim 1, wherein said housing comprises a first portion and a second portion, the first and second portions being movable relative to one another.

24. An injector device according to claim 23, wherein the first portion is movable, relative to the second portion, between and open configuration and a closed configuration;

wherein, in said open configuration, the first portion is configured to receive the syringe; and

wherein, in said closed configuration, the first portion is configured to at least partially enclose the syringe within the housing.

25. An injector device according to claim 24, wherein the housing further comprises: means for biasing the first portion into the open configuration;

means for securing the first portion in the closed configuration; and

means for releasing the securing means when the first portion is secured in the closed position to allow the first portion to move from the closed configuration to the open configuration under the influence of the biasing means.

26. An injector device according to claim 25, wherein said mechanical energy transferring means is adapted to trigger said release means to release the securing means.

27. An injector device according to claim 26, wherein said mechanical energy transferring means is adapted to trigger said release when the mechanical energy storing means has stored at least enough energy to drive said plunger advancing means to expel the medicament held by the syringe.

28. An injector device according to claim 26 or 27, wherein said mechanical energy transferring means is adapted to trigger said release while the mechanical energy storing means is in a process of storing energy for driving said plunger advancing means.

29. An injector device according to any of claims 22 to 28, wherein the plunger advancing means is movable, under a force provided from the energy storing means, from a primed position in which it is primed for driving the plunger of the syringe when accommodated in the housing, to a discharge position; and

wherein movement of the plunger advancing means from its primed position to its discharge position causes the plunger advancing means to engage with and advance the plunger of the syringe, when accommodated in the housing, to expel any medicament held by the syringe.

30. An injector device according to claim 29, wherein the plunger advancing means is operable to engage with the mechanical energy storing means when it is moved from its discharge position to its primed position to cause the mechanical energy storing means to store energy for driving said plunger advancing means.

31. An injector device according to claim 30, wherein the mechanical energy storing means comprises a spring; and

wherein movement of the plunger advancing means from its discharge position to its primed position causes the spring to be compressed thereby storing said mechanical energy for driving said plunger advancing means.

32. An injector device according to any of claims 30 to 31, wherein the mechanical energy transferring means is adapted to drive the plunger advancing means from its discharge position to its primed position thereby transferring energy to the mechanical energy storing means for driving said plunger advancing means..

33. An injector device according to any of claims 22 to 32, wherein the mechanical energy transferring means comprises a rotatable element and is adapted to convert rotational energy from the rotatable element into energy for storing by said mechanical energy storing means whereby mechanical energy comprising rotary motion can be transferred from the external energy source to the injector device.

34. An injector device according to claim 33, wherein the mechanical energy transferring means further comprises a reciprocating element; wherein the rotatable element of the mechanical energy transferring means is coupled to the reciprocating element; and wherein said coupling is configured to convert rotary motion of the rotatable element into linear motion of the reciprocating element whereby to convert said rotational energy from the rotatable element into energy for storing by said mechanical energy storing means.

35. An injector device according to claim 34, wherein the reciprocating element of the mechanical energy transferring means is coupled to the plunger advancing means.

36. An injector device according to claim 28, wherein the reciprocating element comprises a cord or wire; and wherein the coupling between the rotatable element and the reciprocating element comprises a spindle adapted to wind up the cord or wire.

37. An injector device according to any of claims 22 to 36, wherein the housing further comprises a syringe holder for holding a syringe in said housing.

38. An injector device according to claim 37 wherein said syringe holder is movably mounted within the housing in order to allow the syringe, when held in the holder, to move between: a home position in which a needle of the syringe is located within the injector device such that a user is inhibited from touching the needle; and an advanced position in which the needle is located outside the injector device such that the needle can be inserted into a user's skin.

39. An injector device according to claim 37 or 38, wherein said syringe holder forms part of the first portion of the housing.

40. An injector device according to any of claims 36 to 39, wherein the syringe holder forms at least part of the plunger advancing means.

41. An injector device according to any of claims 36 to 40, wherein the syringe holder comprises means for guiding said syringe into position in said syringe holder.

42. An injector device according to claim 41 wherein said guiding means is adapted to engage with a complementary handling element fitted to said syringe whereby to assist said guiding of said syringe into position in said syringe holder.

43. An injector device for use with a syringe holding a medicament to be injected, said injector device comprising:

a housing for receiving the syringe;

means for heating the fluid held by the syringe whilst housed in said housing;

means for vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe; and

means for operating the syringe, whilst housed in said housing, to expel fluid held by the syringe that has been heated by the heating means.

44. An injector device according to claim 43, wherein the housing further comprises a syringe holder, for holding a syringe, movably mounted within the housing and wherein said means for vibrating said syringe is coupled to said syringe holder whereby vibration of said syringe holder causes said vibration of said syringe, while heating is progressing.

45. A method of preparing an injector device according to any of claims 1 to 42 for performing an injection using a syringe holding a medicament, said method comprising:

receiving the syringe comprising said medicament;

heating the fluid held by the syringe whilst housed in said housing; wherein said heating comprises controlling said heating based on an error representing the difference between a temperature setpoint and a measured temperature, wherein said heating is controlled based on a proportional term that is proportional to said error and an integral term representing an integral of said error over time, and accumulation of said integral term is disabled when measured temperature is greater than said temperature setpoint (error < 0).

46. A method of preparing an injector device, according to any of claims 4, 5 to 42 when dependent on claim 2, or claim 43 or 44, for performing an injection using a syringe holding a medicament, said method comprising:

receiving the syringe comprising said medicament;

heating the fluid held by the syringe whilst housed in said housing; and

vibrating said syringe, while heating is progressing, whereby to mix said fluid held by said syringe.