WO2022032024A1 - Dispositif d'injection et procédé d'indication d'un état d'injection pour un dispositif d'injection - Google Patents

Dispositif d'injection et procédé d'indication d'un état d'injection pour un dispositif d'injection Download PDF

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Publication number
WO2022032024A1
WO2022032024A1 PCT/US2021/044836 US2021044836W WO2022032024A1 WO 2022032024 A1 WO2022032024 A1 WO 2022032024A1 US 2021044836 W US2021044836 W US 2021044836W WO 2022032024 A1 WO2022032024 A1 WO 2022032024A1
Authority
WO
WIPO (PCT)
Prior art keywords
injection device
housing
medicament container
injection
safety sleeve
Prior art date
Application number
PCT/US2021/044836
Other languages
English (en)
Inventor
John BASISTA
Lawton Edward LAURENCE
Lauren NUTT
Original Assignee
West Pharmaceutical Services, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by West Pharmaceutical Services, Inc. filed Critical West Pharmaceutical Services, Inc.
Publication of WO2022032024A1 publication Critical patent/WO2022032024A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/20—Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically
    • A61M5/2033—Spring-loaded one-shot injectors with or without automatic needle insertion
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
    • A61M5/3202—Devices for protection of the needle before use, e.g. caps
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/20—Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically
    • A61M2005/2026—Semi-automatic, e.g. user activated piston is assisted by additional source of energy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M5/32—Needles; Details of needles pertaining to their connection with syringe or hub; Accessories for bringing the needle into, or holding the needle on, the body; Devices for protection of needles
    • A61M5/3205—Apparatus for removing or disposing of used needles or syringes, e.g. containers; Means for protection against accidental injuries from used needles
    • A61M5/321—Means for protection against accidental injuries by used needles
    • A61M5/3243—Means for protection against accidental injuries by used needles being axially-extensible, e.g. protective sleeves coaxially slidable on the syringe barrel
    • A61M5/326—Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user
    • A61M2005/3267—Biased sleeves where the needle is uncovered by insertion of the needle into a patient's body
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/33—Controlling, regulating or measuring
    • A61M2205/3317—Electromagnetic, inductive or dielectric measuring means

Definitions

  • the present disclosure relates to an injection device comprising an induction sensor for detecting an injection status of the injection device, and to a method of indicating an injection status for an injection device.
  • Injection devices such as syringes and autoinjectors, use hypodermic needles to deliver medicaments subcutaneously. Because used hypodermic needles can harbor harmful pathogens, they must be handled and disposed of safely. If improperly used or disposed of, injection devices may therefore lead to the transmission of disease.
  • both types of autoinjectors discussed above ensure that the hypodermic needle is not exposed after an injection is completed.
  • the needle may be exposed if the injection device is removed from the injection site prematurely (e.g. before the injection process has been completed) and further no indication is provided as to whether or not a required dose of medicament was delivered to the patient
  • the above-described types of autoinjectors may indicate a successful delivery even when a full dose has been delivered but the autoinjector was prematurely removed from the patient, which results in less than the entire dose actually being delivered to the intended subcutaneous location.
  • the above-described types of autoinjectors may provide an incomplete picture of injection status.
  • an injection device that better informs a user regarding injection status.
  • the present disclosure provides an injection device that includes an inductive element having discrete inductive states, wherein the inductive element is operatively coupled with the injection device such that it is in a first of the discrete inductive states when the injection device is in a first configuration, and such that it is in the second of the discrete inductive states when the injection device is in a second configuration.
  • the inductive element may be a conductive loop, wherein the first inductive state corresponds to the conductive loop being closed, and the second inductive state corresponds to the conductive loop being broken.
  • the inductive element can be a binary inductive element, comprising two discrete states.
  • an injection device comprising: a housing having a longitudinal axis, the housing configured to receive a medicament container containing a medicament and a needle operatively coupled to the medicament container; a first contact positioned within the housing; a safety component (e.g.
  • safety sleeve configured to advance relative to the housing from a first position to a second position; a second contact operatively connected to the safety sleeve; wherein the housing and the safety sleeve are configured to form a closed conductive loop comprising the first contact and the second contact when the safety sleeve is in one of the first position and the second position, and to form a broken conductive loop when the safety sleeve is in the other of the first position and the second position, the injection device further comprising: an induction sensor configured to detect a change of inductance.
  • the conductive loop When the conductive loop is closed, a current is able to flow around it. Therefore, when the conductive loop is closed and subjected to an alternating magnetic field, a current will be induced. Similarly, when the conductive loop is broken, a current is unable to flow around it. Therefore, when the conductive loop is broken and subjected to an alternating magnetic field, a current will not be induced.
  • the conductive loop has a binary inductive characteristic - i.e. it has a non-zero inductance when it is closed, and has substantially zero inductance when it is broken.
  • the inductance of the conductive loop undergoes a step-change. Because of the binary nature of the inductive property, the position of the safety sleeve can be reliably detected.
  • the induction sensor may be configured to detect a change of inductance associated with the breaking and closing of the conductive loop.
  • the induction sensor may be configured so that an induction signal is inducible in the induction sensor.
  • the induction sensor may comprise an induction coil (in which an induction signal is inducible) and a sensor circuit configured to detect induction signals in the induction coil. That is to say, the sensor circuit may be configured to detect a current induced in the induction coil (for example detect one or more of alternating frequency, and amplitude, of the current flowing in the induction coil). More specifically, the sensor circuit may be configured to detect changes in a current flowing through the induction sensor (e.g. changes in one or more of the alternating frequency, and amplitude, of the current flowing through the induction sensor).
  • induction signal will be used to define an electrical signal that is induced in an induction sensor, and that is attributable to proximity of the inductive sensor with an inductive element (such as the closed conductive loop). Moreover, an increased proximity to the closed conductive loop will increase the induction signal detected at the induction sensor. Similarly, breaking of the conductive loop reduces the inductance of the conductive loop to substantially zero, such that substantially no inductance signal may be detected at the induction sensor.
  • the first contact may be disposed concentrically within the safety sleeve when the safety sleeve is in the first position.
  • the first contact may be disposed concentrically within the safety sleeve so as to engage the second contact to form the closed conductive loop, when the safety sleeve is in the first position.
  • the first and second contacts may move out of engagement with each other, thereby breaking the conductive loop, when the safety sleeve advances to the second position.
  • the first contact may define a partial annular ring disposed on one of the housing and the safety sleeve, the partial annular ring comprised of a conductive material and defining first and second circumferential ends, wherein the first and second circumferential ends are separated by a gap.
  • the second contact may be a bridging component comprised of a conductive material and configured to engage the first and second circumferential ends of the first contact when the safety sleeve is in the one of the first position and the second position.
  • the bridging component may comprise a spring contact.
  • the bridging element and the partial annular ring may collectively form the closed conductive ring when the bridging contact engages the first and second circumferential ends of the first contact.
  • the partial annular ring may be disposed on the housing, and the bridging element may be disposed on the safety sleeve.
  • this arrangement could be reversed.
  • the safety sleeve may surround at least a portion of the housing. That is to say, the safety sleeve may be arranged around a proximal end of the housing.
  • the partial annular ring may be located on an outer surface of the housing, and the bridging element may be located on an inner surface of the safety sleeve.
  • the bridging element may be able to engage the partial annular ring to thereby close the conductive loop as described above.
  • the injection device may further comprise a medicament container containing a medicament and a needle operatively coupled to the medicament container; and a plunger mechanism configured to engage a stopper disposed within the medicament container and configured to move through the injection device 100 and through the medicament container 112.
  • a drive spring may be configured to drive the plunger mechanism through the medicament container.
  • the induction sensor may be coupled to, e.g. housed within, the plunger mechanism. Therefore, when the conduction loop is closed, movement of the plunger mechanism (and hence the induction sensor) through the medicament container and towards the closed conductive loop may be detectable as a change (e.g. increase) in induction signal.
  • movement of the plunger through the medicament container may be detectable as a gradual (e.g. non-binary) change of inductance signal; and movement of the safety sleeve between the first and second positions may be detectable as a discontinuous (e.g. binary) change of inductance signal.
  • movement of the plunger through the medicament container may be detectable as a gradual change of inductance signal; and advancement of the safety sleeve to the second position may be detectable as a discontinuous drop of inductance signal, e.g. to substantially zero (due to the conductive loop being broken).
  • the detected induction signal may be indicative of injection status (namely, movement of the plunger through the medicament container to expel a medicament, and advancement of the safety sleeve). That is to say, a gradual change (e.g. increase) in detected inductance signal may be indicative of a movement of the plunger mechanism; and a discontinuous change in detected inductance signal (e.g. a drop to substantially zero inductance) may be indicative of an advancement of the safety sleeve.
  • a detected drop in inductance signal to substantially zero may indicate incorrect use of the injection device, and/or incomplete delivery of the medicament to a patient.
  • the injection device may therefore enable a full picture of injection status to be provided to a user, by detecting change in inductance signal.
  • the injection device may further comprise a microprocessor in communication with the induction sensor, wherein the microprocessor is configured to determine an injections status based on an induction signal detected at the induction sensor. Moreover, the microprocessor may be configured to determine, based on an induction signal detected at the induction sensor, one or both of: a position of the plunger within the medicament container; and a position of the safety sleeve.
  • the position of the plunger may be determined based on an increased induction signal detected at the induction sensor.
  • the position of the safety sleeve may be determined based on an induction signal detected at the induction sensor dropping to substantially zero.
  • the microprocessor may be able to determine the injection status of the injection device, based on the detected inductance signal.
  • the plunger mechanism may include an electronics subassembly disposed therein, the electronics subassembly including the induction sensor.
  • the electronics subassembly may also include the microprocessor discussed above.
  • the electronics subassembly may also comprise a memory and a power source.
  • One or more of the memory, the power source, the microprocessor, and the induction sensor, may be attached to a printed circuit board (PCB).
  • PCB printed circuit board
  • the electronics subassembly may also include a wireless transmitter configured to send a signal that is indicative of the inductance signal (and thus injection status) to a remote device.
  • the wireless transmitter may be attached to the PCB.
  • the remote device may be a cell phone, a tablet, a personal computer (PC), or a remote server. Accordingly, the remote device may be configured to provide a user with an audible, visual, or tactile indication of injection status, based on the signal received from the electronics subassembly.
  • the injection device and remote device may collectively be capable of providing a user with a full picture of injection status.
  • the injection device may further comprise an output device.
  • the output device may be configured to send a signal indicative of the inductance (and thus injection status) to the output device.
  • the output device may be physically connected to, or housed within, the injection device.
  • the output device may include an LED, a visual display, or an audible output (e.g. speaker or buzzer).
  • the output device may be configured to output a signal that is indicative of an injection status of the injection device.
  • the injection device may be capable of providing a user with a full picture of injection status, via the output device.
  • the first and second contacts may be electrically isolated from the induction sensor. As the reader will understand, this is possible because it is a detected inductance of the conductive loop that is used as the determinant of safety sleeve position and optionally plunger position. Inductance can be detected wirelessly.
  • the injection device may be configured to supply the induction sensor with an alternating current. That is to say, a microcontroller may supply the induction sensor with an alternating current.
  • the alternating current may be a square wave current. Square wave currents having a consistent frequency and wave shape are straightforward for the microcontroller to produce (e.g. relative to a sine wave AC signal), particularly considering the constraints imposed when the microcontroller and its power source are to be housed within the injection device.
  • the microcontroller for supplying the induction sensor may be the same as the microcontroller described above, or may be different from the microcontroller described above.
  • the induction sensor may comprise an LC circuit (i.e. a circuit containing an inductor coil, L, and a capacitor, C).
  • the microcontroller may supply the LC circuit (also known as a tank circuit) with the alternating current.
  • the microcontroller may be configured to supply the LC circuit with an alternating current having a frequency that matches the fundamental frequency of the LC circuit.
  • the LC circuit may be driven at its resonant frequency.
  • the microcontroller may further be configured to detect changes in frequency and/or amplitude at the LC circuit, and from this may identify changes in the inductance signal.
  • the injection device may further include a spring arranged to advance the safety component into the second position.
  • the safety sleeve may be configured to conceal a needle protruding from a proximal end of the injection device when in the second position.
  • the safety sleeve may be configured to advance relative to the housing from the first position to the second position in response to removal of the injection device from an injection site prior to completion of delivery of a dose of the medicament.
  • the injection device may be configured with a releasable locking mechanism; wherein the releasable locking mechanism is configured, when in a locked position, to prevent advancement of the safety sleeve; and is configured, when in an unlocked position to allow advancement of the safety sleeve.
  • the releasable locking mechanism may be configured to occupy the unlocked position when the injection device is removed from an injection site prior to completion of delivery of a dose of the medicament.
  • the injection device may further comprise: a needle assembly coupled with the medicament container; and a safety mechanism.
  • the safety mechanism may be configured, in response to completion of delivery of a dose of medicament, to retract the medicament container to a retracted position relative to the housing, and in response to removal of the injection device from an injection site prior to completion of delivery of the dose of the medicament, to advance the safety component relative to the housing from the first position to the second position.
  • the device can also be configured to indicate a third end-state, which indicates that the device was removed from the injection site prematurely and an incomplete dose has been delivered.
  • aspects of the disclosure can further provide for an injection device having visibly distinct end-states, which inform the user both of whether the device was incorrectly used (leading to incomplete delivery of the medicament), and how the device was incorrectly used.
  • the first position of the safety component may be visually distinct from the second position of the safety component.
  • the injection device may further comprise a releasable locking mechanism configured to prevent advancement of the safety component to the second position when the medicament container is in the retracted position.
  • the releasable locking mechanism can be configured to allow advancement of the safety component to the second position when the medicament container is in the injection position.
  • the safety component can comprise a sleeve configured to shield a proximal end of the needle when the sleeve is in the second position.
  • the sleeve may comprise a generally closed tubular body.
  • the tubular body can be open at its proximal end (e.g. without an end wall).
  • the safety sleeve can comprise an end wall with an opening provided therein to allow the needle to extend through for injection.
  • the device can further comprise a biasing element configured to urge the safety component into the second position.
  • the biasing element can be a safety spring arranged between the safety component and the housing.
  • the biasing element can form part of the retraction mechanism for retracting the medicament container relative to the housing after completion of an injection.
  • the releasable locking mechanism can comprise a flexible latch arm configured to be moved between a first position in which it engages a latching surface to prevent movement of the safety component relative to the housing, and a second position in which it does not engage the latching surface such that the safety component is permitted to move relative to the housing.
  • a track on one of the housing and the safety component there is provided a nub on the other of the housing and the safety component, the nub configured to move within the track.
  • the track can comprise a one-way latch configured to prevent movement of the safety component from the second position to the first position after the safety component has been advanced relative to the housing.
  • the device can be configured such that movement of the safety component to the second position is configured to expose a visual indicator, wherein the visual indicator is not visible when the safety component is in the first position.
  • the safety mechanism may be entirely mechanically actuated. This can provide for a robust device that can provide passive shielding of the needle without the need for actuation of a safety mechanism by the user or by a control system.
  • the needle assembly can be selectively coupled with the medicament container. Alternatively, the needle assembly can be fixedly coupled to the medicament container.
  • the injection device can be provided without the medicament container, or with the medicament container disposed therein.
  • the releasable locking mechanism can comprise at least one flexible latch arm located on one of the safety component and the housing, and at least one corresponding latching surface on the other of the safety component and the housing, and wherein each flexible latch arm can be configured to be disengaged from the latching surface by the needle assembly or the medicament container.
  • a method of indicating an injection status for an injection device comprising a housing, a safety component (e.g. safety sleeve) configured to advance relative to the housing from a first position to a second position, a conductive loop, and an induction sensor.
  • the method comprising: advancing the safety sleeve to the second position, thereby closing or breaking the conductive loop; and detecting, at the induction sensor, a change of inductance associated with the closing or breaking of the conductive loop.
  • the method of the second aspect may be combined with the injection device of the first aspect, so as to indicate an injection status of the injection device according to the first aspect.
  • a third aspect there is provided a method of indicating an injection status of an injection device according to the first aspect.
  • the method may comprise advancing the safety sleeve to the second position, thereby closing or breaking the conductive loop; and detecting, at the induction sensor, a change of inductance associated with the closing or breaking of conductive loop.
  • the injection device further comprises a medicament container containing a medicament, and a plunger mechanism configured to engage a stopper disposed within the medicament container and to move through the medicament container, and wherein the induction sensor is arranged to move with the plunger mechanism
  • the method may further comprise: prior to advancing the safety sleeve, moving the plunger mechanism through the medicament container; and detecting, at the induction sensor, a change of inductance signal associated with a change in distance between the induction sensor and the conductive loop.
  • Advancing the safety sleeve to the second position may break the conductive loop. This in turn may cause the induction signal detected by the induction sensor to drop to substantially zero.
  • the method may further comprise reporting advancement of the safety sleeve when the change of inductance signal detected at the induction sensor is indicative of the conductive loop having been broken.
  • the method may further comprise reporting advancement of the safety sleeve when the inductance signal detected at the induction sensor drops to substantially zero.
  • the method may further comprise issuing an alert when a detected change in inductance signal is indicative of an incorrect operation of the injection device.
  • the method may comprise advancing the safety sleeve to the second position when the injection device has been removed from an injection site prior to completion of a dose of the medicament. Therefore, the method may issue the alert when the induction signal detected at the induction sensor drops to substantially zero.
  • Moving the plunger mechanism through the medicament container may comprise activating a drive spring of the injection device, the drive spring arranged to drive the plunger mechanism through the medicament container.
  • the method may further comprise: upon fully moving the plunger mechanism through the medicament container, retracting the medicament container relative to the housing; and locking a releasable locking mechanism configured to prevent extension of the safety component by retracting the medicament container relative to the housing.
  • the step of retracting the medicament container relative to the housing can further comprise moving a first indicator from a concealed position to a visible position by retracting the medicament container.
  • the method may further comprise: biasing the safety component into the second position, the second position being an extended position in which the safety component shields a proximal end of the needle assembly; maintaining a releasable locking mechanism in an unlocked configuration when the medicament container is in an injection position; and removing the injection device from an injection site with the releasable locking mechanism in the unlocked configuration; thereby allowing the safety component to advance to the second position while the releasable locking mechanism is in the unlocked position.
  • the method can further comprise retracting the medicament container relative to the housing after advancement of the safety component to the second position, wherein the step of retracting the medicament container relative to the housing optionally further comprises moving a first indicator from a concealed position to a visible position by retracting the medicament container.
  • the method may further include the steps of: in response to removal of the device from the injection site before completion of a dose of medicament, advancing the safety component to the second position to shield the needle of the device with the needle in an advanced injection position; in response to removal of the device from the injection site after completion of a dose of medicament, retaining the safety component in the first position, and retracting the needle of the device relative to the housing to a position in which the needle is retracted within the safety component with the safety component in the retracted position.
  • Figure 1 a shows an external view of an exemplary injection device according to the present disclosure, with the housing cap removed;
  • Figure 1 b shows a cross-sectional view of the injection device of Figure 1 a with the housing cap in situ;
  • Figure 2b illustrates the injection device of Figure 1 , with certain components in an injection position
  • Figure 3 shows a sub-assembly of the injection device of Figure 1 ;
  • Figure 4a shows a perspective view of a housing of the sub-assembly of Figure 3;
  • Figure 4b shows an alternate perspective view of the housing of the sub-assembly of Figure 3;
  • Figure 4c shows a schematic view of a track of the sub-assembly shown in Figures 4a and 4b;
  • Figure 5a shows a perspective view of a safety component of the safety system of Figure 3;
  • Figure 5b shows an alternate perspective view of the safety component of the safety system of Figure 3;
  • Figure 6 shows a needle hub of the medicament container assembly of Figure 2
  • Figure 7 is a flow chart illustrating operation of the injection device of Figure 1 ;
  • Figures 8a illustrates a first end-state of the injection device of Figure 1 ;
  • Figure 8b illustrates a second end-state of the injection device of Figure 1 ;
  • Figure 8c illustrates a third end-state of the injection device of Figure 1 ;
  • Figure 9a shows a first inductive state of the injection device of Figure 1 ;
  • Figure 9b shows a second inductive state of the injection device of Figure 1
  • Figure 10 is a flow chart illustrating a method of indicating an injection status for the injection device of Figure 1 ;
  • Figure 11 is a schematic diagram showing components of an electrical system for indicating an injection status of the injection device of Figure 1 ;
  • Figure 12 is a flow chart showing processing steps performed by a microcontroller according to the present disclosure.
  • the inductive element for indicating the status of a delivery device and the method of indicating the status of delivery device using the device are described below in the context of an exemplary delivery device comprising an exemplary safety mechanism.
  • the inductive element and associated methods described herein are not limited to use in the context of this device. Rather, the systems and methods described herein are applicable to delivery devices in which components of the device move relative to each other during an injection procedure, for example devices in which a safety sleeve moves relative to a housing. This will be understood by the person skilled in the art.
  • the safety mechanisms described herein are particularly suited to use in connection with autoinjectors configured to advance a medicament container from a housing, deliver a dose of medicament, and retract the medicament container after injection of a dose of medicament has been completed.
  • the safety mechanisms described herein may be combined with mechanical, electromechanical, or pneumatic drive assemblies configured to advance the medicament container and deliver a dose of medicament.
  • the exemplary embodiment described below with reference to the accompanying drawings comprises an autoinjector comprising a mechanical drive assembly, which includes a drive spring.
  • the safety mechanism described below may be implemented in autoinjectors comprising other drive arrangements.
  • Figure 1 a shows an external view of an injection device 100 according to the present disclosure.
  • the injection device 100 can be broadly split into two parts - a casing 102, which houses the drive components of the device (to be discussed in more detail with reference to Figure 1 b); and a subassembly 104, which is attached to the casing 102, which comprises an opening 103 through which an injection is administered and a safety mechanism.
  • the casing 102 and the sub-assembly 104 provide an enclosure for housing the medicament container and the drive assembly of the injection device.
  • a housing cap 106 (shown in Figure 1 b) may optionally be provided to close an open end of the injection device 100 through which the injection is administered.
  • At least a portion of the casing 102 and/or the sub-assembly 104 may be formed of a transparent material so that the user may view the contents of a medicament container 112 (shown in Figure 1 b) through the housing components (casing 102 and sub-assembly 104) of the injection device 100.
  • one or more of the housing components may comprise a viewing window through which internal components of the injection device 100 may be viewed.
  • the viewing window may be closed with a transparent material (which may help to maintain a sterile environment within the housing) or the viewing window may comprise an opening in one or both of the casing 102 or the sub-assembly 104.
  • the housing cap 106 may also be transparent, allowing the user to view the sub-assembly 104 after the housing cap 106 has been replaced. Since the sub-assembly 104 can be configured to act as an indicator of the status of an injection after use of the device, a transparent housing cap 106 can allow the user to view the status of the device 100 even after the housing cap 106 has been optionally replaced after use. Note that in some embodiments, the housing cap 106 can be configured to prevent reattachment of the housing cap 106 to the sub-assembly 104.
  • the sub-assembly 104 can comprise snap fit components configured to mate with corresponding components on the casing 102 to secure the two parts together.
  • One or both of the housing components can comprise a moulded plastic material, or one or both of the housing components can be formed of metal.
  • the casing 102 and the sub-assembly 104 define a hollow interior configured to house the medicament container and the drive assembly of the device 100.
  • the sub-assembly 104 is at a proximal end of the injection device 100.
  • a proximal end of the injection device 100 refers to an end of the injection device 100 from which a needle 210 extends during injection of a medicament.
  • the casing 102 forms a distal portion of the injection device 100, i.e. at the end of the device opposite the proximal end of the device.
  • the device 100 generally extends a long a longitudinal axis L.
  • Figure 1 b shows a cross-sectional view of the injection device 100 of Figure 1 a.
  • the subassembly 104 is covered by a housing cap 106.
  • the injection device 100 includes a medicament container assembly 118, which comprises a medicament container 112 configured to contain a liquid medicament 114.
  • a needle assembly 116 is provided to deliver a dose of medicament 114 from an internal volume of the container 112 to a patient via a needle 210.
  • the needle 210 is initially not in fluid communication with the internal volume of the medicament container 112, and is brought into fluid communication with the internal volume of the medicament container 112 as the medicament container 112 is advanced into an injection position (as will be described in more detail with reference to Figures 2a and 2b).
  • the medicament container assembly 118 may alternatively comprise a medicament container having a needle fixedly coupled thereto.
  • the medicament container 112 is closed at its distal end with a stopper 110.
  • the stopper 110 is slidably arranged within the medicament container 112 and can be advanced in a proximal direction (along the longitudinal axis L) to discharge a dose of medicament through the needle 210 and into an injection site.
  • the stopper 110 is configured to be driven in a proximal direction by a drive assembly.
  • the drive assembly comprises a plunger assembly 108, which comprises a first plunger portion 108a and a second plunger portion 108b.
  • the first and second plunger portions 108a, 108b can be formed of separate components fixedly coupled to each other, or they may be formed as a single component.
  • the first plunger portion 108a is configured to engage the stopper 110, as shown in Figure 1 b.
  • a drive spring 109 arranged within the casing 102 is configured (upon actuation of the injection device 100) to longitudinally expand and thus drive the plunger assembly 108 in a proximal direction to advance the medicament container 112, the stopper 110, and the needle assembly 116 axially along the longitudinal direction L, and thereby deliver a dose of medicament from the medicament container 112.
  • a disengagement mechanism 120 is configured to decouple the plunger assembly 108 from the drive spring 109 to allow the medicament container 112 to retract within the sub-assembly 104 once the contents of the medicament container 112 have been discharged, to remove the needle 210 from the injection site.
  • the drive spring 109 comprises a helical spring arranged coaxially with a longitudinal axis L of the device 100.
  • the drive spring 109 is illustrated as a single spring coaxially arranged with the plunger assembly 108.
  • the drive spring may alternatively comprise multiple springs.
  • a helical spring is illustrated here, other mechanical springs may be provided.
  • the stopper 110 is arranged within the container 112 such that it abuts the plunger assembly 108.
  • the plunger assembly 108 in an initial configuration (priorto actuation ofthe device) can be spaced from the stopper 110, and can engage the stopper 110 only after an initial displacement caused by the drive assembly.
  • the drive assembly is also configured to advance the medicament container 112 from a retracted position (in which the needle 210 is contained within the housing) to an extended position, which the needle 210 extends through the opening 103 to perform an injection.
  • separate drive assemblies may be provided for (I) advancing the medicament container into an injection position, and (ii) discharging a dose of medicament from the container.
  • the casing 102 houses the drive spring 109, the disengagement mechanism 120, the plunger assembly 108 and a distal portion of the medicament container 112.
  • the drive assembly (comprising the spring 109, the disengagement mechanism 120 and the plunger assembly 108) can be supported within the casing 102 with an insert 107.
  • the insert 107 may be configured to maintain alignment of the drive assembly with the medicament container 112 along the longitudinal axis L of the device.
  • the insert 107 may be integrally formed with the casing 102 or it may be a removable component. In some embodiments, the insert 107 may be omitted entirely.
  • the safety mechanism comprised in the sub-assembly 104 can be configured to occupy at least two, and optionally three or more end-state configurations, which are visually distinct from each other.
  • the end state of the device can be determined by the status of the injection at the point at which the injection device 100 was removed from the injection site. This can provide the user with a visual indication of the status of the injection as delivered to the injection site.
  • the safety mechanism of the present disclosure can also provide passive shielding of the needle 210 from the moment the device 100 is removed from an injection site, thus ensuring that the user is protected from needle stick injuries even if the device is removed from an injection site prematurely.
  • the components of the safety mechanism will be described in more detail with reference to Figures 3- 6.
  • the disengagement mechanism 120 is configured to decouple the medicament container 112 from the drive spring 109, to allow the medicament container 112 to be retracted relative to the sub-assembly 104 once a dose of medicament has been delivered. Retraction of the medicament container 112 relative to the sub-assembly 104 also retracts the needle 210 relative to sub-assembly 104 until the proximal end of the needle 210 no longer extends through the opening 103. Retraction of the medicament container 112 relative to the sub-assembly 104 therefore renders the device 100 safe after a complete dose of medicament has been delivered.
  • the force needed to retract the medicament container 112 relative to the sub-assembly 104 may be provided by a retraction spring 309.
  • the retraction spring 309 is generally configured to be compressed (or further compressed) when the medicament container 112 is moved towards the injection position underthe influence of the drive spring 109.
  • the drive spring 109 is therefore sufficiently stiff to overcome the force of the retraction spring 309 to maintain the medicament container 112 in the injection position until the disengagement mechanism 120 releases the plunger assembly 108 from the influence of the drive spring 109.
  • the sub-assembly 104 which comprises the safety mechanism referred to above, will now be described in more detail with reference to Figures 2-6.
  • Figures 2a and 2b show in more detail operation of the injection device 100, and in particular the coupling between the needle 210 and the container 112, and operation of the safety mechanism at the injection end of the device 100.
  • the sub-assembly 104 comprises a housing 302 configured to receive at least portion of the medicament container 112.
  • a safety component which here takes the form of a safety sleeve 308, is movably mounted relative to the housing 302 and is configured to be selectively advanced relative to the housing 302 to shield the needle 210 after the device 100 has been removed from the injection site.
  • the subassembly 104 comprises a releasable locking mechanism, which is movable between a locked position (in which it prevents proximal movement of the safety sleeve 308 relative to the housing 302) and an unlocked position (in which it allows proximal movement of the safety sleeve 308 relative to the housing 302).
  • the safety sleeve 308 is urged proximally by a biasing element (explained in more detail below), such that upon release of the releasable locking mechanism, the safety sleeve 308 advances relative to the housing 302 in the proximal direction.
  • the sub-assembly 104 also comprises a retraction spring 309 configured to bias the medicament container 112 in a distal direction (away from the injection site) to move the medicament container 112 and the needle 210 to a retracted position after an injection has been completed.
  • the retraction spring 309 can comprise a helical spring arranged between the medicament container 112 and a shoulder of the housing 302. As shown in Figure 2b, the retraction spring 309 can be compressed as the medicament container 112 is advanced to an injection position. The medicament container 112 is maintained in the advanced position by the proximal bias of the drive spring 109.
  • the sub-assembly 104 also comprises a safety spring 311 , which is arranged to bias the safety component 308 into an advanced position.
  • the safety spring 311 is arranged between the housing 302 and the safety component, and is compressed between these two components when the safety component 308 is in its start position.
  • the safety spring 311 is configured to advance the safety component 308 relative to the housing 302.
  • the retraction spring can also be configured to advance the safety component 308. This can be achieved by compressing the retraction spring 309 between the medicament container 112 and the safety component 308.
  • the safety component 308 can comprise a projection having a bearing surface that extends through an opening in the housing 302.
  • the return spring 309 can be compressed between the bearing surface and the medicament container 112. In this manner, the compressed return spring 309 can act to advance the safety component 308 and retract the medicament container 112.
  • Figure 2a shows the proximal end of the device 100 with the medicament container 112 and needle assembly 116 in a first retracted position relative to the housing 302 (with the needle 210 shielded within the housing 302), before the medicament container has been moved to the injection position.
  • the needle 210 has not yet been coupled to the medicament container 112.
  • the releasable locking mechanism that prevents translational movement of the sleeve 308 relative to the housing is engaged and relative movement between the sleeve 308 and the housing 302 is prevented.
  • the locking mechanism comprises a plurality of latch arms 506 provided on the safety sleeve 308, which are configured to engage corresponding latching surfaces (reference numeral 408 in Figures 4a-4b) provided on the housing 302.
  • the latch arms 506 are initially in a position in which they engage the latching surfaces 408 on the housing 302 (not shown in Figures 2a or 2b) to prevent proximal movement of the safety sleeve 308 relative to the housing 302.
  • the latch arms 506 provided on the safety sleeve 308 are configured to be deflected from their rest position (as shown in Figure 2a) by the medicament container 112 or needle assembly 116 (or an associated component) when the medicament container 112 is in the injection position.
  • the latch arms 506 are no longer in a position in which they engage the corresponding latching surface 408 on the housing 302. Due to the deflection of the latch arms 506, if the injection device 100 is removed from the injection site whilst the medicament container 112 is in the injection position (with the needle 210 extending through the opening 103), the safety sleeve 308 is free to advance under the influence of the biasing element (or elements).
  • the biasing element configured to advance the safety sleeve 308 relative to the housing 302 can take different forms.
  • the biasing element configured to bias the safety sleeve 308 in a proximal direction relative to the housing 302 can be the retraction spring 309 configured to bias the medicament container 112 into a retraction position after a dose of medicament has been completed (and the disengagement mechanism 120 described above has decoupled the plunger assembly 108 from the influence of the drive spring 109).
  • a dedicated safety spring can be provided to bias the safety sleeve 308 into the second, extended position relative to the housing 302.
  • the safety sleeve 308 remains in the unextended position only if the injection device 100 is held against the injection site for the duration of the injection (e.g. throughout the period in which the latch mechanism is unlocked, when the medicament container 112 is in the injection position).
  • Deflection of the latch arms 506 can be by the medicament container 112, the needle assembly 116 or a dedicated unlocking component configured to translate with the medicament container 112 during the injection procedure.
  • the needle assembly 116 comprises a needle hub 600 having a shoulder 604 (shown in detail in Figure 6).
  • the shoulder 604 can comprise a bevelled surface configured to deflect the latch arms 506. Therefore, in the illustrated embodiments, proximal movement of the medicament container 112 brings the shoulder 604 into contact with the latch arms 506 to unlock the releasable locking mechanism when the medicament container is in the injection position.
  • the skilled person will appreciate that other components of the medicament container 112 or medicament container assembly 118 can be configured to deflect the latch arms 506 to their unlocked position.
  • the plunger assembly 108 With the needle hub 600 coupled to the medicament container 112, and the medicament container 112 in the injection position, the continued proximal advancement the plunger assembly 108 causes the stopper 110 moves proximally towards the needle 210, thereby discharging the liquid medicament 114 through the needle 210 and into the injection site.
  • FIG. 2a and 2b includes a sealed medicament container 112 comprising a perforate seal or septum 202 configured to be pierced by a needle 210
  • the medicament container 112 can instead comprise an integrated needle assembly in which the needle 210 is fixedly coupled to the medicament container 112.
  • the medicament container 112 is configured to be retracted relative to the housing 302 to a second retracted position. It will be understood that the first retracted position of the medicament container 112 (before injection) and the second retracted position of the medicament container 112 (after injection) may be the same. Alternatively, the first and second retracted positions may be different.
  • the retraction of the medicament container 112 relative to the housing 302 may be under the influence of a retraction spring 309, after the medicament container 112 has been decoupled from the drive spring 109 by the disengagement mechanism 120.
  • a motorised drive assembly e.g. a motor driven telescopic screw assembly.
  • the safety mechanism is thus configured to perform a first function of retracting the medicament container 112 and the needle assembly 116 after a complete dose of medicament has been delivered.
  • the safety mechanism is configured to advance the safety sleeve 308 relative to the housing 302 only if the injection device 100 is removed from the injection site prematurely, i.e. before the dose of medicament has been delivered and the medicament container 112 returned to the second retracted position within the housing 302.
  • the needle is in fact a part of the medicament container assembly 118 of Figures 1 and 2, and is not part of the sub-assembly 104 (which, in some embodiments, may be retrofittable to the injection device 100 and medicament container assembly 118 of Figures 1 and 2).
  • the safety sleeve 308 is movable relative to the housing 302 between a first (unextended) position and a second (extended) position.
  • first (unextended) position relative to the housing 302
  • second (extended) position When the safety sleeve 308 is in the first (unextended) position relative to the housing 302, and the needle 210 is in the injection position (as illustrated in Figure 3), the needle 210 protrudes through the opening 103 beyond the proximal end of the safety sleeve 308 such that it can puncture the skin of a patient for delivery of a dose of medicament.
  • the safety spring 311 is arranged to bias the safety sleeve 308 into the second (extended) position.
  • the retraction spring 309 can be configured to bias the safety sleeve 308 into the second position.
  • Figures 4a and 4b show the housing 302 of Figure 3, with the retraction and/or safety springs and safety sleeve 308 removed.
  • the housing 302 includes a first portion 402 (the visible part of the housing 302 in Figure 3), and a second portion 404 at the proximal end of the housing 302 (the portion of the housing 302 that is concealed from view by the safety sleeve 308 in Figure 3).
  • the second portion 404 can have a smaller outer diameter than the first portion.
  • the first portion 402 has an outer diameter that is larger than the inner diameter of the safety sleeve 308.
  • the second portion 404 has an outer diameter that is smallerthan the inner diameter of the safety sleeve 308, such that the safety sleeve 308 can slide relative to the housing 302, with the retraction spring positioned therebetween.
  • a central aperture 406 At the proximal end of the housing 302 is a central aperture 406, through which the needle 210 can protrude when the needle assembly 116 is in the injection position.
  • four latching surfaces 408 are arranged around the central aperture 406. As the reader will understand, there could be fewer latching surfaces (for example, there could be one latching surface, or two latching surfaces, or three latching surfaces). Or there could be more latching surfaces (for example, there could be five or more latching surfaces).
  • the openings 409 each comprise a relatively narrow portion 409a and a relatively wide portion 409b.
  • the latch arms 506 When the flexible latch arms 506 are in the rest position (shown in Figure 2a), the latch arms 506 extend through the narrow portion 409a of the openings 409 and the limbs 507 of the T-shaped latches 506 engage the latching surfaces 408. With the latch arms 506 in this position, the releasable locking mechanism is locked and the safety sleeve 308 is therefore blocked from proximal movement relative to the housing 302, and the safety sleeve 308 is retained in the first (unextended) position relative to the housing 302.
  • releasable locking mechanism is configured with T-shaped latch arms 506 and corresponding openings 409
  • other latch arrangement configured to selectively prevent proximal movement of the safety sleeve 308 relative to the housing 302
  • a releasable locking arrangement comprising a plurality of teeth configured to engage a plurality of corresponding grooves (similar to the first and second disengagement components described above) may also be used.
  • Other suitable releasable locking mechanisms will also be apparent to the skilled person in light of the present disclosure.
  • the sub-assembly 104 is also configured to maintain the safety sleeve 308 in a safety position after the injection device 100 has been removed from the injection site, as will be described in more detail below.
  • the second portion 404 of the housing 302 includes a track 410, within which a pin or nub 504 of the safety sleeve 308 (see Figures 5a, 5b) is arranged to move.
  • a pin or nub 504 of the safety sleeve 308 see Figures 5a, 5b
  • the nub 504 and track 410 constrain the movement of the safety sleeve 308 relative to the housing 302.
  • the nub 504 When the safety sleeve is in the first position relative to the housing, the nub 504 is located at a distal end 411 of the track 410.
  • the track 410 is configured with a one-way latch 412 which allows the nub 504 to advance past the latch 412 (as the sleeve 308 advances relative to the housing 302), but which prevents movement of the nub 504 in the opposite direction.
  • the one-way latch 412 results in the fact that that the safety sleeve 308, once advanced, is not able to move back to the first position.
  • the position of the sleeve 308 relative to the housing 302 is confined to the end-states (described in more detail with reference to Figures Base).
  • the confinement of the nub 504 within portions of the track 410 therefore provides the safety mechanism with a mechanical logic that dictates the possible end position(s) of the safety sleeve 308, thereby providing a visual indicator to the user regarding the status of an injection delivered by the device.
  • Figure 4c shows a schematic view of the track 410 with the nub 504 in different locations within the track 410.
  • the nub 504 occupies position A within the track 410. If the injection device is removed from the injection site before an injection is complete (e.g. when the larch arms 506 are disengaged from the latching surfaces 408), the latch arms 506 pass through the openings 409 and the nub 504 advances along the track 410 in a proximal direction indicated with arrow M. Further proximal movement of the nub 504 along the track 410 deflects the one-way latch 412, to allow the nub 504 to move into position B. Once past the latch 412, the nub 504 cannot be pushed backwards (towards position A) because the latch 412 prevents the nub’s progress in the distal direction.
  • the nub’s travel continues from position B to position C against the bottom 413a of trap 413, which is the position that the nub 504 occupies when the sleeve 308 is fully advanced into its second position, relative to the housing 302. As shown in Figure 4c, with the nub 504 is position C within the trap, the safety sleeve 308 is locked into the extended position relative to the housing 302.
  • the nub 302 is now confined in the trap 413 at the proximal end of the track. Therefore, if the user pushes against the safety sleeve 308 in an attempt to retract it, the nub 504 moves to position D in which it is confined against the top 413b of the trap 413. It will also be noted with the nub 504 in the trap 413, the latch 412 has returned to its undeflected position (shown in Figure 4c), In this position, the free end of the latch 412 blocks the entry to the trap 413. Accordingly, once the nub 504 has moved into the trap, the safety sleeve 308 cannot be retracted relative to the housing 302 and the safety sleeve 308 is thus locked in a needle shielding position.
  • the first conductive contact takes the form of a partial annular metallic (e.g. aluminium or copper) ring 420.
  • the partial annular ring 420 is disposed an outer surface of the housing 302, towards the distal end of the housing 302.
  • the partial annular ring 420 is broken. That is to say, it defines first and second circumferential ends 422, 424, which are separated by a gap. Therefore, when the gap between the first circumferential end 422 and the second circumferential end 424 is not being bridged by a second conductive contact, current cannot flow around the partial annular ring 420. When the gap is not being bridged, the partial annular ring 420 may therefore be considered a broken conductive loop, having substantially zero inductance.
  • Figures 5a and 5b show the safety sleeve 308 of Figure 3. Included in the proximal end of the safety sleeve 308 is a central aperture 502, through which the needle 210 protrudes when the needle assembly 116 is in the injection position and the safety sleeve 308 is in the first position relative to the housing 302. On an inner side-surface of the safety sleeve 308 is nub 504 which (as discussed above) is arranged to move within the track 410 of the housing 302. However, it is contemplated that in other embodiments the nub can be defined on the outer surface of the housing 302, while the track can be defined by the safety sleeve 308.
  • the flexible latch arms 506 which each take the form of a T-shaped body comprising transverse limbs 507. As shown, there are four flexible latch arms 506 - each of which is arranged to engage with a corresponding one of the latching surfaces 408 in Figures 4a and 4b. As the reader will understand, the number of flexible latch arms 506 will match the number of latching surfaces 408. The flexible latch arms 506 are arranged to engage with the latching surfaces 408 when the safety sleeve 308 is in the first position relative to the housing 302 (as described above).
  • Each flexible latch arm 506 is biased into a first position in which it engages a corresponding latch surface 408 so as to prevent advancement of the safety sleeve 308 from the first position to the second position relative to the housing 302. In other words, the safety sleeve 308 is locked in the first position, when the flexible latch arm 506 is in the first position.
  • FIGS 5a and 5b also show a second conductive contact 520.
  • the second conductive contact 520 takes the form of a spring contact 520. It may be formed of aluminium or copper, but as the reader will understand any suitable conductor could be used.
  • the spring contact 520 is provided on an inner surface of the safety sleeve 308, and is positioned so as to engage the first and second ends 422, 424 of the partial annular ring 420, when the safety sleeve 308 is in the first position relative to the housing 302. In other words, the spring contact 520 acts as a bridging element when the safety sleeve 308 is in the first position relative to the housing 302.
  • the spring contact 520 and the partial annular ring 420 collectively form a closed conductive loop around which current can flow. Because current can flow, the closed conductive loop has non-zero inductance when closed. However ,when the safety sleeve 308 advances towards the second position, the gap between the first and second ends 422, 424 of the partial annular ring 420 is not bridged, such that the conductive loop is broken and no current can flow. This is discussed in more detail below with reference to Figures 9-11 .
  • Figure 6 shows a needle hub 600 from the medicament container assembly 118 of Figures 2a and 2b.
  • the needle hub 600 includes a proximal end 602, for attachment to the needle 210 (not shown in Figure 6).
  • the needle hub 600 is arranged to be slidable within the casing 102. It is therefore movable, at least partially, with the needle assembly 116, between the retracted and injection positions.
  • the latching surfaces 408, flexible latch arms 506, and needle hub 600 together form a releasable locking mechanism that is operable to selectively lock the safety sleeve 308 in the first position.
  • the medicament container assembly 118 operates the locking mechanism (in that it is movement of the medicament container 112 by the plunger mechanism 108 and the helical retraction spring that moves the needle hub).
  • Figure 7 shows the steps after termination of the delivery of medicament, as will be apparent from the description below. These steps represent a method of activating a safety mechanism of an injection device 100 to indicate a status of an injection delivered by the device. Figure 7 also shows three possible end-states for the injection device 100 after activation of the safety mechanism, as will be explained below.
  • the retraction mechanism i.e., the retraction spring
  • the retraction mechanism is activated to retract the medicament container 112 after completion of a dose of medicament.
  • the injection device 100 is pressed against the injection site, but the needle 210 is no longer inserted into the injection site because the medicament container 112 has been retracted.
  • retraction of the medicament container after completion of a dose of medicament locks the releasable locking mechanism to prevent activation of a second safety sub-mechanism. Because the medicament container 112 is not in the injection position, the latch arms 506 on the safety sleeve 308 are engaged with the corresponding latching surfaces 408 on the housing 302 and the safety sleeve 308 is locked in the first position.
  • the user removes the injection device 100 from the injection site.
  • the releasable locking mechanism is in the locked configuration, and so the safety sleeve 308 does not advance into the second position.
  • the method ends in a first end-state (shown in Figure 8a) with the needle retracted, and the safety sleeve in the first position.
  • the user can be provided with a visual indication that the injection device has been correctly used because the first indicator band 800 is visible (indicating that the medicament container 112 has been retracted) and with the safety sleeve 308 occupying its first, unextended position (indicating that the device 100 was maintained against the injection site for the duration of drug delivery).
  • the nub 504 remains at the distal end 411 of the track 410 to prevent movement of the safety sleeve 308 into the first position.
  • Figure 7 shows two further scenarios, each of which indicates a different status of the injection delivered by the injection device.
  • Advancement of the safety sleeve 308 relative to the housing 302 can be configured to expose a second indicator band 804 to the user.
  • the second indicator band 804 thus indicates that the injection device 100 was prematurely removed from the injection site. This is shown as step 716 in Figure 7. At this point, two outcomes are still possible.
  • the method ends at a second end-state with the medicament container 112 in the injection position.
  • the safety sleeve 308 is in its extended position but the medicament container 112 has not been retracted.
  • This end state (shown in Figure 8b) indicates that the injection device 100 was removed from the injection site prematurely and that the dose of medicament has not been completely discharged from the medicament container 112.
  • only the second indicator band 804 is visible to the user because the first indicator band 800 has not been moved to into view by retraction of the medicament container 112.
  • the nub 504 has moved into the proximal end 413 of the track 410, such that it is prevented from moving back to the distal end 411 of the track 410 by the one-way latch 412. Therefore, the mechanical logic of the track 410 and the nub 504 means that the safety sleeve 308 cannot be returned to the first position without the use of excessive force.
  • the method continues with step 718 in which the plunger assembly 108 continues to deliver medicament through the needle 210 after the injection device 100 has been removed from the injection site.
  • the plunger assembly 108 completes delivery of the dose of medicament (with the needle removed from the injection site) the medicament container 112 is retracted relative to the housing 302, which brings the first indicator band 800 into view.
  • both the first and second indicator bands 800, 804 are visible to the user.
  • the injection device in this third end-state shown in Figure 8c
  • the user can determine that the medicament has been discharged from the injection device 100 but that the device was removed from the injection site too early to complete delivery of a full dose of medicament to the desired subcutaneous location.
  • the nub 504 has moved into the proximal end 413 of the track 410, such that it is prevented from moving back to the distal end 411 of the track 410 by the one-way latch 412. Therefore, the mechanical logic of the track 410 and the nub 504 means that the safety sleeve 308 cannot be returned to the first position without the use of excessive force.
  • a third end-state indicating incorrect use of injection device 100, complete delivery of the medicament through the needle 210, and incomplete delivery of the medicament to the injection site.
  • the needle 210 is in the second retracted position
  • the safety sleeve 308 is in the second (extended) position
  • both the first and second indicator bands 800, 804 are visible.
  • This end state is shown in Figure 8c.
  • Figures 8a-8c illustrate the three visually distinct injection end-states of the injection device 100 described above. Note that for clarity, the drive spring 109 and the retraction spring are omitted from these figures.
  • a fourth visually distinct state is also possible, which is shown in Figure 2b.
  • the visually distinct end states may be indicated using coloured first and second indicator bands 800, 804.
  • the first indicator band 800 In end-states where the first indicator band 800 is visible, it may be seen through a viewing window 802 defined by the housing 302.
  • Each of the states will be described in more detail below.
  • the housing 302 may comprise a transparent material that allows the medicament container 112 to be viewed through the housing 302. As shown in Figure 2b, during delivery of medicament, the medicament container 112 can be visible through the housing 302 (or at least a window portion 802 in the housing 302).
  • a first indicator band 800 occupies a first position and is shielded by the sleeve 308 and is not visible to the user.
  • a second indicator band 804 is also shielded from view by the sleeve 308.
  • Figure 8b shows the injection device 100 in the second end-state before the medicament container 112 has been retracted, but in the scenario described above in which the device was removed from the injection site before a complete dose of medicament has been completely delivered.
  • the first indicator band 800 is in the forward position (and has not yet been retracted into a visible position within the viewing window 802 by the medicament container 112).
  • the safety sleeve 308 has been advanced in this position, the second indicator band 804 has been exposed by advancement of the safety sleeve 308.
  • the first indicator band 800 is therefore not visible to the user, whereas the second indicator band 804 is visible.
  • the first indicator band 800 can be obscured from view in multiple ways in this state in multiple ways.
  • the second indicator band 804 can be provided inside or outside the housing 302, or as part of the housing 302.
  • the second indicator band 804 can be provided as a coloured region on the housing 302.
  • the second indicator band 804 can be configured as a ring or tube section, similar to the ring or tube section that forms the first indicator band 800.
  • Figures 9a and 9b respectively show a first inductive state, and a second inductive state, of the injection device 100 of the present disclosure.
  • the safety sleeve 308 is in the first position relative to the housing 302, and the first and second conductive contacts 420, 520 engage one another to thereby form a closed conductive loop around which current can flow. Because current can flow, the first and second conductive contacts 420, 520 therefore collectively have a non-zero inductance when the safety sleeve 308 is in the first position relative to the housing 302.
  • the electrical subassembly 1110 housed within the plunger mechanism 108 comprises an induction sensor 1112. The electrical subassembly is described in more detail later, with reference to Figure 11 .
  • the plunger mechanism 108 is moveable through the injection device 100 and through the medicament container 112, so as to advance the needle assembly 116 and expel the medicament 114 from the medicament container 112.
  • the induction sensor 1112 also moves closer to the first and second conductive contacts 420, 520. Therefore, while an injection is being performed (at which point the safety sleeve 308 will be in the first position as has been described above), the induction sensor 1112 moves closer to the closed conductive loop shown in Figure 9a. Accordingly, the induction sensor detects an increasing induction signal, as the separation between the induction sensor 1112 and the closed conductive loop reduces. Therefore, by monitoring the induction signal detected at the induction sensor 1112, the electrical subassembly 1110 can detect movement of the plunger mechanism 108 through the medicament container 112.
  • the induction signal detected at the induction sensor is indicative both of a position of the plunger rod 108, and of a position of the safety sleeve 308. Moreover, a detected increase in the induction signal is indicative of movement of the plunger mechanism 108, and a detected drop in the induction signal is indicative of advancement of the safety sleeve 308.
  • Figure 10 is a flow chart illustrating a method of indicating an injection status for the injection device of Figure 1.
  • the method shown in Figure 10 is preceded by a step of the user activating the injection device 100 (e.g. a step of a user pressing a button so as to activate the injection device 100).
  • the method shown in Figure 10 may occur alongside the method shown in Figure 7.
  • the plunger mechanism 108 moves through the medicament container 112 to thereby advance the medicament container 112 and the plunger 110 as has been discussed above. This in turn initiates an injection, by advancing the needle assembly 116 into the injection position and then advancing the plunger 110 through the medicament container 112.
  • the increased proximity between the induction sensor 1112 an the closed conductive loop is detected as a corresponding increase in induction signal at the induction sensor 1112.
  • the detected increase in induction signal is measured by a microprocessor 1118 (c.f. Figure 11).
  • the microprocessor analyses the increase in induction signal. In one example, since the amount by which the induction signal increases is proportional to a distance by which the plunger mechanism 108 has moved, the microprocessor may determine a specific distance by which the plunger mechanism 108 has moved, and may further report this distance in real-time to a user (e.g. via a remote user device 1140, c.f. Figure 11).
  • the microprocessor determines that the plunger mechanism 108 has moved through the full length of the medicament container 112, and therefore reports that a complete dose of medicament 114 has been delivered through the needle 210 (e.g. via the remote user device).
  • the safety sleeve 308 advances to the second position.
  • the induction signal detected at the induction sensor 1112 drops to substantially zero, due to the breaking of the conductive loop.
  • the drop is measured by the microprocessor.
  • the microprocessor analyses the drop in induction signal, and issues an alert to a user (e.g. via the remote device) to inform the user that the injection device has been misused. Misuse may also be reported to a remote server. In so-doing, the user’s doctor or pharmacist may be able to access this information, and prescribe the user with a further dose, as appropriate.
  • a supplier of the injection device or medicament may be provided with anonymized data pertaining to use of the injection device. For example, the supplier may be provided with injection success and injection device misuse data, and associated information such as associated timestamp information. Such data could be used to understand when and/or why devices are misused.
  • Memory 1116 has stored thereon instructions which, when executed by the at least one microprocessor 1118, cause the at least one microprocessor 1118 to execute the detecting and reporting steps outlined in Figure 10.
  • Microprocessor 1118 is electrically connected to the LC circuit so as to detect at least the frequency of oscillation and amplitude of the current in the LC circuit, from which changes in the inductance signal can be identified (wherein the frequency and the amplitude are indicative ofthe induction signal).
  • the at least one microprocessor 1118 is further configured to analyse and report changes in inductance signal as detected at the induction sensor 1112.
  • Transceiver 1120 is configured, under control ofthe at least one microprocessor 1118, to send a signal indicative of detected induction signal and/or injection status to remote device 1140.
  • Remote device 1140 may be a mobile phone, PC, tablet computer, or remote server.
  • Remote device 1140 includes (among other components as are commonly found in such devices) a display 1142 and a wireless received/transceiver.
  • Remote device is configured to display, on display 1142, information indicative of injection status as received from the injection device 100 at the receiver, transceiver 1144.
  • Remote device may also include a memory for storing a log ofthe information received from the injection device 100.
  • Figure 12 is a flow chart showing processing steps performed by the microprocessor 1118 from Figure 11.
  • a current passes through the induction coil 1122 of the LC circuit, a magnetic field is generated.
  • this magnetic field will induce a current in the conductive loop.
  • this current will generate its own magnetic field, which will act to oppose the magnetic field which caused it.
  • This ‘opposing’ magnetic field will thus generate an induction signal in the induction coil 1122, and hence the LC circuit.
  • the induction signal is detectable via the oscillating frequency and amplitude of the current in the induction coil 1122, and hence the LC circuit.
  • the microprocessor 1118 first measures the frequency of oscillation and amplitude of the current in the LC circuit. Next, at step 1202, the microprocessor determines whether the changes in the frequency and amplitude are indicative of an increased induction signal, or a decreased induction signal.

Abstract

La présente invention concerne un dispositif d'injection. Le dispositif d'injection comprend un logement ayant un axe longitudinal, le logement étant conçu pour recevoir un récipient de médicament contenant un médicament et une aiguille fonctionnellement accouplée au récipient de médicament. Le dispositif d'injection comprend également un premier contact positionné à l'intérieur du logement, un manchon de sécurité conçu pour avancer par rapport au logement depuis une première position vers une seconde position, et un second contact fonctionnellement relié au manchon de sécurité. Le logement et le manchon de sécurité sont conçus pour former une boucle conductrice fermée comprenant le premier contact et le second contact lorsque le manchon de sécurité se trouve dans la première position ou la seconde position, et pour former une boucle conductrice brisée lorsque le manchon de sécurité se trouve dans l'autre de la première position et de la seconde position. Le dispositif d'injection comprend en outre un capteur d'induction conçu pour détecter un changement d'inductance.
PCT/US2021/044836 2020-08-07 2021-08-05 Dispositif d'injection et procédé d'indication d'un état d'injection pour un dispositif d'injection WO2022032024A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1001821B1 (fr) * 1997-08-06 2006-09-27 Pfizer Health AB Dispositif d'apport automatique
US20170124284A1 (en) * 2014-06-03 2017-05-04 Amgen Inc. Drug delivery system and method of use
US20190060577A1 (en) * 2017-08-31 2019-02-28 Cypress Semiconductor Corporation Smart syringe
WO2019133648A1 (fr) * 2017-12-29 2019-07-04 Genentech, Inc. Dispositif de surveillance d'injection à signature d'administration
US20190282761A1 (en) * 2016-11-09 2019-09-19 Sanofi-Aventis Deutschland Gmbh Injector Device
EP3545992A1 (fr) * 2018-03-29 2019-10-02 Tecpharma Licensing AG Estimation d'état pour des systèmes d'administration de médicament

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1001821B1 (fr) * 1997-08-06 2006-09-27 Pfizer Health AB Dispositif d'apport automatique
US20170124284A1 (en) * 2014-06-03 2017-05-04 Amgen Inc. Drug delivery system and method of use
US20190282761A1 (en) * 2016-11-09 2019-09-19 Sanofi-Aventis Deutschland Gmbh Injector Device
US20190060577A1 (en) * 2017-08-31 2019-02-28 Cypress Semiconductor Corporation Smart syringe
WO2019133648A1 (fr) * 2017-12-29 2019-07-04 Genentech, Inc. Dispositif de surveillance d'injection à signature d'administration
EP3545992A1 (fr) * 2018-03-29 2019-10-02 Tecpharma Licensing AG Estimation d'état pour des systèmes d'administration de médicament

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