Automatic injection device with safety function

Abstract

The present disclosure provides an automatic injection device comprising a housing for receiving a syringe having a plunger, a needle, and a cartridge containing a dose of medicament. The automatic injection device further comprises a drive mechanism for driving the plunger from the first position to the second position to expel a dose from the syringe barrel through a needle at the forward end of the automatic injection device, and a detector device for detecting that the plunger has reached the second position to expel a dose from the syringe barrel through the needle at the forward end of the automatic injection device. And for detecting removal of the needle from the injection site and for providing a signal indicative of the time of occurrence of each detected event.

Description

Technical Field

[0001] The present disclosure relates to an automatic injection device for delivering a medicament from a syringe. In particular, the present disclosure relates to an automatic injection device that increases the likelihood of optimal and completely full-dose medicament delivery. Background Art

[0002] Injection devices, particularly automatic injection devices, are often used for self-administering medications. Such automatic injection devices are configured to receive a syringe containing the medication in a barrel and then actuate the syringe's plunger into the barrel to deliver the medication. Typically, actuation of the plunger occurs without requiring any user-applied actuating force, except for a small amount of force that may be required to trigger the automatic injection device.

[0003] During the process of delivering a medicament from an automatic injection device, the user is required to hold the front end of the automatic injection device against the injection site in order to keep the needle inserted into the injection site while the medicament is being delivered. Specifically, the user may need to hold the needle in place until the plunger has fully moved through the barrel, resulting in a so-called "full dose delivery" of the medicament. To assist the user in this process, the automatic injection device may be equipped with an indicator device that generates an indication corresponding to the stage of use of the device.

[0004] However, while the user holds the automatic injection device against the injection site until the plunger has fully moved through the barrel, various factors may result in suboptimal or incomplete delivery of the medication.

[0005] Improved automatic injection devices are needed to ensure optimal and complete delivery of a medication. Summary of the Invention

[0006] According to a first aspect of the present disclosure, there is provided an automatic injection device as defined in claim 1 .

[0007] The plunger's arrival at the second position can be used as an indicator of the completion of the delivery stroke. Advantageously, the timing of plunger arrival and needle removal provides a proxy for whether optimal and complete delivery of the full dose has occurred. For example, the autoinjector can determine whether the syringe's stopper has loosened between these occurrences. Alternatively or additionally, the autoinjector can determine whether the delivered dose has dissipated below the injection site (e.g., absorbed by soft tissue) between these occurrences. The detected events are detection of the plunger's arrival at the second position and detection of needle removal from the injection site.

[0008] The housing may include a hinged door that can be opened to accommodate the syringe in the automatic injection device. The syringe may include a safety syringe. The safety syringe may include a safety mechanism that protects the user from injury from the needle. The safety syringe may include a needle sheath. The needle sheath may be configured to cover the needle after use of the syringe. Alternatively or additionally, the safety syringe may be configured to retract the needle into the barrel of the syringe.

[0009] The drive mechanism may include a drive spring configured to provide a force to drive the plunger from the first position to the second position. The drive spring may include a compression spring and / or an extension spring. The drive mechanism may include a plunger driver configured to abut against the plunger and provide a force to drive the plunger.

[0010] The automatic injection device may include a pre-priming mechanism configured to pre-prime the drive mechanism before the release mechanism operates. The pre-priming mechanism may be operated by moving a door of the automatic injection device.

[0011] The detector arrangement may be configured to measure the time elapsed from the plunger reaching the second position and provide a signal indicating that the elapsed time is equal to or greater than a threshold time. Alternatively, the detector arrangement may be configured to stop measuring the elapsed time when the needle is removed from the injection site.

[0012] Advantageously, measuring the time elapsed between plunger arrival and needle removal can provide a proxy for whether full-dose delivery has occurred optimally and completely. For example, the autoinjector can determine whether the syringe's stopper has been released based on the elapsed time. Alternatively or additionally, the autoinjector can determine whether the delivered medicament has dissipated below the injection site (e.g., absorbed by soft tissue) based on the elapsed time.

[0013] The threshold time can be the typical time period required for an elastic syringe stopper to relax and expand. Conventional syringes that can be used with automatic injection devices can include an elastic syringe stopper with known characteristics. For example, the elastic syringe stopper may have a typical compression during the drug delivery process. The compression may be caused by the force and pressure applied by the drive mechanism. The elastic syringe stopper may then expand from its "compressed" state to its "relaxed" state. The expansion may require a known, typical period of time. This period of time may be referred to herein as the "relaxation time." It should be understood that the exact relaxation time is not necessary. Rather, an approximate relaxation time is sufficient. The threshold time can then be selected to be equal to or slightly longer than the relaxation time. For example, the relaxation time may be 1, 2, 3, 4, 5, 6, or even longer seconds from the completion of the delivery stroke.

[0014] Advantageously, by comparing the elapsed time to a threshold time including the relaxation time, it can be determined whether the stopper has expanded before or after the automatic injection device is removed from the injection site. Since expansion of the stopper may cause more medication to be delivered from the syringe, this can be used to determine whether a full dose has been delivered.

[0015] The threshold time is optionally the typical period of time it takes for the agent to diffuse into the soft tissue.

[0016] After the drug is delivered, it may be present in the soft tissue immediately adjacent to the needle. At this stage, the drug may be present under sufficiently high pressure that if the needle is removed, the drug will leak from the injection site. After a period of time, the drug may disperse into or be absorbed by the surrounding soft tissue. This may cause the drug pressure to decrease, so that leakage from the injection site does not occur. This period of time, referred to herein as the "dispersion time", may be well known. It should be understood that it is not necessary to know the exact dispersion time. Instead, it is sufficient to know the approximate dispersion time. The threshold time can then be selected to be equal to or slightly longer than the dispersion time. For example, the dispersion time can be 1, 2, 3, 4, 5, 6 seconds or longer after the drug is delivered.

[0017] Advantageously, by comparing the elapsed time to a threshold time that includes the dispersion time, it can be determined whether the medicament has been dispersed before or after the automatic injection device is removed from the injection site. This can be used to determine whether the medicament has or will leak from the injection site, as the medicament may leak if it is not adequately dispersed before the automatic injection device is removed.

[0018] The threshold time can be defined by the greater of the slack time and the dispersion time to ensure that both times have elapsed. For example, if the slack time is known to be 4 seconds and the dispersion time is known to be 3 seconds, the threshold time can be selected to be 4 or 5 seconds, making it equal to or greater than the slack time. The threshold time can also be selected to account for any uncertainty in either of these times. For example, if the slack time is approximately 4 seconds, the threshold time can be selected to be 5 or 6 seconds, so that the slack time is likely to have passed the threshold time expiration date.

[0019] The detector device may be configured to transmit a signal to an indicator device, wherein the indicator device is configured to provide an indication to a user based on the received signal. Advantageously, this allows the user to be informed of the delivery status regarding how long the automatic injection device remains against the injection site. The indication may inform the user that the plunger has reached the second position. The indication may inform the user that the needle has been removed from the injection site. The indication may inform the user of the duration of the elapsed time. Alternatively or additionally, the indication may inform the user of the relationship between the elapsed time and a threshold time, e.g., whether the elapsed time is longer, shorter, or equal to the threshold time.

[0020] These signals can be alarm signals configured to cause the indicator device to provide an alarm indication that the needle has been removed from the injection site before a threshold time has expired. Advantageously, this alerts the user to the fact that the delivery of the medication is suboptimal and / or incomplete. The user can then take any necessary action to counteract the negative effects. For example, regarding the stopper's relaxation time, the indication can inform the user that the delivered dose is slightly less than a full dose. As another example, regarding the medication's dispersion time, the indication can inform the user that medication may have leaked from the injection site.

[0021] The signal may be a completion signal configured to cause the indicator device to provide a completion indication when an elapsed time equals or exceeds a threshold time. Advantageously, this notifies the user that the delivery of the medication is optimal and / or complete. More specifically, this notifies the user that the needle of the autoinjector can be removed with minimal risk of medication leakage (due to medication pressure leaking from the injection site, or due to leakage from the needle due to expansion of the stopper). The user can then remove the autoinjector from the injection site, knowing that the delivery is complete.

[0022] The indicator device may also be configured to provide a progress indication to the user as the plunger is actuated to deliver the medicament. More specifically, the indicator may provide a progress indication between the plunger's movement from the first position and the plunger's arrival at the second position. Furthermore, the indicator may continue to provide a progress indication between the plunger's arrival at the second position and the needle's removal from the injection site, or may provide an elapsed time exceeding a threshold time. Alternatively, the indicator may provide a different indication when the plunger reaches the second position. For example, the different indication may indicate that the plunger's movement is complete, but the automatic injection device should continue to remain in position until the threshold time has elapsed.

[0023] The indicator device may be configured to provide visual, audible, and / or tactile indications. For example, the indicator device may include an illumination device. For example, the indicator device may include one or more light-emitting diodes (LEDs) and / or a display screen. In this case, when the indicator device is located on the autoinjector itself, the housing may include a viewing window through which the illumination device is visible. The indicator device may include an audible emitter. The indicator device may include a tactile feedback device.

[0024] The indicator device may be located on the automatic injection device, and wherein the detector device is configured to transmit the signal as an electrical signal to the indicator device.

[0025] Optionally, the indicator device is a user device separate from the automatic injection device, wherein the automatic injection device further comprises a transmitter, and wherein the detector device is configured to transmit the signal to the indicator device via the transmitter using the short-range transmission protocol.

[0026] The user device may include a handheld device. The user device may include a dedicated indicator device for use with the automatic injection device. Alternatively, the user device may include a mobile phone. In this case, the mobile phone may use a dedicated application to detect and / or connect with the automatic injection device. The short-range transmission protocol may include Bluetooth (RTM).

[0027] The detector device can detect the departure of the plunger from the first position. One or more switches of the detector device can be configured (as described below) to be actuated when the plunger leaves the first position. The detector device can be configured to detect the arrival or departure of the plunger from different positions during the conveying process. For example, the detector device can be configured to detect the arrival or departure of the plunger from the first position, the second position and / or one or more intermediate positions. Reference to detecting the position of the plunger may refer to detecting the position of the plunger driver, which naturally serves as a proxy for the position of the plunger.

[0028] The automatic injection device may have a needle guard at a front end of the automatic injection device, wherein the needle guard is configured to move forward to an extended position when the front end is removed from the injection site.

[0029] The needle shield may be biased forward by a shield spring. The needle shield may be configured to lock in an extended position to prevent access to the needle after the front end is removed from the injection site. The needle shield may be biased forward to the extended position prior to operation of the drive mechanism, pre-activation mechanism, and / or release mechanism. The needle shield may be configured to move rearward when the front end is pressed against the injection site. The needle shield may be configured to move rearward before injection and may be configured to lock after injection. Rearward movement of the needle shield may expose the needle and allow the needle to pierce the injection site. Rearward movement of the needle shield may operate the release mechanism, thereby causing the drive mechanism to activate the plunger.

[0030] The detector arrangement may comprise a shroud sensor configured to sense a position of the needle shroud, wherein the detector arrangement detects removal of the needle from the injection site in response to the shroud sensor sensing that the needle shroud has moved forwardly to the extended position.

[0031] The detector device can use the position of the needle shield as a proxy for the position of the needle relative to the injection site. More specifically, the detector device can use the position of the needle shield as a proxy for whether the needle is embedded in or removed from the injection site. Advantageously, this allows for determining whether an injection is in progress or has been terminated. Advantageously, this reduces the need for additional components on the automatic injection device to sense whether the automatic injection device is retained at the injection site. Furthermore, this can reduce the manufacturing complexity and cost of the automatic injection device.

[0032] To this end, references herein to removing a needle from an injection site or similar operations may interchangeably refer to moving the needle shield to an extended position, and vice versa. The extended position may correspond to the needle shield being fully extended from the front end of the automatic injection device. Alternatively, the extended position may correspond to an extension of the needle shield corresponding to the length of the needle.

[0033] The shield sensor may be a switch. The shield sensor may be a mechanical switch, a micro switch, an electrical switch, a magnetic switch and / or any other suitable switch known to those skilled in the art.

[0034] The detector device may include one or more switches. The one or more switches may include mechanical switches, micro switches, electrical switches, magnetic switches and / or any other suitable switches known to those skilled in the art. The one or more switches may be configured to be actuated when the plunger reaches the second position.

[0035] The detector arrangement may include a trigger point coupled to the movement of the plunger. For example, the trigger point may be located on the plunger. Alternatively, the trigger point may be located on the plunger driver. The detector arrangement may include a switch coupled to the housing. The trigger point may be configured to actuate the switch upon relative movement between the trigger point and the switch. For example, the trigger point may include a first magnet, and the switch may include a second magnet, the first magnet configured to interact with the second magnet when the first magnet moves past the second magnet. Alternatively, the trigger point may include a rib, and the switch may include a mechanical switch, the rib configured to operate the switch when the rib moves past the switch.

[0036] The detector device may include a proximity sensor for sensing the proximity of the front end to the injection site. The proximity sensor may be a mechanical sensor and / or an optical sensor. The proximity sensor may detect whether the needle is inserted into the injection site.

[0037] The automatic injection device may comprise a release mechanism which, when actuated, causes the drive mechanism to drive the plunger, wherein the release mechanism is configured to allow actuation only if the detector means detects contact of the leading end with the injection site.

[0038] For example, the release mechanism may be a trigger button. In this case, the trigger button may remain locked until the detector device detects that the needle is embedded in the injection site (e.g., until it detects that the needle shield is pressed against the injection site and moves backward). Alternatively, the release mechanism may be a needle shield. In this case, by pressing the front end against the injection site, the needle shield moves backward, thereby causing the drive mechanism to actuate the plunger.

[0039] The automatic injection device may further comprise a syringe having a plunger, a needle and a barrel. The syringe may comprise a resilient stopper. The automatic injection device may further comprise a power source to provide power to the detector device, the indicator device and / or the drive mechanism.

[0040] According to a second aspect of the present disclosure, there is a system as defined in claim 19 . BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Exemplary embodiments will now be described with reference to the accompanying drawings, in which:

[0042] Figure 1 is a front view of an automatic injection device including a syringe with a plunger in a first position;

[0043] Figure 2A yes Figure 1 an enlarged perspective view of the interior of the automatic injection device, wherein the plunger is in a first position;

[0044] Figure 2B yes Figure 1 an enlarged perspective view of the interior of the automatic injection device, wherein the plunger is in a second position; and

[0045] Figure 3 yes Figure 1 A front view of the automatic injection device with the plunger in the second position. DETAILED DESCRIPTION

[0046] Generally disclosed herein are exemplary devices for automatic injection devices. The term "automatic injection device" is used herein to refer to a device configured to receive a syringe and provide mechanical assistance to a user during delivery of a medicament from the syringe. The automatic injection device can be configured to receive and operate with a standard syringe (i.e., not a safety syringe) and / or a safety syringe.

[0047] In the following examples, the terms "forward" and "front" refer to the end of the automatic injection device or its components that faces the injection site. The injection site is typically the patient's skin. In other words, the front end of the automatic injection device is the end that is closest to the injection site during use. Similarly, the term "rear" refers to the end of the automatic injection device or its components that is not the injection site. In other words, the term "rear" refers to the direction that is away from the injection site during use. Furthermore, the term longitudinal is used to include directions along or parallel to the longitudinal axis of the injection device, which extends from the rear to the front of the injection device.

[0048] Features of the exemplary arrangements disclosed herein are described as being "coupled" to other features. This term encompasses any coupling that causes the coupled features to move together in any direction. The term "coupled" also encompasses any of a connection between features, abutment of one feature against another, and engagement of one feature with another, and such coupling may be direct or indirect, i.e., with a third feature between them.

[0049] Generally speaking, the present disclosure is directed to improving the delivery of medication from an automatic injection device by ensuring optimal and complete delivery. "Optimal and complete" means that substantially all of the medication present in the syringe is delivered to and absorbed by the injection site. Applicants have recognized that once an automatic injection device is removed from the injection site, leakage may occur at both the injection site and the needle, resulting in suboptimal or incomplete medication delivery. Applicants have recognized that such leakage may occur via two different mechanisms.

[0050] First, the plunger of a syringe typically includes a stopper made of an elastic material, such as rubber. During drug delivery, the stopper typically undergoes a certain degree of compression, followed by a period of "relaxation" and expansion after the plunger completes its movement through the barrel. During this expansion period, a small amount of drug may be expelled from the syringe. If the automatic injection device, particularly the needle, is prematurely removed from the injection site, this relaxation and expansion may cause the drug to be expelled from the injection site, resulting in an incomplete dose being delivered.

[0051] Secondly, after delivery, the medication may be temporarily under high pressure under the user's skin. Over a short period of time, the medication dissipates into the surrounding soft tissue, causing the pressure to decrease. If the autoinjector, and particularly the needle, is removed from the injection site prematurely, the medication will not have dissipated, and the high pressure may cause some medication to leak out of the injection site.

[0052] The exemplary automatic injection devices disclosed herein provide signals indicating the completion of the delivery stroke and the removal of the needle from the injection site. By providing these signals, sufficient time can be ensured for the stopper to relax and / or for the medicament to disperse beneath the injection site before the needle is removed from the injection site, thereby reducing or effectively preventing the aforementioned leakage. The exemplary automatic injection devices disclosed herein can also measure the time after the plunger has completed its delivery stroke and optionally provide an indication to the user. The time can be measured until the automatic injection device detects that the needle has been removed from the injection site.

[0053] Figure 1 An exemplary automatic injection device 100 is depicted having a syringe 200 installed within a housing of the automatic injection device 100. The automatic injection device 100 is depicted prior to delivery of a medicament from the syringe 200. The housing of the automatic injection device 100 includes a body 101 and a door 102 that can be hinged relative to the body 101. The door 102 is operable between an open position, into which the syringe 200 can be inserted, and a closed position. Figure 1 Door 102 is depicted in an open position.

[0054] The automatic injection device 100 includes a viewing window 118 and an indicator device 120. Figure 1In the figures, the viewing window 118 and the indicator device 120 are depicted as being located on the door 102, but it will be understood that these components may be located elsewhere on the housing of the automatic injection device. The indicator device 120 may not be located on the automatic injection device 100 at all, but rather provided by a separate device. For example, the indicator device 120 may comprise a separate user device configured to communicate with the automatic injection device 100. In the figures, the indicator device 120 is depicted as a device comprising four LEDs arranged in a circle. It will be understood that other configurations of LEDs are possible. Furthermore, other indicator devices, such as audio or tactile indicators, or visual indicators in addition to LEDs, are also contemplated herein.

[0055] The viewing window 118 allows the user to observe the interior of the housing of the automatic injection device 100. The specific purpose of the viewing window 118 will be described in detail below with respect to the injection process.

[0056] The syringe 200 installed in the automatic injection device can be a safety syringe, as shown in the figure. The syringe 200 includes a plunger 202 for driving the medication from the barrel 204 and expelling it from the needle 206. The front end of the plunger 202 includes a stopper 208. The stopper 208 is typically made of an elastic material. Specifically, the stopper 208 refers to the portion of the plunger 202 that directly contacts the medication contained in the barrel 204.

[0057] The automatic injection device 100 also includes a needle shield 108 , or simply “shield” 108 . Figure 1 The shield 108 is not shown in the figure. When the cap is removed from the automatic injection device, the shield 108 extends from the front end of the automatic injection device 100. The shield 108 is biased forward by a spring (not shown). Thus, in its current state (i.e., before medicament delivery), the shield 108 extends from the front end of the automatic injection device 100, but can be pressed rearward (i.e., against the bias of the spring) to expose the needle 206. For example, when the front end of the automatic injection device 100 is pressed against an injection site, the shield 108 can be pressed rearward to insert the needle 206 into the injection site. The automatic injection device also includes a shield sensor 116 that detects the position of the shield 108 relative to the housing of the automatic injection device (e.g., whether the shield 108 is in the extended position).

[0058] The automatic injection device 100 includes a drive mechanism 104 for driving the plunger 202 from a first position 110a to a second position 110b. The first position 110a can be considered an initial position and may refer to a position in which the plunger 202 is completely removed from the barrel 204, such that no medicament has been delivered from the needle 206. The second position 110b can be considered a final position and may refer to a position in which the plunger 202 is fully inserted into the barrel 204, such that a full dose of medicament has been delivered from the needle 206. In the figures, the first position 110a and the second position 110b are labeled as corresponding positions of the plunger head (i.e., the distal end of the plunger). This is for illustrative purposes only, and it should be understood that the first and second positions generally refer to positions of the plunger, not necessarily specific portions of the plunger.

[0059] The drive mechanism 104 generally includes a drive spring 105 and a plunger driver 106. The drive spring 105 provides a forward bias against the plunger driver 106, which is coupled to the plunger 202. When the automatic injection device 100 is actuated, the drive spring 105 drives the plunger driver 106 forward, thereby driving the plunger 202, resulting in the delivery of a medicament. Those skilled in the art will appreciate that many different types of drive mechanisms are known for automatic injection devices, and the present disclosure may be applicable to automatic injection devices having different types of drive mechanisms 104.

[0060] The automatic injection device 100 also includes a release mechanism that, when operated, causes the drive mechanism 104 to actuate the plunger 202. As shown, the release mechanism can be operated by the shield 208. That is, when the shield 208 is depressed, the drive mechanism 104 is released to actuate the plunger 202. In this case, after assembling the syringe 200 into the automatic injection device 100, the user simply presses the front end of the automatic injection device 100 against the injection site (thereby moving the shield 208 rearward) to initiate the injection process. It should be understood that alternative release mechanisms can be provided, for example, by a trigger button on the rear end of the automatic injection device 100.

[0061] Now refer to Figure 2A-3 Describe the injection procedure.

[0062] Figure 2A and 2B The plunger driver 106 is shown abutting the plunger 202. As can be seen from these views, the automatic injection device 100 also includes a detector arrangement comprising a first switch 112a and a second switch 112b. In this example, the first switch 112a and the second switch 112b are magnetic switches, however, it will be appreciated that other forms of switches may be used.

[0063] The plunger driver 106 includes a trigger point 114. The trigger point 114 is configured to interact with the first switch 12a and the second switch 12b when the trigger point 114 passes the corresponding switch. In this case, this means that the trigger point 114 is a magnet that interacts with the switch. It should be understood that the trigger point 114 can take different forms depending on the type of switch. For example, in the case of a mechanical switch, the trigger point 114 can be a protruding rib. Because the trigger point 114 is located on the plunger driver 106, the trigger point 114 is coupled to the plunger driver 106 and the plunger 202. In an alternative arrangement, the trigger point 114 can be located directly on the plunger 202 itself.

[0064] from Figure 2A Initially, the plunger 202 is shown in the first position 10a. In this position, the plunger driver 106 is positioned so that the trigger point 114 is aligned with the first switch 112a. In this position, the plunger 202 is fully extended from the barrel 204. In other words, this shows the position of the component before the medicament is delivered. After the release mechanism is operated, the plunger driver 106 begins to move forward, driving the plunger 202 into the barrel 204. The trigger point 114 will leave the first switch 112a, thereby triggering the first switch 112a. This indicates the start of the delivery sequence or delivery stroke. In response to the triggering of the first switch 112a, the detector device can send a signal to the indicator device 120, so that the indicator device 120 provides an indication that the delivery sequence has begun.

[0065] The plunger driver 106 and plunger 202 continue to move forward along the automatic injection device 100. During this time, the indicator device 120 can provide an indication that the delivery sequence is ongoing.

[0066] Go to Figure 2A , the plunger 202 has advanced to the second position 110b, which may correspond to the delivery of a full dose of the medicament from the barrel 204. In other words, the second position 110b may correspond to the stopper 208 being located at the front end of the barrel 204. When the plunger 202 reaches the second position 110b, the trigger point 114 aligns with the second switch 112b. The arrival of the trigger point 114 at the second switch 112b triggers the second switch 112b, signaling the end of the delivery sequence or delivery stroke. In response to the triggering of the second switch 112b, the detector device may send a signal to the indicator device 120, causing the indicator device 120 to provide an indication that the delivery sequence has been completed. Alternatively, the indicator device 120 may continue to provide an indication that the delivery sequence is ongoing (because the user should not yet remove the automatic injection device 100 from the injection site).

[0067] Alternatively or additionally, the plunger driver 106 may serve as a visual indicator to the user that the delivery sequence is complete. Figure 3As shown, the plunger driver 106 is aligned with the viewing window 118 when it reaches the second switch 112b. The visible presence of the plunger driver 106 in the viewing window 118 serves as an indication that the plunger 202 has advanced to the second position 110b. The plunger driver 106 may include a visual indicator (e.g., a marking) to help it be visible through the viewing window 118.

[0068] When the plunger 202 reaches the second position 110b (i.e., once the second switch 112 is triggered), the detector device can provide a signal (e.g., by sending a signal to the indicator device) indicating that the plunger 202 has reached the second position 112. The detector device can also begin measuring elapsed time. The elapsed time indicates how much time has elapsed since the delivery stroke was completed.

[0069] The detector device may continue to measure the elapsed time until the shield sensor 116 detects that the shield 108 has been extended. When the shield 108 is extended, the detector device may provide a signal (e.g., by sending a signal to an indicator device) indicating that the needle 206 has been removed from the injection site. When the automatic injection device 100 is held against the injection site, the shield 108 will be depressed into the automatic injection device 100, as shown in FIG. Figure 3 As shown. Since the extension of the shield 108 corresponds to the removal of the needle 206 from the injection site, the elapsed time will correspond to the total time that the automatic injection device 100 remains against the injection site after delivery is complete. For example, the indicator device 120 can indicate the elapsed time to the user so that the user knows how long they should hold the automatic injection device 100 in place after delivery is complete.

[0070] The detector device can compare the elapsed time with a threshold time. The indicator device 120 can provide an indication to the user based on the comparison of the elapsed time with the threshold time. For example, the indicator device 120 can provide an indication that the elapsed time is less than, equal to, or greater than the threshold time.

[0071] The threshold time can be selected based on the time period required for the stopper 208 to relax and expand after the delivery stroke is completed. This time period can be referred to as the "relaxation time." The threshold time can be selected based on the time period required for the delivered medicament to disperse into the soft tissue. This time period can be referred to as the "dispersion time." The relaxation time and / or the dispersion time can be known values or can be calculated prior to manufacturing the automatic injection device 100. The threshold time can be selected as the longer of the relaxation time and the dispersion time. The threshold time can be, for example, 5 seconds.

[0072] Once the second switch 112b is triggered, the detector device begins measuring the elapsed time and comparing it to the threshold time. The indicator device 120 can continue to provide an indication that delivery is in progress while the elapsed time is less than the threshold time. If the shroud sensor 116 detects that the shroud 108 has moved to the extended position (i.e., the user has removed the automatic injection device 100 from the injection site), and the elapsed time is less than the threshold time, the indicator device 120 provides an alarm indication to indicate to the user that the automatic injection device 100 was removed prematurely. If the automatic injection device 100 was not removed prematurely, the indicator device 120 can provide a completion indication to the user when the elapsed time equals the threshold time. This indicates to the user that the threshold time has been reached and the automatic injection device 100 can be removed from the injection site. Once the shroud sensor 116 detects that the shroud 108 has moved to the extended position, the detector device can stop measuring the elapsed time.

[0073] As described above, after the automatic injection device 100 is removed from the injection site by its forward bias, the shield 108 moves to the extended position. Figure 1 In contrast to the extended position of the shield 108 described above, the shield 108 can be locked in the extended position after delivery so that the needle 206 can no longer be accessed. In other words, when in the extended position before delivery, the shield 108 can be depressed against its bias (e.g., to initiate a delivery sequence), but when in the extended position after delivery, the shield 108 cannot be depressed against its bias.

[0074] The automatic injection device 100 can be reset and reused by opening the door 102, removing the syringe 200, replacing it with a new syringe, and repeating the above process.

Claims

1. An automatic injection device comprising: a housing for receiving a syringe having a plunger, a needle, and a barrel containing a dose of a medicament; a drive mechanism for driving the plunger from a first position to a second position to expel a dose from the syringe barrel through a needle at a front end of the automatic injection device; Detector means for detecting arrival of the plunger at the second position and for detecting removal of the needle from the injection site, and for providing a signal indicative of the time of occurrence of each detected event.

2. The automatic injection device according to claim 1, wherein: The detector arrangement is configured to measure the time elapsed since the plunger reached the second position and to provide a signal indicating that the elapsed time is equal to or greater than a threshold time.

3. The automatic injection device according to claim 2, wherein: The detector arrangement is configured to stop measuring the elapsed time at the occurrence of removal of the needle from the injection site.

4. The automatic injection device according to claim 2 or 3, wherein: The threshold time includes the typical period of time it takes for an elastic syringe stopper to relax and expand.

5. The automatic injection device according to any one of claims 2 to 4, wherein: The threshold time comprises the typical period of time it takes for the agent to diffuse into the soft tissue.

6. An automatic injection device according to any one of the preceding claims, wherein: The detector device is configured to transmit the signal to an indicator device, wherein the indicator device is configured to provide an indication to a user based on the received signal.

7. The automatic injection device according to claim 6, wherein: The signal comprises an alarm signal configured to cause the indicator device to provide an alarm indication that the needle has been removed from the injection site before expiration of the threshold time.

8. The automatic injection device according to claim 6 or 7, wherein: The signal comprises a completion signal configured to cause the indicator device to provide an indication of completion when the elapsed time is equal to or greater than the threshold time.

9. The automatic injection device according to any one of claims 6 to 8, wherein: The indicator arrangement is configured to provide a visual, audible and / or tactile indication.

10. The automatic injection device according to any one of claims 6 to 9, wherein: The indicator device is located on the automatic injection device, and wherein the detector device is configured to transmit the signal as an electrical signal to the indicator device.

11. The automatic injection device according to any one of claims 6 to 10, wherein: The indicator device comprises a user equipment separate from the automatic injection device, wherein the automatic injection device further comprises a transmitter, and wherein the detector device is configured to transmit the signal to the indicator device via the transmitter using a short-range transmission protocol.

12. An automatic injection device according to any one of the preceding claims, wherein The detector arrangement is further configured to detect movement of the plunger from the first position.

13. An automatic injection device according to any one of the preceding claims, wherein: The automatic injection device includes a needle guard located at a front end of the automatic injection device, wherein the needle guard is configured to move forward to an extended position when the front end is removed from the injection site.

14. The automatic injection device according to claim 13, wherein: The detector arrangement comprises a shroud sensor configured to sense a position of the needle shroud, wherein the detection arrangement detects removal of the needle from the injection site in response to the shroud sensor sensing that the needle shroud has moved forward to the extended position.

15. An automatic injection device according to any one of the preceding claims, wherein: The detector arrangement comprises a mechanical switch and / or a magnetic switch.

16. An automatic injection device according to any one of the preceding claims, further comprising a release mechanism which, when actuated, causes the drive mechanism to drive the plunger, wherein The release mechanism is configured to allow activation only when the detector arrangement detects contact of the front end with the injection site.

17. The automatic injection device of any preceding claim, further comprising a syringe having a plunger, a needle, and a barrel.

18. The automatic injection device of claim 17, wherein: The syringe also includes an elastic stopper.

19. A system comprising: An automatic injection device according to any one of the preceding claims; and A user equipment is configured to receive one or more indication signals using a short-range transmission protocol and further configured to provide an indication corresponding to the received signal in response to receiving the one or more indication signals.

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