Patent Publication Number: US-2020276390-A1

Title: E-connected auto-injectors

Description:
FIELD OF THE INVENTION 
     The present invention relates to smart autoinjectors and/or autoinjectors that are connected to the Internet or to computing devices, such as smart phones, computer tablets, laptops and desktops, and that have an array of sensors to ascertain metrics for the autoinjectors in real-time and due to its connectivity these metrics can be read by the computing devices and/or transmitted via the Internet to be read by other computing devices. 
     BACKGROUND OF THE INVENTION 
     Medical insurers are moving away from a unit priced payment model toward a more outcome based compensation model. Enabling medical device digital connectivity would provide valuable added information for patient, healthcare providers, doctors, pharmaceutical companies and payers. 
     An additional problem is that drug viscosity varies with temperature; the colder the temperature the higher viscosity the drug becomes. Cold drugs with higher viscosity may negatively impact successful drug delivery and potentially cause patient discomfort. For this reason, many instructions for drug delivery instruct the patient to let the drug warm to a proper or predetermined temperature, such as room temperature or body temperature, before injection to prevent cold injection. 
     There remains a need for a medicine delivery system that can monitor the injection of the medication and that can prevent the delivery system from activation when the temperature of the medication reaches the proper or predetermined temperature. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention relates to capturing usage information obtained by magnetic proximity sensors integrated into the inventive autoinjector. 
     The present invention also captures and utilizes drug product temperature data to prevent device use, when the drug products have not reached proper temperature by locking the autoinjector, to prevent injection of below proper temperature medication into the patients. When the device and drug product reach desired injection temperature, the device would be automatically unlocked. The patients and/or healthcare provider may manually override this locking feature to inject the medication at any time. 
     While autoinjectors are used here as example to demonstrate the invention, the invention described in this document can be applied to any drug delivery devices with mechanical or electromechanical internal moving parts. The term “medication” used herein include, but is not limited to, medicines, vaccines, and any liquids that can be injected into human and animal patients. 
     The present invention relates to a device configured to delivery medication. The device contains a plurality of sensors, including a magnetic proximity sensor and a temperature sensor. The proximity magnetic sensor can detect whether all the medication has been injected into a patient. The temperature sensor can ascertain whether the temperature of the medication has reached a predetermined or proper level for injection. The device also contains a locking device that can lock the device when the temperature of the medication is below this proper temperature and can automatically unlock the device when the temperature reaches or exceeds this proper temperature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views: 
         FIG. 1A  is a cut-away exploded view of a conventional autoinjector;  FIG. 1B  is a partial cutaway view of  FIG. 1A  showing a prefilled syringe with a temperature sensor and the cut-away cover sleeve; 
         FIG. 2A  is an exploded view showing the autoinjector and e-connected adaptor;  FIG. 2B  shows an assembled version of  FIG. 2A ; 
         FIG. 3A  is a plan view of an autoinjector with embedded wires and other electrical connectors in an unconnected configuration;  FIG. 3B  shows the autoinjector of  FIG. 3A  in the connected configuration; 
         FIG. 4A  shows internal components of the autoinjector including a magnetic sensor positioned on the firing pin, the firing spring and the cover lock;  FIG. 4B  is a perspective view of the firing pin; 
         FIGS. 5A-5B  are cut away view of the autoinjector with a magnetic sensor showing the device in a pre-activation configuration and post-activation configuration, respectively; 
         FIG. 6A  is a perspective view of the distal end of the lock sleeve;  FIG. 6B  plan views of the lock sleeve as it is assembled with interacting component shown with and without the firing spring present and shown with the magnetic sensor and/or temperature sensor possible placement location; 
         FIG. 7  is a plan view of the lock sleeve with at least one permanent magnet inserted therein; 
         FIG. 8  is a plan view of the body of the autoinjector with a Hall Effect type sensor adhered thereto; 
         FIG. 9  shows graphs of the magnetic signals from the sensors of  FIGS. 7 and 8 ; 
         FIG. 10  shows graphs showing the magnetic signals from the sensors of  FIGS. 7 and 8  with the permanent magnets in  FIG. 7  assembled with opposite polarity; 
         FIG. 11A  is a perspective view of the lock sleeve with a locking tab;  FIG. 11B  is an enlarged view of  FIG. 11A ;  FIG. 11C  is a partial, cross-sectional view of  FIG. 11B  showing the locking tab; 
         FIG. 12A  is a perspective view of the cover sleeve with the locking tab;  FIG. 12B  is an enlarged, partial view of the locking tab of  FIG. 12A ;  FIG. 12C  is a cross-sectional view of the locking tab in  FIGS. 12A-B  with a portion of the body of the autoinjector and the syringe; 
         FIG. 13A  an exploded view of the inventive adaptor showing the firing pin, the firing spring and cap;  FIG. 13B  is an enlarged view of the firing pin showing a locking slot and  FIG. 13C  is a further enlarged view of the locking slot;  FIG. 13D  is an exploded view of the adaptor&#39;s cap with the rotatable turn lock and a top view of the cap; and  FIG. 13E  is a perspective view of the turn lock;  FIG. 13F  is a side view of a rotatable fork to rotate the turn lock; 
         FIG. 14A  is a side cut-away view of the autoinjector with another embodiment of the locking mechanism;  FIG. 14B  is an end view showing the firing pin latch and the firing pin latch channel; 
         FIG. 15A  is a side, cut-away view of another embodiment of the locking mechanism incorporating a solenoid-type actuator;  FIG. 15B  is an enlarged view of the firing mechanism latch and lock; and  FIG. 15C  is a side view of  FIG. 15B ; 
         FIG. 16  is an exploded view of a conventional autoinjector. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An autoinjector, as illustrated in  FIG. 16 , is a drug delivery device with a stored power for injection type delivery of drugs stored within prefilled syringe  94 . The autoinjector contain a cap  96  that enables the end user to remove the enclosed prefilled syringe&#39;s rigid needle shield  97 . Once cap  96  is removed, the autoinjector can be fired whereby the stored energy within the power unit  95  is released. When the autoinjector is activated by depressing the Cover Sleeve  34 , the Cover Sleep pushes up the Lock Sleeve  36  which allow the power unit to release the firing pin lock  99  holding the firing pin in place. The release of the firing pin lock  99  allows the firing pin spring  100  to push the firing pin forward against the syringe plunger. (See  FIG. 17 ) The stored energy is directed against the plunger rod/firing pin  98 , which pushes against the prefilled syringe&#39;s plunger  99  expelling the drug content.  FIG. 16  provides a pictorial representation of the autoinjector and prefilled syringe  94  prior to assembly. The autoinjector generally comprises power unit  95  and front shield  93  with cap  96  attached. 
     In one embodiment, the inventive autoinjector is sensor rich, and is connected to computing devices, such as smart phones, computing tablets, laptop and desktop computers, as well as mainframe computers or servers and storage clouds through direct connection or through connection to the Internet. In one embodiment, as shown in  FIGS. 1A and 1B , certain autoinjectors  10 , such as a 2.25 ml autoinjector, do not have sufficient internal space to accommodate the sensors. As shown, in the enlarged view of  FIG. 1B , a prefilled syringe  12  is typically inserted into autoinjector  10  and remaining internal space  14  is used as a window viewing area. Preferably, the sensors are located in an adaptor  16  or are connected to adaptor  16 , as best shown in  FIGS. 2A and 2B , and is sized and dimensioned to be removably attached to autoinjector  10 . 
     Adaptor  16  may include a number of electrical and display components, such as but not limited to a digital display, sensors, such as position, acoustic, and vibration sensors, a microprocessor, a storage memory such as flash memory, NFC detector, contact switches and Bluetooth transmission system. The sensors would detect device usage information, such as internal component movement (e.g., via magnetic position sensors), device firing sound and vibration (e.g., acoustic and vibration sensors). The NFC detector can be utilized to detect device unique information that can be embedded within the device label via an NFC chip. The microprocessor will process the gathered sensor and other input data (e.g., data from NFC embedded label) and store said information onto the storage memory until ready for transmission via the Bluetooth or other transmission system. 
     Adaptor  16  may also have a power source, such as a battery or solar panel, and a DC motor or solenoid valve, labeled as element  100  hereinafter, to provide rotational or translational movements within adaptor  16  and/or autoinjector  10  to move the device between an interfering configuration, in which the operation of autoinjector  10  is blocked or restricted, and a non-interfering configuration, in which the operation of autoinjector  10  is operable. 
     In one embodiment, the present invention is capable of determining when adaptor  16  is attached and then removed from autoinjector  10 . As best shown in  FIGS. 3A and 3B , autoinjector  10  in this embodiment has two electrical wires  22  that are embedded in the wall of the housing of the autoinjector. The proximal ends of these wires are spaced apart to form an open gap  24 , as best shown in  FIG. 3A . Adaptor  16  comprises a conductive strip or bridge  26  that is sized and dimensioned to bridge the proximal ends of wires  22 , so that when the adaptor is fully inserted onto autoinjector  10 , conductive strip  26  connects the proximal ends of wires  22  to close the circuit formed by the circuitry in adaptor  16 , wires  22  and bridge  28 . 
     The removal of adaptor  16  would open this circuit, which is readable by adaptor  16 , and the insertion of adaptor would close this circuit, which is also readable by adaptor  16  and indicates that adaptor  16  is operational. The microprocessor in adaptor  16  can transmit this information to connected computing devices and/or stores this information locally in a memory inside adaptor  16 . 
     Adaptor  16  of the present invention may also detect whether a medication delivery was completed and whether a delivery error had occurred. Heretofore, patient vigilance by viewing the viewing window after delivery is relied on to confirm whether the delivery was completed or successful. To relieve the patient or health care provider from this task, the present inventors are adapting a magnetic proximity sensor to adaptor  16  and autoinjector  10 . Magnetic proximity sensors generally comprise two magnetic components. When these components are located proximate to each other, their magnetic fields affect each other and the effects can be measured and the distance between the two components can be derived. Magnetic proximity sensors would detect a strong signal when their two components are near each other, and a weak signal or no signal when the two components are distant from each other. An example of magnetic proximity sensors includes, but is not limited to, a Hall Effect sensor disclosed in www.electronics-tutorials.ws/electromagnetism/hall-effect.html, and in U.S. Pat. No. 7,698,936, which are incorporated herein by reference in its entirety. 
     Referring to  FIGS. 4A-B , one magnetic proximity sensor  28  is attached to or adhered to the distal end of firing pin  30 , which is biased by firing spring  32 . The other proximity sensor (not shown) is housed within adaptor  16  and connected to its circuitry and microprocessor. Due to the space constraint, namely space  14  within autoinjector  10  taken by firing pin  30  and firing spring  32 , magnetic sensor  28  is located at the distal end of firing pin  30 . Prior to the deployment of firing pin  30  with firing spring  32  in a fully compressed state, magnetic sensor  28  is located proximate to the other proximity sensor within adaptor  16 . In this configuration, the circuitry within adaptor  16  can detect magnetic sensor  28 . When firing pin  30  is deployed successfully, magnetic sensor  28  should be located far from adaptor  16 , such that the circuitry and the other half of the proximity sensor can no longer detect magnetic sensor  28  or detects only a weak signal. This would indicate a successful injection of the medication. 
     On the other hand, if the injection is incomplete and some of the medication remains in the syringe, then magnetic sensor  28  would remain close to adaptor  16  and the other magnetic sensor, and the circuitry would still detect magnetic sensor  28 . The circuitry within adaptor  16  preferably would communicate a warning to the patient or healthcare provider, such as an audible alarm or visual signal, e.g., LED light. 
     To minimize potential damage to magnetic sensor  28 , preferably it is at least partially embedded within the material of firing pin  30 . 
     In another embodiment, magnetic sensor  28  can be placed on cover sleeve  34 , as shown in  FIG. 1 . As best shown in  FIGS. 5A and 5B , magnetic sensor  28  is positioned on the distal end of cover sleeve  34 .  FIG. 5A  illustrates autoinjector  10  before activation or deployment and  FIG. 5B  illustrates autoinjector  10  after activation showing proximity magnetic sensor  28  to have moved distally along with cover sleeve  34 . The embodiment of  FIGS. 5A and 5B , otherwise, functions similarly to the embodiment of  FIGS. 4A and 4B . 
     A variation of the embodiment of  FIGS. 5A and 5B  is shown in  FIGS. 6A-6B , where magnetic sensor  28  is placed on lock sleeve  36 .  FIG. 6A  shows end cap  35  of lock sleeve  36  with magnetic sensor  28  and/or temperature sensor  42  attached thereon. Since lock sleeve  36  moves when cover sleeve  34  moves, as shown in  FIGS. 5A and 5B , locating magnetic sensor  28  on lock sleeve  36  functions in a similar fashion. 
     In accordance with another aspect of the present invention, the timing and the time duration of the injection of the medication can be measured with the magnetic proximity sensors or Hall Effect sensors described above. In this embodiment, both components of the magnetic proximity sensors are located on or within the body of autoinjector  10 , as best shown in  FIGS. 7 and 8 . In this embodiment, at least one permanent magnet  38  in inserted or otherwise attached to the moving end of lock sleeve  36  of autoinjector  10 . Preferably, Neodynium permanent magnet is used. This magnet is generally made from an alloy of Neodynium, iron and boron (NdFeB), and is available in sizes, e.g., 1/16 or 1/32 inch in thickness, that can fit into lock sleeve  36 , as shown in  FIG. 7 . A single magnet  38  can be inserted or two magnets  38  with opposite poles oriented to each other can be used. As shown in  FIG. 8 , a single component  40  of a Hall Effect sensor is attached, e.g., taped or epoxied, to the body of autoinjector  10 .  FIG. 8  shows a prototype of this embodiment; a production version would have the component  40  either embedded to the body or permanently affixed thereto. The wires would also be embedded or permanently affixed to the autoinjector&#39;s body, and be connected to the circuitry and microprocessor in adaptor  16 . Two Hall Effect sensors  40  can provide redundancy and accuracy. 
       FIG. 9  shows the measured magnetic fields when a single permanent magnet  38  passes by two Hall Effect sensors  40  during activation. The horizontal axis represents a time axis and may commence recording when the patient/user activates the autoinjector. The detected magnetic fields by the Hall Effect sensors show an abrupt change when permanent magnet  38  passes by Hall effect sensor  40 , as the medication is ejected. Both the timing and the time duration  44  of the injection can readily be extracted from the graphs in  FIG. 9 . 
     When two permanent magnets  38  with opposite polarity, as discussed above, are used and the two Hall Effect magnets  40  are placed on either side of the two permanent magnets  38 , the detected magnetic fields are illustrated in  FIG. 10 . The opposite polarities produce two signals that are also opposite from each other and the user can ascertain the signal that corresponds with a particular permanent magnet. 
     When the patient or health care provider removes autoinjector  10  from the injection site, lock sleeve  36  would return passed its original position and be locked into place. This return motion would also be captured by the magnetic proximity sensor. 
     The embodiments shown in  FIGS. 7-10  may also determine whether the medication was completely ejected from autoinjector  10  or from syringe  12  by evaluating the length of time duration  44  illustrated in  FIGS. 9 and 10 . If the graphs stop within the expected time duration segment  44 , then the graphs indicate that firing pin  30  did not reach its expected destination. Additionally, if time duration segment  44  on the graphs in  FIGS. 9 and 10  is shorter or longer than the expected duration, this may also indicate anomalies that are detectable by the circuitry and microprocessor in adaptor  16 . 
     The embodiments shown in  FIGS. 7-10  can also detect the movement of autoinjector  10 , because this movement may transfer a slight motion through cover sleeve  34  to lock sleeve  36 , and this motion can be picked up by the magnetic proximity sensor. Locking latches, discussed below, when released can also be detected by the magnetic proximity sensor. 
     In accordance to another aspect of the present invention, the present invention also includes a temperature sensing capability to measure the temperature of the medication to ensure that the medication reaches a predetermined or proper temperature, such as room temperature, body temperature, or another comfortable temperature, prior to being injected into the patient. The thermal sensor  42  can directly measure the temperature of prefilled syringe  12 , which is typically refrigerated before use, by being attached to syringe  12  or to the inside of cover sleeve  34  which encloses syringe  12 , as shown in  FIG. 1B . Thermal sensor  42  can also indirectly measure this temperature by being attached to another component in autoinjector  10 , such as lock sleeve  36  as shown in  FIG. 6 . In situation where thermal sensor  42  is not in direct contact with syringe  12 , the circuitry and microprocessor in adaptor  16  can implement a time delay from when thermal sensor  12  reaches the target injection temperature and when injector  10  is unlocked to inject to take into account the differences in heat transfer and heat capacitance properties of the different materials inside autoinjector  10 . Suitable temperature sensors include but are not limited to thermistors and thermocouples, such as those discussed in U.S. Pat. No. 7,698,936, and strain gages, etc. 
     In accordance with another aspect of the present invention, the temperature readings from thermal sensor  42  can be employed to lock autoinjector  10  to prevent activation before the pre-filled syringe reaches the proper temperature. The autoinjector  10  in one embodiment is automatically unlocked when the syringe temperature reaches the proper temperature. A user can also manually unlock autoinjector  10  if the event that an injection is necessary before the syringe reaches the proper temperature. 
     Referring to  FIGS. 11A-C , lock sleeve  36  is provided with one or more locking tabs  46  connected at its proximal end to a lid of lock sleeve  36  in a cantilever manner, and has a free protruding end  48 , which is sized and dimensioned to interfere with a wall  50  of the housing of autoinjector  10 . Locking tab  46  acts like a live-hinge at its connection to the lid of lock sleeve  36  and protruding end  48  can be moved inward automatically, or pushed inward manually by a user to a non-interfering position with wall  50  to allow lock sleeve  36  to be actuated to eject the medication from syringe  12 . 
     Alternatively, the one or more locking tab  46  can be positioned on cover sleeve  34 , as best illustrated in  FIG. 12 . Locking tab  46  operates in the same or similar fashion when locating on cover sleeve  34  or lock sleeve  36 . 
     In another embodiment, a weak, breakable string made from a shape memory alloy (SMA) connects protruding end  48  of locking tab  46  to a rigid, immovable portion of autoinjector  10  or adaptor  16 . The SMA string has one shape, e.g., longer length at a certain lower temperature, e.g., temperature that the medications are refrigerated, and another shape, e.g., shorter length at a certain higher temperature, e.g., the proper, predetermined temperature for injection. In this embodiment, when the syringe&#39;s temperature rises to the proper temperature, the SMA string automatically lengthens to push protruding end(s)  48  inward allowing it to overcome wall  50 . When a cooled or refrigerated syringe  12  is inserted into autoinjector  10 , the SMA string automatically shortens allowing locking tab(s)  46  to flex to the interfering position. Suitable SMA materials include, but are not limited to, nickel-titanium or nitinol, which is commercially available as Flexinol™. Other suitable SMA materials include the alloys of Ag—Cd, Au—Cd, Cu—Al—Ni, Cu—Sn, Cu—Zn, Cu—Zn—X (X═Si, Al, Sn), Fe—Pt, Mn—Cu, Fe—Mn—Si, Pt alloys, Co—Ni—Al, Co—Ni—Ga, Ni—Fe—Ga, Ti—Pd in various concentrations, Ni—Ti—Nb and Ni—Mn—Ga. 
     Another embodiment of the locking mechanism to be applied to firing pin  30  is shown in  FIGS. 13A-E .  FIG. 13A  shows firing pin  30 , firing spring  32 , spring support  31  and end cap  37 .  FIGS. 13B-13C  show at least one locking slot  52 , which comprises a longitudinal slot  54  and at least one side slot  56 , on the body of firing pin  30 . Locking slot  52  may be a bayonet-type slot, and is sized and dimensioned to receive bent arms  58  of rotatable turn lock  60 . As best shown in  FIG. 13D , turn lock  60  resides within end cap  37  and is rotatably supported on pin  62 , which is received by aperture  64  on top of turn lock  60 . The top of turn lock  60  also have divots  66 , which are accessible through curved openings  68  on top of end cap  37 . 
     In a non-interfering configuration, i.e., firing pin  30  is free to activate and discharge medication from syringe  12 , bent arms  58  of turn lock  60  are located in longitudinal slot  54 . Turn lock  60  is rotatable, so that bent arms  58  are rotated into side slot  56  to place bent arms  58  in an interfering configuration by not allowing firing pin  30  to activate. A rotatable fork  101 , as best shown in  FIG. 13F , within adaptor  16 , which is preferably attached to the DC motor or solenoid valve  100  discussed above, may be inserted through curved openings  68  and engage divots  66  via two pegs  102  on rotatable fork  101  to rotate turn lock  60  from the non-interfering configuration to the interfering configuration, depending for example on the readings of temperature sensor  42 , as discussed above. In other words, when the temperature is at the proper injection temperature, bent arms  58  are positioned within longitudinal slot  54 , and when the temperature is below the proper temperature, bent arms  58  are positioned within side slot  56 . 
     Yet another embodiment of the locking mechanism is shown in  FIGS. 14A-14B . As best shown in  FIG. 14B , firing pin  30  is blocked from activation by at least one ferrous firing pin latch  70  restrained within latch channel  72 . In an interfering configuration, two firing pin latches  70  pinch firing pin firing  30  thereby preventing it from deploying. The two firing pin latches  70  are sized and dimensioned to be partially inserted within two corresponding slots oriented about 180° from each other in the interfering configuration. Alternatively, firing pin latch  70  is positioned across firing pin  30  thereby preventing it from deploying. Due to its ferrous property, firing pin latch(es)  70  can be moved by an electromagnetic force, within latch channel  72 . This magnetic force can be provided, as best shown in  FIG. 14A , by one or more electromagnets  74 . Electromagnet  74  may comprise a metallic, preferably ferrous, rod  76 , wrapped by conductive coil  78 . A magnetic force is generated when an electrical current flows through coil  78  to move firing pin latch  70 . As shown, two electromagnets  74  are deployed to move two firing pin latches  70  pinching firing pin  30 . The circuitry and microprocessor in adaptor  16  can selectively connect the adaptor&#39;s battery to conductive coil  78  to move firing pin latch  70  when the temperature of syringe  12  reaches the proper temperature, as discussed above. 
     Optionally, an electromagnetic shield  80 , such as a Faraday cage, is deployed either to contain the electromagnetic field generated by electromagnet  74  or to isolate the circuitry and microprocessor in adaptor  16  from the electromagnetic field. 
     Another locking mechanism is shown in  FIGS. 15A-C . In this embodiment, an electromagnetic coil  82  is placed within adaptor  16 , as shown in  FIG. 15A , which is electrically connected to the circuitry/microprocessor  84  in adaptor  16 . Positioned within adaptor  16  is trigger mechanism  86 , which moves upward to trigger firing pin  30  to move downward to activate autoinjector  10 . This locking mechanism prevents trigger mechanism  86  from moving upward due to the interference between firing mechanism latch(es)  88  and firing mechanism lock(s)  90 . As best shown in  FIGS. 15B-15C , firing mechanism latch  88  are hinged tabs, similar to tabs  46  shown in  FIGS. 11A-11C . The free end of firing mechanism latch  88  protrudes from firing pin  30  in a cantilevered fashion to create a live hinge connection, and interferes with firing mechanism lock  90 , which is preferably connected to trigger mechanism  86 . In a relaxed state, firing mechanism latch  88  would tuck within firing pin  30 , and this embodiment would be in a non-interfering configuration, i.e., trigger mechanism  86  is free to move upward. A metal rod  92  is inserted within firing pin  30 , as shown, and pushes firing mechanism latch  88  outward to interfere with firing mechanism lock  90 . This metal, preferably ferrous, rod is maintained in this interfering configuration by a relatively weak spring  94 . 
     When the temperature of syringe  12  reaches the proper injection temperature, the circuitry and microprocessor  84  would sense this temperature from thermal sensor  42  and would send a current from the battery within adaptor  16  to electromagnetic coil  82  in a direction that produces a magnetic field/force in the upward direction. Spring  94  is sized and dimensioned not to resist this magnetic force and metal rod  92  is pushed upward above firing mechanism latch  88 . Latch  88  would revert to its relaxed state and move to the non-interfering configuration. Firing mechanism lock  90  can move upward passed firing mechanism latch  88  and trigger mechanism  86  can move upward to activate autoinjector  10 . 
     Alternatively, adaptor  16  can send the current continuously through electromagnetic coil  82  to keep autoinjector  10  in the non-interfering configuration continuously and an electromagnetic shield  80  is deploy to contain the electromagnetic field, or adaptor  16  can send the current at the end of a predetermined time delay period, e.g., a few seconds, after trigger mechanism is activated. 
     All the embodiments described herein can be used in any drug delivery apparatus and the present invention is not limited to those described and/or illustrated herein. 
     While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.