Patent Publication Number: US-2022226193-A1

Title: Two-component syringe

Description:
PRIORITY CLAIM AND RELATED APPLICATIONS 
     This Continuation-In-Part application claims the benefit of priority from non-provisional application U.S. Ser. No. 17/151,159 filed Jan. 16, 2021. Said application is incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention relates to a syringe useful for reconstituting a component to form a mixture to be applied with a needle. More specifically, the present invention is directed to a syringe useful for effectively mixing two components held therein or held in two different ambient conditions to form a mixture to be applied with or without a needle. 
     2. Background Art 
     Vaccines and medications that require reconstitution, e.g., COVID-19 vaccines, are often kept separately in two different vials. The primary benefit of separating the components is to increase shelf life; these products are often unstable after a short period of time after reconstitution. Traditional packaging methods can be taxing on healthcare workers and provide multiple disadvantages. The process is time-consuming and error-prone and it increases waste. 
     Before administering these products, trained and authorized personnel must follow the reconstitution procedure. Both vial stoppers must be cleaned with alcohol pads. A sterile needle and syringe are then used to withdraw the liquid component, e.g., from a first vial. The contents of the syringe are then transferred into the dry component, e.g., in a second vial. The second vial is then gently shaken thoroughly until the contents are dissolved. The vial contents are then withdrawn and inspected for impurities before it is ready to be used. This procedure is a time-consuming process and can slow down workflow in a hospital, clinic and pharmacy, etc. 
     Wastes generated from a conventional reconstitution includes two vials, two vial caps, one needle, time wasted during product preparation, and any reconstituted products that have lost their efficacies. The raw materials required to house the two different components alone are a noticeable waste compared to having one pre-filled syringe. The opportunity cost of conventional reconstitutions varies depending on which healthcare professionals are preparing the products; nevertheless, the time and attention needed to prepare the reconstituted products can be invested in other parts of the workflow to prepare an injectable material. 
     According to International Safety Center Exposure Prevention Information Network (EPINet®) Report for Needlestick, when looking at devices associated with percutaneous injuries, 24.5% of all reported injuries are from disposable syringes, while only 1.20% are from pre-filled syringes. 
     U.S. Pat. No. 3,016,896 to Van Sickle (hereinafter Van Sickle) discloses a hypodermic syringe for use in treating human beings as well as animals. Van Sickle discloses a syringe with a mixing chamber that does not encompass a first volume in which a liquid is held and a second volume in which a powder material is held. As the skirt (74 of Van Sickle) is fixedly attached to the plunger (52 of Van Sickle), the skirt (74 of Van Sickle) cannot be pulled sufficiently far to clear the area where the inner diameter of the main body portion (58 of Van Sickle) transitions from a first dimension to a second dimension. It shall also be noted that in Van Sickle, the powder material is disposed at the needle end of a Van Sickle&#39;s syringe. As such, a poorly mixed powder material or clumping of the powder material, due potentially to moisture intrusion, can potentially cause plugging of the needle hole, preventing the mixture from exiting the syringe efficiently. 
     WIPO Pub. No. 2007034020 of Rolla (hereinafter Rolla) discloses a unit for mixing and supplying injectable substances including a plurality of chambers with different cross-sections which are disposed consecutively from smallest to biggest in an axial direction from the injection end. Injectable substances that are mixed when the chambers are communicated following the reverse movement of separating means and a piston which are moved by a coaxial rod that is disposed in the unit. Again, it shall also be noted that in Rolla, the powder material is disposed at the needle end of a Rolla&#39;s syringe. As such, a poorly mixed powder material or clumping of the powder material, due potentially to moisture intrusion, can potentially cause plugging of the needle hole, preventing the mixture from exiting the syringe efficiently. Further, as the rod diameter is significantly smaller than the piston diameter, undissolved powder can potentially be disposed on the rod side of the plunger, preventing the plunger from being retracted fully to allow proper mixing of the powder and liquid. 
     U.S. Pat. No. 3,477,431 to Walecka (hereinafter Walecka) discloses a combined syringe and plural-compartment container for storing solid and liquid ingredients separately for subsequent mixing and injection. The syringe barrel includes an enlarged portion around its periphery at about the center of its longitudinal dimension, and together with the syringe pistons forms a plural-compartment container. When two pistons are used, one of the pistons is positioned immediately adjacent to the enlarged portion of the syringe barrel and the other seals off the open end of the barrel, thus forming two compartments, each of which may contain a different ingredient. By depressing the syringe plunger slightly so that the one piston extends into the enlarged portion of the barrel, a flow path is provided whereby the two ingredients can mix. Lock means are also provided in Walecka in order to prevent accidental displacement of the plunger during transport and storage. FIG. 6 of Walecka discloses a two-compartment syringe where communication between the two components in the two compartments are separated by a piston. It shall be noted however that one of the drawbacks of Walecka&#39;s device is the rod end bore diameter which allows a mixture to be inadvertently trapped. It shall be noted that the main body portion 70 is fixedly attached to the rod or is part of the rod. As such, the total volume allowed for mixing is limited to the space between a retracted position of the piston and the dispensation tip of the syringe. 
     Chinese Pat. App. Pub. No. CN211561395U of Xing et al. (hereinafter Xing) discloses an injector with powder-liquid hybrid chamber. Xing discloses the concept of retracting the rod of a syringe to establish communication between two substances disposed in two different compartments although Xing&#39;s device could not have worked well for mixing a liquid and a solid material. 
     U.S. Pat. No. 4,599,082 to Grimard (Hereinafter Grimard) discloses a two-component syringe includes a barrel having a chamber for retaining fluid and a distal end of the barrel having a passageway therethrough communicating with the chamber. A by-pass stopper is slidably positioned in fluid-tight engagement inside the barrel. The stopper has a distal rib contacting the barrel, a recess on the proximal side of the rib and a groove in the rib for allowing fluid communication between the recess and the chamber. This groove is positioned angularly with respect to the longitudinal access of the barrel so that liquid passing therethrough is directed angularly with respect to the longitudinal axis of the barrel. The barrel also includes a raised peripheral portion serving as a by-pass and defining a by-pass zone. The by-pass zone is shorter than the length of the stopper along the longitudinal axis of the barrel. The by-pass is sufficiently long and raised enough to allow liquid to flow around the stopper between the proximal end of the stopper and the recess when the proximal end of the stopper is positioned in the by-pass zone. Also included is a piston slidably positioned in fluid-tight engagement inside the barrel. This piston is adapted to engage a plunger rod to facilitate its operation. Grimard&#39;s device functions according to a principle similar to Walecka&#39;s device although the rod is “extended” to activate mixing in Grimard&#39;s device while the rod is “retracted” to activate mixing in Walecka&#39;s device. 
     U.S. Pat. No. 2,761,447 to Hersee (Hereinafter Hersee) discloses a syringe adapted to mix parenteral medicaments which are relatively unstable in solution. FIG. 3 of Hersee shows a disposable body member having an upper chamber and a lower chamber, which is of lesser diameter than the upper chamber. In the preferred form of Hersee, the upper chamber contains only the diluent (30 of Hersee) and the lower chamber contains only the medicament (31 of Hersee). The two chambers are separated by a removable plunger tip (36 of Hersee). In operation, a disposable member appears as shown in FIG. 3 of Hersee with the contents of the lower chamber separated from the contents of the upper chamber by the plunger rod, which is, at the outset, positioned to extend into the lower chamber to form a seal. The plunger rod is then lifted upwardly to the position shown in FIG. 6 of Hersee, thereby allowing the contents of the upper chamber to flow into the lower chamber. The body member is then shaken to mix the contents. Holding the body member in an upright position, the plunger rod is pushed downwardly to the position shown in FIG. 7 of Hersee. A needle is next attached to the casing member. As the medicament (31 of Hersee) is disposed in the lower chamber, a medicament, e.g., one which includes solids or a fluid with low solubility, can cause the needle to be clogged, rendering the syringe useless. Further, the narrow cylindrical space of the lower chamber (27 of Hersee) may be unsuitable to provide thorough mixing of the diluent (30 of Hersee) and the medicament (31 of Hersee). 
     There exists a need for a syringe capable of holding more than one component therewithin where the components may be mixed efficiently to form a mixture or a component may be reconstituted just prior to its use with actions that are already familiar to the user. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided a method for mixing a first substance of a first chamber of a syringe and a second substance of a second chamber of the syringe, wherein communication of the first chamber and the second chamber is blocked by a removable member, the method including: 
     (a) positioning the first chamber at an elevation higher than the second chamber; 
     (b) removing the removable member to enable communication of the first substance with the second substance to form a mixture; 
     (c) positioning the second chamber at an elevation higher than the first chamber; and 
     (d) replacing the removable member to confine the mixture in the first chamber. 
     In one embodiment, the method further includes a step of agitating the mixture between step (b) and step (c). In one embodiment, the first substance includes a liquid and the second substance includes a solid. In one embodiment, the removing step further includes an action applied along a first axis and the replacing step further includes an action applied along a second axis and the first axis is disposed coaxially with the second axis. In one embodiment, the first chamber includes a first hollow cylinder having a first diameter, the second chamber includes a second hollow cylinder having a second diameter greater than the first diameter. 
     An object of the present invention is to provide a syringe where two ingredients or components of an injectable material can be mixed just prior to its administration to keep the injectable material fresh. 
     Another object of the present invention is to provide a syringe configured to administer an injectable material composed of two components capable to be stored separately until an administration of the injectable material. 
     Another object of the present invention is to provide a syringe where two components of an injectable material can be mixed easily and thoroughly just prior to its administration to keep the injectable material fresh. 
     Another object of the present invention is to provide a syringe composed essentially of the storage structures of the two components that form the injectable material that is prepared just in time for use. 
     Whereas there may be many embodiments of the present invention, each embodiment may meet one or more of the foregoing recited objects in any combination. It is not intended that each embodiment will necessarily meet each objective. Thus, having broadly outlined the more important features of the present invention in order that the detailed description thereof may be better understood, and that the present contribution to the art may be better appreciated, there are, of course, additional features of the present invention that will be described herein and will form a part of the subject matter of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 2  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 1  as taken along line A-A of  FIG. 1 . 
         FIG. 3  is a front longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 1  as taken along line A-A of  FIG. 1 . 
         FIG. 4  is a longitudinal view of one embodiment according to a present syringe in a post-administration condition. 
         FIG. 5  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 4  as taken along line B-B of  FIG. 4 . 
         FIG. 6  is a front longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 4  as taken along line B-B of  FIG. 4 . 
         FIG. 7  is a cross-sectional view of a safety shield, depicting a limiter useful for immobilizing the safety shield with respect other parts of a present syringe upon a ring of the syringe becoming lodged in an opening of the limiter. 
         FIG. 8  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 9  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 8  as taken along line C-C of  FIG. 8 . 
         FIG. 10  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 11  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 10  as taken along line D-D of  FIG. 10 . 
         FIG. 12  is a bottom perspective view of a stopper of a present syringe with the two portions of the stopper attached to one another. 
         FIG. 13  is a bottom perspective view of a stopper of a present syringe with the two portions of the stopper detached from one another. 
         FIGS. 14-18  is a series of diagrams depicting an order in which a present syringe can be used to administer an injectable material. 
         FIGS. 19-22  depict assemblies useful for constructing one embodiment of a present syringe such that an injectable mixture can be mixed therein prior to its use. 
         FIG. 23  depicts one embodiment of a present syringe constructed from parts disclosed in  FIGS. 20-22 . 
         FIG. 24  is a rear longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 25  is a rear longitudinal view of one embodiment according to a present syringe in a pre-administration condition of  FIG. 24  with the stopper shown in  FIG. 24  removed to reveal the second hollow cylinder. 
         FIG. 26  is a rear longitudinal view of one embodiment according to a present syringe of  FIG. 24  in a condition where the stopper has been operationally removed and the rod has been sufficiently withdrawn to cause communication between a first and a second component. 
         FIG. 27  is a top perspective view of a stopper of a present syringe with the two portions of the stopper attached to one another. 
         FIG. 28  is a rear longitudinal view of one embodiment according to a present syringe of  FIG. 24  with its contents having been emptied. 
         FIG. 29  is a longitudinal cross-sectional view of one embodiment according to a present syringe of  FIG. 24  where the syringe is shown as two separate parts prior to being combined to form the syringe. 
         FIG. 30  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 31  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 30  as taken along line E-E of  FIG. 30 . 
         FIG. 32  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 33  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 32  as taken along line F-F of  FIG. 32 . 
         FIG. 34  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 35  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 34  as taken along line K-K of  FIG. 34 . 
         FIG. 36  is a longitudinal view of one embodiment according to a present syringe in a condition where a second part of the rod has been liberated from a packaged arrangement of the present syringe. 
         FIG. 37  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 36  as taken along line G-G of  FIG. 36 . 
         FIG. 38  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 36  in a condition where the rod has been formed. 
         FIG. 39  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 36  in a condition where the rod has been sufficiently withdrawn to cause communication between a first and a second component. 
         FIG. 40  is a close-up view of a portion of the seal of a present syringe that prevents detachment of the rod from the present syringe. 
         FIG. 41  is a longitudinal view of the embodiment of a present syringe in a post-administration condition. 
         FIG. 42  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 41  as taken along line H-H of  FIG. 41 . 
         FIG. 43  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 44  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 43  as taken along line I-I of  FIG. 43 . 
         FIG. 45  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 43  in a condition where the rod has been formed. 
         FIG. 46  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 43  in a condition where the rod has been formed and the rod has been fully retracted. 
         FIG. 47  is a close-up view of a portion of the seal of a present syringe that prevents detachment of the rod from the present syringe. 
         FIG. 48  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 49  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 48  as taken along line J-J of  FIG. 48 . 
         FIG. 50  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 48  in a condition where one of the two parts of the rod has been released such that the rod may be subsequently formed. 
         FIG. 51  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 48  in a condition where the rod has been fully retracted. 
         FIG. 52  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 48  in a condition where the rod has been fully formed. 
         FIG. 53  is a diagram depicting two parts of the rod of  FIG. 52 . 
         FIG. 54  is a diagram depicting a manner in which the second part of the rod is pulled against the first part of the rod such that the ribs of the second part can clear the ridges of the first part. 
         FIG. 55  is a diagram depicting a manner in which the second part of the rod is rotated coaxially with respect to the first part of the rod. 
         FIG. 56  is a diagram depicting a rod has been formed by locking a first part to a second part. 
         FIG. 57  is a longitudinal view of one embodiment according to a present syringe in a pre-administration condition. 
         FIG. 58  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 57  as taken along line L-L of  FIG. 57 . 
         FIG. 59  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 57  in a condition where one of the two parts of the rod has been released such that the rod may be subsequently formed. 
         FIG. 60  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 57  in a condition where the second part is being retracted. 
         FIG. 61  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 57  in a condition where the rod has been formed. 
       PARTS LIST 
       
           
             2 —syringe 
             4 —piston 
             6 —rod or plunger 
             8 —chamber or space for holding first component 
             10 —chamber or space for holding second component 
             12 —hypodermic needle or cannula 
             14 —first component, ingredient or substance, e.g., a liquid pharmaceutical 
             16 —second component, ingredient or substance, e.g., a solid pharmaceutical 
             18 —first hollow cylinder 
             20 —second hollow cylinder 
             22 —tube 
             24 —stopper 
             26 —portion of stopper 
             28 —grasping point for stopper 
             30 —pin 
             32 —screw thread groove or track 
             34 —bushing 
             36 —cap 
             38 —threaded receptacle 
             40 —cap 
             42 —threaded receptable 
             43 —screw thread 
             44 —cap including a threaded receptacle 
             46 —transition angle 
             48 —safety shield 
             50 —screw 
             52 —ring 
             54 —opening 
             56 —limiter 
             58 —cup 
             60 —protruding ring 
             62 —groove 
             64 —central axis of syringe 
             66 —flange 
             68 —tongue 
             70 —groove 
             72 —filler tube 
             74 —first inner diameter 
             76 —second inner diameter 
             78 —skirt 
             80 —recess 
             82 —space between two engaged portions of a stopper 
             84 —barrel 
             86 —direction 
             88 —direction 
             90 —seal 
             92 —sleeve 
             94 —seal 
             96 —first part 
             98 —second part 
             100 —spring 
             102 —tongue 
             104 —groove 
             106 —wedge 
             108 —tip of wedge 
             110 —piston base 
             112 —spring 
             114 —first part of rod 
             116 —second part of rod 
             118 —main body 
             120 —rim of piston base 
             122 —tip of seal 
             124 —spring 
             126 —casing 
             128 —rib 
             130 —through channel 
             132 —blocked channel 
             134 —ridge between through channel and blocked channel 
             136 —perforation in casing around second part 
             138 —male screw threads 
             140 —female screw threads 
             142 —aperture 
             144 —cap 
         
      
       Particular Advantages of the Invention 
       In use, the present syringe requires a pull-back of the rod of a piston to expose a first component to a second component. As the first component is held in a first storage space that expands into a space previously taken by a piston as the piston is pulled back, this creates a vacuum that results in an in-rush of slightly compressed air from the shrinking second storage space, causing the first component, a liquid, to scatter violently while also under the influence of gravity to mix with the second component, e.g., a powder, to aid in initiating mixing of the first and second components. 
       The present syringe does not require a forward (or compression) motion of a syringe in which two components are held for the two components to communicate with one another. As such, a user of the syringe does not need to guess the amount of force required to cause the communication. Communication of the two components can occur when the rod is pulled back until it can be no longer be retracted. In an embodiment in which a stopper is used, the action useful for dismantling the stopper also causes the rod to be pulled back to enable communication of the two components. 
       The stopper further eliminates the risk of accidental reconstitution due to vibrations caused during transportation. 
       The present syringe includes a sufficiently large mixing chamber that includes not only the storage space of a first component, the storage space of a second component but also the space vacated by the piston and rod of the syringe. 
       The present syringe includes assemblies that can be combined to form a functional syringe. A first assembly of the syringe is useful for holding a first component and a second assembly of the syringe is useful for holding a second component. As the assemblies are available separately, they can be stored at two different locations or ambient conditions until they become necessary to be combined. Further, the present syringe allows healthcare workers to immediately prepare the products at the time of administration, decreasing post-reconstituted waste. 
       The present syringe decreases the time and steps that reconstituted vaccines and medications require, allowing healthcare workers to be utilized in a more efficient manner. Also, the present syringe reduces raw material wastes, e.g., glass vials and plastic caps, etc. The present syringe offers limited opportunities for error when compared to traditional disposable syringes as a stopper is provided in the present syringe to both prevent accidental administration of an injection of a material that has not been mixed. The removal of the stopper automatically causes a material to be reconstituted. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     The term “about” is used herein to mean approximately, roughly, around, or in the region of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” is used herein to modify a numerical value above and below the stated value by a variance of 20 percent up or down (higher or lower). 
       FIG. 1  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 2  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 1  as taken along line A-A of  FIG. 1 .  FIG. 3  is a front longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 1  as taken along line A-A of  FIG. 1 . The syringe  2  includes a first hollow cylinder  18 , a second hollow cylinder  20 , a tube  22 , e.g., a frustum, and a piston  4 . The first hollow cylinder  18  includes a first end, a second end and a first inner diameter  74 . The second hollow cylinder  20  includes a first end, a second end and a second inner diameter  76 , wherein the second end of the second hollow cylinder  20  is fixed with respect to the first end of the second hollow cylinder  20 . In other words, the distance between the first end of the first hollow cylinder  18  and the second end of the second hollow cylinder  20  does not change. The tube  22  includes a first end having the first inner diameter  74  and a second end having the second inner diameter  76 , wherein the tube  22  is configured to connect the first hollow cylinder  18  at the second end of the first hollow cylinder  18  and the second hollow cylinder  20  at the first end of the second hollow cylinder  20 . In one embodiment, the tube  22  extends outwardly at a transition angle  46  of about 10 to about 80 degrees in a direction from the first hollow cylinder to the second hollow cylinder. In the embodiment shown in  FIG. 2 , the first and second hollow cylinders  18 ,  20  and the tube  22  are constructed as a single unit. In another embodiment disclosed elsewhere herein, the first hollow cylinder  18  is made separately available from the second hollow cylinder  20  and the tube  22 . The piston  4  is configured to slide within the first hollow cylinder  18  and through the tube  22  and the second hollow cylinder  20 . While disposed in a first position of the piston  4  within the first hollow cylinder  18 , the piston  4  isolates the lumens of all three hollow cylinders into two spaces, i.e., a first space  8  between the piston  4  and the first end of the first hollow cylinder  18  and a second space  10  between the piston  4  and the second end of the second hollow cylinder  20 . It shall be noted that the piston  4 , first hollow cylinder  18 , second hollow cylinder  20  and tube  22  are all coaxially disposed with the central axis of the syringe  2 , i.e., the central axis of the piston  4 , the central axis of the first hollow cylinder  18 , the central axis of the second hollow cylinder  20  and the central axis of the tube  22  coincide with one another. It shall also be noted that the second diameter  76  is greater than the first diameter to allow the contents of the first hollow cylinder  18  to flow into the second hollow cylinder  20  unimpeded once communication between the two spaces  8 ,  10  has been enabled or established. 
     There is further provided a safety mechanism to prevent exposure of a user to the needle  12 . Referring to  FIGS. 1-3 , a safety shield  48  is shown disposed in an undeployed position as the syringe  2  has yet to be used and therefore a patient shall be exposed to the needle  12  to receive an injection. The safety shield  48  includes a protruding ring  60  disposed on one end of the safety shield  48 , the protruding ring  60  configured to be removably coupled to a groove  62  integrally built with the tube  22 . 
     A communication of a first substance within the first space  8  and a second substance within the second space  10  is enabled through the tube  22  by an act of withdrawing the piston  4  from the first space  8  and the communication is configured to occur in a total volume of at least a combined volume of the first space  8  and the second space  10  as shown in  FIG. 17 . In the embodiments shown throughout, the piston  4  is connected to a rod  6  configured to be slideable through an opening at the second end of the second hollow cylinder  20 . One end of the rod  6  is terminated with a screw  50  configured to receive a piston  4  while the other end of the rod  6  is terminated with a thumb engageable flange  66 . The piston  4  may alternatively be constructed as a single unit with the rod  6  provided that the piston  4  is capable of sealing the first space  8  from the second space  10 . In one example, the piston  4  is constructed from a polymeric material, e.g., rubber, etc., an elastomeric material sufficiently resilient yet sufficiently rigid to seal the first space  8  from the second space  10  while it is disposed partially or in its entirety at the second end of the first hollow cylinder  8 . 
     The syringe further includes a needle for delivering at least one of the first substance and a mixture of the first substance and the second substance where the needle  12  is disposed on the first end of the first hollow cylinder  18 . The first substance  14  may include a liquid and the second substance  16  may include a solid, e.g., a powder. In another embodiment, both the first and second substances may include a liquid. In yet another embodiment, the first substance may be a gas and the second substance may be a liquid or solid. If one of the two substances is a solid, the solid is preferably stored in the second space  10  to promote mixing and lessen the opportunity that an undissolved or poorly dissolved solid can be found clogging the needle  12 . 
     As the inner diameter of the tube  22  expands from a first end of the tube  22  to the second end of the tube  22  and the diameter of the rod  6  is no larger than the diameter of the piston  4 , a retraction of the rod  6  away from the first hollow cylinder  18  enables a path for the first substance  14  to be mixed with the second substance  16 . The syringe  2  can be accidentally or intentionally misused without a means for immobilizing the rod  6  with respect to the first hollow cylinder  18  against a squeezing action applied to the syringe  2 . A user who is under the influence of the ubiquitous act of depressing a rod or plunger to cause an inward stroke to expel a substance from the tip of a syringe, may proceed to do so without having mixed the two components contained within the syringe before use, potentially requiring the syringe to be discarded and causing harm to the recipient of an injection of an ineffective substance due to the lack of mixing with a complementary substance. In preventing an inadvertent depression of the syringe, a stopper that is easily removable, is provided.  FIGS. 1-3  are shown without a stopper. 
       FIG. 4  is a longitudinal view of one embodiment according to a present syringe  2  in a post-administration condition.  FIG. 5  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 4  as taken along line B-B of  FIG. 4 .  FIG. 6  is a front longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 4  as taken along line B-B of  FIG. 4 .  FIG. 7  is a cross-sectional view of a safety shield, depicting a limiter useful for immobilizing the safety shield with respect other parts of a present syringe  2  upon a ring  60  of the syringe becoming lodged in an opening  54  of the limiter  56 . Here, the piston  4  is shown to assume a position that leaves no space between the piston  4  and the needle  12  as a mixture previously held in the syringe has been expelled through needle  12 , e.g., via an injection into a patient. It shall also be noted that the safety shield  48  is now disposed in its erected position, shielding a user as well as a patient from an accidental contact with the needle  12 . In deploying the safety shield  48 , a user simply grasps before pulling the safety shield  48  forwardly towards the needle  12  until ring  52  becomes lodged in an opening  54  of the limiter  56 . The safety shield  48  is preferably constructed from a sufficiently resilient material such that a sufficiently large pulling force causes deformation of the safety shield  48  to detach the protruding ring  60  from the groove  62  to allow the limiter  56  to be disposed in a position to be coupled with ring  52  to secure the safety shield  48  in place to avoid contact of the needle  12  with a user or patient. Upon deploying the safety shield  48 , the syringe can now be safely discarded. 
       FIG. 8  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 9  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 8  as taken along line C-C of  FIG. 8 .  FIG. 10  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 11  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 10  as taken along line D-D of  FIG. 10 .  FIG. 12  is a bottom perspective view of a stopper of a present syringe  2  with the two portions  26  of the stopper  24  attached to one another.  FIG. 13  is a bottom perspective view of a stopper  24  of a present syringe  2  with the two portions  26  of the stopper  24  detached from one another. Here, a stopper  24  is utilized to prevent improper use of the syringe  2 . Note that a portion of the rod  6  is recessed at a recess  80  to accommodate the stopper  24 . A skirt  78  is configured to extend from the second end of the second hollow cylinder  20  to both provide a shroud to contain the stopper  24  and to provide tracks  32  along which the stopper  24  can be screwed into a secure position within the shroud to be seated. Two pins  30  are disposed substantially on a first end of the stopper  24  while two grasping points  28  are disposed substantially on a second end of the stopper  24 . Each grasping point  28  is essentially a diametrically-extending protrusion that a user can easily grasp with one or more fingers to apply a twisting force thereto in either direction  86  or direction  88 . In coupling the stopper  24  to the syringe  2 , two halves  26  of the stopper  24  are brought around the recess  80  and arranged such that a tongue  68  of one is aligned with a groove  70  of the other before the halves  26  are clamped onto the recess  80  to result in an arrangement where the two pins  30  and the two grasping points  28  are opposingly disposed about the central axis of the rod  6  and a space between two engaged halves  26 . The stopper  24 , now clamped onto rod  6 , is then disposed so that the pins  30  are each aligned with one of the tracks  32  disposed on an inner wall of the skirt  78  before the stopper is seated in the skirt  78  following a twisting motion in a first direction  86  that advances the stopper  24  until the second end of stopper  24  coincides with the end of the skirt  78  away from the second hollow cylinder  20 , leaving the grasping points  28  exposed. In one embodiment, the stopper  24  requires about 0.1 to about 2 turns to be unseated from its fully seated position. In one embodiment, the pitch of the grooves or tracks  32  is about 35 mm per revolution. This translates to about 14 mm in linear motion along the central axis of the second hollow cylinder  20  per 0.4 turn of the stopper  24  about the central axis of the second hollow cylinder  20 . While seated within the skirt  78 , a pull of the rod  6  with respect to the cylinders  18 ,  20 ,  22  will be met with sufficient resistance that immobilizes the rod  6 . In order to remove the stopper  24  to allow an administration of an injection, a user first grasps the grasping points  28  before twisting the stopper  24  about the central axis of the rod  6  in a second direction  88  that is opposite of the first direction. In addition to exposing the stopper  24 , upon clearing the skirt  78  so that the stopper  24  can disintegrate into the halves  26  and subsequently removed and discarded, such action also withdraws the rod  6 . In one embodiment, such action also withdraws the rod  6  sufficiently to allow communication of the first substance and the second substance. Therefore, in this embodiment, in addition to serving as a means to prevent misuse of the syringe, the stopper  24  forces the user to use the syringe  2  in a manner intended, i.e., by forcing the user to allow mixing of the substances provided in the syringe  2  before the syringe  2  can be used. 
       FIGS. 14-18  is a series of diagrams depicting an order in which a present syringe  2  can be used to administer an injectable material. The syringe  2  is pre-filled with an injectable material composed of two separate components  14 ,  16 . If the injectable material is a mixture of a liquid and a solid, the liquid is preferably disposed in the first space  8 , i.e., the space adjacent a needle  12 . Disclosed herein is a method for mixing a first substance of a first space  8  and a second substance of a second space  10 , wherein communication of the first space and the second is blocked by a removable member, e.g., a piston  4 . First, the syringe is orientated such that the first space  8  is disposed at an elevation higher than the second space  10  as shown in  FIG. 14 . In other words, the syringe  2  is held such that the needle  12  is pointed upwardly. This is followed by removing the piston  4  to enable communication of the first substance  14  with the second substance  16  to form a mixture as shown in  FIGS. 15 and 16 . Referring to  FIG. 15 , as the first component is held in a first storage space that expands into a space previously taken by a piston  4  as the piston  4  is pulled back, this creates a vacuum that results in an in-rush of slightly compressed air from the shrinking second storage space, causing the first component  14 , a liquid, to scatter violently while also under the influence of gravity to mix with the second component  16 , e.g., a powder, to aid in initiating mixing of the first and second components. As the rod  6  continues to be withdrawn as shown in  FIG. 16 , the stopper  24  eventually clears the skirt  78  and falls out as it disintegrates into its halves  26  as the tongue  68  of a half disengages from the groove  70  of another and the first substance continues to mix with the second substance. It shall be noted that upon full retraction of rod  6  as shown in  FIG. 17 , the first space  8  is no longer partially occupied by the piston  4  and the second space  10  is no longer partially occupied by a portion of rod  6 , resulting in the maximum total space or “mixing chamber” for mixing. The mixing chamber now includes the volume occupied by the first space  8  and the second space  10  without including the volume taken up by the piston  4 . It shall be noted that, in this configuration, the communication is configured to occur across substantially the entire longitudinal cross-sectional area of the second hollow cylinder where the cross-sectional area is disposed at right angle to a central axis of the second hollow cylinder  20 . When mixing has been considered satisfactory, the syringe  2  is flipped over, i.e., by positioning the second space  10  at an elevation higher than the first space  8  until the mixture has drained into the first space  8  in its entirety before the rod  6  is advanced and before the piston  4  enters the lumen of the first hollow cylinder  18  to capture the entire volume of the mixture in the first hollow cylinder  18  to be injected in a patient. The total volume of the mixture is preferably equal to or less than the first space to avoid waste as any mixture not contained within the first space  8  is left behind in the syringe  2 . The syringe  2  may simply be held in a position as shown in  FIG. 17  for several seconds for the mixing of a liquid and a highly dissolvable solid or two liquids. For a solid with low dissolvability, the mixture is agitated in the syringe  2  while disposed in an orientation shown in  FIG. 17  or in any other orientations. Fluids of the smaller-diameter first space  8  rush to the larger-diameter second space  10 . In a syringe of Hersee, as a diluent (30 of Hersee) is disposed in an upper chamber with a larger diameter, once communication between the upper chamber has been established with a lower chamber, as the fluids are contained in the upper chamber with the larger diameter, no rush of the fluids can occur towards the lower chamber with the smaller diameter, failing to enhance mixing. In contrast, in a present syringe, fluids contained in the first space  8  rush in the same direction as gravity, increasing the impact velocity of the fluids against the solids, e.g., powder, found in the second space  10 , thereby enhancing the mixing of the fluids and solids. The syringe  2  is intuitively configured as both the action required to prepare the syringe  2  for an injection and the action required to administer the injection both rest on a common axis, i.e., the central axis  64  of the syringe  2 . The present syringe  2  can alternatively be useful for administering a single substance. For an application where the contents of the second space is unnecessary or undesired, the syringe  2  can simply be used to provide only the contents pre-loaded in the first space  8 . 
       FIGS. 19-22  depict assemblies useful for constructing one embodiment of a present syringe  2  such that an injectable mixture can be mixed therein prior to its use. Referring to  FIG. 19 , a cup  58  is provided with a rod  6  already inserted through an opening through the bottom of the cup  58 . The cup  58  is filled with a second substance  16  through a filler tube  72  and the halves  28  are clamped around recess  80 . Referring to  FIGS. 20 and 21 , the cup is then fixedly installed within a barrel  84 , e.g., with an adhesive or by ultrasonic welding to essentially result in a second hollow cylinder  20  that is connected to a tube  22  and a piston disposed to block a lumen at a first end of the barrel  84 . In the embodiment shown in  FIGS. 20 and 21 , a cap  40  is secured to the first end of the barrel  84  by means of a threaded receptacle  42  to protect the piston.  FIG. 22  depicts a first hollow cylinder  18  that is capped at its first end with a cap  36  secured to the first hollow cylinder  18  with a screw thread and terminated at its second end with a screw thread  43  coupled with a threaded receptacle of a cap  44 . To fill the first hollow cylinder  18 , one of the caps  40 ,  44  is removed to receive a substance before the cap is replaced to seal the substance therein.  FIG. 23  depicts one embodiment of a present syringe  2  constructed from assemblies disclosed in  FIGS. 20-22 . In doing so, the cap  40  of barrel  84  is removed to expose the threaded receptacle  42 . The orientation at which the barrel  84  is held is inconsequential as space  10  is sealed at one end with the piston  4  and the other with the rod  6 . The first hollow cylinder  18  is first held with the end of first hollow cylinder  18  capped with cap  44  pointed upwardly before the cap  44  is removed such that the substance contained therein remains. The exposed threaded receptacle  42  is then aligned with and coupled to screw thread  43  to form the syringe  2  depicted in  FIG. 23 .  FIGS. 20 and 21  show an assembly that can be stored independently and separately from the assembly of  FIG. 22 . Therefore, the two substances of the syringe can be stored separately in two different locations and under two highly diverse ambient conditions. For instance, the assembly shown in  FIG. 22  and hence the first substance stored therein, may be stored at a very low temperature while the assembly shown in  FIGS. 20 and 21  and hence the second substance stored therein, may be stored at room temperature prior to the reconstitution of the second substance by adding the first substance. In one embodiment not shown, the assembly shown in  FIG. 22  may also be secured to the assembly shown in  FIGS. 20 and 21  by means of an adhesive, ultrasonic welding, etc., for a syringe having substances that may be disposed at the same ambient condition. Upon mixing, the mixture of the substances is ready to be injected. At this point, the cap  36  may be replaced with a needle supported on a bushing  34  as shown in  FIG. 1  where the screw thread equipped bushing  34  is coupled with threaded receptacle  38 . To fill a syringe where the first and second hollow cylinders  18 ,  20  and the tube  22  are constructed as a single unit, the process to fill the syringe  2  is similar to the process disclosed earlier, except for the lack of a need to first attach the first hollow cylinder to a barrel as the first hollow cylinder is already part of the barrel. 
       FIG. 24  is a rear longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 25  is a rear longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition of  FIG. 24  with the stopper shown in  FIG. 24  removed to reveal the second hollow cylinder.  FIG. 26  is a rear longitudinal view of one embodiment according to a present syringe  2  of  FIG. 24  in a condition where the stopper  24  has been operationally removed and the rod has been sufficiently withdrawn to cause communication between a first and a second component.  FIG. 27  is a top perspective view of a stopper  24  of a present syringe with the two portions of the stopper attached to one another.  FIG. 28  is a rear longitudinal view of one embodiment according to a present syringe  2  of  FIG. 24  with its contents having been emptied.  FIG. 29  is a longitudinal cross-sectional view of one embodiment according to a present syringe  2  of  FIG. 24  where the syringe is shown as two separate parts prior to being combined to form the syringe  2 . It shall be noted that the stopper  24  is configured to be removably coupled to the outer wall of the second hollow cylinder  20 . In this embodiment, no skirt is required to contain a stopper, e.g., as in the embodiment shown in  FIG. 9 . Instead, screw thread grooves  32  are disposed on the outer wall of the second hollow cylinder  20 . Referring to  FIG. 27 , two pins  30  are disposed substantially on a first end of the stopper  24 . In coupling the stopper  24  to the syringe  2 , two halves  26  of the stopper  24  are brought around a recess  80  and arranged such that a tongue  68  of one is aligned with a groove  70  of the other before the halves  26  are clamped onto the recess  80  to result in an arrangement where the two pins  30  are opposingly disposed about the central axis of the rod  6 . The stopper  24 , now clamped onto rod  6 , is then disposed in a manner so that the pins  30  are each aligned with one of the two tracks  32  disposed on an outer wall of the second hollow cylinder  20  before the stopper  24  is seated around the second hollow cylinder  20  following a twisting motion in a first direction  86  that advances the stopper  24  until the second end of stopper  24  coincides with the second end of the second hollow cylinder  20  and the stopper  24  can no longer be advanced. While seated around the second hollow cylinder  20 , a pull of the rod  6  with respect to the cylinders  18 ,  20 ,  22  will be met with sufficient resistance that immobilizes the rod  6 . In order to remove the stopper  24  to allow an administration of an injection, a user first grasps the stopper  24  before twisting it about the central axis of the rod  6  in a second direction  88  that is opposite of the first direction. In one embodiment, the stopper  24  requires about 0.1 to about 2 turns to be unseated from its fully seated position. In one embodiment, the pitch of the grooves or tracks  32  is about 35 mm per revolution. This translates to about 14 mm in linear motion along the central axis of the second hollow cylinder  20  per 0.4 turn of the stopper  24  about the central axis of the second hollow cylinder  20 . Upon clearing the tracks  32 , the stopper  24  disintegrates into the halves  26  as the pins  30  are no longer confined in tracks  32 . The halves  26  are subsequently removed and discarded. It shall be noted that the act of twisting the stopper  24  also withdraws the rod  6 . In one embodiment, such action withdraws the rod  6  sufficiently to allow communication of the first substance and the second substance. Therefore again, in this embodiment, in addition to serving as a means to prevent misuse of the syringe, the stopper  24  forces the user to use the syringe  2  in a manner intended, i.e., by forcing the user to allow mixing of the substances provided in the syringe  2  before the syringe  2  can be used.  FIG. 30  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 31  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 30  as taken along line E-E of  FIG. 30 . It shall be noted that the barrel of the syringe  2  is assembled from two parts, i.e., a first part  96  encompassing the first hollow cylinder  18  and the tube  22  and a second part  98  encompassing the second hollow cylinder  20  where the second part  98  is formed in the shape of a cup. In this embodiment, a seal  94 , e.g., an O-ring is used between the first part  96  and the second part  98  to prevent leakage when the first part  96  and the second part  98  are assembled to form space  10 . The screw thread grooves  32  are disposed on a sleeve  92  attached to the first part  96  and the second part  98 , e.g., with an adhesive. Another seal  90  is provided to seal a gap between the second part and the rod  6 . In one example, the first and second parts  96 ,  98  are both made from glass. 
       FIG. 32  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 33  is a longitudinal cross-sectional view of the embodiment of a present syringe of  FIG. 32  as taken along line F-F of  FIG. 32 . Here, a first part encompasses the first hollow cylinder  18 , second hollow cylinder  20  and tube  22 . A second part  98 , formed in the shape of a cup, is configured to be coupled to the first part  96 , e.g., with an adhesive. The screw thread grooves  32  are disposed on a sleeve  92  attached, e.g., with an adhesive, to a bottom portion of the first part  96 . In one example, the first and second parts  96 ,  98  are both made from glass. 
     It shall be noted that, in the ensuing figures, no components are shown contained in the cylinders  18 ,  20  of a syringe  2  for simplicity. It shall be understood however that the functions of the two cylinders  18 ,  20  and tube  22  of the present syringe  2  disclosed elsewhere herein remain applicable to the embodiments of the present syringe shown in  FIGS. 34-61 . It shall also be noted that, the rod  6  disclosed elsewhere herein may be made more compactly by disposing the rod in a two-part form where the rod is only formed at the time of use. As disclosed in  FIGS. 34-61 , a rod is composed of a first part  114  and a second part  116 .  FIG. 34  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 35  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 34  as taken along line K-K of  FIG. 34 .  FIG. 36  is a longitudinal view of one embodiment according to a present syringe  2  in a condition where a second part of the rod has been liberated from a packaged arrangement of the present syringe.  FIG. 37  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 36  as taken along line G-G of  FIG. 36 . Here, the main body  118  including a first hollow cylinder  18 , a second hollow cylinder  20  and tube  22 , is formed as a single unit, e.g., from glass or by using additive manufacturing techniques. A seal  90  with a central opening is inserted in one end of the main body  118  before the seal  90  is secured, e.g., by clamping, to the main body  118  with a casing  126  that is formed as a single unit with a flange  66 . Another process fuses the flange  66  to the second part  116 . In a pre-administration condition, the second part  116  of the rod  6  is disposed in a manner in which the rod  6  comes in contact with a wedge  106 . A tip  108  of the wedge  106  is configured to be disposed in a tapered aperture  142  of a piston base  110 . In one embodiment, a surface of the tapered aperture  142  is a roughened surface to increase grip of the piston base  110  by the wedge  106 . While the tip  108  of the wedge  106  is pushed against the tapered aperture  142 , it causes the elastic tip of the piston  4  to expand, effectively preventing any movement of the piston  4  with respect to the cylinders  18 ,  20  and leaks between the spaces defined by the cylinders  18 ,  20  in storage or transit. To use the syringe  2 , a user first breaks the bond between the flange  66  and the casing  126  by, e.g., inserting one&#39;s finger nail in a space between the flange  66  and the casing  126  and prying the flange  66  away from the casing  126 . Once the perforation  136  in casing  126  around second part  116  has been broken, a spring  100  that is disposed in the piston base  110  and urged against the tip  108  causes the tip  108  to be removed from the tapered aperture  142 , relieving the hold of the piston  4  against an internal wall of cylinder  18 , allowing the first part  114  of the rod to be slideably moved with a pulling force applied to the rod. Referring to  FIG. 37 , the flange  66  is shown disposed in a state where it has been separated from the casing  126 . 
     When the rod of  FIG. 37  continues to be retracted, the second part  116  is eventually coupled with the first part  114  to form a rod with sufficient length to push a mixture of materials disposed in the first and second cylinders  18 ,  20  and tube  22  as shown in  FIG. 38 .  FIG. 38  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 36  in a condition where the rod has been formed. The second part  116  is coupled with first part  114  when the tongue  102  disposed about one end of the first part  114  is lodged in a groove  104  disposed about one end of the second part  116 . When the rod continues to be retracted, it eventually reaches a position where the rod cannot be further retracted.  FIG. 40  is a close-up view of a portion of the seal of a present syringe that prevents detachment of the rod from the present syringe. Here, the rim  120  of the piston base  110  interferes with the tip  122  of the seal  90  to prevent the rod from being pulled or retracted further.  FIG. 41  is a longitudinal view of the embodiment of a present syringe  2  in a post-administration condition.  FIG. 42  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 41  as taken along line H-H of  FIG. 41 . 
       FIG. 43  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 44  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 43  as taken along line I-I of  FIG. 43 .  FIG. 45  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 43  in a condition where the rod has been formed.  FIG. 46  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 43  in a condition where the rod has been formed and the rod has been fully retracted.  FIG. 47  is a close-up view of a portion of the seal of a present syringe  2  that prevents detachment of the rod from the present syringe  2 . Compared to the embodiment shown in  FIGS. 34-42 , the syringe  2  in this embodiment lacks a wedge which exerts a force that expands the piston base  110  to further secure the piston  4  in position, simplifying the syringe design for applications which does not require the level of secure positioning of the piston  4  with respect to the cylinders  18 ,  20  and tube  22 . 
       FIG. 48  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 49  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 48  as taken along line J-J of  FIG. 48 .  FIG. 50  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 48  in a condition where one of the two parts of the rod has been released such that the rod may be subsequently formed.  FIG. 51  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 48  in a condition where the rod has been fully retracted.  FIG. 52  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 48  in a condition where the rod has been fully formed by locking the second part  116  to the first part  114 . Referring to  FIG. 48 , upon liberating the cap  144  from the second part  116 , e.g., by prying using a finger of a user, spring  112  pushes the second part  116  from the first part  114 , extending the rod. A spring  124  disposed at a location bounded by one end of the first part  114  and one end of the second part  116  remains uncompressed. As the second part  116  continues to be pulled by the user, spring  124  compresses, making it harder for the user to continue pulling the second part  116 . This increase in resistance to the pull helps inform the user that the second part  116  is now required to be rotated about its axis such that it can be locked with respect to the first part  114  via a twist-and-lock mechanism. Upon being locked in place with respect to the first part  114 , the second part  116  extends the total length of the rod to enable the syringe to be used while allowing the syringe  2  to be transported and stored in a compact format. 
       FIGS. 53-56  shows details of forming a rod as shown in  FIG. 52 .  FIG. 53  is a diagram depicting two parts  114 ,  116  of the rod of  FIG. 52 . In this embodiment, the second part  116  includes three ridges  128  and their respective through channels  130  and blocked channels  132  where the ridges  128 , through channels  130  and blocked channels  132  are all disposed about the second part&#39;s central axis. It shall be noted that the second part  116  is disposed within a cavity of the first part  114  and urged towards the first part  114  by spring  124 .  FIG. 54  is a diagram depicting a manner in which the second part  116  of the rod is pulled against the first part  114  of the rod from through channels  130 , compressing spring  124 .  FIG. 55  is a diagram depicting a manner in which the second part  116  of the rod is rotated or twisted coaxially with respect to the first part  114  of the rod until the ribs  128  clear the ridges  134  and are all aligned with the blocked channels  132 . Upon release, the ribs  128  which are now aligned with the blocked channels  132 , will be urged towards the first part  114  by spring  124  to result in an arrangement disclosed in  FIG. 56  which shows the ribs  128  which have been seated and locked in the blocked channels  132 .  FIG. 56  is a diagram depicting a rod has been formed by locking a first part  114  to a second part  116 . 
       FIG. 57  is a longitudinal view of one embodiment according to a present syringe  2  in a pre-administration condition.  FIG. 58  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 57  as taken along line L-L of  FIG. 57 .  FIG. 59  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 57  in a condition where one of the two parts  114 ,  116  of the rod has been released such that the rod may be subsequently formed. It shall be noted that, in this embodiment, when cap  144  has been removed as shown in  FIG. 59 , spring  142  urges the second part  116  to extend.  FIG. 60  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 57  in a condition where the second part  116  is being retracted to a point before the second part  116  can be secured to the first part  114 .  FIG. 61  is a longitudinal cross-sectional view of the embodiment of a present syringe  2  of  FIG. 57  in a condition where the rod has been formed by twisting the second part  116  with respect to the first part  114  such that the male screw threads  138  of the second part  116  can mate with the female screw threads  140  of the first part  114 , forming a rod. 
     The detailed description refers to the accompanying drawings that show, by way of illustration, specific aspects and embodiments in which the present disclosed embodiments may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice aspects of the present invention. Other embodiments may be utilized, and changes may be made without departing from the scope of the disclosed embodiments. The various embodiments can be combined with one or more other embodiments to form new embodiments. The detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, with the full scope of equivalents to which they may be entitled. It will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of embodiments of the present invention. It is to be understood that the above description is intended to be illustrative, and not restrictive, and that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Combinations of the above embodiments and other embodiments will be apparent to those of skill in the art upon studying the above description. The scope of the present disclosed embodiments includes any other applications in which embodiments of the above structures and fabrication methods are used. The scope of the embodiments should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.