Syringe for injection by pulling plunger rod backwards

BACKGROUND OF THE INVENTION

Field of the Invention

0001The present invention is directed to a syringe assembly adapted for dispensing and delivery of a fluid. More particularly, the present invention is directed to a syringe assembly such as a hypodermic syringe having a reduced profile prior to use, and which is adapted for delivering the contents thereof through a conventional movement by the user, but involving an inverse delivery operation.

Related Technology

0002Syringe assemblies, and in particular hypodermic syringes, are well known in the medical field for dispensing fluids, such as medication. A conventional syringe typically includes a syringe barrel with an opening at one end and a plunger mechanism disposed through the other end. The plunger typically includes a plunger rod extending through the barrel, with a plunger head or stopper at the end of the plunger rod within the barrel, and with a finger flange at the other end of the plunger rod extending out of the barrel. In use, the plunger rod is retracted through the syringe barrel to aspirate or fill the syringe barrel with a fluid, such as a medication, with the plunger rod extending out from the rear end of the syringe barrel. For delivery of the medication to a patient, the opening of the syringe barrel is adapted for fluid communication with a patient, such as through a hypodermic needle fitted at the front end of the syringe barrel or through a luer-type fitting extending from the front end of the syringe barrel for attachment with a fluid line of a patient. Upon depressing of the plunger rod, the plunger rod and stopper travel through the syringe barrel, thereby forcing the contents of the syringe out through the opening at the front end for delivery to the patient. Such an operation is well known in the medical field, and medical practitioners have become well accustomed to the use of such common fluid delivery procedures through standard syringes.

0003Conventional syringes are well known to be used in connection with a vial of a medication, where the user draws the fluid into the syringe immediately prior to injection and delivery of the fluid to the patient. Oftentimes, hypodermic syringes may be packaged as "pre-filled" devices, wherein the syringe is pre-filled with medication prior to being packaged and delivered to the end user. In this manner, there is no need for the user to fill the device prior to injection, thereby saving time for the end user and maintaining consistent volumes for delivery.

0004Packaging of such pre-filled syringes, however, tends to be bulky. A pre-filled syringe is typically packaged with the opening at the front end of the barrel including a cap thereover and with the plunger rod retracted out of the back end of the syringe barrel, with the fluid pre-filled "pre-filled" devices, wherein the syringe is pre-filled with medication prior to being packaged and delivered to the end user. In this manner, there is no need for the user to fill the device prior to injection, thereby saving time for the end user and maintaining consistent volumes for delivery.

0005Packaging of such pre-filled syringes, however, tends to be bulky. A pre-filled syringe is typically packaged with the opening at the front end of the barrel including a cap thereover and with the plunger rod retracted out of the back end of the syringe barrel, with the fluid pre-filled within the syringe barrel. Such packaging creates an elongated package that can be awkward for shipping and storage.

0006Pre-filled syringes are often filled with narcotics or other drugs at a production facility, packaged, and then shipped to a medical facility. Once at the facility, these syringes are often placed in controlled storage and/or locked cabinets to reduce theft of the syringes themselves and/or of the contents of these syringes. The space within these controlled storage locations is often limited, thus there is a need for a syringe assembly that has a smaller packing footprint, to reduce the storage space required for containing the syringe. It is also desirable to produce syringes that are uniform in terms of an outer surface shape to allow for stacking of these syringes within the storage cabinet.

0007<patcit id="pcit0001" dnum="WO0035518A"><text>WO 00/35518</text></patcit> describes a syringe assembly comprising a barrel defining a chamber, a proximal end and a distal end having an opening therethrough. The chamber is separated into a proximal chamber adjacent to the proximal end and a distal chamber adjacent to the distal end with the opening. In the distal chamber, a moveable plunger is disposed which is in a pre-used condition adjacent to the distal end. The distal chamber is filled with an injection liquid and upon movement of the plunger head in a proximal direction, the injection liquid passes through a channel in the plunger head and is expelled through the distal opening.

SUMMARY OF THE INVENTION

0008The present invention provides a syringe assembly in accordance with claim 1 having a reduced profile prior to use, thereby occupying less space than a conventional syringe and providing a mechanism for reduced overall size and for efficient packaging that reduces or eliminates excess waste. Further, actuation of a syringe assembly of the present invention is accomplished using a similar operation as with a conventional syringe, thereby providing a standardized mechanism for ease of use.

0009The reduced profile is achieved by providing a syringe assembly that, when filled, comprises an overall profile that is substantially similar to the profile of the syringe barrel. This may be accomplished by providing the syringe assembly with a plunger rod that is significantly disposed within the syringe barrel when filled for use, with the plunger rod adapted to be retracted from the syringe barrel during dispensing of the contents of the syringe barrel.

0010The syringe assembly includes a syringe barrel having an inside surface defining a chamber, an open proximal or rearward end, and a distal or forward end having an opening therethrough. A plunger assembly is disposed at least partially within the syringe barrel, with the plunger assembly comprising an elongated plunger rod and a plunger head disposed on the plunger rod and slidably disposed within the syringe barrel. The plunger head separates the chamber of the syringe barrel into a proximal chamber adjacent the proximal end and a distal chamber adjacent the distal end. A conduit extends between the proximal chamber and the opening at the distal end of the syringe barrel. The syringe assembly is adapted to contain a fluid in the proximal chamber, such fluid being expelled through the conduit and out of the opening at the distal end of the syringe barrel upon movement of the plunger head toward the proximal end of the syringe barrel. Movement of the plunger head toward the proximal end of the syringe barrel occurs based on conventional operation of expelling fluid from a conventional syringe with a squeezing movement between a thumb and forefinger. Such movement is well recognized to syringe users, which typically involves squeezing between a thumb pad on a plunger rod and a forefinger on a finger flange on a syringe barrel. Through embodiments of the present invention, an inverse delivery is accomplished with similar operational movement of a conventional syringe, thereby achieving a reduced profile syringe without any perceived change in operational use by the user.

0011The plunger assembly further includes an actuator portion at least partially extending externally outside of the syringe barrel and adapted to effect movement of the plunger head within the syringe barrel. The actuator portion is interconnected to the plunger head, for example, through the sidewall of the syringe barrel or through an open proximal end of the syringe barrel. The actuator portion includes at least one flange configured to receive a forefinger of a user, while the proximal end of the syringe barrel may be closed with a closure that may include a thumb pad. Such flange and thumb pad are adapted to accommodate the conventional squeezing operational movement of a conventional syringe while accomplishing the inverse delivery of the contents of the syringe.

BRIEF DESCRIPTION OF THE DRAWINGS

0012<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001"><b>FIG. 1A</b></figref> is a perspective view of a syringe assembly in one embodiment of the present invention shown in a pre-filled state prior to use.</li><li><figref idref="f0001"><b>FIG. 1B</b></figref> is a front plan view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref><b>.</b></li><li><figref idref="f0002"><b>FIG. 1C</b></figref> is a side plan view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref><b>.</b></li><li><figref idref="f0002"><b>FIG. 1D</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref><b>.</b></li><li><figref idref="f0003"><b>FIG. 2</b></figref> is a perspective view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref> shown during use by a user.</li><li><figref idref="f0004"><b>FIG. 3</b></figref> is a perspective view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref> shown after use by a user after the medication is expelled.</li><li><figref idref="f0005"><b>FIG. 4A</b></figref> is a perspective view of the syringe assembly of <figref idref="f0001"><b>FIG. 1A</b></figref> shown after dispensing of the medication after use.</li><li><figref idref="f0005"><b>FIG. 4B</b></figref> is a front plan view of the syringe assembly of <figref idref="f0005"><b>FIG. 4A</b></figref> after use.</li><li><figref idref="f0006"><b>FIG. 4C</b></figref> is a side plan view of the syringe assembly of <figref idref="f0005"><b>FIG. 4A</b></figref> after use.</li><li><figref idref="f0006"><b>FIG. 4D</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0005"><b>FIG. 4A</b></figref> after use.</li><li><figref idref="f0007"><b>FIG. 5A</b></figref> is a side plan view of a syringe assembly similar to that of <figref idref="f0001"><b>FIG. 1A</b></figref> shown in a pre-filled state prior to use and further including a bellows.</li><li><figref idref="f0007"><b>FIG. 5B</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0007"><b>FIG. 5A</b></figref><b>.</b></li><li><figref idref="f0008"><b>FIG. 5C</b></figref> is an enlarged side cross-sectional view of <figref idref="f0007"><b>FIG. 5A</b></figref> showing the details of the bellows.</li><li><figref idref="f0009"><b>FIG. 6A</b></figref> is a side plan view of the syringe assembly of <figref idref="f0007"><b>FIG. 5A</b></figref> shown after dispensing the medication after use with the bellows expanded.</li><li><figref idref="f0009"><b>FIG. 6B</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0009"><b>FIG. 6A</b></figref><b>.</b></li><li><figref idref="f0010"><b>FIG. 6C</b></figref> is an enlarged side cross-sectional view of <figref idref="f0009"><b>FIG. 6A</b></figref> showing the details of the expanded bellows.</li><li><figref idref="f0011"><b>FIG. 7A</b></figref> is a perspective view of a syringe assembly in a further embodiment shown in a pre-filled state prior to use.</li><li><figref idref="f0011"><b>FIG. 7B</b></figref> is a front plan view of the syringe assembly of <figref idref="f0011"><b>FIG. 7A</b></figref><b>.</b></li><li><figref idref="f0012"><b>FIG. 7C</b></figref> is a side plan view of the syringe assembly of <figref idref="f0011"><b>FIG. 7A</b></figref><b>.</b></li><li><figref idref="f0012"><b>FIG. 7D</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0011"><b>FIG. 7A</b></figref><b>.</b></li><li><figref idref="f0013"><b>FIG. 8A</b></figref> is a perspective view of the syringe assembly of <figref idref="f0011"><b>FIG. 7A</b></figref> shown after dispensing of the medication after use.</li><li><figref idref="f0013"><b>FIG. 8B</b></figref> is a front plan view of the syringe assembly of <figref idref="f0013"><b>FIG. 8A</b></figref> after use.</li><li><figref idref="f0014"><b>FIG. 8C</b></figref> is a side plan view of the syringe assembly of <figref idref="f0013"><b>FIG. 8A</b></figref> after use.</li><li><figref idref="f0014"><b>FIG. 8D</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0013"><b>FIG. 8A</b></figref> after use.</li><li><figref idref="f0015"><b>FIG. 9</b></figref> is a side cross-sectional view of a syringe assembly in a further embodiment shown in a pre-filled state prior to use.</li><li><figref idref="f0015"><b>FIG. 10</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0015"><b>FIG. 9</b></figref> shown after dispensing of the medication after use.</li><li><figref idref="f0016"><b>FIG. 11</b></figref> is a side cross-sectional view of a syringe assembly in yet a further embodiment shown in a pre-filled state prior to use.</li><li><figref idref="f0016"><b>FIG. 12</b></figref> is a side cross-sectional view of the syringe assembly of <figref idref="f0016"><b>FIG. 11</b></figref> shown after dispensing of the medication after use.</li><li><figref idref="f0017"><b>FIG. 13</b></figref> is a perspective view comparing a conventional syringe to a syringe assembly in accordance with the present invention.</li></ul>

DETAILED DESCRIPTION

0013For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

0014Reference is now made to <figref idref="f0001 f0002"><b>FIGS. 1A-1D</b></figref><b>,</b> which depict a syringe assembly, generally indicated as <b>10,</b> adapted for dispensing and delivery of a fluid. Syringe assembly <b>10</b> is intended for use for injection or infusion of fluid such as a medication into a patient, and is generally shown and described for purposes of the present description as a hypodermic syringe. Syringe assembly <b>10</b> is contemplated for use in connection with a needle such as by connecting syringe assembly <b>10</b> to a separate needle assembly (not shown), or alternatively for connection with an intravenous (IV) connection assembly.

0015Syringe assembly <b>10</b> includes syringe barrel <b>12</b> defined by barrel wall <b>14</b> extending between a forward or distal end <b>16</b> and a rearward or proximal end <b>18,</b> thereby defining interior chamber <b>20</b> of syringe barrel <b>12.</b> Syringe barrel <b>12</b> may be in the general form of an elongated cylindrical barrel as is known in the art for the general shape of a hypodermic syringe, although other forms for containing a fluid for delivery are also contemplated. Forward end <b>16</b> of syringe barrel <b>12</b> includes an outlet opening <b>22,</b> and rearward end <b>18</b> is generally open-ended, but is intended to be closed off to the external environment, as will be discussed in more detail herein. Syringe barrel <b>12</b> may include markings, such as graduations <b>26</b> on the wall thereof, for providing an indication as to the level or amount of fluid contained within syringe barrel <b>12.</b> Such markings may be provided on the external wall, the internal wall, or integrally formed or otherwise within the wall of syringe barrel <b>12.</b> Alternatively, or in addition thereto, the markings may provide a description of the contents of the syringe, or other identifying information, as may be known in the art.

0016As noted, forward end <b>16</b> of syringe barrel <b>12</b> includes an outlet opening <b>22.</b> The profile of outlet opening <b>22</b> may be adapted for engagement with a separate device, such as a needle assembly or IV connection assembly, and therefore may include a mechanism for such engagement, for example, a generally tapered luer tip <b>28,</b> for engagement with a separate tapered luer mating surface (not shown) of such a separate device for attachment therewith. In addition, a mechanism for locking engagement therebetween may also be provided, such as luer lock <b>30</b> including interior threads <b>32.</b> Such luer connections and luer locking mechanisms are well known in the art. Additionally, syringe barrel <b>12</b> includes at least one opening through the wall thereof extending into the interior chamber <b>20</b> adjacent forward end <b>16,</b> such as vent <b>34,</b> the use of which will be described in further detail herein.

0017Syringe assembly <b>10</b> further includes a plunger assembly <b>40,</b> a portion of which is disposed at least partially within syringe barrel <b>12.</b> Plunger assembly <b>40</b> provides a mechanism for dispensing fluid contained within the interior chamber <b>20</b> of syringe barrel <b>12.</b> In particular, plunger assembly <b>40</b> includes a plunger head or stopper portion <b>50</b> disposed within interior chamber <b>20,</b> and in contact with the internal surface of syringe barrel wall <b>14,</b> thereby separating interior chamber <b>20</b> into a proximal chamber <b>20a</b> adjacent proximal or rearward end <b>18,</b> and a distal chamber <b>20b</b> adjacent distal or forward end <b>16</b> of syringe barrel <b>12.</b> Plunger head <b>50</b> may include one or more annular ribs extending about the outside perimeter thereof, such as rib <b>52,</b> for providing sealing engagement with the interior surface of syringe barrel wall <b>14.</b>

0018Plunger head <b>50</b> is adapted for movement within the interior chamber <b>20</b> of syringe barrel <b>12,</b> with plunger head <b>50</b> sliding or riding along the interior surface of syringe barrel wall <b>14.</b> Such movement may be effected by a separate actuator portion of plunger assembly <b>40</b> which at least partially extends externally outside of syringe barrel <b>12.</b> An actuator in the form of a perimetrical flange collar <b>48</b> including finger flanges <b>48a</b> and <b>48b</b> may extend external to syringe barrel <b>12,</b> for example, along the external surface of syringe barrel wall <b>14,</b> and is interconnected with plunger head <b>50,</b> such as directly through an opening or channel through wall <b>14,</b> through an assembly which extends through generally open-ended rearward end <b>18</b> of syringe barrel <b>12,</b> or through a further interconnection. While the actuator is shown as a flange collar <b>48</b> including a pair of finger flanges <b>48a, 48b,</b> it is contemplated that any number of finger flanges may be present.

0019In one embodiment as depicted in <figref idref="f0001 f0002"><b>FIGS. 1A-1D</b></figref><b>,</b> plunger assembly <b>40</b> includes a plunger rod <b>42</b> for connecting plunger head <b>50</b> with external flange collar <b>48</b> and finger flanges <b>48a</b> and <b>48b.</b> Plunger rod <b>42</b> and plunger head <b>50</b> may be integrally formed, or may be separate elements that are attached or otherwise interconnected together. For example, plunger rod <b>42</b> may be constructed of a stiff polymeric material, with plunger head <b>50</b> formed from a separate silicone or rubberized material that is molded integrally with plunger rod <b>42,</b> such as through a two-shot molding process, or may be a separate material that is mechanically attached or adhesively fixed to plunger rod <b>42.</b>

0020Various assemblies are contemplated for interconnecting actuator portion of plunger assembly <b>40</b> with plunger head <b>50</b> through open rearward end <b>18</b> of syringe barrel <b>12.</b> For example, plunger rod <b>42</b> of plunger assembly <b>40</b> may include a first elongated portion that is connected with plunger head <b>50</b> and that extends within the interior <b>20</b> of syringe barrel <b>12</b> and out through open rearward end <b>18</b> of syringe barrel <b>12.</b> As shown in <figref idref="f0002"><b>FIG. 1D</b></figref><b>,</b> plunger assembly <b>40</b> may further include an external arm <b>44</b> extending externally along syringe barrel <b>12</b> for connection with flange collar <b>48</b> and finger flanges <b>48a</b> and <b>48b,</b> and with connecting arm <b>46</b> interconnecting internal plunger rod <b>42</b> and external arm <b>44.</b> In this manner, finger flanges <b>48a, 48b</b> are interconnected with plunger head <b>50</b> through the open rearward end <b>18</b> of syringe barrel <b>12</b> by way of external arm <b>44,</b> connecting arm <b>46,</b> and internal plunger rod <b>42,</b> respectively.

0021As noted, rearward end <b>18</b> of syringe barrel <b>12</b> is open-ended. Syringe assembly <b>10</b> may further be provided with a closure, such as cap <b>60,</b> for closing the open rearward end <b>18</b> of syringe barrel <b>12,</b> thereby providing interior chamber <b>20</b> as a closed chamber. Cap <b>60</b> includes an elongated portion in the form of neck <b>62</b> that has an outer diameter substantially the same as an inner diameter of syringe wall <b>14,</b> so as to provide an interference fit therein, thereby holding cap <b>60</b> in place. Cap <b>60</b> may be fixedly adhered in place, such as through a mechanical engagement, a biocompatible adhesive, sonic welding, etc. Cap <b>60</b> includes a finger pad portion <b>64</b> that extends external to syringe barrel <b>12,</b> which may be provided with finger ribs <b>66</b> for providing a tactile surface for a user. Cap <b>60</b> may also include an angled profile <b>68</b> on the end of neck <b>62</b> extending within syringe barrel <b>12,</b> providing a recessed area adjacent proximal end <b>18</b> of syringe barrel <b>12</b> for accommodating the outflow of fluid, as will be described in more detail herein. Plunger head <b>50</b> may also include an angled profile <b>54</b> at a proximal end thereof for cooperating engagement with angled profile <b>68</b> of cap <b>60</b> upon full displacement of plunger head <b>50</b> within interior chamber <b>20,</b> as will be described in further detail.

0022Syringe assembly <b>10</b> further includes a conduit <b>70</b> extending between a first end <b>72</b> positioned adjacent forward end <b>16</b> of syringe barrel <b>12,</b> and a second end <b>74</b> positioned adjacent rearward end <b>18</b> of syringe barrel <b>12,</b> with fluid channel <b>76</b> extending therethrough. Conduit <b>70</b> extends across plunger head <b>50,</b> with first end <b>72</b> of conduit <b>70</b> extending within or through forward opening <b>22</b> of syringe barrel <b>12,</b> providing for fluid communication with forward opening <b>22,</b> and with second end <b>74</b> of conduit <b>70</b> extending within proximal chamber <b>20a,</b> such that fluid channel <b>76</b> is in fluid communication with proximal chamber <b>20a.</b> Second end <b>74</b> of conduit <b>70</b> may be positioned within the recess at proximal end <b>18</b> created by the angled profile <b>68</b> of cap <b>60.</b> In this manner, the rearward-most or proximal-most portion of proximal chamber <b>20a</b> is established by the recess of angled profile <b>68,</b> with an inlet into conduit <b>70</b> provided at second end <b>74</b> being positioned in this proximal-most portion of proximal chamber <b>20a.</b> This positioning is particularly useful for removing any air trapped within proximal chamber <b>20a</b> prior to expelling any drug therefrom, as will be described in more detail with respect to the use of syringe assembly <b>10.</b>

0023All of the components of syringe assembly <b>10</b> may be constructed of any known material, and are desirably constructed of medical grade polymers.

0024Syringe assembly <b>10</b> is particularly useful as a pre-filled syringe, and therefore may be provided for end use with a fluid, such as a medication, contained within proximal chamber <b>20a</b> of syringe barrel <b>12,</b> pre-filled by the manufacturer. In this manner, syringe assembly <b>10</b> can be manufactured, pre-filled with a medication, sterilized, and packaged in appropriate packaging for delivery, storage, and use by the end user, without the need for the end user to fill the syringe with medication from a separate vial prior to use.

0025In use, syringe assembly <b>10</b> is provided with a medication pre-filled and contained within proximal chamber <b>20a</b> of syringe barrel <b>12.</b> For use, syringe assembly <b>10</b> is grasped with the user's thumb on finger pad <b>64</b> and with the user's fingers extending between finger flanges <b>48a</b> and <b>48b</b> of flange collar <b>48.</b> In this manner, syringe assembly <b>10</b> is grasped by the user in a well known and well recognized manner similar to the operation of a conventional hypodermic syringe.

0026Prior to dispensing of medication, any air trapped within proximal chamber <b>20a</b> can be expelled by arranging syringe assembly <b>10</b> with the forward end <b>16</b> pointed downward, such that any air within proximal chamber <b>20a</b> will be forced toward rearward end <b>18</b> at the recessed area established by the angled profile <b>68</b> of cap <b>60.</b> With second end <b>74</b> of conduit <b>70</b> positioned within this recess adjacent angled profile <b>68,</b> initial movement of plunger assembly <b>40,</b> by sliding movement of plunger head <b>50,</b> will cause any such air trapped within proximal chamber <b>20a</b> at the recess of angled profile <b>68</b> to be expelled through second end <b>74,</b> into conduit <b>70</b> and out first end <b>72</b> into outlet opening <b>22</b> out from syringe barrel <b>12</b> prior to any medication being expelled.

0027The user can attach luer tip <b>28</b> to a separate needle assembly or IV connection assembly and lockingly engage through threads <b>32</b> of luer lock <b>30</b> in a known manner. When it is desired to deliver the medication, the user effects a squeezing movement between the thumb and forefingers as shown in <figref idref="f0003"><b>FIG. 2</b></figref><b>,</b> thereby causing finger flanges <b>48a, 48b</b> and flange collar <b>48</b> to move in the direction of arrow <b>A</b> away from distal or forward end <b>16</b> and toward proximal or rearward end <b>18.</b> Such movement of finger flanges <b>48a, 48b</b> and flange collar <b>48</b> is transferred to plunger head <b>50</b> through the interconnection of internal plunger rod <b>42,</b> external arm <b>44,</b> and connecting arm <b>46</b> that interconnects plunger head <b>50</b> with flange collar <b>48.</b> Such movement of plunger head <b>50</b> within interior chamber <b>20</b> of syringe barrel <b>12</b> reduces the volume of proximal chamber <b>20a,</b> thereby creating a positive pressure therein. In order to prevent a negative pressure within distal chamber <b>20b,</b> air can be drawn into distal chamber <b>20b</b> through vent <b>34,</b> which provides a mechanism for air flow between distal chamber <b>20b</b> and the external environment.

0028Since proximal chamber <b>20a</b> is sealed to the external environment through plunger head <b>50</b> and through cap <b>60</b> at a rearward opening <b>24,</b> the medication fluid within proximal chamber <b>20a</b> is forced into fluid channel <b>76</b> at second end <b>74</b> of fluid conduit <b>70.</b> Such fluid medication travels through fluid channel <b>76</b> and out through first end <b>72</b> of conduit <b>70,</b> entering into forward opening <b>22.</b> In this manner, the fluid medication can be expelled from the syringe barrel <b>12</b> through forward opening <b>22,</b> and into the separate needle assembly or IV assembly and into the patient.

0029Upon full movement of plunger head <b>50</b> through syringe barrel <b>12,</b> plunger head <b>50</b> "bottoms out", with plunger head <b>50</b> contacting the internal end of cap <b>60,</b> as shown in <figref idref="f0004"><b>FIGS. 3</b></figref> and <figref idref="f0005"><b>4A</b></figref><b>-4D,</b> with the corresponding angled profiles <b>54, 68</b> of plunger head <b>50</b> and cap <b>60,</b> respectively, in corresponding engagement. The second end of conduit <b>74</b> is arranged within proximal chamber <b>20a</b> at a position adjacent the portion of the angled profile <b>68</b> of cap <b>60</b> that is closest to proximal or rearward end <b>18.</b> In this manner, the fluid medication is funneled toward first end <b>72</b> of conduit <b>70,</b> and the internal volume of proximal chamber <b>20a</b> remains filled with fluid medication through the entire sliding movement of plunger head <b>50</b> through syringe barrel <b>12.</b> At this point, plunger rod <b>42,</b> external arm <b>44,</b> and connecting arm <b>46</b> all extend substantially externally of syringe barrel <b>12.</b>

0030With such an arrangement, the overall size and shape of syringe assembly <b>10</b> when filled for use is of an overall profile similar to a conventional syringe after use, with a plunger completely extended within a syringe barrel, as seen in <figref idref="f0017"><b>FIG. 13</b></figref><b>,</b> which depicts the profile of a conventional syringe <b>1</b> in comparison to syringe assembly <b>10</b> in accordance with an embodiment of the present invention. As such, the profile is significantly reduced from that of a conventional pre-filled syringe, which includes the plunger retracted from the barrel prior to use.

0031<figref idref="f0007 f0008"><b>FIGS. 5A-5C</b></figref> and <b>6A-6C</b> depict syringe assembly <b>10</b> in an alternate embodiment that is substantially the same as that described above with respect to <figref idref="f0001 f0002 f0003 f0004 f0005 f0006"><b>FIGS. 1A-4D</b></figref><b>,</b> but further including a mechanism for preventing exposure to the syringe contents and for preventing contamination. In particular, during the injection and syringe discharge sequence as described above, the plunger rod <b>42</b> is retracted from within the syringe barrel <b>12.</b> Prior to such retraction, the plunger rod <b>42</b> is in direct contact with the fluid contained within the proximal chamber <b>20a</b> of syringe barrel <b>12.</b> In order to prevent the user from being exposed to the contents of the syringe during the retraction of the plunger rod <b>42</b> based on the plunger rod <b>42</b> being "wetted" with such fluid, a barrier, such as an expandable bellows <b>80,</b> can be provided. Bellows <b>80</b> can encompass the portion of plunger rod <b>42</b> that extends external to syringe barrel <b>12</b> during retraction. As such, bellows <b>80</b> encompasses and wraps around the externally exposed portion of plunger rod <b>42,</b> and is adapted to expand upon retraction of plunger rod <b>42.</b> For example, bellows <b>80</b> may be of an accordion-style construction, interconnected between an end of plunger rod <b>42</b> adjacent connecting arm <b>46</b> and extending to cap <b>60</b> at a location where plunger rod <b>42</b> extends through cap <b>60.</b> When syringe assembly <b>10</b> is in a pre-filled state prior to use with plunger rod <b>42</b> extending within syringe barrel <b>12,</b> bellows <b>80</b> is at least partially, and likely fully, collapsed, as shown in <figref idref="f0007 f0008"><b>FIGS. 5A-5C</b></figref><b>.</b> When plunger rod <b>42</b> is retracted to the exterior upon movement of finger flanges <b>48a, 48b,</b> bellows <b>80</b> expands to encompass and maintain plunger rod <b>42</b> in a sealed environment. As such, any fluid in contact with plunger rod <b>42</b> is maintained within bellows <b>80</b> and is prevented from contacting the user. Moreover, if the user pushes the plunger rod <b>42</b> back into syringe barrel <b>12</b> during or after use, sterility is maintained within the syringe barrel <b>12,</b> since bellows <b>80</b> prevents plunger rod <b>42</b> from contacting the external environment.

0032<figref idref="f0011 f0012"><b>FIGS. 7A-7D</b></figref> and <b>8A-8D</b> depict a syringe assembly in a further embodiment similar to that described above in the embodiments of <figref idref="f0001 f0002 f0003 f0004 f0005 f0006"><b>FIGS. 1A-4C</b></figref><b>,</b> but with a different arrangement for the conduit. In particular, in the embodiment of <figref idref="f0011 f0012"><b>FIGS. 7A-7D</b></figref> and <b>8A-8D,</b> conduit <b>170</b> is provided as an expandable or extendable member adapted for movement with plunger head <b>50.</b> Conduit <b>170</b> is similar to conduit <b>70</b> described above, including an internal fluid channel extending between a first end <b>172</b> and a second end <b>174,</b> and across plunger head <b>50,</b> with first end <b>172</b> positioned adjacent forward end <b>16</b> of syringe barrel <b>12.</b> In this embodiment, however, the second end <b>174</b> of conduit <b>170</b> extends across plunger head <b>50</b> and into proximal chamber <b>20a</b> at a position directly adjacent the rearward or proximal end of plunger head <b>50,</b> with second end <b>174</b> fixed with plunger head <b>50.</b> As such, the fluid channel extending through conduit <b>170</b> is in fluid communication with proximal chamber <b>20a</b> directly at the area of contact between plunger head <b>50</b> and proximal chamber <b>20a</b> when syringe assembly <b>10</b> is in a pre-filled state prior to use, as opposed to extending entirely through syringe barrel <b>12</b> to rearward end <b>18</b> prior to use as in the prior embodiments. Furthermore, in the embodiment of <figref idref="f0011 f0012"><b>FIGS. 7A-7D</b></figref> and <b>8A-8D,</b> conduit <b>170</b> is extendable, such that when plunger head <b>50</b> slides or moves along syringe wall <b>14</b> within syringe barrel <b>12,</b> the second end <b>174</b> of conduit <b>170</b> moves with plunger head <b>50.</b> This may be accomplished, for example, by providing conduit <b>170</b> as a flexible tubing that can be contained within distal chamber <b>20b</b> prior to use of syringe assembly <b>10</b> and extended during use, or as a wound coil that can be extended during use, or other manner.

0033Operation of syringe assembly <b>10</b> depicted in the embodiment of <figref idref="f0011 f0012"><b>FIGS. 7A-7D</b></figref> and <b>8A-8D</b> is similar to that of the prior described embodiments. It is noted, however, that in the embodiment of <figref idref="f0011 f0012"><b>FIGS. 7A-7D</b></figref> and <b>8A-8D,</b> syringe assembly <b>10</b> does not have to be arranged with the forward end <b>16</b> pointed downward in order to first expel any trapped air from within the syringe, but instead can be arranged with the forward end <b>16</b> pointed upward, as in a more conventional syringe operation, since the initial point of fluid flow out of proximal chamber <b>20a</b> occurs directly at the interface of plunger head <b>50</b> within proximal chamber <b>20a</b> in this embodiment. To expel medication, plunger assembly <b>40</b> is actuated as in the prior embodiment, upon movement of flange collar <b>48</b> through finger flanges <b>48a, 48b</b> to cause movement of plunger assembly <b>40,</b> thus causing fluid to flow from within proximal chamber <b>20a</b> into the fluid channel of conduit <b>170</b> directly at second end <b>174</b> and out first end <b>172.</b>

0034<figref idref="f0015"><b>FIGS. 9</b> and <b>10</b></figref> depict yet a further embodiment of a syringe assembly in accordance with the present invention. Syringe assembly <b>10</b> of <figref idref="f0015"><b>FIGS. 9-10</b></figref> includes similar components as that of the previously described embodiments of <figref idref="f0001 f0002 f0003 f0004 f0005 f0006"><b>FIGS. 1A-4D</b></figref><b>,</b> but with conduit <b>70</b> extending radially centered with respect to the general elongated axis of syringe assembly <b>10.</b>

0035In a further embodiment, it is contemplated that a controlled dosing system could be provided. For example, an external surface of the syringe barrel <b>12</b> may be provided with notches or protrusions along the graduations of the syringe barrel <b>12</b> at predetermined increments, such as at each 1 ml increment. A further protrusion or flap would also be provided on the flange collar <b>48,</b> such as a flap extending around at least a portion of the internal perimeter of flange collar <b>48.</b> As flange collar <b>48</b> rides along the outer surface of syringe barrel <b>12</b> toward the rearward end <b>18</b> during delivery of the medication, the flap on the flange collar <b>48</b> would contact and interfere with each successive notch or protrusion on the syringe barrel <b>12,</b> thereby providing an audible or tactile indication to the user of each predetermined dosage increment. In this manner, the user could hear or feel when each volume of dosage is delivered in specific increments.

0036<figref idref="f0016"><b>FIGS. 11</b> and <b>12</b></figref> depict an alternate embodiment of a syringe assembly in accordance with the present invention. This alternate embodiment depicted in <figref idref="f0016"><b>FIGS. 11</b> and <b>12</b></figref> repositions the outlet end of the syringe assembly at the retraction end of the plunger rod. More particularly, syringe assembly <b>200</b> includes a syringe barrel <b>212</b> having a wall <b>214</b> extending between first end <b>216</b> and second end <b>218,</b> forming an interior chamber <b>220</b> therein. First end <b>216</b> includes an opening <b>222,</b> including a luer tip <b>228,</b> which may be offset from the central axis of syringe assembly <b>200.</b> Vent <b>238</b> is positioned adjacent second end <b>218.</b>

0037Syringe assembly <b>200</b> further includes plunger assembly <b>240</b> including plunger rod <b>242</b> connected with plunger head <b>250.</b> Plunger head <b>250</b> separates interior <b>220</b> of syringe barrel <b>212</b> into two distinct chambers, namely, first chamber <b>220a</b> and second chamber <b>220b.</b> Plunger rod <b>242</b> extends within interior <b>220</b> of syringe barrel <b>212</b> and out to the external environment through first end <b>216.</b>

0038With such an arrangement, syringe assembly <b>200</b> works as follows. Fluid such as medication is contained within first chamber <b>220a</b> of syringe barrel <b>212.</b> To expel the medication, plunger assembly <b>240</b> is activated by pulling on plunger rod <b>242,</b> thereby causing plunger head <b>250</b> to slide within syringe barrel <b>212.</b> Medication is forced out through opening <b>222</b> at first end <b>216</b> of syringe barrel <b>212,</b> which is in fluid communication with first chamber <b>220a.</b> Vent <b>238</b> prevents negative pressure within second chamber <b>220b.</b> In this manner, medication can be expelled and delivered through luer tip <b>228.</b> Such an embodiment is similar to the prior discussed embodiments, albeit with the syringe opening <b>222</b> arranged in an opposite end of the assembly.

0039In each of the embodiments provided herein, the overall profile and dimensions of a syringe assembly when filled with a fluid such as medication prior to use is significantly reduced when compared with a traditional syringe. This reduced profile is accomplished by maintaining a significant portion of the plunger rod that is used for extending the stopper or plunger head within the syringe barrel when the syringe assembly is filled for use. Thus, the plunger rod occupies little space prior to use, thereby reducing packaging and eliminating waste. For disposal, the clinician has the option to push the plunger rod to its starting position to reduce the overall profile for disposal, such as in a sharps disposal container, thereby reducing the amount of storage space required for disposal.

0040In addition, certain embodiments involve a conventional operation for use of the syringe assembly to expel medication. For example, the tactile surfaces of the syringe assembly of the present invention include finger flanges and thumb presses situated for accommodating a user's fingers and thumb in a similar manner as with conventional syringes, such that a conventional squeezing movement expels the medication, albeit with a different arrangement within the syringe assembly causing an inverse movement of the fluids therein. As such, the user perceives no change in operation or use to dispense the medication even with the decreased overall profile of the assembly.