Abstract
A dual-chamber syringe system is disclosed. Critical system oriented elements are disclosed, including plunger valve designs for accurate measurement and true, non-canting displacement; tamper and inadvertent valve actuation indicators, as well as, valve status indicators; anti-reflux construction; novel indicia patterns for dual-chamber syringe operation; structure and method for quality assurance that no gas can be delivered from a proximal chamber of the dual-chamber syringe and a kit for single step dose transfer. In addition, a tapered fitting valve is disclosed. The tapered fitting valve comprises a single molded incompressible, but supple part and a skeletal support whereby the tapered fitting valve is opened by insertion into a tapered fitting. The preferred embodiment of an actuator portion of the valve is elliptical in shape. The valve opens by compressing a slit which is parallel to, but offset from the major elliptical axis to provide sufficient space for other valve components within a limited size, such as that of a luer fitting. A syringe barrel comprising a skeletal support structure for an affixed valve for a tapered fitting is also disclosed.
Claims
1. A dual-chamber syringe system comprising: a dual-chamber syringe comprising a medical syringe having a conventional hollow syringe barrel which comprises a hollow, substantially constant diameter inner wall, a distal end at which a distal chamber is filled and a proximal end which comprises a flanged opening sized and shaped for plunger introduction; said syringe also comprising a plunger rod and associated plunger tip which is disposed within said barrel for the purpose of displacing fluid therein; said dual-chamber syringe further comprising a plunger valve which is disposed to divide said barrel into two disparate chambers, a distal chamber which is disposed between said plunger valve and said distal end and a proximal chamber which is disposed between said plunger valve and said plunger tip, said proximal chamber being pre-filled with fluid which is dispensed only upon completion of a dispensing cycle of fluid from the distal chamber and said plunger valve being displaced only by force of fluid communicating with said plunger rod and associated plunger tip; said plunger valve comprising a valve plunger comprising an interfacing cylindrical outer wall which compressively wipes against said barrel inner wall to maintain disparity between the distal and proximal chambers and a fluid pathway tube between the proximal and distal chambers which is closed until fluid within the distal chamber is fully dispensed and further comprising integral structure disposed about said tube to compressively interface with said barrel inner wall to assure no fluid flow between said inner wall and said cylindrical outer wall and to keep said valve plunger from canting when displaced by only the liquid communication within said barrel thereby assuring maintenance of disparity between chambers when said plunger valve is closed and accuracy of measurement when said plunger valve is displaced and visually monitored for volume measurement; said system comprising a visible indicator for valve and system readiness status for the purpose of avoiding use after inappropriate system handling due to a group of causes comprising tampering and inadvertent premature valve actuation; said dual-chamber syringe further comprising a stop actuated at the end of a proximal chamber dispensing cycle which is effective in producing no refluxive flow; and wherein the syringe barrel includes a pattern of indicia provided on a surface thereof, the indicia comprising first and second sets of indicia overlapping and offset to clearly communicate volumetric measurement status for each distal and proximal chamber dispensing cycles, whereby the first indicia begins at the distal end of the syringe to correspond to a volume of fluid retained within the distal chamber and the second indicia begins a distance offset from the distal end corresponding to the size of the valve plunger in order to correspond to the volume of fluid retained within the proximal chamber.
2. A dual-chamber syringe system according to claim 1 wherein said plunger valve comprises a displaceable valve stem comprising a distal footing which is visible only when said plunger valve is closed to provide a closed valve indicator and a proximal plunger valve stem section which is visible only when the valve is opened to provide an indicator of an open valve thereby providing said visible indicator.
3. A dual-chamber syringe system according to claim 2 wherein said system comprises a removable sleeve affixed to said plunger rod to retard said rod from fully being displaced into said barrel and thereby impede premature displacement of said stem and resultant actuation of said plunger valve.
4. A dual-chamber syringe system according to claim 1 wherein said proximal chamber fluid comprises a liquid and a predetermined maximum volume of air which is not dispensed and said plunger valve pathway comprises an extended tube into a liquid only zone whereby only liquid is dispensed from the proximal chamber.
5. A dual-chamber syringe system according to claim 1 wherein said plunger rod comprises a shoulder disposed to provide a hard stop upon impact against said flanged opening to thereby deter refluxive flow at the end of a proximal chamber dispensing cycle.
6. A dual-chamber syringe system according to claim 1 comprising an additional measurement indicia patterned for measurement by a single displacing element.
7. A dual-chamber syringe system according to claim 6 wherein the displacing element is said plunger rod which comprises a pattern of indicia disposed thereon.
8. A dual-chamber syringe system according to claim 1 wherein said integral structure comprises solid wall construction perforated by at lest one of dead-ended hole, thereby providing space for collection of gas about said tube while providing support structure for said cylindrical outer wall.
9. A dual-chamber syringe system kit according to claim 1 further comprising a female luer syringe containing fluid to be drawn into said dual-chamber syringe, said dual-chamber syringe barrel comprising a male luer syringe such that fluid transfer is accomplished by a single male to female luer fitting connection.
10. A dual-chamber syringe system according to claim 1 wherein said barrel comprises a skeletal support for a tapered fitting valve.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is an exploded perspective of a presently preferred embodiment of a dual-chamber syringe made according to the instant invention.
(2) FIG. 2 is a magnified side elevation of a valve stem made according to the instant invention.
(3) FIG. 3 is a perspective of a valve plunger when disposed in a dual-chamber syringe.
(4) FIG. 3A is a perspective of a valve plunger, similar to the valve plunger seen in FIG. 3, but comprising a different hollow interior.
(5) FIG. 4 is a perspective of a valve stem disposed in a valve plunger such that a pathway in which the stem is disposed is closed to fluid flow.
(6) FIG. 5 is a perspective to the valve stem and plunger seen in FIG. 2 with the valve stem displaced to open the pathway to fluid flow.
(7) FIG. 6 is a cross section of an assembled dual-chamber syringe wherein a plunger valve divides a syringe barrel into two disparate chambers, both chambers being filled with liquid.
(8) FIG. 7 is a cross section of a dual-chamber syringe similar to the syringe seen in FIG. 6 but rotated to provide a measurement of gas residing in the proximal chamber.
(9) FIG. 8 is a cross section of the dual-chamber syringe seen in FIG. 7 syringe inverted to continue dispensing liquid from the distal chamber.
(10) FIG. 9 is a cross section of the dual-chamber syringe seen in FIG. 8 with a distal portion of a stem impacting an inner surface of the barrel of the associated syringe.
(11) FIG. 10 is a cross section of the dual-chamber syringe seen in FIG. 9 with the stem displaced such that the proximal portion of the stem is visible, such viability indicating actuation of the valve plunger to an open state.
(12) FIG. 11 is a cross section of the dual-chamber syringe seen in FIG. 10 at the end of a proximal chamber dispensing cycle with further displacement of a plunger rod being impeded by collision of shoulders of the plunger rod with proximal portions of the syringe barrel.
(13) FIG. 12 is a side elevation of a syringe barrel for a dual-chamber syringe showing a pattern of indicia disposed on the outer surface of the barrel.
(14) FIG. 13 is a side elevation of a syringe barrel, similar to the barrel of FIG. 12, but comprising an alternate indicia pattern.
(15) FIG. 13A is a side elevation of a syringe barrel and associated plunger rod and plunger tip comprising indicia disposed on the plunger rod.
(16) FIG. 13B is a side elevation of a syringe barrel and plunger rod, similar to FIG. 13A, but with a pattern of indicia proximally disposed on the syringe barrel.
(17) FIG. 13C is a side elevation of a syringe barrel and plunger rod showing an indicia pattern which is similar to the pattern of FIG. 13B, but specifically designed for flush and dose volumes different than those seen in FIG. 13B.
(18) FIG. 13D is a side elevation of the syringe barrel and plunger rod seen in FIG. 13C with a plunger valve and associated plunger rod tip displaced to empty a distal chamber.
(19) FIG. 13E is a side elevation of the syringe barrel and plunger rod seen in FIG. 13D with the plunger valve and plunger rod tip displaced to complete dispensing from a proximal chamber of the dual-chamber syringe.
(20) FIG. 13F is a side elevation of a dual-chamber syringe similar to the syringes seen in FIGS. 13A-E, but with another indicia pattern.
(21) FIG. 14 is a perspective of a valve for a tapered fitting with a medically disposed slit.
(22) FIG. 15 is a perspective of a valve similar to the valve seen in FIG. 14, but with a slit offset from a medial line (major axis of an ellipse).
(23) FIG. 16 is a perspective of the valve seen in FIG. 15 with three intersecting planes disposed at the distal face, medial section and proximal face of the valve, respectively.
(24) FIG. 17 is a cross section of the valve seen in FIG. 15 rotated to show disposition of an offset valve slit and a cavity disposed in a proximal portion of the valve.
(25) FIG. 17A is a cross section of the proximal end of the valve.
(26) FIG. 18 is a cross section of the proximal face of the valve seen in FIG. 17.
(27) FIG. 19 is a cross section at a medial plane, seen in FIG. 16, of the valve seen in FIG. 17.
(28) FIG. 20 is a cross section at a proximal plane, seen in FIG. 16, of the valve seen in FIG. 17.
(29) FIG. 21 is a cross section of the elliptically shaped valve seen in FIG. 18 compressed to a circular shape.
(30) FIG. 22 is a cross section of the elliptically shaped valve seen in FIG. 19 compressed to a circular shape.
(31) FIG. 23 is a cross section of the elliptically shaped valve seen in FIG. 20 compressed to a circular shape.
(32) FIG. 24 is a cross section of the valve seen in FIG. 17, rotated 90 degrees with a section taken in the plane of the slit and a skeletal support, seen in FIG. 26 disposed to provide a brace for the valve.
(33) FIG. 25 is a cross section of a skeletal support for the valve seen in FIG. 17.
(34) FIG. 26 is a cross section of the skeletal support seen in FIG. 17, but rotated 90 degrees.
(35) FIG. 27 is a frontal elevation of the skeletal support seen in FIG. 25.
(36) FIG. 28 is a cross section of a male adapter device comprising a valve for a female tapered luer fitting.
(37) FIG. 29 is a cross section of the male adapter device seen in FIG. 28, rotated 90 degrees.
(38) FIG. 30 is an exploded view of parts for a dual-chamber syringe having a barrel which is structured to employ a valve for a tapered luer fitting.
(39) FIG. 31 is an exploded view of the parts seen in FIG. 30 with a valve affixed to provide a male luer fitting for the dual-chamber syringe.
(40) FIG. 32 is a cross section of a fully assembled dual-chamber syringe with barrel affixed with the valve and compression ring.
(41) FIG. 33 is a magnified copy of the circled portion of the barrel seen in FIG. 30.
(42) FIG. 34 is a magnified copy of the circled portion of the barrel seen in FIG. 31.
(43) FIG. 35 is a magnified copy of the circled portion of the barrel seen in FIG. 32.
(44) FIG. 36 is a perspective of a combination of a dual-chamber syringe and a female fitting syringe.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
(45) While the instant inventions disclosed herein are applicable to a wide variety of dual-chamber syringe applications and a number of tapered male/female insertion type fluid connectors, the detailed description provided herein is focused upon examples of medical devices. In this description, the term proximal is used to indicate that segment of a device which is a closest part to an object of reference. The term distal refers to an opposite orientation. Reference is now made to the embodiments illustrated in FIGS. 1-36 wherein like numerals are used to designate like parts throughout and primes of numbers generally indicate parts which are similar in shape and/or function of those numbers, but not exactly the same.
(46) An Exemplary System
(47) Seen in FIG. 1 is an exploded view of parts which can be used to assemble a version of a dual-chamber syringe system 10, the parts being part of a system used to prepare and deliver medical preparations followed by a flushing liquid in a medical environment. While similar to art cited in the Continuity section provided supra, all but one of the parts, a plunger rod tip 20, has added novelty required for system's applications for dual-chamber syringes.
(48) In addition to plunger rod tip 20, dual-chamber syringe system 10 comprises a rear plunger rod 30 used to directly displace tip 20 and an associated plunger rod sleeve 32, a plunger 40 which is part of a normally closed valve, an actuating stem 50 which is disposed within a valved pathway of plunger 40 to form a plunger valve 70 and displaced to open a fluid pathway within plunger 40 thereby providing a normally closed valve, and a conventional syringe barrel 60. Barrel 60 comprises a male luer lock fitting 62 for drawing and dispensing fluid. Application and need for sleeve 32 is fully disclosed hereafter.
(49) A Pre-Filled System
(50) An assembled dual-chamber syringe system 10 is seen in FIG. 8. Actuating stem 50 is displaced into plunger 40 to form plunger valve 70. A chamber 80 disposed between plunger valve (valve) 70 and plunger rod tip 20 contains a fluid 84 and is anticipated to comprise both a liquid 84 and a gas 86. It is preferred that chamber 80 be pre-filled by a manufacturer before delivery to a site of use. As is well known in medical syringe use art, unless otherwise prescribed, only liquid should be dispensed from chamber 80 with all gas remaining resident in chamber 80 at the end of a chamber 80 dispensing cycle.
(51) A second chamber 90, disposed between valve 70 and fitting 62, is kept disparate from chamber 80 for sequential fluid delivery by action of valve 70 as disclosed in detail hereafter. Fluid withdrawal and dispensing associated with chamber 80 is conducted by displacing plunger rod 30 in the same manner as fluid is manipulated in a conventional syringe and is performed prior to dispensing liquid from chamber 80.
(52) Displaceable Stem Plunger Valve
(53) A magnified view of stem 50 is seen in FIG. 2. Generally, stem 50 comprises an enlarged footing 94 sized to collide with syringe barrel 50 at a distal dispensing hole without inhibiting flow through the hole and a bulbous central portion 96 which is sized to obstruct the fluid pathway of plunger 40 when disposed therein. Between footing 94 and portion 96, stem 50 comprises a substantially constant diameter, linear extension 98 which leads to a conical segment 99. Bulbous portion 96 is shaped to be retained by compression within the valve plunger 40 pathway until stem displacement and compressive forces act to extricate stem 50 from the pathway. Once that condition occurs, the shape of conical segment 99 is acted upon by the interactive compressive forces associated with barrel 60 and plunger 40 to further expel bulbous portion 96 from the pathway. A channel 102 which is disposed along footing 94, extension 98 and segment 99 provides an open passageway for fluid flow when bulbous portion 96 is outside the pathway.
(54) Stem 50 further comprises a finned section 100 having a plurality of bladed parts which provide for stability within the pathway and a clear fluid path. Length of section 100 is an important dimension as disclosed in detail hereafter.
(55) A magnified image of a proximal side of plunger 40 is seen in FIG. 3. Similar plungers are disclosed in art from which U.S. patent application continues-in-part. However, plunger 40 does not require a separate support ring disposed to provide a brace against canting and other unwanted off-axis displacement, as formerly disclosed in previous art cited supra.
(56) Rather, plunger 40 comprises integral support structure which provides open space for gas capture and yet added rigid support provided for communicating plunger rings against an associated internal syringe barrel wall. Those familiar with syringe fabrication art well understand effect of non-homogeneous surface friction distribution, knowing that a variance in such distribution, if not accounted and corrected for, can cause a plunger, which is displaced only by fluid communication, to cant (be angularly displaced relative to a long axis of a syringe barrel). Such canting can result in either unwanted communication between fluids in otherwise disparate chambers or misreading volumetric measurements made between indicia on barrel 60 and a predetermined measurement edge-site on plunger 40.
(57) Canting Protection
(58) To guard against such canting, plunger 40 comprises a plurality of air-capturing holes, commonly numbered 110 which are closed on a distal side (not shown), surrounded by a support structure 112 constructed to maintain a firm and compressive contact against an associated barrel 60 internal surface. Structure 112 also provides a make-up which maintains integrity of a tube 114 which surrounds and provides an entrance to fluid pathway 116 from a liquid only zone disposed within a fluid fulled chamber of barrel 60. While many different geometries can provide such support, structure which comprises the support structure about hollow cylinders is preferred.
(59) An alternate plunger 40 is seen in FIG. 3A. While it is effective to reduce canting to an acceptable level using support structure 112 (seen in FIG. 3, holes 110 associated with such structure can harbor gas during a filling process. Such a gas refuge can be eliminated with a larger cone-shaped cavity 110 . However, cavity 110 yields a thinned wall 111 near a proximal ring 111. As rings, such as ring 111, are generally oversized relative to an internal surface of a barrel, such as barrel 60 (see FIG. 1), to assure sufficient compression to be fluid tight against the barrel, a variation in size of plunger rings can also be used to reduce canting. As an example, a distal ring 111 of plunger 40 can be oversized by four percent while ring 111 can be oversized by 6 six percent. Such variation in oversizing produces a compressive force in the region of ring 111 which compensates for thinning More details concerning delivery of only liquid from the liquid only zone is provided hereafter.
(60) Valve State, Tamper Evidence Indicators and Premature Valve Actuation Protection
(61) Reference is now made to FIGS. 4 and 5 wherein a stem 50 is disposed to close pathway 116 in FIG. 4 to form a closed state of a plunger valve 70. Note that plunger valve 70 is in an open state in FIG. 5 resulting from displacement of stem 50. Further note that, when plunger valve 70 is in a closed state (FIG. 4), footing 94 is visible outside plunger 40 and section 100 is not seen. When plunger valve 70 is in an open state, stem 50 has sufficient length that section 100 is visible outside plunger 40 and footing 94 is hidden.
(62) Knowledge of the state of plunger valve 70 is critical in determining validity of usefulness of dual-chamber syringe system 10. Display of footing 94, as seen in FIGS. 6-9 provides assuring evidence that no tampering or inadvertent valve actuation has occurred. For when footing 94 is so visible, plunger valve 70 is closed. Such is the case in FIGS. 6-9.
(63) To guard against premature opening of plunger valve 70, a removable sleeve 32, seen in FIGS. 7 and 8, provides a guard when affixed to plunger rod 30. So affixed, a barrier is provided to prevent footing 94 being displaced into contact with barrel inner surface wall 120 resulting in such valve opening. With sleeve 32 in place, plunger rod 30 can be displaced arbitrarily without inadvertent plunger valve 70 displacement to a valve 70 open state. As is seen in FIG. 1, sleeve 32 comprises opposing wings, commonly numbered 122, which are pinched to spread attaching legs, commonly numbered 124, for removal from rod 30. Once sleeve 32 is removed reference for dual-chamber syringe 10 is changed herein to dual-chamber syringe 10. Sleeve 32 can be made by extruding polypropylene.
(64) Other than delinquent tampering, a plunger valve 70 of a dual-chamber syringe system 10 could be inadvertently and improperly triggered to an open state simply by premature displacement of stem 50 against in internal surface wall 120 of barrel 60 after safety sleeve 32 is removed. Displacement for triggering plunger valve 70 is seen in FIGS. 9 and 10. Note that sleeve 32 is no longer affixed to plunger stem 30. Note that such displacement is made evident by disappearance of footing 94, which is seen in FIG. 9, but unseen in FIG. 10. Also, section 100, being clearly visible as in FIG. 10, indicates transition of plunger valve 70 to an open state and is not seen in FIG. 9. Of course, operation of dual-chamber syringe system 10 after premature opening of plunger valve 70 should be avoided and evidence of such is critical.
(65) Proximal Chamber Considerations and Obviation of Gas Delivery
(66) For many purposes a dual-chamber syringe system 10 is delivered from a manufacturer proximal chamber 80 being pre-filled (see FIG. 8). Different from distal chamber 90 of system 10, gas is not easily purged from chamber 80 immediately prior to use. As seen in FIG. 3, valve plunger 40 comprises tube 114 which has an entry orifice 126 set apart a predetermined distance from holes 110. Space within holes 110 and from holes 110 to just short of orifice 126 is provided for accumulating gas which is kept away from orifice 126 by physical material state properties thereby forming a liquid only zone. It is preferred that holes 110 be asymmetrical such that gas is not retained in the holes 110 when vertically oriented with hole 110 orifices open upwards. It should be recognized that only a limited volume of gas can be so retained. For this reason, a quality assurance procedure provides opportunity to confirm gas-free delivery and safety of system 10. As seen in FIG. 7, to perform quality control procedures during manufacturing and before use, a dual-chamber syringe system 10 (or 10) is held upright and the relative level of a liquid/gas interface is determined to be above orifice 126. As seen in FIG. 7, for safety, the gas/liquid interface 140 resides above orifice 126 when system 10 (or 10) is so oriented. It should be noted that holes are but one alternative for providing space for collection of gas. As an example, a shallow cavity which permits the same space as the volume of gas which can be resident in holes 110 can be used within the scope of the invention.
(67) Further, it should be noted that gas within the pathway associated with orifice 126 should be cleared of gas by the filler (e.g. manufacturer) at the time of filling. Due to the liquid only zone, no further consideration need be given to gas resident in the pathway. However, when filling chamber 90, care should be taken to purge gas from all parts of chamber 90 including the distal portion of the pathway associated with orifice 126. Such care is generally performed for purging gas from filled conventional syringes before dispensing.
(68) Filling and Dispensing the Dual-Chamber Syringe
(69) Sleeve 32 should be retained in place while chamber 90 is being filled. Generally, a fluid 142 is drawn into barrel 60 by displacing plunger rod 30 in direction of arrow 144. Once a fluid 94 is resident in chamber 90, sleeve 32 can be removed, as seen in FIG. 6. Dispensing of fluid 94 from chamber 90 is accomplished by displacing plunger rod 30 in direction of arrow 146. As seen in FIG. 9, near the end of chamber 90 dispensing cycle, footing 94 collides with syringe inner surface 120. As footing 94 is further displaced, chamber 90 is fully emptied. As seen in FIG. 10, at the end of a chamber 90 dispensing cycle, footing 94 is no longer visible and section 100 provides an indicator for a plunger valve open state, ready for flushing delivery from chamber 80.
(70) Guard Against Refluxive Flow at the End of a Flushing Cycle
(71) Continued displacement of plunger rod 30 in direction of arrow 146, as seen in FIG. 11, dispenses flushing liquid. It is important to consider the state of system 10 at the end of the flushing cycle. First, it is important to note that the flushing cycle should be terminated before any gas has been dispensed from chamber 80. Of equal concern is that, at the end of a chamber 80 dispensing cycle, any refluxive flow back into system 10 is undesirable. It is common knowledge to those skilled in patient care that such flow can produce an unsafe condition for an interconnected patient (e.g. through a catheter). In system 10, there are two methods for obviating refluxive flow. A first method involves reintroducing bulbous portion 96 into a sealing state within pathway 116. (see FIGS. 4 and 5) by displacing plunger tip 20 against section 100 of stem 50 However, length of stem 50 may not effect reintroduction of portion 96 sufficiently to close plunger valve 70.
(72) A second and preferred method is by providing a hard stop against continued displacement of plunger rod 30 and associated tip 20. It may be noted that gas within chamber 80 at the end of a flushing cycle has a sufficiently high pressure to assure continued dispensing at a moment when displacement of plunger 30 ends. However, if there is any concurrent reflexive action, such as may occur due to resiliency of tip 20 against stem 50 at section 100, dynamics of such reflexive action are generally slower than pressure reduction in gas in chamber 80. As such reflexive action is counter to direction of plunger rod 30 displacement and slower than chamber 80 pressure reduction, the result being a material volumetric displacement which produces refluxive flow.
(73) For this reason, system 10 preferably employs a hard stop. Such a hard stop is provided in system 10 by a collision between a shoulder 150 strategically disposed as an outwardly extending part 151 of plunger rod 30 and a flanged proximal portion 152 of barrel 60, as seen in FIG. 11. Such a hard stop, without reflexive motion has proved to take advantage of pressure resident in gas in chamber 80 to produce a limited amount of dispensing flow at the end of a flushing cycle which would not otherwise occur should there be a reflexive response.
(74) Indicia Alternatives
(75) Volumetric measurement of fluid dispensed from a dual-chamber syringe, such as syringe 10, produces needs for indicia presentation previously not required for single chamber syringes. As may be noted in FIGS. 6 and 9, regions along barrel 60 (of syringe 10) have different starting points and delivery sectors for fluid dispensed from each chamber 80 and 90. For purposes of this discussion, distal chamber 90 shall be considered to be a drug delivery chamber and proximal chamber 80 shall be considered to be a flush delivery chamber. One exemplary pattern of indicia is provided in each FIG. 12 and FIG. 13. A first item to note is that all of the effective measurement indica, generally numbered 200 in FIG. 13, are disposed at a distal end of barrel 60. Referring to FIG. 12, it may be noted that separate measurement lines, identified as 210 and 220, are provided for contents of each chamber 80 (dose fluid) and chamber 90 (flush), respectively. Of necessity, due to sequential delivery of system 10 contents and space required for plunger valve 70 and a gas safety reservoir, indicia scales ( 210 and 220 ) and related numbers are offset and overlapping.
(76) Similarly, there is an overlapping pattern seen in FIG. 13. However, common indicia lines 230 are provided for both drug and flush metering. A separate set of numerical measurement indicators (240 and 250) is provided for differentiating metering of dose and flush, respectively.
(77) An advantage of indicia layout in FIG. 12 is that the two sets of indicia for dose and flush are entirely separate. As such, flush indicia 220 are not required to have a line-to-line correspondence and better use of available barrel 60 space than for the pattern of indicia in FIG. 13, results. A marked advantage of indicia layout in FIG. 13 is the provision for use of common indicia lines. Another consideration one must take into consideration is a likelihood of confusion about indicia used for measurement of drug or flush (i.e. that which is effective during each system 10 dispensing cycle). For this purpose, it is recommended that color differentiation be provided to differentiate dispensing of contents from chambers 80 and 90, as seen in FIG. 12.
(78) Still another consideration for indicia patterns, seen in FIGS. 12 and 13, is that line indicia are not required along the length of barrel 60 as is commonly the case in conventional syringes. Generally the most proximal line along a conventional barrel is also an indicator for limiting proximal displacement of a plunger rod and associated tip. For this purpose, a limit line 260 is provided as seen in each FIGS. 12 and 13. It should be noted that a basic advantage for patterns seen in FIGS. 12 and 13 is that measurement of volumes in each chamber is independent of fluid quantities in the other chamber. However, use of these patterns does require a change of plunger reference when switching from dispensing from one chamber to another.
(79) It is well known that conventional single chamber syringes have a dead space (volume of undeliverable fluid) disposed in the space between the barrel and distal end of the male luer fitting. As such does not exist in a distal chamber of a dual-chamber syringe (due to distal chamber flushing following dispensing from the distal chamber), a correcting offset in an associated indicia pattern is required for delivery of otherwise undispensed fluid.
(80) If it is preferred to measure all dispensed volumes by reference to a single plunger (such as plunger tip 20 (see FIG. 1), indicia seen in FIGS. 13A-13E may be employed. In FIG. 13A, indicia pattern 270 comprises a single linear line of volumetric measurement marks and descriptors 272 and 274 for dose and flush, respectively. It is important to note that for a single linear line of volumetric measurement lines to be used, the linear distance between plunger tip 20 and plunger valve must be of known predetermined length and held constant in all such dual-chamber chamber syringes 10. Such is true for all indicia seen in FIGS. 13B-13D, as well. In the case of measurement being made by displacement of plunger rod 30, measurement is made at the interface between syringe barrel flange 152 and a respective coinciding mark of indicia pattern 270 on stem of rod 30.
(81) As seen in FIGS. 13B-13E, a set of indicia lines 280, comprise a single linear line of marks for both dose and flush. In this case, the distal edge of plunger tip 20 provides the measurement reference line (as is the case for single chamber syringes). Note that dose (282) and flush (284) patterns are reversed on indicia of FIG. 13B compared to indicia of FIG. 13A. Note also that there is a blank region 286 where no indicia is printed. Region 286 represents space for plunger volume and fluid (liquid and gas) residual in chamber 80. Since plunger tip 20 is restricted from further displacement by contact of shoulder 150 with flange 152 (see FIG. 13E) no volumetric measurement is required in region 286.
(82) Dispensing steps are seen in sequence in FIGS. 13B to FIG. 13E. A syringe 10 comprises filled chambers 80 and 90 for a twenty ml dose in FIG. 13C and a 10 ml dose in FIG. 13C. No markings denoting fluid (gas or liquid) content in barrel 60 is provided to guard against confusion with indicia marks. In FIG. 13D, all dose, except that contained in dead space in the throat 290 of barrel 60, is dispensed. In FIG. 13E, liquid in chamber 80 is dispensed along with dose remaining in throat 290.
(83) Still another indicia pattern is seen in FIG. 13F. As it may be preferable to fill and measure volumes in chamber 90 using the most distal plunger (plunger valve 40), a set of indicia numbers (generally referenced by 292) are provided as seen on the left side of barrel 60. Later, when dispensing a set of indicia numbers (generally referenced by 294) are provided as seen on the right side of barrel 60. It should be noted that use of indicia 292 provides a direct and accurate measure for volumetric measurement of fluid in chamber 90, while use of indicia 294 provides a measurement independent of canting of plunger valve 40.
(84) As system 10 can be delivered as a dual-chamber syringe with one chamber pre-filled, it is recommended that all parts used in system 10 be compatible with gamma sterilization.
(85) Tapered Valve Fittings for Closed System Operation
(86) One of the major applications for dual-chamber syringe systems is in dispensing oncology drugs where need for a closed system is preeminent. Of course, oncology uses are not the only applications for dual-chamber syringe systems, but the toxic nature of oncology drugs has produced a significant impetus for the development of closed systems.
(87) Reference is now made to FIGS. 14-35 wherein a valve for tapered fittings is disclosed. As seen in FIG. 14, a valve 300, made according to the instant invention, is seen. Valve 300 comprises four separate sections, an elliptically shaped slit valve 310, a transition section 320 and a circularly shaped portion 330. For a valve 300 to be used with a female tapered luer fitting, each section comprises a 3 taper.
(88) Similar to a back-to-back valve disclosed in Thorne 681, slit valve 300 comprises an internal cavity disposed to provide a closing force upon medially disposed slit 340 when acted upon by internal syringe pressure. The cavity portion of valve 300 is part of back-to-back valving which is only opened by compressing slit valve 300, preferably into a circular shape. Further, as in all the art from which this U.S. Patent Application continues, slit 340 is medially disposed, in this case along a major axis 342 of an elliptical face 344 of valve 300. Due to very limited space available within a luer fitting and a need for a cavity whereby fluid pressure within the valve compresses slit 340 to obviate syringe dispensing flow, a medially disposed slit 340, seen in FIG. 14, the space for both a cavity and adequate wall thickness in the region of the cavity is not adequate for a reasonable design.
(89) To accrue a better utilization of available space within dictates of luer fitting dimensions, a different slit valve 400, seen in FIG. 15, valve 400 comprises similar sections to valve 300 comprising an elliptically shaped slit valve actuator 410, a transition section 420 and a circularly shaped portion 430. However, in valve 400, a slit 440 is offset from a major elliptical axis 442, indicated by a dashed line 444. As is clarified hereafter, establishing slit dimensions, which determines a hole diameter which is formed by compressively deforming elliptical valve parts to circular parts which conform to a female luer fitting into which valve 400 is inserted, also can be used to determine major and minor axis dimensions of valve 400 with an offset slit, as disclosed hereafter.
(90) Reference is now made to FIG. 16. Valve actuator 410 comprises a distal part 450 and proximal part 460. Extremities of parts 450 and 460 are distinguished by cross-cutting planes 462, 464 and 466. Plane 462 is disposed across a face 468. Plane 464 is disposed between parts 450 and 460. Plane 466 is disposed at the most proximal extremity of part 460. A slit 440 is disposed offset from a major axis (not shown) of an ellipse 469 at the plane 462 of face 468.
(91) Valve 440 is seen in a side cross-cut view in FIG. 17. Part 450 is seen to be solid, except for slit 440. Part 460 comprises both a cavity 480 and slit 440. As mentioned supra, cavity 480 permits pressurized fluid to be applied orthogonal to the plane of slit 440 effecting closure when valve 440 is not compressively opened by insertion into a tapered fitting. A wide collar 481 is disposed on a proximal end of valve 440 for sealing installation as disclosed hereafter.
(92) A cross section of part 460 in plane 466 (see dashed line 470 in FIG. 17) is seen in FIG. 17A. Disposition of slit 440 below cavity 480 (and an associated major elliptical axis permits a wider wall thickness, indicated by numbers 482 and 484 than possible if slit 440 is disposed on the major axis).
(93) Referring once more to FIG. 17, a valve 400 comprises a hole 490 which is closed internally at plane 466 (see FIG. 16) which is the proximal end of valve actuator 410. As material from which valve 400 is made must be supple to be compressed to open slit 440 and must be rigid enough to be effectively fully inserted into a tapered female fitting, an inner skeletal support is needed. As seen in FIG. 25, such a skeletal support 500, preferably injection molded of syringe compatible polypropylene, is sized and shaped to fit snugly within hole 490. As better seen in FIG. 26, support 500 comprises distal extensions, generally numbered 502, at the end of a support member 504. A collar 506 is provided for assembly support. A thru hole 510 provides a fluid communication pathway. Distal extensions 502 provide skeletal support for inserting valve actuator 410 while also providing a space for a fluid pathway for an opened slit 440 to cavity 480. An end-on view of support 500 is seen in FIG. 27.
(94) A cross section, in the plane of slit 440 is seen in FIG. 24 to comprise a skeletal support 500 and a valve 400 which combine to provide an insertable valve 600. Unless valve 400 can be made with sufficient rigidity to be self-supporting, skeletal support 500 should be provided. As disclosed hereafter, such support may be provided by an associated housing.
(95) Reference is now made to FIGS. 18-23 which provide comparisons between closed and open slits. Seen in FIG. 18 is a closed slit disposed across plane 462; similarly, FIGS. 19 and 20 disclose closed slits associated with planes 464 and 466, respectively. FIGS. 21-23 are disposed in the same planes as FIGS. 18-20, respectively. Compressing valve actuator 410 within a circular tapered fitting results in valve 400 being opened as seen in FIGS. 21-23. Note that volume of cavity 480 is reduced while a through hole 602 is opened. Due to physical material constraints, hole 602 may not be round, but have acute lip separations at slit ends, generally numbered 604. For this reason, slit 440 should be lengthened beyond pi times desired hole diameter.
(96) An insertable valve according to the instant invention may be assembled as a stand-alone male adapter 700 from three parts. As seen in FIGS. 28 and 29, male adapter 700 comprises a valve 400, a male luer lock fitting 702 and a female luer lock fitting 704. Female fitting 704 comprises an integrally molded skeletal support 706 (which is consistent in form and function with skeletal support 500 seen in FIGS. 24-26.
(97) For syringe applications, a conventional syringe barrel, such as barrel 60 (see FIG. 1), can be modified to provide a skeletal support as seen in FIGS. 30 and 33. As best seen in FIG. 33, rather than a conventional male luer fitting, barrel 60 comprises a skeletal support 706 which, like support 706 (see FIGS. 28 and 29) is consistent in form and function with skeletal support 500 seen in FIGS. 24-26. Assembly of a dual-chamber syringe with an associated valve 400 is seen in FIGS. 30-32. A valve 400, seen separate in FIG. 30, is disposed about skeletal support 706 as seen in FIGS. 31 and 34. A compression ring 710, designed to be inserted compressively to provide a fluid seal about support 706, provides for a seal and physical containment of valve 400.
(98) As can be seen in FIGS. 30-32, a plunger valve 40 disposed in barrel 60 converts a single barrel syringe into a dual-chamber syringe 10, which provides closed system operation with a valve only opening when inserted into a female luer fitting. One skilled in medical syringe art well understands that, similarly, a single chamber syringe having a barrel 60 without a chamber dividing plunger valve would have similar closed system qualities. Critical parameters for building a model for a valve 400 can be calculated as provided hereafter. As an example, if a hole radius (R) is desired, a slit length (L) would be:
L=pi*(R)
However, as disclosed supra, for a given hole diameter, the slit length should be lengthened to account for lip separation 604 anomalies (See FIGS. 21-23). As an example, for a hole diameter of 0.055 inches, adding five percent to the length increases the slit length from 0.086 to 0.091.
(99) Offsetting slit 440 (see FIG. 15) by twenty thousandths is preferred; however other offsetting amounts can be made within the scope of the instant invention. Once the slit length (hole size) and effective slit lengthening and offset are determined, it is recommended that ISO specifications be followed for calculating valve 400 design parameters. The following table I summarizes contemporary ISO specifications. It should be remembered that these specifications are provided for single chamber syringes.
(100) TABLE-US-00001 TABLE I Current Applicable ISO Specifications inches Male luer length .295 Female luer length .295 Insertion variance .159 Maximum engagement length .159 Maximum insertion length .226 Male end diameter .154 Female insertion diameter .159 Male diameter at end .156 Variance of male fitting .002 Fitting taper 3%
(101) For an elliptically formed valve, the only critical specifications are major and minor elliptical axes, insertion depth and associated fitting dimensions (diameter) at that depth and valve length. In the case of the current example, the desired parameters are
(102) 1. Fitting radius, i.e. at distal face 468 of inserted valve (r): 0.077 inches
(103) 2. Circumference at face 468 (C) 0.485
(104) 3. Slit offset (from major axis) (O) 0.020
(105) 4. Length of inside female fitting chord at slit offset (F) 0.149
(106) 5. Precompression length of valve at slit (P) 0.180
(107) Given the above listed parameters, a value for a half major axis (A) can be calculated by the following:
(108) The tangent (T) of an angle defined by a base of precompression length (P) and slit offset (O) is given by:
T=O/P
(109) The angle () associated with T is:
=arctan (T)
(110) An estimate for A is preferably calculated by:
A=F/(cos )=0.093 inches
Noting that calculated A, while close to a true value of the major axis is not exactly so, a value for the minor half axis (B) of the associated ellipse can be approximated from a known area (a) of the inner surface of the female fitting. Noting that desired area (a) is area of the fitting less area of hole which equals pi times R squared. Thus:
a=pi(r.sup.2R.sup.2) and an estimated value for B is estimated B=a/(pi A)=0.058 inches
However, noting that both A and B are estimates, a check on the value of B by calculating circumference of the associated ellipse shows that a correction of +0.002 to B decreases an error in circumference comparing circumference of the associated ellipse to the circumference of the fitting to less than 0.2 percent. With A and B and slit length so determined, a cavity with a maximum width of 0.020 provides all of the necessary dimensions to fabricate a valve actuator 410 (see FIGS. 15 and 16) which is 0.100 inches long.
(111) It should be noted that major axis (2A) being 0.186 inches long requires filleting 467 of the face 468 for facile insertion. Also, transition geometry within transition section 420 (See FIG. 15) should be linear to retain corresponding circumference between the associated female fitting and exterior surface of valve 400.
(112) Systems Kit for Step Reduction
(113) Reference is now made to FIG. 36 wherein a system 10 and a pre-filled female luer fitting syringe 800 are seen. Note that system 10 comprises a male luer fitting 810 and syringe 800 comprises a female luer fitting 820. Syringe 800 is a single chamber syringe pre-filled with a dose 830 destined to be dispensed into distal chamber 90 of system 10. It should be noted that syringe 800 may be specially made for storage of dose 830 (e.g. made from glass). Transferring dose 830 into chamber 90 of system 10 is accomplished by a single luer fitting connecting step thus eliminating other commonly used components, such as male/male connectors. By reducing system 10 filling to a single connection, problems, such as those associated with nosocomial infections, are reduced.
(114) Conclusion
(115) Inventions disclosed herein may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the inventions being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
