Abstract:
An injection device includes a housing having a proximal end and a distal end, the housing defining a distal opening, and a first opening in a side of the housing and between the proximal and distal ends; a propellant disposed inside the housing and spaced from the distal end; and a movable member disposed inside the housing and between the distal end and the propellant, wherein the propellant is in fluid communication with the movable member and the first opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 USC §119(e)(1) to U.S. Patent Application Ser. No. 60/174,876, filed on Jan. 7, 2000, and entitled “Injection Device”, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The invention relates to injection devices (e.g., injection devices including a needleless syringe), as well as components that can be used in injection devices. 
     Injection devices can be used for fluid injection into a body. Some injection devices can include a needleless syringe. 
     SUMMARY 
     The invention provides one or more components (e.g., a gas generant unit and/or a housing unit) that can be used in an injection device (e.g., an injection device including a needleless syringe), and injection devices containing one or more of these components. 
     The components can be removable, replaceable and/or adaptable to fit different sized injection devices. The injection devices can be re-usable. The injection devices can be in any of a variety of shapes and sizes. 
     For embodiments in which the injection device includes a gas generant unit, the gas generant unit can be removed before or after use of the injection device. Moreover, a gas generant unit that is removed from the syringe can be replaced with a different gas generant unit, which may contain the same or different gas generant compounds. Furthermore, a gas generant unit can be adaptable to fit different sized injection devices. Advantages associated with an injection device that is capable of using such a gas generant can include re-usability, relatively low cost to manufacture, relatively low cost to use, and/or enhanced flexibility in materials used as gas generant and/or injection fluid. 
     The injection device can include a housing that allows a fluid (e.g., a gas, such as a product of the reaction of the gas generant) to travel between the interior of the injection device and the exterior of the injection device without passing through the distal end of the injection device (e.g., the exit port of a syringe, such as a needleless syringe, contained within the injection device). In certain embodiments, this feature can be provided, for example, by including the following components in the housing: a sliding piston, a sleeve (which can have one or more venting mechanisms, such as one or more venting grooves, e.g., annular venting groove(s)), and one or more pressure relief mechanisms (e.g., one or more pressure relief holes). In these embodiments, the sliding piston can be designed to move along the sleeve so that, at one or more points along the path of motion of the sliding piston, the pressure relief mechanism(s) of the sliding piston align (e.g., partially align or fully align) with the pressure relief mechanism(s) in the sleeve. When this occurs, the fluid (e.g., reactant gas) can pass between the respective relief mechanism(s). The fluid (e.g., reactant gas) then exits the injection device via a passageway that does not include the distal end of the injection device (e.g., the exit port of a syringe, such as a needleless syringe, contained within the injection device). 
     In one aspect, the invention features an injection device, such as a needleless injection device, having a housing having a proximal end and a distal end, the housing defining a distal opening, and a first opening in a side of the housing and between the proximal and distal ends; a propellant disposed inside the housing and spaced from the distal end; and a movable member disposed inside the housing and between the distal end and the propellant, wherein the propellant is in fluid communication with the movable member and the first opening. 
     Embodiments include one or more of the following features. 
     The propellant is capable of forming a gas capable of moving the movable member in a distal direction and flowing through the first opening to the exterior of the housing. 
     The movable member comprises a piston defining a cavity, and the propellant is in fluid communication with the cavity. The movable member further defines a second opening in fluid communication with the first opening. 
     The device further includes a hollow sleeve configured to mate with the piston, the sleeve defining a second cavity in fluid communication with the propellant. The sleeve further defines a third opening alignable with the second opening. The sleeve further defines a groove, and the third opening is disposed in the groove. 
     The device further includes a button at the proximal end of the housing; a battery inside the housing and adjacent to the button; electrical leads in electrical communication with the battery; and a wire in electrical communication with the electrical leads, the wire configured to trigger the propellant. 
     The distal opening of the housing is configured to mate with a proximal end of a syringe. The syringe includes a plunger, and the movable member is configured to move the plunger in a distal direction. 
     The propellant includes a chemical pyrotechnic material. 
     The housing is composed of a plurality of detachable housings. 
     In another aspect, the invention features an injection device, such as a needleless injection device, having a housing having a proximal end and a distal end, the housing defining a distal opening, and a first opening in a side of the housing and between the proximal and distal ends; a propellant disposed inside the housing and spaced from the distal end; a sleeve disposed inside the housing and between the distal end and the propellant, the sleeve defining a second opening and a first cavity, the second opening and the first cavity in fluid communication with the propellant; and a piston mateable with the sleeve and movable in a distal direction, the piston defining a third opening alignable with the second opening, wherein the propellant is in fluid communication with the first opening when the second and third openings are aligned. 
     Embodiments include one or more of the following features. 
     The propellant is capable of forming a gas capable of flowing through the first cavity to move the piston, wherein the gas flows through the second and third openings when aligned, and through the first opening. The propellant includes a chemical pyrotechnic material. 
     The piston is coaxial with the sleeve and slidable over the sleeve to align the second and third openings. The piston defines a plurality of openings alignable with the second opening. 
     The sleeve defines a groove, such as an annular groove, the second opening disposed in the groove. 
     The distal opening of the housing is configured to mate with a syringe having a plunger, and the piston is configured to move the plunger. 
     The device further includes a button at the proximal end of the housing; a battery inside the housing and adjacent to the button; electrical leads in electrical communication with the battery; and a wire in electrical communication with the electrical leads, the wire configured to trigger the propellant. 
     The housing further defines an elongate passageway between the first opening and the third opening. 
     The device further includes a filter between the propellant and the first cavity. 
     The housing is composed of a plurality of detachable housings. 
     In another aspect, the invention features an apparatus that includes a housing, a button connected to the housing, a battery adjacent the button and connected to the housing, electrical leads in electrical communication with the battery, and a wire in electrical communication with the electrical leads. 
     In another aspect, the invention features an apparatus that includes a sleeve having a surface having at least one hole, a movable piston having at least one hole and a surface adjacent the surface of the sleeve, and a first housing connected to the sleeve and the movable piston. 
     In a further aspect, the invention features an injection device including first, second, third and fourth housings. The first housing is demountably attached to the second housing. The second housing is demountably attached to the third housing. The third housing is demountably attached to the fourth housing. The first housing includes a button and a battery adjacent the button. The second housing includes an inner housing, electrical contacts within the inner housing, a wire within the inner housing and in electrical communication with the electrical contacts, and a gas generant within the inner housing. The third housing includes a syringe adaptor housing having an outer vent sleeve, a movable piston having an end and at least one relief hole, a fixed sleeve having a groove with a hole (e.g., a pressure relief hole), the fixed sleeve being adjacent the movable piston, a drive piston having at least one groove, the drive piston being adjacent the end of the movable piston and a sealing device within the groove of the drive piston. The fourth housing includes a plunger having an end, a syringe adjacent the end of the plunger, and an elastomeric spring adjacent the syringe. 
     Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     DESCRIPTION OF DRAWINGS 
     FIG. 1 is a cross-sectional view of an embodiment of an injection device; 
     FIG. 2 is a partial cross-sectional view of an embodiment of a portion of an injection device; and 
     FIG. 3 is a partial cross-sectional view of an embodiment of a portion of an injection device. 
    
    
     DETAILED DESCRIPTION 
     The invention relates to injection devices (e.g., injection devices containing needleless syringes) and components that can be used in such injection devices. Advantages of the injection devices can include that they are relatively safe to use, relatively less painful to use, capable of delivering fluid in a predetermined and/or desirable manner, and/or reusable. 
     FIG. 1 shows a cross-sectional view of an embodiment of an injection device  5 . Device  5  includes housings  10 ,  20 , and  30 . Housing  10  is demountably attached to housing  20  at section  25  by, for example, screw threads or a bayonet lock. Housing  20  is demountably attached to housing  30  at section  26  by, for example, screw threads or a bayonet lock. Housing  30  is permanently attached to a bayonet interlock syringe adaptor  200  to provide a mechanism for fitting a syringe configuration. 
     Housing  10  includes a button  40 , a battery  50 , and an electrically insulative (e.g., non-metallic) cup  620  (FIG.  3 ). 
     Housing  20  encloses a housing  80  (e.g., a disposable housing) having electrical contacts  60 , a wire  70  and a propellant  90 , such as a gas generant (FIG.  2 ). 
     The syringe adaptor  200  has an outer vent sleeve  150 , a sliding piston  100  having pressure relief holes  130 , sleeve  110  (e.g., a fixed sleeve) having a groove  120  (e.g., an annular groove), and a drive piston  170  having grooves containing sealing devices  180  (e.g., o-rings) and a syringe interface  190  (e.g., a custom syringe interface) located at its distal end. 
     In some embodiments, the injection device  5  is assembled as follows. Sleeve  110  is permanently attached to housing  30 , followed by permanently attached outer vent sleeve  150  to the flange of sleeve  110 . Then, the elastomeric spring  210  is bonded to the end of housing  30 , and syringe adaptor  200  is subsequently permanently attached to housing  30 . 
     Syringe adaptor  200  (e.g., an interlock adaptor) accepts a syringe housing  220  with its associated plunger  230 . 
     FIG. 2 shows an exploded view of an embodiment of housing  80  including electrical contacts  60 , wire  70 , propellant  90 , screen  240 , filter  250  and cap  260  with an exit hole  270 . 
     FIG. 3 shows an exploded view of an embodiment of sleeve  110 , annular groove  120  having hole(s)  300 , sliding piston  100  and vent holes  130 . 
     During operation of injection device  5 , button  40  (e.g., a molded plastic button) is pressed, compressing a wave spring  610  which causes battery  50  (e.g., a replaceable battery) to come into contact with electrical contacts  60 . This causes an electrical current to pass through wire  70  (e.g., a metal wire such as nickel/chromium wire, and/or a wire having a diameter of from about 0.005 inch to about 0.010 inch, such as about 0.010 inch), thereby heating wire  70  (e.g., causing wire  70  to become red hot in about one second). The heat generated by wire  70  is sufficient to cause the reaction of chemical components contained in propellant  90 . Such chemical components can include a fuel and an oxidant. A nonlimiting, illustrative list of examples of chemical components that can be used in propellant  90  (e.g., a gas generant) are disclosed in U.S. Pat. Nos. 4,103,684; 4,342,310; 4,447,225; 4,518,385; 4,592,742; 4,623,332; 4,680,027; 4,722,728; 4,913,699; 5,024,656; 5,049,125; 5,064,123; 5,190,523; 5,304,128; 5,312,335; 5,334,144; 5,383,851; 5,399,163; 5,499,972; 5,501,666; 5,503,628; 5,520,639; 5,569,189; 5,630,796; 5,704,911; 5,730,723; 5,840,061; 5,851,198; 5,879,327; 5,899,879; 5,899,880; 5,911,703; and 5,993,412, each of which is hereby incorporated by reference. Other chemical components are described in commonly-assigned Application No. 60/250,573, filed Nov. 30, 2000, and entitled “Injection Devices”, hereby incorporated by reference. 
     The gas formed by the reaction of the chemical components in propellant  90  passes through screen  240  (e.g., metal screen, such as a stainless steel screen of, for example, about 50 to 200 mesh) and filter  250  (e.g., a glass fiber filter). Screen  240  can cool the reactant gas and/or trap slag, and filter  250  can trap particulates (e.g., small particulates, such as those generated during the reaction). 
     After passing through filter  250 , the reactant gases cause sliding piston  100  to move along the surface of sleeve  110 . As piston  100  moves along the surface of sleeve  110 , piston  100  urges drive piston  170  to push against plunger  230  which, in turn, pushes against fluid within syringe  220 , thereby ejecting fluid from syringe  220  via outlet  310 . 
     The movement of piston  100  along the surface of sleeve  110  also causes holes  130  to reach the annular groove  120 . When this occurs, the reactant gas can pass through one or more holes  300  (i.e., one, two three or four holes) in the annular groove  120  and one or more holes  130 . The reactant gas that passes through holes  300  and hole(s)  130  can flow through the relief channels  140 , into space  160  (e.g., an open space, or a space containing a filter material, such as glass wool) and out device  5  via gas vent  7 . 
     The number, size, and location of holes  130  can vary to assist in controlling the pressure of fluid exiting through distal end  310  of injection device  5 . The location of holes  130  can be determined by interfacing the end of the syringe to a pressure transducer that in turn is interfaced to a real time data acquisition system. One example is a model PCI-731/6040E data acquisition board (commercially available from National Instruments of Austin, Tex.), which can be interfaced to a computer (e.g., a personal computer) for real time pressure transducer measurements. Changes in the pressure profile due to changes in the placement, shape, and size of holes  130  can be monitored and optimized accordingly. 
     The use of annular groove  120  can obviate the need for a precise alignment of holes  130  because holes  130  are not required to be keyed to contact groove  120 . 
     Syringe  220  and plunger  230  can take on a variety of shapes and sizes. For example, syringe  220  and plunger  230  can be commercially available components (e.g., such as available from Bioject Medical, located in Portland, Oreg.; Injet Medical Products, Inc., located in Lake Forest, Ill.; and Avant Drug Delivery Systems, Inc., located in San Diego, Calif.). 
     The end of housing  30 , syringe adaptor  200  and elastomeric spring  210  form an interlock, which, in certain embodiments, can be designed to accept the attachment of commercially available syringes and/or ampules. The interlock may be one of several types including a bayonet type. 
     In certain embodiments, housing  80  is replaceable. In these embodiments, after an injection housing  80  can be removed and replaced with a different housing, and device  5  can be re-used. 
     The invention is not limited by the above description, and the invention contemplates variations and modifications to this description. For example, in some embodiments, housings  10 ,  20 , and  30  can be non-demountable. 
     In some embodiments, the invention provides for the delivery of a mixture of two substances. 
     The first substance can be a dry substance, e.g., a lyophilized protein, nucleic acid, e.g., RNA or DNA, or polysaccharide. The first substance can be a vaccine, or a drug. The first substance can be a peptide, polypeptide, or protein, e.g., an antibody, an enzyme, a hormone or growth factor. Preferred first substances include insulin. The first substance can be: a blood protein, e.g., clotting factor VIII or a IX, complement factor or component; a hormone, e.g., insulin, growth hormone, thyroid hormone, a catecholamine, a gonadotrophin, PMSG, a trophic hormone, prolactin, oxytocin, dopamine and the like; a growth factor, e.g., EGF, PDGF, NGF, IGF&#39;s and the like; a cytokine, e.g., an, interleukin, CSF, GMCSF, TNF, TGF-alpha, TGF-beta. and the 25 like; an enzyme, e.g., tissue plasminogen activator, streptokinase, cholesterol biosynthetic or degradative, glycosolases, and the like; a binding protein, e.g., a steroid binding protein, a growth hormone or growth factor binding protein and the like; an immune system protein, e.g., an antibody, SLA or MHC gene or gene product; an antigen, e.g., a bacterial, parasitic, or viral, substance or generally allergens and the like. 
     The second substance can be a liquid, e.g., a diluent or solute. Such liquids can include buffers, inert fillers, pharmaceutically acceptable carriers, or the like. 
     The subject can be a human or an animal, e.g., a laboratory animal, or pet, e.g., a dog or cat, or other animal, e.g., a bovine, a swine, a goat, or a horse. The first and second substance can be combined by the subject, or by another person. 
     Other embodiments are in the claims.