Abstract:
Disclosed is medical device, such as a mass injector, that has a protective cap disposed on it that minimizes or eliminates cross contamination, wherein the cap can be ejected in a quick manner.

Description:
CROSS REFERENCE OF RELATED APPLICATIONS 
     This application claims priority to, and benefit from, Russian Patent Application 99124268, filed Nov. 23, 1999, now issued as Russian Patent No. 2152228; and Russian Patent Application 99121141, filed Oct. 12, 1999; now issued as Russian Patent No. 2152227 the disclosures of which are entirely incorporated by reference herein. 
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to a medical device having a mechanism that protects against cross contamination by utilizing a removable cap. 
     BACKGROUND OF THE INVENTION 
     The most effective measure to prevent many diseases is the mass immunization with vaccines. Since medical science has come to understand the principles of viral theory and its importance to the transmission of diseases, the need to break the viral or bacterial transmission chain from host to host has become well-established. There are wide varieties of methodologies accepted by medical science to break the chain depending on the requirements of the situation. The most stringent protocols include: sterilization, disinfection, and sanitation utilizing heat chemicals and/or ionizing radiation. 
     Barriers are another common protocol and can be as simple as establishing an imaginary boundary where one side of the boundary is kept clean and the other is defined as contaminated. Any object being transferred from the clean to the contaminated side of the boundary is not returned to the clean side without being disinfected, sanitized, or sterilized. A typical example of this type of protocol is within the medical surgical fields. The surface of the operating table is defined as the boundary. Any item that is dropped below the surface of the operating table is immediately defined as contaminated. This includes surgical implements or the surgeon&#39;s hands. 
     With needle injection devices there are two common protocols both of which start from the premise that a used syringe is, by definition, contaminated. The first, which is commonly used in dentistry, uses syringes and sometimes needles that are sterilized after each use. The second is more commonly used in general medicine in the U.S. and other developed countries. This is the disposable syringe and needle assembly. Because of the low cost of production typically—less than $0.10 per syringe assembly—this protocol is well-accepted. 
     Jet injector systems on the other hand continue to be characterized by relatively high cost per injection ($1.00 or more) when the syringe portion of the injector is discarded with each use. Additionally, there is the challenge in developing countries where lack of understanding of viral theory and/or a general hoarding mentality discourages following generally accepted protocols within all aspects of health and hygiene. With the identification of blood-borne pathogens like HIV, Hepatitis B, Hepatitis C and others, the need to follow proper protocols becomes more critical. 
     In the past, jet injectors such as Ped-O-Jet®, Ammo-Jet®, and similar mass campaign jet injectors were brought to health care systems. Such injectors had no provision for preventing the transfer of blood-borne pathogens except through the complicated disassembly and disinfecting process. In mass immunization campaigns these types of injector systems fell out of favor starting in the mid and late 1980&#39;s when it was determined that bodily fluids are easily transmitted from one patient to another. 
     To eliminate the possible transmission of blood-borne pathogens between individuals, disposable or partially disposable jet injector systems were developed. Bio-Jet®, J-&#39;Tip®, and others characterize this type of jet injector. General acceptance of these units is limited by relatively high direct costs, even in developed countries like the United States. The standard paradigm of breaking the contamination transmission chain has been addressed by either syringe disposal or designing the syringe so it can easily be decontaminated. Currently, there exists a steadily growing danger of the epidemic diseases (AIDS, hepatitis, tuberculosis and other viral diseases transferred through blood) being transmitted between individuals through the use of needleless injectors. 
     The traditional needleless injectors comprise the basic design, a housing with an inner power unit, a medication unit, and a nozzle. The function of the power unit pumps the medication into an under-plunger cavity of the medication unit chamber and to expel the medication through the nozzle. 
     At the initial stage of needleless injector development, when no check valves were used as a control for the functioning of the medication chamber, a method to prevent foreign particles from entering the injector nozzle was to use a sealed nozzle cap. Such cap was limited by the filling of the medication chamber with medication and could not guarantee contamination prevention. 
     Another approach to the contamination prevention problem has been the use of a disposable, low cost, one-shot nozzle assembly for jet injectors. The nozzle assembly comprises a two-piece molded device incorporating a generally cylindrical nozzle body having a central longitudinal bore of a predefined diameter, extending from a proximal end of the nozzle towards its distal end, terminating in a conical portion of the nozzle. A very small diameter jet-forming bore is formed at the apex of the conical portion of the bore in general. The disadvantage of this device is its lower efficiency (i.e., low vaccination rate) because of poor flow due to the conical design. Moreover, a plastic nozzle element also increases the vaccination cost. 
     A typical jet injector design has additional drawbacks. Even in the practice of using a protective cap, there is a possibility of infection transfer from one person to another by means of fluids (blood, lymph, medication) reflected from the skin surface during injection (“back splash”) that may get on the nozzle and be transferred from one patient to the next. The protective cap can be a one-shot cap, including the injection nozzle. A purpose of this device is to prevent the multiple use of a cap with a nozzle. This is achieved through the removal, replacement, and/or destruction of the cap at the later stage of the injection. However, cross- contamination continues to be problematic because in the injection stage, the contaminated matter can be transferred through the nozzle to inside the injector such as, for example, into the cavity and be transmitted to a new patient through a new cap and nozzle. 
     With all the known devices, there is no guarantee that the minimum safety requirements for cross-contamination prevention, as recently introduced (Glenn Austin et al.,  Gross Contamination Testing of Vaccine Jet Injectors, A Preliminary Report , PATH, Seattle, Wash., 98109), will be achieved. Other studies indicate a very dangerous situation. For example, Russian and Brazilian studies have shown unfavorable data in up to 1.0% of the subjects studied—a level of risk far too great to ignore. 
     When jet injectors were introduced in the 1940&#39;s, they were popular for needle phobic patients or small veined patients. Improvements permitted jet injectors to administer hundreds of millions of vaccinations that saved countless lives. However, when the discovery of pathogen transfer occurred, jet injectors fell out of favour to such an extent that the WHO and the US Department of Defense no longer recommended jet injector use. 
     For example, in the mid- 1980&#39;s an outbreak of Hepatitis B was caused by use of one high workload injector in a weight loss clinic. See, Canter et al., An Outbreak of Hepatitis B Associated With Jet Injections In A Weight Loss Clinic, Arch. Intern. Med., 150:1923-1927 (1990). 
     Present parenteral injection technology has recently been deemed by the World Health Organization (WHO) to be incompatible with their requirements for the planned Global Programme of Vaccination and Immunization (GPV) initiatives. It is estimated that 6 additional parenteral vaccines will be recommended for childhood vaccination by the year 2005, requiring a total of 3.6 billion immunization injections per year. The total number of parenteral injections, including injected drugs as well as vaccines, will be roughly ten times this number. This is in addition to the hundreds of millions needed in military induction centers, epidemic situations, worldwide immunizations, and veterinary uses. Major health care providers such as UNICEF, the WHO and CDC have recently confirmed that a radical new technology is required that can be used by personnel with minimal training and that is safer, more convenient, and more comfortable than the syringe and needle. (Jodar L., Aguado T., Lloyd J. and Lambert P-H,(1998) Revolutionizing Immunizations Gen. Eng. News 18, p. 6.) 
     In other words, what used to be a continent wide life saver, became an undesirable product. The present invention solves problems associated with pathogen transfer and solves many problems associated with the high costs of disposable units. 
     In addition, other problems with mass injection involve time and labor. For example, to replace the cap each time manually expends significant time, especially when considering the hundreds, if not thousands, of inoculations that are needed. To this end, a device that permits easier removal of the cap and replacement is substantially needed. 
     Accordingly, there is a need in the art of needleless injection devices to solve the problem of cross-contamination during mass vaccinations. More particularly, there is a need for a protector designed for the nozzle head of needleless injectors, which halts “back splash” contamination, and which is low enough in cost to ensure its practical application as a disposable unit even for mass vaccinations. 
     SUMMARY OF THE INVENTION 
     The foregoing problems are solved and a technical advance is achieved by the present invention. Disclosed is medical device, such as a mass injector, that has a protective cap disposed on it that minimizes or eliminates cross contamination, wherein the cap can be ejected in a quick manner. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 demonstrates a simple embodiment of the invention. 
     FIG. 2 demonstrates another embodiment of the present invention. 
     FIG. 3 demonstrates a cross section view of the cap and body. 
     FIG. 4 describes another embodiment of the present invention, particularly the cap. 
     FIG. 5 demonstrates another embodiment of the present invention. 
     FIG. 6 demonstrates yet another embodiment of the present invention. 
     FIG. 7 demonstrates yet another embodiment of the present invention. 
     FIG. 8 is yet another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 demonstrates a simple embodiment of the invention. The device  10  is shown having a main body  12 , with the main body  12  further having a main body proximal end  14  and a main body distal end  16 . A protective cap  18  is shown disposed near the main body distal end  16 . The cap  18  can be detachably attached to the main body distal end  16  using conventional techniques, such as friction fits, bayonet fixing, male-female receptacles, or the like. Also shown is a means or mechanism for removing  20  the detachably attached cap  18 . In this particular embodiment, the means for removing  20  the cap is a rod that pushes against a cap extension. Although not shown, the means for removing  20  can be attached to the main body  12 . In this regard, as the means moves in the direction indicated by movement arrow X, the cap  18  is pushed off the distal end  16 . 
     FIG. 2 demonstrates another embodiment of the present invention. Shown again is the protective cap  18  disposed at or near the main body distal end  16 . In this embodiment however, the mechanism or means for removing  20  the cap is not a rod, but a collar or sleeve. In this regard, as the collar moves in the direction designated by arrow Y, the cap  18  is popped off. This permits a greater degree of contact between the cap  18  and the means  20  to permit the ejection of the cap  18 . 
     FIG. 3 demonstrates a cross section view of the cap  18  and body  12 . Shown in this embodiment is a cap orifice  22  that is coincident with a main body lumen  24 . Injected medicines will pass through the lumen  24  and through the cap orifice  22 . 
     FIG. 4 describes another embodiment of the present invention, particularly the cap  18 . To minimize cross contamination, the cap  18  can be configured in various ways. For example, an insert  26  having an insert orifice  27  can be used. Insert  26  can be inserted into a baffle  28 . The baffle  28  can also include a protective film  30  disposed near or on the baffle  28 . The cap  18  can also include a cap flange  32 . The flange  32  can have a flange proximal face  33 . Therefore, in a simple embodiment, the means for removing  20  the cap could contact the flange proximal face  33 . Also include in the cap can be a baffle orifice  36  to further the goal of transmitting medication therethrough. The baffle may also include a baffle proximal face  38  upon which, as shown in FIG. 4, the film  30  may be disposed by coinciding a film distal face  40  to the baffle proximal face  38 . 
     However, it should be noted that the film need not be solely found proximal to the baffle. The film  30  or a plurality of films can be located proximal to the baffle, distal to the baffle, proximal to the insert, distal to the insert, or sandwiched in between the insert and baffle. On the other hand, if many films are used, then the films may be disposed at any location deemed proper. In addition, the many components of the cap are optional. For example a cap need not have a cap flange  32  if a collar means  20  is used. Furthermore, an insert or baffle may not be necessary. Other configurations are described in copending U.S. Patent Application filed on Oct. 10, 2000, under attorney docket number 70006780-0004, entitled Universal Anti-Infectious Protector For Needleless Injectors, by the inventors B. Smolyarov, V. Rogachev, V. Katov, A. Felton, and N. Leon, the disclosure of which is entirely incorporated by reference herein. 
     FIG. 5 demonstrates another embodiment of the present invention. The means for removing  20  is shown in a cutaway view. The means for removing  20  may comprise an ejection assembly  41 . In the simple embodiment of FIG. 1, the means for removing  20  can comprise an ejection assembly that comprises the rod shown. However, in FIG. 5, the ejection assembly can further comprise an ejector rod  42  (or an ejector rod  42   a  or collar  42   a  wherein no flange is needed), an ejector body  44 , and may further include a mechanism or means  46  for biasing the ejector rod. In one embodiment, the means  46  for biasing may include a spring to bias the rod in the directions indicated by arrow Z . 
     However, it should be noted that the means for biasing can also include those means known in the art and can further include, but is not limited to, pistons, gears, rods, springs, worm gears, screws, electromagnets, optical components, and jacks. The means for biasing may also include various driving mechanisms, such as pneumatics, hydraulics, or manual drives. In addition, the means for biasing may also include phase change materials or other shape memory materials, such as those materials that change size or shape due to temperature application. One such material is Nitinol, which allows for size or shape transformation in its austenite and martensite states. Accordingly, the means for biasing is meant to include not only the structures described herein, but also, any acts or materials described herein, and also include any equivalent structures, equivalent acts, or equivalent materials; or equivalent structures, act equivalents, or material equivalents, to those described herein. 
     FIG. 6 demonstrates yet another embodiment of the present invention. Shown is an ejection assembly  41  comprising a first ejector  43  and a second ejector  45 . The first ejector  43  may further include an ejector body  44 , which may further comprise a means  46  for biasing an ejector rod  42 . The second ejector  45  may include a collar, rod, or nozzle  56 , or a means for biasing the nozzle. The nozzle  56  may comprise a nozzle sleeve  50  and a nozzle flange  52 . Nozzle  56  may also include a means  54  for biasing the nozzle such as a spring. In this embodiment, the means for biasing the rod  42  may also bias the nozzle flange  52 , thus causing the nozzle sleeve  50  to bias against the cap  18 , thereby causing the cap to pop off. Once the means  46  for biasing the rod  42  is released, the means  54  for biasing the nozzle can then return the nozzle sleeve  50  back into position. Therefore, it is contemplated that the ejection assembly may include: (a) just the first ejector, (b) just the second ejector, (c) both ejectors, (d) both ejectors plus other components, or (e) any combination thereof. In this regard, the means  20  for removing the cap  18  may be the ejection assembly as defined herein. 
     FIG. 7 demonstrates yet another embodiment of the present invention. In this embodiment, more detail of the injection system is shown. A medication vial  60  containing medication  62  (in one embodiment an aqueous solution) is shown detachably attached to the injector system. A check valve  64  is disposed along the connection to moderate medication flow. Also shown is a hydraulic assembly  66  that is connected to the injector system via hose  68 . The injector system comprises an injector head, which is attached to a plunger  72 . These components may be found in a cylinder  74 , which may comprise the main body  12 . Within the cylinder may be a cylinder piston  76 , which itself may be within a cylinder chamber  78 . The cylinder piston  76  can be driven by another biasing means  80 , such as a spring or the other means described herein. Functionally, as hydraulic pressure is applied in the direction marked by arrow A, the plunger  72  is driven in the direction of arrow B. The plunger movement causes the biasing means  80  to compress. In addition, the plunger movement causes medication  60  to enter into cylinder chamber  78  distal to injector head  70 . Once the hydraulic pressure is removed, the means  80  biases the plunger and it moves in the direction opposite to arrow B, thereby driving the medication into the cap  18  and therethrough. 
     It should be noted that in any embodiment of the present invention, the medication need not be liquid. In addition to aqueous solutions, the present invention may employ suspensions, aqueous gels, emulsions, or controlled release injectable medications. One other dosage form includes powder. For example, Powdeiject Pharmaceuticals, of Oxford, United Kingdom, and/or Powdeiject Vaccines (Madison, Wis.) have developed an injector that propels medicine in powder form in the same manner as traditional needleless injectors. For example, see, U.S. Pat. Nos. 5,733,600; 6,053,889; and 5,899,880, the disclosures of which are expressly and entirely incorporated herein. Since the powder form of drugs take up less than 1% of the volume of drugs in liquid form, adapting the powder injectors to be used in accordance with the present invention is also contemplated. Generally, but not exclusively, the powder particles of one dose can range in size but are generally 50 microns wide, as compared to a 500 micron wide syringe needle. In other words, powder form vaccines, such as recombinant DNA based vaccines, including Hepatitis B and HIV vaccines; and other medications for treating influenza, tetanus, erectile dysfunction, allergies, pain, cancer, etc., are contemplated. Such powder forms may be admixed with small amounts of sterile water or other physiologically acceptable diluents (e.g., about 1-10%) to form pastes or suspensions. Therefore, adapting the powder injectors to have a means for ejecting a cap and a protective cap and/or film consistent with the present invention is within the ordinary skill in the art. 
     FIG. 8 is yet another embodiment of the present invention. In this embodiment, the means  20  for removing the cap may comprise an ejection assembly  41 , which may comprise a first ejector  43 , a second ejector  45 , or a hydraulic assembly  66 . The first ejector  43  or second ejector  45  may comprise either the nozzle  56  assembly, or the ejector rod  42  assembly. Therefore the means  20  for removing the cap can comprise the following: (a) the nozzle assembly only; (b) the ejector rod  42  assembly only; (c) the hydraulic assembly  66 ; or (d) or combination thereof. 
     In this embodiment, the hydraulic assembly  66  is shown comprising a hydraulic piston  82  and a return means  84 , such as spring. As the hydraulic fluid is pumped up the hose  68 , it travels past the ejector port  88  (with some fluid entering this port) and into the cylinder port  90 . As fluid enters the main body  12 , it begins to fill up the cylinder chamber  78 . As pressure increases in this chamber, the plunger  72  begins to move in the direction of arrow K. In this regard the cylinder piston  76  moves and causes compression of the cylinder spring  80 . The piston  76  moves until it reaches a locking position and is locked in place by locking mechanism  86 . Since the piston  76  moves in the direction of arrow K, the injector head  70  also moves in that direction. This causes the medication  62  to dispense into the injector chamber  92 ; ready for injection. 
     In the meanwhile, as hydraulic fluid flows into the hose  68 , some of the fluid will enter the ejector port  88  and cause the ejector piston  48  to move in the direction of arrow L. This causes the ejector rod  42  to contact the nozzle flange  52  on the flange proximal face  33 . This will cause movement of the means  46  for biasing the ejector rod, such as spring compression. 
     As the nozzle flange  52  begins to move in the direction of arrow M, the nozzle sleeve  50  will impact the cap  18 . In doing so, the means  54  for biasing the nozzle, such as a spring will move or compress. Thus, as the ejector rod  42  reaches a critical distance, the cap  18  will pop off. 
     After the cap is popped off and replaced, the medication  62  sits ready for injection into a new cap. The hydraulic fluid pressure is released or reduced. In one embodiment, the as the fluid pressure is reduced, then the means  54  for biasing the nozzle pushes the nozzle back into place; the means  46  for biasing the ejector rod pushes the ejector rod back into place; thereby causing the system to reset. The locking mechanism  86  is then released and the force of the decompressing cylinder spring  80  drives the plunger  72 , cylinder piston  76 , and the injector head  70  in the direction of arrow N. This pushes the medication  62  into the cap and subsequent patient injection. 
     While the steps outlined aboveappear to be sequential, they need not be. For example, as the hydraulic fluid pressure is being reduced, the injection may occur when it is made sure that the new cap is sufficiently replaced. The ejector means need not be in a completed reset position before injection can occur. 
     It should be understood that the foregoing relates only to a limited number of embodiments that have been provided for illustration purposes only. It is intended that the scope of invention is defined by the appended claims and that modifications to the embodiments above may be made that do not depart from the scope of the claims.