Displacement activated medical check valve

Details Displacement activated medical check valve Displacement activated medical check valve

1998-06-22

2001-05-08

Kennedy, Sharon (Department: 3763)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

Reexamination Certificate

active

06228065

ABSTRACT:

BACKGROUND AND SUMMARY OF THE INVENTION
Application Ser. No. 08/196,455 presents the background of multi-chambered syringes which are used for sequential injection and/or the mixing of drugs and solutions. Additional background of enclosed drug-mixing systems is provided in U.S. Pat. No. 4,614,267. As described within the backgrounds of the many patents presented in the aforementioned application, it is advantageous to store a drug in a powdered or liquid form and then mix the drug in the same enclosure which is subsequently placed in fluid connection with the patient. More specifically, it is advantageous to provide mixing within a syringe so that reconstitution within a separate drug vial becomes unnecessary. This, however, must be provided at minimum cost and would preferably utilize materials to store the drug, such as glass, which have been determined appropriate by the U.S. Food and Drug Administration for long-term storage of drugs so that the evaluation of the leaching or interaction between the drug and the drug container is unnecessary. Such compatibility evaluations are associated with considerable delay and development expenses. PCT patent application No. WO 92/01485 describes a syringe for this purpose having a glass insert and including dual pistons. The syringe, however, includes a complex barrel having multiple bores and bypass regions. This syringe requires complex molding, assembly, and sealing. However, with respect to drug administration systems, reduced cost, simplicity of design and molding, versatility of use, compatibility with automated drug dispensing systems, and ease of sterile assembly and use are the major factors defining success. It is particularly useful to provide a system using a conventional type glass vial and a convention smooth bore syringe barrel of the type in wide use and inexpensively molded of polypropylene in mass quantities and in a wide variation of bore sizes. As will be evident from the following discussion, the present invention operates to overcome many existing problems in the present art.
The sequential aspiration, mixing, and injection syringe includes a barrel having an inner wall and a main bore which is preferably conventional and smooth along substantially its entire length. The syringe includes a piston assembly having a proximal portion and a distal portion and a connecting element intermediate the portions. The portions are sized to be received into a main bore of the barrel and to fit snugly against the barrel wall. This distal portion preferably includes at least one projecting lateral member for engaging the inner walls of the barrel, thereby effectively fixing the position of the distal portion at a maximally advanced position along the barrel which preferably adjacent the distal end of the barrel, although the position could be midway along the barrel. After the pistons have been received into the barrel, the proximal portion is moveable along the barrel away from the distal portion and moveable along the barrel toward the distal portion to define a variable volume mixing chamber intermediate the proximal portion and the distal portion. The connecting element can be a fluid reservoir or a drug vial which can be comprised of glass or the connecting element can be a conduit or tube, or can be a tether or other tensile element. The glass vial can have a proximal end and a distal end. In one embodiment, both ends of the vial are open. The proximal portion can be a piston and can be positioned to occlude the proximal end and the distal portion can be a stopper to occlude the distal end of a drug vial or the distal end of a fluid reservoir or tube. The connecting element provides for mutually equivalent advancement of the proximal and distal portions along the barrel. The combined piston assembly and the connecting element can be seen to represent a reservoir or drug vial piston connectable to a syringe handle. The distal stopper is displaceable from the fluid reservoir or drug vial by retraction of the reservoir or vial away from the distal stopper and by frictional or other engagement of the distal stopper and the barrel after the reservoir or vial and the attached piston assembly have been moved to an advanced position and then the reservoir or vial is retracted from the advanced position. This allows for retraction of the proximal piston away from the distal stopper after displacement of the stopper from sealing engagement with the fluid reservoir or drug. In several embodiments, the proximal piston is further moveable along the vial toward the distal stopper. Relative advancement of the proximal piston along the vial can be caused by advancement of the handle in one embodiment wherein the proximal piston is attached to the handle. In another embodiment, wherein the proximal piston is connected to the displaced distal stopper by a tensile element, relative advancement is achieved by retraction of the vial and subsequent tensile force transmitted through the tensile element. The distal portion and the proximal portion are preferably carried by the drug vial, the distal portion being displaceable from the drug vial to open the vial into the mixing chamber, the proximal portion being moveable along the vial to displace the drug from the vial into the mixing chamber, the proximal portion effectively converting the open-ended drug vial into a closed-ended vial piston and thereafter functioning to push the drug solution within the mixing chamber out of the syringe and into a recipient with minimal deadspace-trapped drug remaining within the syringe after injection.
A method of drug injection is provided using an embodiment having a main piston or vial piston having a handle. The vial piston includes a drug vial having a proximal end and a distal end and containing stopper piston assembly having a proximal portion connected to a distal portion by a connecting element which can be a tensile element or which can be the drug vial itself, as will be described. The syringe operates, after assembly, to achieve the following drug injection method with a single retraction and advancement of the handle, steps of: 1. aspirate diluent into the main bore; 2. open the end of a drug vial into the main bore; 3. positively expel the drug from the vial; 4. subsequently convert an open-ended drug vial into a closed-ended injection piston; 5. inject the mixed drug and diluent with minimal residual drug remaining in the syringe after injection.
As noted, the present invention can utilize a drug container or vial which can be cylindrical for insertion into a syringe barrel. The drug vial is preferably made of glass or other material which can safely contain a large variety of different drugs, either in powder or liquid form. In one embodiment, the drug vial includes a closed bottom or proximal end which may include a small air vent and an open top or distal end which is preferably widely open and can, therefore, easily be filled by conventional automated drug dispensing systems. The drug vial can include a narrow neck and larger body to facilitate handling by automated equipment. The drug vial further preferably includes an outer housing member which can be polymeric. At least one sliding member is preferably provided about the vial to slidably engage the syringe barrel bore to facilitate advancement and retraction of the drug vial along the syringe barrel bore. The sliding member can be a thin rubber boot or sleeve. Alternatively, the polymeric housing member may itself be sized to sealingly engage the bore. The sliding member can be a rubber wiper of the type utilized in conventional syringe pistons or can be an o-ring or soft polymeric ring or otherwise fashioned. The sliding member is preferably carried by the housing or vial and may be positioned proximal, distal to, or along the length of the housing or vial. The outer member further can have a recess for receiving the retainer of the handle of a conventional syringe piston or, alternatively, the handle can be molded integrally with the outer vial housing member. The vial can, therefo

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