Fluent material handling – with receiver or receiver coacting mea – Processes – Plural materials
Reexamination Certificate
2001-12-26
2002-11-05
Maust, Timothy L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
Plural materials
C141S002000, C141S027000, C141S319000, C141S321000, C141S383000, C141S384000
Reexamination Certificate
active
06474369
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to devices and methods for storing and mixing injectants, and to devices and methods for filling an ampoule of a needle-less injector prior to an injection. In particular embodiments, the invention relates to devices and methods for filling an ampoule of a needle-less injector with a medication that must be mixed just prior to administration of an injection, and to the storage of such medication prior to mixing and filling. More particularly, the invention relates to injectable medications wherein one component of the medication is a reagent that is stored in dry form.
BACKGROUND OF THE INVENTION
A number of medications are maximally effective when mixed immediately prior to administration to a patient. These medications may include multiple liquids, or, alternatively, at least one liquid that is mixed with an active stored in solid form. Generally, the need for mixing immediately prior to injection is due to the rapid loss of medicinal efficacy of a particular reagent included in the medication once the components thereof are combined.
This is often the case with lyophilized actives. Lyophilized actives are essentially freeze-dried pharmaceuticals that do not maintain efficacy when stored for a substantial period of time in solution. In fact, most lyophilized actives become medicinally ineffective once in solution for more than a few hours, and many such actives lose effectiveness after just a few minutes. This rapid loss of medicinal efficacy creates a storage and delivery problem, frequently obviated by storing the lyophilized active in solid form and mixing it with a liquid immediately prior to injection.
The liquid with which a lyophilized active is mixed often adds little therapeutic quality to the final mixture. Rather, the liquid is usually a delivery vehicle, able to carry the otherwise dry active through a needle into the tissue of a patient. Since liquid delivery vehicles present the same efficacy loss problems discussed above, delivery of lyophilized actives by other means has been attempted. For instance, in one system lyophilized actives are coated on the surface of gold particles, and helium gas is used to accelerate these coated particles against and into the skin surface of a patient. This method has several drawbacks, however, as it can be painful to a recipient, and because the lyophilized active may not be delivered to an appropriate segment of a patient's tissue. Frequently such actives require subdermal delivery, which is not readily achieved by the acceleration method.
In general, a typical injection is performed with a syringe that pierces the skin with a needle to deliver medication to a desired location on a body. Oftentimes, the syringes are pre-filled with a medication. However, if a particular medication does not have a long shelf life, as is generally the case with lyophilized actives in solution, the medication must be mixed just prior to an injection to maintain potency. This requires the medication to be mixed externally to the syringe and then drawn in using needles or the like. After drawing in the medication, the injection may be administered in a normal manner. But, after the injection there are one or more needles that need to be disposed of, increasing both cost and the potential for health hazards from exposure to used needles.
As an alternative to needle delivery injections, needle-less medication injections have been performed with “permanent gun” instruments, generally referred to as “jet injectors.” These devices use either a compression spring or a compressed inert gas to propel a fluid medication (via a push rod plunger) through a small orifice (an injector nozzle) which rests perpendicular to and against the injection site. The fluid medication is generally accelerated at a high rate to a speed of between about 800 feet per second (fps) and 1,200 fps (approximately 244 and 366 meters per second, respectively). This causes the fluid to pierce through the skin surface without the use of a needle, resulting in the medication being deposited in a flower pattern under the skin surface.
Reusable jet injectors can accept pre-loaded medication cartridges, but the cartridges must be pre-loaded just prior to an injection for certain medications with short shelf lives. The procedure is to again use a needle and a syringe to mix and then load the medication in the cartridge prior to an injection. After drawing in the medication, the needle-less injection is administered in a normal manner. But, after the injection there are again one or more needles that need to be disposed of, presenting problems of cost and safety, as described above.
Single use needle-less jet injectors offer an alternative to multi-use, needle-less injectors, since they are low cost and can be pre-loaded at the point of manufacture. However, if the medication does not have a long shelf life, the pre-loading is impractical for the same reasons discussed above. Thus, single-use, needle-less injectors have generally not been usable with medications that must be mixed prior to injection. An alternative to overcome this drawback was to include a two compartment ampoule in the injector, which is opened up with a piercing mechanism such that two components are combined together to mix a medication as an injection takes place. Although this obviates the need for needles, the results are unsatisfactory, since the medication is not always thoroughly mixed and properly deposited under the skin. In addition, improper mixing can allow the medication (large molecule medications in particular) to be destroyed or altered during the injection process. Further, the piercing mechanism included in the ampoule may block or obscure the orifice, or jam the needle-less injector leading to an improper injection.
U.S. Pat. No. 6,223,786 and U.S. Pat. No. 6,302,160 describe devices and methods for mixing medications and filling the ampoule of a needle-less injector, thus obviating some of the limitations inherent in using needle-less injectors for the administration of actives with short shelf lives.
SUMMARY OF THE DISCLOSURE
It is an object of an embodiment of the present invention to provide an improved device and method for filling an ampoule of a needle-less injector with a mixture that is prepared just prior to administration of an injection, and to the storage of the components of such mixture prior to mixing and filling, that obviates for practical purposes, the above-mentioned limitations.
According to an embodiment of the present invention, an apparatus for preparing a mixture and filling an ampoule of a needle-less injector suitable for injecting the mixture includes an ampoule and a fluid holder. The ampoule may initially contain a dry reagent, and the fluid holder may initially contain a fluid. Preferably, the fluid holder also includes a fluid plunger rod, and the ampoule is coupled to the fluid holder to provide fluid communication therebetween. The fluid plunger rod may be depressed, loading the fluid into the ampoule where it mixes with the dry reagent, thus creating a mixture in the ampoule. In most preferred embodiments, the fluid holder includes a breakable membrane that prevents the fluid from being in communication with the dry reagent until the breakable membrane is broken by the application of pressure upon the fluid plunger rod. In yet further embodiments, the ampoule may include an ampoule plunger rod. After the mixture is prepared, the ampoule plunger rod may be depressed to expel air or gas either into the fluid holder from the ampoule of the needle-less injector, or to the local atmosphere if the fluid holder has already been detached from the ampoule. If the fluid holder has not been detached from the ampoule, the fluid holder plunger rod may be partially withdrawn to pull air or gas from the ampoule into the fluid holder. Most preferably, the mixture of the fluid and the dry reagent is prepared just prior to injection of the mixture due to a short shelf life of the mixture. After mixing and filling is completed, the f
Maust Timothy L.
Penjet Corporation
Pillsbury & Winthrop LLP
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