Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-02-19
2001-08-28
Nguyen, Anhtuant T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S891100, C604S132000, C128SDIG001
Reexamination Certificate
active
06280416
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to medication infusion pumps for controlled delivery of a selected medication to a patient over an extended period of time.
BACKGROUND OF THE INVENTION
Medication infusion pumps that supply a medication to a patient at a substantially constant flowrate are known. Exemplary infusion pumps are described in U.S. Pat. No. 3,731,681, to Blackshear; U.S. Pat. No. 3,951,147, to Tucker et al.; U.S. Pat. No. 5,167,633, to Mann et al.; and U.S. Pat. No. 5,722,957, to Steinbach. Modern infusion pumps have been developed that are implantable into the body of a patient, particularly a human patient, to whom the medication is to be supplied.
Known infusion pumps typically include a housing that contains a medication chamber and a propellant chamber, together with appropriate means for loading the selected medication into the medication chamber and for supplying the medication to the patient. The propellant chamber typically contains a gaseous or liquid/vapor propellant at a pressure above atmospheric pressure, and applies a predetermined positive pressure to the medication within the medication chamber. This affords a substantially continuous and constant flow of the medication to the patient.
Modern environmental concerns mandate that propellants employed in the foregoing infusion pumps, as well as other devices requiring propellants, be environmentally benign. It is of particular concern to avoid propellants that have an adverse effect on ozone.
A need exists for a medication infusion pump that employs an improved propellant. It would be particularly desirable to provide a medication infusion pump that employs a propellant that is not ozone-depleting.
SUMMARY OF THE PREFERRED EMBODIMENTS
In accordance with one aspect of the present invention, there is provided a medication infusion pump that includes a housing, a medication chamber defined within the housing, a medication delivery device in fluid communication with said medication chamber, a propellant chamber defined within the housing and adapted to apply a predetermined positive pressure to a medication in the medication chamber, and a propellant within the propellant chamber. The propellant preferably has a vapor pressure between about 11 psig and about 50 psig at 37° C., and is non-ozone-depleting and non-toxic.
A mixture of two or more propellants, or of a propellant and one or more diluent gases, can also be employed.
In a preferred embodiment, the propellant is a gas selected from the group consisting of HFA-134a, HCFC-141b and neopentane.
In accordance with another aspect of the invention, there is provided a medication infusion pump that dispenses a medication at a substantially constant flowrate by application to the medication of a predetermined positive pressure. The predetermined positive pressure is exerted by a non-ozone depleting, non-toxic propellant having a vapor pressure between about 11 psig and about 50 psig at 37° C.
In accordance with another aspect of the present invention, there is provided a method of supplying a medication to a patient from a medication infusion pump as described herein. The method includes the steps of filling the propellant chamber with a non-ozone-depleting, non-toxic propellant having a vapor pressure between about 11 psig and about 50 psig at 37° C., and dispensing the medication from the medication chamber.
Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.
REFERENCES:
patent: 3731681 (1973-05-01), Blackshear et al.
patent: 3951147 (1976-04-01), Tucker et al.
patent: 4140122 (1979-02-01), Kuhl et al.
patent: 4668231 (1987-05-01), De Vries et al.
patent: 4820273 (1989-04-01), Reinicke
patent: 4969873 (1990-11-01), Steinbach et al.
patent: 5085656 (1992-02-01), Polashegg
patent: 5167633 (1992-12-01), Mann et al.
patent: 5318540 (1994-06-01), Athayde et al.
patent: 5514103 (1996-05-01), Srisathapat et al.
patent: 5527307 (1996-06-01), Srisathapat et al.
patent: 5607418 (1997-03-01), Arzbaecher
patent: 5722957 (1998-03-01), Steinbach
patent: 5766150 (1998-06-01), Langkau
patent: 5769823 (1998-06-01), Otto
patent: 5785688 (1998-07-01), Joshi et al.
patent: 5814019 (1998-09-01), Steinbach et al.
patent: 5908414 (1999-06-01), Otto et al.
patent: 5957890 (1999-09-01), Mann et al.
patent: 0488701 (1992-06-01), None
patent: 9740873 (1997-11-01), None
EPA, “http://www.epa.gov/ozone/”, 23 pages, see entire collection.
Lord Peter C.
McConnell Susan M.
Van Antwerp William P.
Gates & Cooper LLP
MiniMed Inc.
Nguyen Anhtuant T.
Thompson Michael M.
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