Surgery – Means for introducing or removing material from body for... – Treating material applied to or removed from external...
Reexamination Certificate
1999-11-08
2001-07-03
Seidel, Richard K. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material applied to or removed from external...
C604S218000, C604S256000, C604S311000
Reexamination Certificate
active
06254579
ABSTRACT:
The present invention generally relates to apparatus for dispensing microliter amounts of medicament and is more particularly directed to apparatus for instilling a medicament into an eye.
A great number of devices have been developed for instilling medicament to an eye. Well known eye drop containers conventionally include a squeezable container and a nozzle for releasing drops of medicament into the eye by compression of the container. Obviously, this apparatus affords no practical method of dispensing a measured dose of medicament inasmuch as the liquid dispensed from the nozzle is dependent upon the amount of compression of the container. Thus, there is no way of accurately controlling the volume of each dose of medicament released into the eye and, further, the smallest drop obtainable is the result of the combined effective gravity and surface tension.
When preservative-free medicaments are utilized, simple eye drop dispensers are not practical because there are no means for preventing the tip from being contaminated due to its exposure to air. Such tip contamination ultimately spreads to the medicament in the container.
In an attempt to overcome these problems, apparatus has been developed for applying a medicament to an eye which includes a nozzle having a seam which is normally in a closed position for preventing the passage of medicament through the nozzle, and which opens in response to a flow of medicament of sufficient pressure to enable opening of the seam in order to permit the passage of medicament through the nozzle for release into the eye, see U.S. Pat. No. 5,685,869.
While this nozzle is suitable, there is difficulty in coupling the nozzle with a suitable reservoir of medicament in order to create a working, producible device for multiple dose delivery of a preservative-free product of sufficient dose accuracy for consumer benefit and regulatory body registration over an extended period of time of up to six months or more.
Operation of prior art devices such as set forth in the hereinabove referenced U.S. patent, typically causes a small negative pressure, or vacuum, within the medicament container during operation. When a collapsible container is utilized to accommodate shrinking of volume of the medicament reservoir, the materials of construction do not satisfactorily inhibit the permeation of air through the container walls to provide a desired long term use in storage of the device without compromise of the stored medicament.
The present invention overcomes the shortcomings of the prior art devices by providing nozzle and medicament reservoir combination which enables multiple dose delivery of a preservative-free product with accurate dose dispensing over extended periods of time.
SUMMARY OF THE INVENTION
Apparatus in accordance with the present invention for instilling a medicament to an eye generally includes a rigid housing which provides a means for containing the reservoir medicament. The rigid housing can be formed from materials which prevent any permeation of medicament or the air therethrough.
A nozzle provides a means for instilling a dose of the medicament into an eye and displacement means, sealing a front end of the rigid housing and in fluid communication with the reservoir, is provided for metering doses of the medicament from the reservoir to the nozzle and for forcing each metered dose through the nozzle.
A stopper, slidably disposed within a rear end of the rigid housing means, provides a means for gradually decreasing a housing volume containing the medicament. This prevents the development of a detrimental amount of residual vacuum within the housing due to removal of medicament therefrom. The stopper prevents such vacuum creation within the housing by sliding within the housing under the force of atmospheric pressure.
Additionally, the displacement means comprises a positive displacement pump within the pump head with an angular skirt valve disposed within the pump body. Importantly, the pump body is integrally molded as part of the housing means front end to further reduce the number of separate parts and provide for more efficient manufacturing of the apparatus.
The pump body comprises a tapered cylinder means for enveloping the pump head with the tapered cylinder means being in fluid communication with the reservoir. Tapered cylinder means protects the skirt valve and breaks up air bubbles, if any. This accordingly improves pump efficiency. In addition, the pump further comprises a collapsible boot having a rear portion fitted to an exterior of the housing means front end and the front portion forming a flexible nozzle outer sleeve. This provides a microbial barrier and requires no further mechanical closures.
The nozzle includes a piston with a rear portion attached to the pump head and a front portion fitted through the nozzle outer sleeve and establishing in it interface therebetween. The piston is movable with the pump and the nozzle includes channel means, disposed within the piston, for conducting each metered amount of medicament from the pump head to the interface, each metered amount of medicament exiting the nozzle means through the interface.
In addition, spring means disposed around the piston and beneath the boot are provided for moving the pump head and piston forwardly after compression thereof. The forward movement causes the pump head angular skirt valve to force the metered amount of medicament from the tapered cylinder into the channel means.
Diaphragm means, disposed in the stopper, may be provided for accommodating transient decreases in the volume containing the medicament reservoir during metering of doses therefrom by said displacement means. In addition, the diaphragm means reduces agitation in the reservoir during metering doses therefrom by the displacement means. It is important to minimize backward movement of the stopper in the medicament reservoir during the transfer of metered amounts of medicament from the reservoir to the nozzle in order to ensure accurate metering of doses.
More particularly, the diaphragm means comprises means for minimizing dead space and trapped air in the reservoir during insertion of the stopper means into the rigid housing. This is particularly important in manufacture of the apparatus whereby the reservoir is filled and capped while under vacuum to prevent bubbles which cause inaccuracies in the metering of doses from the reservoir.
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Cogger John J.
Haffner David S.
Allergan Sales Inc.
Hackler Walter A.
Maynard Jennifer
Seidel Richard K.
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