Surgery – Means for introducing or removing material from body for... – Gas application
Reexamination Certificate
1998-03-26
2001-03-20
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Gas application
C604S027000
Reexamination Certificate
active
06203519
ABSTRACT:
The present invention relates to an insufflator and an insufflator assembly incorporating the same.
Insufflator assemblies are known for blowing or forcing doses of powder containing medicament into the lungs of animals. In particular, insufflator assemblies are used during pharmaceutical trials to deliver powder containing medicament into the lungs of small animals, such as mice.
The dose of powder delivered to small animals is particularly small, typically in the range of from 20 to 25 &mgr;g. As such, it is difficult both to measure a dose of powder accurately and to provide a dose of powder in such a manner that the entire dose of powder is carried into the lungs of an animal.
In addition, the lungs of small animals are comparatively small, such that only a small volume of air can be used to deliver a dose of powder. Typically, for mice, the tidal volume, that is the volume of air passing into and out of the lungs in each breath, is only about 0.15 ml. As such, it is difficult to provide an air flow which will carry the entire dose of powder into the lungs of an animal without exceeding the capacity of the lungs of the animal.
One known insufflator assembly comprises a sample chamber connected between a delivery tube and a syringe. The sample chamber, which is of relatively large dimension, comprises two halves which are separated to load a dose of powder thereinto. In use, a dose of powder is loaded into the sample chamber and the delivery tube is then inserted into an airway of an animal, usually the laryngeal tract. The plunger of the syringe is then pushed rapidly into the body thereof so as to drive a predetermined volume of air through the sample chamber and carry the dose of powder from the sample chamber through the delivery tube and into the lungs of the animal.
In this known insufflator assembly the characteristics of the air flow are highly dependent upon how rapidly the user pushes the plunger of the syringe into the body thereof. In addition, the loading of powder into the sample chamber requires the user both to measure precisely a dose of powder and to ensure that the entire measured dose of powder is loaded into the sample chamber. Further, it is difficult to ensure that the entire dose of powder is delivered into the lungs of the animal.
Accordingly, the present invention provides an insufflator assembly, comprising: an insufflator comprising a delivery component for delivering powder into an airway of an animal, a metering component for providing a dose of powder to the delivery component and an inlet for receiving a stream of gas; and means for providing a stream of gas to the inlet of the insufflator so as to carry the dose of powder into the airway of the animal, the means comprising a chamber of a predetermined volume for containing gas at a predetermined pressure above atmospheric, a pressurized gas source for providing gas of a predetermined pressure to the chamber, a first valve for selectively connecting the chamber to the pressurized gas source and a second valve for selectively connecting the chamber to the inlet of the insufflator.
The present invention also provides a method of providing a stream of gas containing powder, comprising the steps of: pressurizing a chamber of a predetermined volume with gas at a predetermined pressure above atmospheric; sealing the chamber; and connecting the chamber to an inlet of an insufflator loaded with a dose of powder so as to release the pressurized gas into the insufflator and entrain the dose of powder in a stream of gas.
The present invention ensures that too great a volume of gas is not driven into the lungs of an animal. Indeed, the present invention can be configured to use an optimum volume of gas. Furthermore, since the insufflator assembly is triggered on the opening of only a single valve, the flow characteristics of the gas flow are substantially the same for each delivery. In particular, the flow characteristics are independent of the actions of a user.
The flow characteristics are particularly suited to powder delivery, since, on opening the second valve, gas of high pressure and high velocity is immediately released. In contrast, in known insufflator assemblies, there is a time lag while the pressure and the velocity of the gas flow builds up, such that the initial flow of gas is insufficient to carry powder and is hence wasted. The initial high pressure and high velocity gas flow achieved by the present invention is particularly effective in deagglomerating a packed dose of powder.
Preferably, the volume of gas delivered is from 1 to 2 ml.
The valves may be mechanical, but when the valves are any of pneumatic, electrical or magnetic, the insufflator assembly is more readily controllable. Preferably, at least the second valve should be a quick-opening valve.
In a preferred embodiment the second valve is connected to the insufflator by tubing of small bore and short length. In this way, a high pressure and high velocity gas flow is most effectively provided to the insufflator. This is because the dead space downstream of the chamber is minimized and there is only a small volume of gas in the tubing to be compressed, which compression will absorb part of the energy of the gas flow.
The present invention further provides an insufflator assembly, comprising: an insufflator for insertion into an airway of an animal and for delivering a dose of powder into the airway of the animal, the insufilator comprising a tube with two open ends; and a loading component comprising an elongate member having an end face for insertion into one end of the tube and for movement to a predetermined position proximate the other end of the tube so as to define a space between the other end of the tube and the end face of the elongate member, which space is in use filled with a dose of powder.
The present invention still further provides a method of loading a dose of powder into an insufflator comprising a tube with two open ends, comprising the steps of: inserting an elongate member of a loading component into one end of the tube, the elongate member having an end face; moving the end face of the elongate member through the tube to a predetermined position proximate the other end of the tube; and filling a space in the tube between the other end of the tube and the end face of the elongate member with a dose of powder.
In this way, a dose of powder is loaded directly into the tube from which it is delivered. Thus, additional steps of transferring a dose of powder intact to a delivery device are avoided. Furthermore, as the tube is of small dimension, the dose of powder may be accurately selected with relative ease by varying the volume of the space defined in the tube. In a preferred embodiment the volume of the space is set so as to provide a dose of powder of from 20 to
25 &mgr;g.
In a preferred embodiment the insufflator further comprises a further tube having two open ends, one end being for insertion into the airway of the animal and the other end being connectable with the other end of the first-mentioned tube.
The present invention yet further provides an insufflator for delivering a dose of powder into an airway of an animal, comprising: a first tube having two open ends, one end being for insertion into an airway of an animal; and a second tube having two open ends, one end for receiving a stream of gas and the other end being in use loaded with a dose of powder and connected to the other end of the first tube.
The present invention still yet further provides a method of providing a dose of powder in an insufflator for subsequent dispersion in a stream of gas, comprising the steps of: providing first and second connectable tubes; filling one end of one tube with a dose of powder; and connecting the one end of the one tube to one end of the other tube.
In this way, a dose of powder is provided directly in the flow path through the insufflator. In particular, the dose of powder is located at the inlet of the first tube such that the dose of powder can be delivered effectively therethrough.
Preferably, the oth
Eirefelt Marika Nilsson
Erjefält Ingrid
Fagerstrom Per-Olof
Hansson Henri
Nerbrink Ola
Astra Akiebolag
Fish & Richardson PC
Kennedy Sharon
Sirmons Kevin C.
LandOfFree
Insufflator assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Insufflator assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Insufflator assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484255