Details for Patent: 5,775,320

Title:	Method and device for delivering aerosolized medicaments
Abstract:	A device for accurately delivering aerosolized doses of a medicament disperses a measured amount of drug in a measured volume of carrier gas and transfers the resulting aerosol to a chamber prior to inhalation by a patient. The chamber is filled efficiently with the aerosol, and inhalation by the patient draws the aerosol dose into the lungs. This is followed by the inhalation of atmospheric air that will push the initial dose well into the lung interiors. The apparatus optimally includes a dose regulator, a counter, a clock, a dose memory and a signal to indicate when a dose is ready for inhalation. Optimal chamber designs are disclosed.
Inventor(s):	Patton; John S. (San Carlos, CA), Platz; Robert M. (Half Moon Bay, CA)
Assignee:	Inhale Therapeutic Systems (Palo Alto, CA)
Filing Date:	Dec 22, 1995
Application Number:	08/576,885
Claims:	1. An apparatus for producing aerosolized doses of a medicament, said apparatus comprising: means for aerosolizing a preselected amount of the medicament in a predetermined volume of gas from about 10 ml to 750 ml; a chamber having an inlet at one end, a mouthpiece at an opposite end, and a volume in the range from 100 ml to 750 ml; and means for transferring substantially the entire volume of aerosolized medicament from the aerosolizing means to the chamber; wherein the volume and geometry of the chamber are selected so that air initially present in said chamber is displaced without substantial loss of medicament through the mouthpiece or within the chamber. 2. An apparatus as in claim 1, wherein the means for aerosolizing the medicament comprises a dry powder reservoir and means for introducing preselected amounts of the dry powder into a flowing gas stream. 3. An apparatus as in claim 1, further comprising an ambient air inlet disposed tangentially on the chamber relative to the transferring means, whereby inhalation on the mouthpiece will induce a vortical flow of ambient air to sweep medicament through the chamber. 4. An apparatus as in claim 3, wherein the air inlet is located on the same end of the chamber as the aerosolized medicament entry point, whereby patient inspiration sweeps the chamber with air from the air inlet. 5. An apparatus as in claim 3, wherein the air inlet includes a one-way valve which permits inflow and prevents outflow. 6. An apparatus as in claim 1, wherein the means for aerosolizing the medicament comprises a liquid reservoir and a nebulizer for introducing a liquid solution or suspension of the medicament into a gas stream. 7. An apparatus as in claim 6, wherein the chamber has a generally cylindrical interior and receives the aerosolized medicament at a tangential angle so that a vortical flow is established, and wherein the aerosolized medicament enters at one end of the chamber and the mouthpiece is at the other end. 8. The apparatus of claim 1, wherein the chamber includes a longitudinal axis extending between the front end and the rear end, and wherein the air inlet and the mouthpiece are offset from each other relative to the longitudinal axis. 9. An apparatus for producing aerosolized doses of a medicament, said apparatus comprising: means for aerosolizing and dispersing a predetermined amount of the medicament in a preselected amount of gas from about 10 ml to 750 ml; and a chamber having an inlet at one end, a mouthpiece at an opposite end, and a volume in the range from about 100 ml to 750 ml said chamber being adapted to receive the entire volume of dispersed medicament from the aerosolizing and dispersing means, wherein the chamber defines an internal flow path along which air is displaced from the chamber as the chamber is being filled with medicament, and wherein the volume and geometry of the chamber are selected to that air initially present in the chamber is displaced without substantial loss of medicament through the mouthpiece or within the chamber. 10. An apparatus as in claim 9, further comprising an ambient air inlet disposed tangentially on the chamber, whereby inhalation on the mouthpiece will induce a vortical flow of ambient air to sweep medicament through the chamber. 11. An apparatus as in claim 10, wherein the air inlet is located on the same end of the chamber as the aerosolized medicament entry point, whereby patient inspiration sweeps the chamber with air from the air inlet. 12. An apparatus as in claim 10, wherein the air inlet includes a one-way valve which permits inflow and prevents outflow. 13. An apparatus as in claim 9, wherein the means for aerosolizing the medicament comprises a liquid reservoir and a nebulizer for introducing a liquid solution or suspension of the medicament into a gas stream. 14. An apparatus as in claim 9, wherein the chamber has a generally cylindrical interior and receives the aerosolized medicament at a tangential angle so that the internal flow path is vortical, and wherein the aerosolized medicament enters at one end of the chamber and the mouthpiece is at the other end. 15. An apparatus as in claim 9, wherein the chamber has a spacer tube disposed axially therein the help establish the vortical flow pattern. 16. The apparatus of claim 9, wherein the chamber includes a longitudinal axis extending between the front end and the rear end, and wherein the air inlet and the mouthpiece are offset from each other relative to the longitudinal axis. 17. A method for producing an aerosolized dose of a medicament for subsequent inhalation by a patient, said method comprising: dispersing a preselected amount of the medicament in a predetermined volume of gas to produce the aerosolized dose from about 10 ml to 750 ml; and capturing substantially the entire volume of the aerosolized dose in a chamber having a mouthpiece, an inlet opposite the mouthpiece through which the aerosolized dose is introduced, and a volume in the range from 100 ml to 750 ml, and maintaining at least about 70 percent by weight of the medicament in aerosolized form while captured, wherein the capturing and maintaining step comprises displacing air initially present in said chamber without substantial loss of medicament through the mouthpiece. 18. A method as in claim 17, wherein the aerosolized dose flows into the chamber in a vortical pattern. 19. A method for delivering an aerosolized medicament to a patient, said method comprising: (a) dispersing a preselected amount of the medicament in predetermined volume of gas to produce a single aerosolized dose from about 10 ml to 750 ml; (b) introducing the aerosolized dose into a chamber having an inlet end, a mouthpiece at an opposite end, and a volume from 100 ml to 750 ml, and capturing substantially the entire volume of the aerosolized dose in the chamber, wherein air initially present in the chamber is displaced without substantial loss of medicament through the mouthpiece or within the chamber; (c) inhaling of the aerosolized dose from the chamber through the mouthpiece by the patient, whereby the chamber is refilled with ambient air; and (d) sweeping any remaining aerosolized dose from the chamber with ambient air during the inhaling step. 20. A method as in claim 19, further comprising repeating steps (a) through (d) a sufficient number of times to deliver a desired total dosage of the medicament. 21. An apparatus for producing aerosolized doses of a medicament, said apparatus comprising: means for aerosolizing a preselected amount of the medicament in a predetermined volume of gas from about 10 ml to 750 ml; a chamber comprising a chamber body defining an internal volume in the range from 100 ml to 750 ml and having a substantially uniform cross-sectional area along its length, said chamber further including an inlet opposite a patient mouthpiece; and means for transferring substantially the entire volume of aerosolized medicament from the aerosolizing means to the chamber; wherein the volume of the chamber is selected so that air initially present in said chamber is displaced without substantial loss of medicament through the mouthpiece or within the chamber.