Method and apparatus for releasing a controlled amount of aerosol medication over a selectable time interval

• US 5,755,218 A
• Filed: 11/27/1996
• Issued: 05/26/1998
• Est. Priority Date: 03/05/1991
• Status: Expired due to Fees

• Current Assignee: Aradigm Corporation
• Original Assignee: Aradigm Corporation
• Inventors: Ritson, Carl, Rubsamen, Reid M., Johansson, Eric T.
• Primary Examiner(s): Lewis, Aaron J.
• Application Number:
  US08/758,042
• Time in Patent Office: 545 Days
• Field of Search: 128/200.14, 128/200.23, 128/204.23
• US Class Current: 128/200.14
• CPC Class Codes: A61J 7/0418 with electronic history memory
• CPC Class Codes: A61M 15/00 Inhalators drug delivery in endotracheal tubes A61M16/04
• CPC Class Codes: A61M 15/0021 Mouthpieces therefor
• CPC Class Codes: A61M 15/008 Electronic counters
• CPC Class Codes: A61M 15/009 using medicine packages with incorporated spraying means, e.g. aerosol cans pocket atomiser of the injector type A61M11/08
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 16/202 electrically actuated
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/60 with identification means
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2205/6027 Electric-conductive bridges closing detection circuits, with or without identifying elements, e.g. resistances, zener-diodes
• CPC Class Codes: A61M 2205/6036 characterised by physical shape, e.g. array of activating switches
• CPC Class Codes: A61M 2205/6045 having complementary physical shapes for indexing or registration purposes
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2205/8212 with means or measures taken for minimising energy consumption
• CPC Class Codes: B01F 23/2132 using nozzles
• CPC Class Codes: B01F 35/71 Feed mechanisms with proportioning B01F35/80
• CPC Class Codes: B01F 35/714 for feeding predetermined amounts B01F35/88 takes precedence
• CPC Class Codes: B01F 35/7179 : using sprayers, nozzles or jets
• CPC Class Codes: B01F 35/7547 : using valves, gates, orifices or openings
• CPC Class Codes: G01F 1/363 : with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 1/40 : Details of construction of the flow constriction devices
• CPC Class Codes: G01F 1/50 : Correcting or compensating means
• CPC Class Codes: G01F 13/006 : measuring volume in function of time
• CPC Class Codes: G01F 15/002 : for gases

Abstract

A portable, battery powered, hand-held system for releasing a controlled dose of aerosol medication for inhalation by a patient including a durable body and a medication cassette inserted in the durable body. The cassette includes a housing for containing a canister of medication, bears an identification code, and permits the canister to be manually depressed to release a dose, e.g., a metered dose, when out of the durable body. The durable body includes an actuator mechanism for engaging an inserted cassette and its canister, and an actuator release mechanism for controlling the actuator mechanism to depress the canister for a selected period of time to release the desired dose of medication and then the release the canister. The actuator mechanism, includes a compression spring for depressing the canister and a torsion spring for reloading the compression spring. The torsion spring is reloaded by rotating the cassette from an open position for delivering aerosol to a closed position. The actuator release mechanism includes a motor and trigger pin assembly that controls the release of the compression spring and the torsion spring, and, hence, the time that the canister is depressed. The motor operates in response to sensed flow satisfying a selected delivery threshold. The durable body includes a flow sensor having an asymmetrical orifice that is calibrated, independent of the cassette, to convert the sensed pressure due to flow into a flow rate. The orifice is separately calibrated for an inhalation flow rate range and an exhalation flow rate range over a selected number of known flow rates. The sensed pressure value is corrected for transducer offset drift and converted to a flow rate using the calibration data and piecewise linear interpolation.

Claims

1. A hand held device for providing an aerosolized burst of a formulation, comprising:

a flow sensor for detecting the inspiratory flow of a patient;

a container having a formulation comprised of a drug and a carrier therein and a valve normally biased closed, which valve may be opened when force is applied to a stem of the valve in a direction toward the container;

a drive element for applying force in a manner so as to open the valve;

a release actuator for actuating the drive element;

a programmable microprocessor which receives information from the sensor and forwards information to the release actuator in order to open the valve and release aerosolized formulation over a period of time of from between 10 and 1,000 msec wherein the amount of time is selectable along with relative time with respect to sensor determined flow rate and flow volume;

a visual display;

wherein the microprocessor is programmed to determine a patient'"'"'s pulmonary function and provide pulmonary function information to the visual display.

2. The device of claim 1, wherein the microprocessor is programmed to forward information to the release actuator at a threshold level of inspiratory flow as determined by the flow sensor.

3. The device of claim 1, wherein the pulmonary function measured and displayed is forced expiratory volume in one second.

4. The device of claim 1, wherein the pulmonary function measured and displayed is forced vital capacity.

5. The device of claim 1, wherein the pulmonary function measured and displayed is peak expiratory flow rate.

6. The device of claim 1, wherein the pulmonary function measured and displayed is a display of trend data obtained by a comparison to prior measurements.