Fluid sprinkling – spraying – and diffusing – Reaction motor discharge nozzle
Reexamination Certificate
2001-09-25
2004-06-01
Hwu, Davis (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Reaction motor discharge nozzle
C239S265170, C239S265190, C239S265230, C239S265270
Reexamination Certificate
active
06742721
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO A COMPUTER PROGRAM APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to aerosol generating devices, and more particularly to inhalers which may be used to dispense liquid medication in short bursts of aerosol.
2. Description of the Background Art
Some medicines cannot withstand the environment of the digestive tract and must be delivered to the bloodstream intravenously or by some other means. One effective means for delivery of such medications to the blood stream is through the membranes and air passageways of the lung.
Inhalers of various types have been widely used for inhalation delivery of aerosols containing medication or other constituents to the conductive airways of the lung and the gas exchange regions of the deep lung. Aerosols are relatively stable suspensions of finely divided droplets or solid particles in a gaseous medium. When inhaled, aerosol particles may be deposited by contact upon the various surfaces of the respiratory tract leading to the absorption of the particles through the membranes of the lung into the blood stream and providing the desirable therapeutic action, or planned diagnostic behavior depending on the particular properties of the particles.
Because of the high permeability of the membranes of the lung and the copious flow of blood through the lung, medications deposed in the lung can readily enter the blood stream for action throughout the body. This may also allow for lower initial doses than would be required to be taken orally to achieve the desired concentration of medication in the blood. Other medications can directly influence the airway epithelium and effect responses via various airway receptors.
Properly generated and formulated aerosols can therefore be helpful in medical treatment. Inhalable aerosol particles capable of deposition within the lung are those with an aerodynamic equivalent diameter between 1 and 5 micrometers.
Still other types of aerosol particles deposited in the lung can act as tracers of airflow or indicators of lung responses and otherwise be a valuable diagnostic tool.
An inhaler produces a burst of aerosol consisting of fine particles intended for inhalation by a patient with a single breath. Inhalers are popular aerosol delivery devices because they are generally portable and are convenient to use. The particle size of the aerosol emitted from a typical inhaler is required to be considerably smaller than a conventional spray atomizer to ensure the appropriate deposition within the lungs. Atomizers are typically equipped with reservoirs, nozzles, and bulbs. Upon squeezing the bulb, liquid medication, which is placed within the reservoir, is entrained and sprayed by the nozzle for inhalation by the patient. However, the particle size produced by atomizers is too large for effective deposition in the lungs, although variants of the technique are still used for deposition of topical medication into the nasal cavity and associated tissues. A further disadvantage of atomizers is that they are unable to deliver a consistent dose due to discrepancies in user technique and the duration of each burst. Accordingly, atomizers are appropriate for delivery of medication to the sinus cavity, where the larger aerosol particle size is more effective for deposition but inappropriate for deposition in the deep lung.
Inhalers known in the art employ several techniques to achieve effective aerosolization of medicines for deposition in the lung. Commonly, inhalers are pre-packaged containers containing a mixture of medication to be aerosolized and a low saturation pressure vapor or gas, such as chlorofluorocarbons (CFCs), which are used as a propellant. The canister carrying the mixture of medication and propellant is equipped with a valve. When the valve is actuated, the inhaler dispenses a set amount of liquid and medication through a jet orifice, creating a spray. Upon release into the atmosphere, the low saturation pressure propellant is able to evaporate quickly leaving small aerosol particles of medication that are suitable for immediate inhalation. One disadvantage to this approach is that the propellant and the medication must be mixed for a significant period of time prior to inhalation by the patient, making them unsuitable for many medications. Furthermore, the pre-mixing of the medication and the propellant requires a different approach to gain regulatory approval, necessitating significant development time and capital, thereby significantly increasing the ultimate cost to the patient than with liquid formulations of same medication. To prevent agglomeration of the medication within the canister, surfactants are also added to the formulation, which often leave an undesirable taste in the mouth of the patient after inhalation.
Another inhaler strategy increasingly being employed is the aerosolization of dry medicament powders. Medicinal powders are prepared in advance and placed in a reservoir within the inhaler, or within blister pouches. Blister pouches have the advantage of being able to better preserve the powder from contamination and moisture. When the patient is ready for a dose of medication, they either access the reservoir to dispense an appropriate amount of powdered medication, or puncture a blister pouch containing the powder medicament. Aerosolization is typically achieved by the gas flow produced by the inhalation of the patient. However, the aerosolization of medicinal powders is plagued by problems of moisture contamination and the inconsistencies in inhalation effort by the patient from dose to dose. Furthermore, powder formulations are as expensive to develop as pre-mixed propellants.
A third inhaler strategy employs ultrasonic energy to aerosolize bursts of liquid medication. These devices require precise electronic valves and associated electronic circuitry, making them expensive to manufacture and prone to malfunction. Additionally, the particle size of the aerosol produced by these devices is often too large for optimal deposition in the lung.
Therefore, a need exists for a technology which can deliver aerosol bursts of liquid medication at a particle size that is appropriate for lung deposition and which is inexpensive for the patient, produces consistent output, uses a formulation which is inexpensive to develop and produce, that is reliable, that is easy to use, and which does not require the mixing of medication and propellant until the moment of aerosolization. The present invention satisfies this need, as well as others and has the further advantages of providing superior aerosol quality, and being lightweight and portable.
BRIEF SUMMARY OF THE INVENTION
The present invention generally pertains to a pneumatic inhaler that is able to deliver a controlled burst or dose of aerosol from a reservoir of liquid medication. The invention is appropriate for the aerosolization of liquid medication that is in solution or in suspension form. The invention is also ideal for the delivery of unique and specialty liquid medications in short aerosol bursts because no additional formulation development is needed. The apparatus has the further advantage of being able to deliver multiple medications, as mixed by the patient, doctor, or pharmacist, with a single burst of aerosol at a repeatable output. Because the medication and the propellant are not mixed until aerosolization occurs, the current invention is appropriate for more pharmaceutical agents than can be used by currently available inhalers at a substantial cost savings.
By way of example and not of limitation, a first embodiment of the present invention employs a cartridge or cylinder for containing virtually any type of compressed gas. Typically, carbon dioxide gas is used at a preferred pressure of approximately 750 psi, because the gas has a low critical temperature and pressure, allowing a small canister to carry significantly more than if filled with many other gases. The compressed gas is r
Evit Laboratories
Hwu Davis
O'Banion John P.
LandOfFree
Shock wave aerosolization method and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Shock wave aerosolization method and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Shock wave aerosolization method and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3362445