Surgery – Liquid medicament atomizer or sprayer
Reexamination Certificate
2002-02-25
2004-03-02
Lewis, Aaron J. (Department: 3761)
Surgery
Liquid medicament atomizer or sprayer
C128S200220, C128S200230
Reexamination Certificate
active
06698422
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a canister inhaler for effectively delivering medications by inhalation through the mouth of patients having a flexible, elastic mouthpiece, a spacer for more effectively mixing the medication and air, and an easy to operate lever mechanism.
BACKGROUND OF THE INVENTION
Inhalation into the lungs of a patient of a metered dose of medication is an increasingly common delivery system for a variety of drugs, including but not limited in any way to anti-asthma medications, insulin (See http://www.msnbc.com
ews/525058.asp), various steroids and treatments specific to various pulmonary diseases. One concern with metered dose inhalers or aerosol pressurized cartridges has been that, while the metered dose inhaler canister dispenses a fixed, metered dose of medication, not all of the metered dose actually reaches the lungs of the patient. Even if a patient times inhalation with the dispersal of the medication from the metered dose inhaler (MDI), the amount of medication reaching the lungs is inconsistent, depending on how much of the medication is dissolved and entrained in the stream of air entering the patient's lungs, and how much of the medication is deposited on surfaces of the inhalation apparatus, the mouth and oropharyngeal area of the patient. Furthermore, deposits in the mouth and oropharyngeal area of the patient can cause complications, such as candidiasis, as well as leave an unpleasant aftertaste. In addition, many patients using inhalation devices have practical problems with the use of typical inhalers, including difficulty with compressing the metered dose inhaler canister, problems timing inhalation with the dispersal of medication, and inability to inhale the complete dose of medication in a single breath, particularly young, elderly, or patients who suffer from asthma and dysphonia or thrush from inhaled corticosteroids. In practice, it is common to see patients activating their metered dose inhalers multiple times, although the metered dose should have been dispensed in a single activation. This is a typical response of patients to the difficulty and inconsistency of medication delivery, undermining the effectiveness of the MDI, which can lead to over-medication, under-medication, or waste and higher than necessary costs for treatment.
The typical solution to the problem of inconsistent medication delivery has been to provide a “spacer” or “chamber” within the inhalation device. A spacer or chamber is merely a reservoir of air. The metered dose of medication, usually an atomized mist or vapor, mixes with the reservoir of air before being inhaled by the patient, reducing the inconsistency of delivery due to timing difficulties. See U.S. Pat. Nos. 4,470,412; 4,790,305; 4,926,852; 5,012,803; 5,040,527; 5,042,467; 5,816,240; and 6,026,807. An additional improvement incorporated into many of the devices with spacers has been a simple valve mechanism to allow the patient to inhale the medication in more than one breath. For example, see U.S. Pat Nos. 4,470,412; 5,385,140. The efficacy of such devices for correcting errors in patient technique has been shown in general medical research. For example, see Demirkan, et al., “Salmeterol Administration by Metered-Dose Inhaler Alone vs. Metered-Dose Inhaler Plus Valved Holding Chamber,”
Chest,
117 (2000) pp. 1314-1318, Finlay and Zuberbuhler, “In vitro comparison of beclomethasone and salbutamol metered-dose inhaler aerosols inhaled during pediatric tidal breathing from four valved holding chambers,”
Chest,
114 (1998) pp. 1676-1680, and Konig, “Spacer devices used with metered-dose inhalers. Breakthrough or gimmick?”
Chest,
88 (1985) pp. 276-284.
One problem not generally addressed is the ease of compression of MDI canisters. One spacer, called the EZ Spacer®, http://www.weez.com, improves the ease of compression by allowing the patient or another to use both thumbs on a pull handle and the forefingers on the MDI canister, but this is only a marginal improvement over the standard design, allowing merely one thumb and forefinger for compression of the MDI, and is no aid to patients who do not have full use of both of their thumbs and forefingers.
For infants or other patients who have difficulty using a mouthpiece, a mask is commonly attached or incorporated onto the MDI inhaler. See U.S. Pat. Nos. 4,809,692; 4,832,015; 5,012,804; 5,427,089; 5,645,049; 5,988,160. Also, some devices include an audible signaling device to warn patients when inhalation exceeds a desirable rate. For example, see U.S. Pat. Nos. 4,809,692 and 5,042,467.
One method of attaching a spacer to the MDI canister is to insert the MDI inhaler into a universal adapter such as shown in U.S. Pat. No. 5,848,588, but this is bulky and awkward to use, and does nothing to ease the difficulty of compressing the MDI canister for infirm or ailing patients. Other devices are designed to have a specific MDI canister inserted into the device. It would be beneficial to be able to insert MDI canisters for various medications into an inhaler with a universal receptor.
SUMMARY OF THE INVENTION
The present invention is directed to an inhaler that has universal receptors for at least one medication canister
10
or metered dose inhaler (MDI) canister, also referred to as a cartridge. By the term inhaler, the inventors mean that the device accepts a canister directly into the device, replacing the typical inhaler with an improved inhaler that comprises a receptor for an MDI canister, a spacer, an easy to operate lever arm, and a mouthpiece. One typical embodiment of the invention accepts a single canister, and has a lever arm
22
that is easy to depress, a chamber
210
that acts as a spacer (for example see
FIGS. 9
,
10
and
12
), having an optional valve mechanism (for example see FIG.
11
). In one embodiment, the optional valve mechanism is integrally molded with the chamber body and includes at least one inhalation vent
218
(for example see FIG.
12
), a diaphragm valve
214
, and an optional over-pressure whistle
212
, which can be included to improve the efficiency of medication delivery by alerting the patient to improper inhalation technique. In another embodiment, the optional valve mechanism is fabricated separately from the chamber body, and the optional valve mechanism is then fixed to the chamber body. Examples of fixation include but are not limited to adhering, fastening, and inserting of the valve mechanism to the chamber body.
In one preferred embodiment of the mouthpiece, for example see
FIG. 10
, the mouthpiece
220
is comprised of a flexible, elastic material, and fits tightly around the chamber body
210
at the mouthpiece mating end
211
. In one particular embodiment, an annular diaphragm valve
214
is positioned on a retaining member
215
in an optional valve mechanism within the chamber body. During inhalation, the diaphragm valve opens, allowing a mixture of air and medication to flow through at least one inhalation vent
218
, then through the mouthpiece
220
and into the patient's lungs. During exhalation, the diaphragm valve
220
closes, keeping the exhaled air from reentering the chamber body. Then, the exhaled air exerts an outward hydrostatic pressure against the sides of the mouthpiece
220
. The hydrostatic pressure causes the exhaled air to escape by forcing the air between the mouthpiece
220
and the chamber body
210
at the mouthpiece mating end
211
. In one particular embodiment, the mouthpiece mating end
211
has at least one exhaust port
216
. In one particular embodiment the exhaust port
216
is a rectangular notch in the side of the mouthpiece mating end
216
of the chamber body
210
, wherein the exhaust port
216
is covered by the flexible, elastic material of the mouthpiece
220
. In this particular embodiment, the exhaled air preferentially exits through the exhaust port
216
, because the flexible, elastic material of the mouthpiece
220
preferentially deflects at the location of the exhaust port
216
. In another embodiment, as show
Fugelsang Eric
Muszak Martin
Birdsong Medical Devices, Inc.
Kenyon & Kenyon
Lewis Aaron J.
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