Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
2001-11-26
2004-03-30
Bennett, Henry (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S200230, C128S203150, C128S203160
Reexamination Certificate
active
06712070
ABSTRACT:
TECHNICAL FIELD
The present invention concerns a gas inhalation device and its use. The invention in particular concerns a gas inhalation device, which is breath-activated, for use with a gas canister and the use of the gas inhalation device.
TECHNICAL BACKGROUND
A basic purpose of many inhalation devices is to provide means for ensuring the administration of a drug in a way establishing physical contact between the drug and the airways, and preferably the lower airways or fine receptors of the lungs, of a patient to be treated. Note that while the present invention was developed with asthma inhalation devices in mind, the present devices may naturally be used for administration of drugs for other diseases.
Two technologies are in widespread use in asthma inhalation devices. One is powder based, the other is gas canister based. Powder devices suffer from the drawback that the particle sizes used are relatively large, making it difficult for them to reach the fine receptors of the lungs. Gas devices provide finer particles, but eject these at a relatively high speed. A typical gas device will by activation in air create a small cloud having a length of typically 30-40 cm. On use such a cloud is likely to get in physical contact with the inner part of the mouth, i.e. the palate, rather than the fine receptors of the lungs where it is intended. A short description of the airways may elucidate this point. The upper airways include the oropharynx and larynx. The lower airways start in the trachea, which is followed by successive bifurcation into bronchi and bronchioli. Down to this point, the spaces are called conductive airways. The terminal bronchioli then divide into respiratory bronchioli until the ultimate respiratory zone, the alveoli, is reached. There is a very steep increase in the surface area with successive airways generations with consequences for drug absorption.
The inventors of the present invention have realized, that a problem occuring with the use of the known gas inhalation devices is achieving an appropriate speed of drug on inhalation. If the speed is too high, a high proportion of the drug is shot directly into the roof of the mouth, i.e. the palate. If the speed is too slow only a small portion of the drug will make it to the fine receptors of the lungs. It is usually regarded desirable to provide a large percentage of the drug in physical contact with the fine receptors of the lungs, i.e. increasing the contact area between drug and alveoli.
As an example of a powder inhaler WO 00/64520 describes a device for two or more medicaments. The powder is administered to the patient when the patient sucks from the mouthpiece and inhales the powder.
As an example of a gas canister based device EP 0 311 770 B1 describes a respiratory therapy device with a large aerosol vortexing chamber. This patent describes the beneficial effects of using a slow aerosol flow. Administration is performed when the patient inhales from a mouthpiece through a valve from the large aerosol vortexing chamber.
Another problem associated with known inhalation devices is that many of them demand coordination of breathing rhythm, activation of the device and application of the device to the mouth of the patient. Such coordination may be difficult, especially for a patient struggling to get air, and for children and aged people. It is desirable to facilitate such coordination in order to optimise administration of the drugs.
According to an aspect of the present invention it is an object of the present invention to provide means for enhancing the probability of a therapeutically effective amount of active substance reaches the fine receptors of the lungs.
According to another aspect of the present invention it is an object of the present invention to provide means for allowing a patient and/or an attending physician to achieve better control of the inhalation process and/or the way a drug is administered.
Some desirable aspects of asthma devices provided according to the present invention may be summarized as: high percentage of drug administered to patient; adequate, adjustable speed of gas on inhalation; easy adjustment of pressure without need of changing gas canister (e.g. by multiple activation of gas canister); utility with many existing gas canisters on the market; portability of device, due to size and design; discrete design; easy use, low price of device; and/or secure locking mechanism to prevent unwanted release of gas.
DISCLOSURE OF THE INVENTION
The present invention concerns a device for the inhalation of at least one drug, from a gas canister having a nozzle, by a person suffering from asthma or bronchospasm, said device comprising: a gas container having at least one wall, said wall surrounding a gas containment chamber adapted to contain gas at a pressure larger than atmospheric pressure, said gas container further having an inlet adapted for connection to the nozzle of the gas canister, said gas container further having an outlet with an outlet valve adapted to allow the person to inhale gas from said device through said outlet; wherein said outlet valve is adapted to be activated by the inhalation of the person independent of the activation of the gas canister.
This aspect allows the person to activate the gas canister, and pause before inhalation. Gas from the gas canister will be contained in the gas containment chamber at a pressure larger than atmospheric pressure. On inhalation the outlet valve may be activated. The gas contained in the gas containment chamber will expand rapidly and enter the airways of the person on activation of the outlet valve. Thus, this aspect may facilitate coordination for the patient inhaling. This encourages the patient to perform a slow, deep inhalation, for maximum deep-lung delivery of the active substance (drug).
Existing, commercially available gas canisters, which may be used with the present invention, are usually provided with a nozzle. Activation of the gas canister is done by pressing or forcing the nozzle in direction towards the gas canister, whereby a dose of active drug is emitted from the nozzle. A usual gas canister contains propellant for a higher number of doses than the number of doses of active drug in the gas canister. A vent inside the gas canister ensures that an approximately constant volume of active drug is administered on each activation of the gas canister, until the active drug has been used. The gas canisters may be any suitable gas ganisters, and inter alia contain drugs such as Bricanyl, Salbutamol, and Beclometasom.
The device according to the invention may be made from any suitable material, inter alia from metal or plastic by e.g. molding, casting or lathing. Especially preferred materials are discussed below.
DETAILED DISCLOSURE
The invention further concerns a device comprising a mouthpiece adapted to allow the person to inhale from said mouthpiece, said mouthpiece being in flow communication with said outlet valve. A mouthpiece facilitates the inhalation through the mouth of the patient.
The invention further concerns a device provided with a removable spacer for said mouthpiece, said spacer allowing extending said mouthpiece on mounting. Some patients prefer to have such a spacer inserted on use, and such a spacer may be recommended for children and aged people.
The invention further concerns a device comprising an exhalation valve; wherein said mouthpiece is in flow communication with said exhalation valve, allowing the person to exhale through the mouthpiece. This aspect further facilitates coordination of activation of gas, exhalation and subsequent inhalation of active substance, as it is not necessary to remove the mouth from the mouthpiece when exhaling.
The invention further concerns a device, wherein said inlet is provided with receiving means being connectable to said inlet of said gas container, wherein said receiving means is adapted to receive the nozzle of the gas canister. This aspect may allow easy adaptation to different gas canisters, simply by changing the receiving means according to
Andersen Per
Drachmann Bo
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