Inhalers

Details Inhalers Inhalers

2001-10-03

2004-05-25

Lo, Weilun (Department: 3761)

Surgery

Means for passing respiratory gas through body of liquid...

Plural orifice means passing gas into liquid

C128S203120

Reexamination Certificate

active

06739332

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to inhalers, and concerns in particular medical inhaler apparatus for use in the treatment of certain lung diseases or conditions.
BACKGROUND OF THE INVENTION
In the Specification of British Patent Application No: 2,283,179 (which corresponds to published PCT International Application WO 95/10,315) there is described and claimed a novel method, and associated apparatus, for the use of nitric oxide in the treatment of various lung conditions and diseases. The present invention relates to improved apparatus which can be used not only for this purpose but also in the treatment of other lung problems.
There are many lung diseases and conditions—suffered both by humans and by other animals—for which the preferred form of treatment involves delivering a medicament of the appropriate sort down the Patient's airways into the lungs themselves, where the medicament can act upon, and perhaps be absorbed into, the tissues of the lungs. One such condition is asthma (an increasingly prevalent and worrying problem), in which the peripheral parts of the lung, namely those tiny airways and air spaces known respectively as bronchioles and alveoli, constrict to restrict the flow of air therethrough.
In other lung conditions the lung's small peripheral arteries—the pulmonary arteries—also constrict, typically those deep in the lungs where the oxygen tension falls as in an asthmatic attack, pneumonia, or chronic lung diseases like bronchitis and emphysema (and it should also be noted that such constriction often occurs without the causative mechanism being fully explained; this is the so-called primary pulmonary hypertension).
The most effective treatments for asthma and like conditions involve the inhalation as an aerosol of some suitable chemical agent in normally inhaled air. At present, to deal with the problem of constricted small pulmonary arteries only a few relieving substances are known, and one of the most powerful—that known as prostacyclin, an extremely potent vasodilator—has to be administered on a continuous basis by infusion into a vein and so to the pulmonary arteries.
The aforementioned British and International Specifications relate to the use of nitric oxide (NO), another well-known and effective dilating agent for treating both lung problems of the blood-vessel-constriction type and of the asthma airway type. More specifically, these Specifications concern the manner in which nitric oxide is administered, and the apparatus used for this administration; they propose that the nitric oxide be administered to the Patient not continuously (either in admixture with, or separately but side by side with a supply of, air, oxygen or oxygen-enriched air) but intermittently and in short pulses of known, pre-determined volume at one or more suitable time during each inhalation. In the treatment of the constriction of the small pulmonary arteries the very short pulse, or spike, of nitric oxide is provided at the start of the inhalation, such that the resultant bolus of nitric oxide mixture inhaled by the Patient has a nitric oxide concentration high enough to have the desired therapeutic effect, even if admixed with some additional air, but is of such short duration (both in time and, as a result, in physical length) that, pushed by the following much larger volume of plain, and therefore nitric oxide-free, air/oxygen, it reaches deeper into the lungs, where it both acts on the small pulmonary arteries and is taken up into the capillaries to react with haemoglobin (so preventing the formation of nitrogen dioxide). By contrast, in the treatment of asthma-like airway diseases or conditions the very short pulse of nitric oxide is timed to fall just before the end of the inhalation. This leaves the nitric oxide in contact with the airway smooth muscle in sufficient concentration to cause relaxation, but because at the end of the inhalation the airway is flushed of all the nitric oxide by the air coming from alveoli and lung periphery, so there is avoided prolonged exposure with the consequent risk of the formation of toxic nitrogen dioxide.
SUMMARY OF THE INVENTION
This previous invention concerns the administration of nitric oxide. The present invention stems from the appreciation that the same controlled breathing-related “pulsatile” delivery to the Patient's lungs can be usefully employed with many other medicaments; the invention is thus treatment apparatus—and in particular small (pocket-sized) hand-held apparatus—that utilises the “spike” principle. More specifically, the invention proposes apparatus for the delivery of a medicament—a drug, which can be in liquid or in solid (powder) form—into the Patient's lungs in the form of a bolus, pulse, or spike of the medicament entrained in and driven by the normal respiration air, which apparatus comprises in essence a drug dispenser (which might be a conventional liquid-dispensing nebuliser or a dry-powder dispenser, in the reservoir of which is stored the medicament to be administered), driven by some suitable pressurised gas from a completely separate valved cylinder thereof to deliver an aerosol cloud of medicament into a tube through which the Patient is breathing (by mouth) normal air, the gas cylinder valve being controlled by a suitably programmed computing device that is fed data describing the pressure within the breathing tube and so is able to open and close the valve at and for a time such as to drive the drug dispenser to deliver (to the tube and thence to the Patient's lungs) a required pulse of medicament at any selected point within the Patient's respiratory cycle. The provision of pulses of medicament is not in itself unknown, and one typical case is the asthma-treatment device the subject of Aradigm (Goodman et al) U.S. Pat. No. 5,404,871, which described an inhaler wherein a computer suitably controls the delivery of a medicament from a propellant-driven reservoir thereof. However, using a combination propellant/medicament source like that makes it quite difficult fully to control the manner in which the medicament is delivered to the Patient; the present invention deals in part with this by having the medicament reservoir and the driving gas source completely separate.
In one aspect, therefore, the invention provides miniature, pocket-sized, hand-holdable apparatus for the delivery of a medicament into the Patient's lungs in the form of a bolus, pulse, or spike of the medicament entrained in and driven by the normal respiration air, which apparatus comprises:
a tube through which the Patient is able to breath (by mouth) normal air;
a drug dispenser (in the reservoir of which is storable the medicament to be administered) the output of which is deliverable into the tube for inhalation by the Patient;
separate from the dispenser, a valved cylinder for a suitable pressurised gas, which cylinder is operatively connectable to the dispenser so as in use to drive the dispenser to deliver an aerosol cloud of medicament into the tube;
pressure sensing means located within or operably connected to the tube, and able to provide data about the air pressure therewithin, and thus about the Patient's respiratory cycle; and
programmed computing means operatively connectable to the gas cylinder valve so as to be able to open and shut that valve, and able to receive pressure data from the pressure sensing means;
such that the computing means can utilise the pressure data to enable the gas cylinder to drive the dispenser to deliver (to the tube and thence to the Patient's lungs) a required pulse of medicament at any selected point within the Patient's respiratory cycle.
The apparatus of this invention is intended to be portable. Indeed, it is the primary purpose of the invention to provide the apparatus in light, pocket-sized form small enough to be held in the hand, and to be used while being so held, and accordingly, hereinafter the apparatus is described in terms most appropriate for such a small hand-held piece of kit.
The invention provides app

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