GB2137886A - Inhalation bag - Google Patents

Abstract

Absorption of aerosol medication is rendered more efficient by a inhalation bag having walls of gas-impermeable and flexible material, said bag having a first aperture through which it may be inflated from a flat condition by a patient exhaling into said bag and deflated by said patient inhaling from said bag, and a second aperture for connection to a metered dose inhaler whereby said inhaler can be discharged into said bag when it is in the inflated condition.

Description

SPECIFICATION Medical Appliance The invention concerns a medical applicance, more particularly for use in conjunction with a metered dose inhaler.

In recent years metered dose inhalers have become the preferred means for administering medicaments to the lungs. They are particularly effective for the treatment of conditions involving reversible airways obstruction (asthma and bronchitis). A controlled dose of the medicament is converted into an aerosol spray in an inhaler by means of a suitable propellant and formulating agents, and the spray is then inhaled by the patient. Approximately 10% of the inhaled dose reaches the lungs, and in this way a more rapid and effective action is obtained with fewer side effects than in oral administration.

Unfortunately, many people have difficulty in using existing metered dose inhalers. In particular, many people are unable to synchronise the discharge of the aerosol with the correct phase of inhalation. Such people include young children, the elderly, arthritic patients, and poor coordinators generally.

The proportion of such patients experiencing difficulty is very high; it has been estimated at about 60% of those who would benefit from aerosol medication. In an attempt to alleviate the problem, teaching aids such as whistles, sirens and breath-actuated electronic devices have been developed. Although sometimes effective, these require a second person to instruct the patient, usually his General Practitioner, Hospital Physician, Nurse, Physiotherapist or other qualified person. There remains a high percentage of patients who still cannot adapt to using a metered dose inhaler, despite adequate instruction.

For such patients various devices have been developed in the form of relatively large rigid containers into which the inhaler can be discharged prior to inhalation. These devices are very cumbersome; indeed, some can hardly be called portable. They also require the injection of several doses into the container to ensure that one unit dose is available to the patient. This is wasteful and causes early exhaustion of the inhaler unit. Such devices are expensive to produce on a large scale owing to oneway valves and other components which are required. It has also been proposed to make such devices collapsible, for storage, against the action of internal springs. This further complicates the device and adds to the cost, besides requiring an additional manipulation which elderly patients may find difficult.

Moreover in all these known devices condensation from the patient's breath causes the inside to be permanently damp and thus provides good conditions for the proliferation of microorganisms. Any such microorganisms are liable to be inhaled deep into the patient's lungs each time the device is used.

The problems of using a metered dose inhaler are such that a proportion of patients have to be placed on oral medication, which is generally less effective and more prone to cause side effects.

We have now found that these difficulties can be mitigated by discharging the inhaler into an inflated inhalation bag, the contents of which are then inhaled by the patient.

Thus, in one aspect our invention provides an inhalation bag having walls of gas-impermeable and flexible material, said bag having a first aperture through which it may be inflated from a flat condition by a patient exhaling into said bag and deflated by said patient inhaling from said bag, and a second aperture for connection to a metered dose inhaler whereby said inhaler can be discharged into said bag when it is in the inflated condition.

Preferably said first and second apertures are at opposite sides of the bag, e.g. at opposite ends when the bag is of generally cylindrical form in the inflated condition. The apertures may be reinforced with coupling members, for example in the form of plastics mouldings, to serve respectively as a mouthpiece and as a connector for a metered dose inhaler. However in a preferred construction the apertures comprise sleeve or neck portions extending from the bag and preferably integral therewith. One sleeve portion, which if desired may be the longer, may be reinforced with a tubular mouthpiece which conveniently is a sliding fit in the sleeve. The other sleeve portion may be dimensioned to connect directly to a standard metered dose inhaler. It will be appreciated that some patients do not require the device of this invention, but will be able to use the inhaler direct.

To avoid any confusion to the patient, it is preferred that both sleeve portions be identical.

Opening of the sleeve portions from the flattened state may be facilitated by providing a cut-out portion at the outer end of the sleeve, or, when the bag comprises two shaped sheets welded or adhered at their edges, by providing a nonoverlapping portion at the outer end of the sleeve which can easily be grasped by the patient.

The inhalation bag of our invention has substantial advantages over the apparatus hitherto proposed for overcoming the same problems. A notable advantage of our device is the enhanced therapeutic efficacy compared to direct use of an inhaler. Our device permits a greater proportion of the absorbed dose to reach the lungs, and hence provides a stronger effect on the respiratory system without any commensurate increase in side effects. In using our device, the patient does not need to coordinate his inhalation with the discharge of the inhaler. Furthermore, the patient will be breathing in warm, moist air, which is less likely to trigger a reaction (e.g. a bronchial spasm) than cold, fastmoving air which must be inhaled when using the inhaler direct.

Our device is also completely portable, and so cheap to manufacture that it can be treated as disposable. There is accordingly no risk of the device becoming unsanitary due to condensation.

The device is easy to use and for young children can even form part of a "game". The invention thus enables patients to use metered dose inhalers who would otherwise have been unable to do so.

Our device also has the unique advantage of providing its own indication of correct breathing, as shown by the expansion and collapse of the bag. The patient thus receives a visual indication that he has inhaled the correct volume of medicated air.

The volume of the bag in the inflated condition can vary over a wide range, depending on the respiratory performance of the patient. For example, volumes in the range 0.5 to 4 litres preferably 1 to 2.5 litres will often be found suitable. Smaller volumes are desirable for pediatric use and female patients will be better suited by bags of relatively smaller volume than used by male patients. Thus, ideally a pediatric size, a female size and a male size of bag should be available to the dispensary.

The bag can be made of any gas impermable, flexible material, such as plastics film. Polyolefin film, and more particularly polyethylene film, has been found to be satisfactory and the techniques for handling such film are highly developed. Such film is available in sheet and tubular form.

Handling of the film by the patient, especially insertion of a tubular mouthpiece, may be facilitated by the use of film which is embossed, at least in the regions of the apertures. Any coupling member or members may be attached to the film by heat sealing or adhesive.

Two embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, wherein:~ Figure 1 is a plan view of an inhalation bag according to the invention, shown deflated and having a detachable tubular mouthpiece; Figure 2 is a diagrammatic view in perspective of an inhalation bag according to the invention attached to a metered dose inhaler; and Figure 3 depicts graphically the effect of medication with the device of Fig. 1, compared with direct use a metered dose inhaler.

Referring now to Fig. 1, the bag 1 is made of thin-walled polyethylene film, the seams 7 being heat sealed, and when inflated has a volume of about two litres. The bag is integral with two sleeve portions 2 and 3. The longer sleeve portion 2 is adapted to receive the tubular rigid PVC mouthpiece 4, as a sliding fit. The shorter sleeve portion 3 is dimensioned to couple to a standard metered dose inhaler (not shown). A plurality of bags 1, e.g. from 2 to 20, may be packaged together with a mouthpiece 4, the individual bags preferably being used only once. In use, the bag is first inflated via the mouthpiece, then the metered dose inhaler is discharged once and the contents of the bag are rebreathed through the mouthpiece.

In another embodiment the sleeves 2 and 3 are the same length and each is provided with a cut out portion at its end to facilitate opening of the sleeve from the flattened condition.

In Fig. 2 the bag 1 is heat sealed to a mouthpiece 4 and to a coupling 5 for attachment to the metered dose inhaler 6. The inhaler 6 is a push-fit onto the coupling 5 and can at any time be detached and used conventionally.

Finally, Fig. 3 illustrates the improved medical efficacy of the inhalation bag according to the invention. Ten patients with asthma, median age 56.5 years, received two puffs of fenoteroi hydrobromide (total dosage 200 mcg) and ipratropium bromide (total dosage 80 mcg) either conventionally by a metered dose inhaler or via the inhalation bag according to the invention. The patients had been taught how to use the metered dose inhaler and all of them used it correctly.

Patients were taught to use the inhalation bag as follows: (1) exhale, filling the bag; (2) actuate the metered dose inhaler; (3) inhale slowly and hold breath for five seconds; (4) exhale refilling bag; (5) inhale and hold breath. Patients had not received oral or inhaled bronchodilators for at least 1 2 hours.

The peak expiratory flow rate (PEFR) was measured for each patient at time zero and at 15, 30, 45 and 60 minutes thereafter and then each hour up to 8 hours. The mean percentage increase in PEFR was significantly greater in the patients treated via the inhalation bag than in those treated directly via the metered dose inhaler (MDI). The pharmacological effect of the inhalation bag treatment was also of much longer duration. There were no significant differences seen in pulse or blood pressure between patients having the two treatments, and no patient reported any side effects.

Claims (16)

1. An inhalation bag having walls of gas impermeable and flexible material, said bag having a first aperture through which it may be inflated from a flat condition by a patient exhaling into said bag and deflated by said patient inhaling from said bag, and a second aperture for connection to a metered dose inhaler whereby said inhaler can be discharged into said bag when it is in theiinflated condition.

2. An inhalation bag as claimed in claim 1 wherein said first and second apertures are at opposite sides of the bag.

3. An inhalation bag as claimed in claim 2 wherein said first and second apertures are at opposite ends of a bag which is of generally cylindrical form, 'in the inflated condition.

4. An inhalation bag as claimed in any of the preceding claims wherein said apertures comprise sleeve or neck portions extending from the bag

5. An inhalation bag as claimed in claim 4 wherein one of said sleeve portions is reinforced with a tubular mouthpiece and the other sleeve portion is dimensioned to connect directly to a standard metered dose inhaler,

6. An inhalation bag as claimed in any of claims 1 to 4 wherein said apertures are reinforced with coupling members, to serve respectively as a mouthpiece and as a connector for a metered dose inhaler.

7. An inhalation bag as claimed in any of the preceding claims having a volume in the range 0.5to41.

8. An inhalation bag as claimed in claim 7 having a volume in the range 1 to 2.51.

9. An inhalation bag as claimed in any of the preceding claims wherein said gas-impermeable and flexible material comprises plastics film.

10. An inhalation bag as claimed in claim 9 wherein said plastics film comprises polyethylene film.

11. An inhalation bag as claimed in claim 9 or 10 wherein said film is embossed, at least in the region of said apertures, to facilitate handling thereof.

12. An inhalation bag as claimed in claim 1, substantially as described herein.

13. An inhalation bag, substantially as illustrated in Fig. 1 of the accompanying drawings.

14. An inhalation bag, substantially as illustrated in Fig. 2 of the accompanying drawings.

15. An inhalation bag as claimed in any of the preceding claims in association with a metered dose inhaler.

16. An inhalation bag as claimed in any of claims 1 to 14 wherein said second aperture is connected to a metered dose inhaler.