Dosimetric spacer for calculating dosage administered

Details Dosimetric spacer for calculating dosage administered Dosimetric spacer for calculating dosage administered

1997-07-14

1998-12-01

Asher, Kimberly L.

Surgery

Liquid medicament atomizer or sprayer

Pre-pressurized container holding medicament

12820014, 12820312, 12820523, A61M 1100, A61M 1610

Patent

active

058424687

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a method and apparatus for administering a measured dosage of fluid medicament to a patient in a gas for inhalation.
Throughout this specification and claims reference is made to a fluid medicament which may be a liquid or a powder in a fluidised form or in any other similar form.
Patient-operated multi-dose inhalers (MDI) are known having a mouthpiece through which a patient inhales. The patient must activate the MDI as he begins to inhale so that a metered dose of medicament is sprayed into a stream of air as it is sucked through the mouthpiece of the patient's inhalation.
Unfortunately the above MDI is often operated incorrectly so that much of the dose of medicament is wasted. The MDI must be activated or fired just as the patient begins to inhale so that the medicament is drawn deep into the periphery of the lungs where it is most effective. If the MDI is fixed too late, most of the medicament remains in the throat or bronchial tracts without any effect. Elderly patients and children are particularly likely to be unable to co-ordinate the firing of the MDI with the start of inhalation.
Some MDIs and dry powder inhalers (DPI) are available which include sensors which detect when a patient is inhaling and automatically activate the MDI. Whilst these MDIs and DPIs work well in detecting the commencement of inhalation in adults, elderly patients and children have difficulty in triggering the firing of the MDI since their inhalation flow rates are too small to be detected. Often, if a child or elderly patient is able to activate the MDI, this only occurs once their inhalation flow rate has increased to near its maximum, and triggering of the MDI therefore only occurs when the lungs of the patient are already half full.
MDIs and DPIs have been proposed which have a spacer chamber or holding chamber in conjunction with the MDI or DPI. When the MDI is activated, a dose of medicament is fired from the inhaler at high velocity. If a patient inhales the dose of medicament directly, then a large proportion of the dose will be impacted at the back of the throat due to the high velocity. Much of the dose does not reach the lungs where the medicament is intended to act. In some cases, less than fifty percent of the dose of medicament is deposited in the lungs. A particular problem with direct inhalation of the medicament by children is that they are often unable to inhale the full dose released due to the small volume of their lungs. The holding chamber may be disposed between the MDI and the patient. The medicament is sprayed into the holding chamber where it is held before the patient inhales from the holding chamber. The spacer chamber absorbs the high velocity of the medicament fired from the MDI and acts as a "buffer" chamber. The patient then inhales the dose at a much lower velocity. This can reduce the amount of the medicament impacting on the back of the throat by upwards of eighty percent, and may double the amount deposited in the lungs.
Furthermore, the use of a holding chamber means that, provided the medicament has already been fired into the holding chamber, the patient no longer needs to co-ordinate the firing with his inhalation.
The above proposal has some disadvantages. Although it is impossible to guarantee that a given dosage of medicament has actually reached deep into the patient's lungs, it is desirable to ensure that a dose as accurate as possible is given so that the patient's treatment is fully effective.
In the past, a dose of medicament has been sprayed into a holding chamber from which the patient has repeatedly inhaled until the whole of the dose is presumed to have been inhaled. Such a presumption is an inaccurate measurement of dose actually inhaled by the patient. Firstly, as the patient inhales, more air is drawn into the holding chamber to replace the air which is inhaled. This causes a dilution of the medicament within the holding chamber. Therefore, even when a patient has inhaled two or three times, medicament remains within the holding chamber.

REFERENCES:
patent: 4790305 (1988-12-01), Zoltan et al.
patent: 5505195 (1996-04-01), Wolf et al.
patent: 5709202 (1998-01-01), Lloyd et al.
patent: 5743252 (1998-04-01), Rubsamey et al.

Affiliated with

Also associated with

Rating

Dosimetric spacer for calculating dosage administered does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dosimetric spacer for calculating dosage administered, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dosimetric spacer for calculating dosage administered will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2389397