Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Patent
1994-08-10
1997-07-08
Millin, V.
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
12820312, 12820321, 12820022, 604 58, A61M 1500
Patent
active
056450508
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to powder inhalers in which the powder used for inhalation is placed in readiness on carriers having specific regular microstructures.
2. Background Art
Of the numerous types of devices for powder inhalation which have already been described, there are some with belt-shaped carriers (WO 90/13328). Such carriers may have very different surface structures, e.g. conical depressions stamped into plastics film for holding the powder, or they may consist, for example, of woven or non-woven (fleece-like) fibrous material in which the powder is incorporated between the fibres or in gaps in the fabric.
SUMMARY OF THE INVENTION
As has now been found, it is particularly favourable to use microstructures arranged in a regular configuration on the carrier surface for the storage and delivery of the powder for inhalation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The microstructures are individual elevations on the planar, belt or plate, or disc-shaped carriers. The microstructures may take various forms, e.g. they may be cylindrical, bump-like, prismatic, conical or frustoconical, they may be in the form of strips or ribs or pyramids or truncated pyramids. The axis directed towards the carrier is preferably perpendicular thereto but it may also form an angle of <90.degree. therewith. The cross-section of the microstructures may be constant, in accordance with what has been said above, but may also vary in form and surface area as the distance from the carrier increases. The cross-section is preferably circular or elliptical or is a regular polygon. However, it may also be of irregular shape, e.g. an irregular polygon or a combination of round and angular shapes, Y- or cross-shaped or lenticular.
The height of the microstructures may be between about 10 and 500 .mu.m, the range from 50 to 200 .mu.m being preferred. The diameter or the corresponding lateral spacings, in the case of a non-circular cross-section, is between about 10 and 500 .mu.m, preferably 30 to 100 .mu.m.
It has proved favourable for the spacing between the microstructures to range from about 10 to 500 .mu.m and more particularly from about 30 to 100 .mu.m.
The surfaces are usually very smooth (optically reflective) and the peak-to-valley height is about 50 nm. However, a significantly greater degree of roughness is also possible for the purpose intended. For example, the peak-to-valley height in microstructures produced with the aid of etching processes is of the order of 10 .mu.m.
The porosity is the ratio of free volume between the microstructures to the total volume filled with microstructures. In the case of prismatic or cylindrical structures, this is equal to the ratio of the surface not covered by microstructures to the total surface area.
The porosity may be adjusted within wide limits, e.g. in the range from 10 to 98% by a suitable choice of forms, sizes and spacings of the microstructures. Typical values are in the range from 50 to 80%. The choice of the figure will also depend on the nature and dosage size of the drug used. As a rule, for particularly small dosages, it is preferable to use a carrier which has a higher density of microstructures, i.e. a lower porosity.
The carriers used according to the invention are preferably produced by injection moulding. Accordingly, the materials generally used are those which can be worked by this process, such as polymethacrylate, polyamide and polyoxymethylene.
The charging of the microstructures with powder can be carried out, for example, by applying powder to the microstructures and using a doctor blade both to press the powder into the microstructures and to wipe off any excess. Another possibility is to fill the microstructures with the powder using a fine brush or other kind of brush. It has proved particularly useful to press the microstructures into the powder so that the powder penetrates into the interstices and a lightly compacted layer adhering to the surface is then removed by means of a blade. The adhes
REFERENCES:
patent: 2816549 (1957-12-01), Webster
patent: 3967761 (1976-07-01), Melton, Jr. et al.
patent: 3998226 (1976-12-01), Harris
patent: 4735358 (1988-04-01), Morita et al.
patent: 5039561 (1991-08-01), Debe
patent: 5192548 (1993-03-01), Velasquez et al.
patent: 5204113 (1993-04-01), Hartley et al.
patent: 5347999 (1994-09-01), Poss et al.
patent: 5349947 (1994-09-01), Newhouse et al.
patent: 5388573 (1995-02-01), Mulhauser et al.
Hochrainer Dieter
Zierenberg Bernd
Boehringer Ingelheim KG
Millin V.
Raymond Robert P.
Rieder Wendy E.
Srivastava V.
LandOfFree
Powder inhaler with powder carrier consisting of regular microst does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Powder inhaler with powder carrier consisting of regular microst, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Powder inhaler with powder carrier consisting of regular microst will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2404272