United States Patent:   5,972,388

Assignee:  Teijin Limited (Osaka, JP)

Filed:  January 7, 1997

An ultrafine particle powder for inhalation to be delivered mainly to a lower airway, containing specific cellulose lower alkyl ethers and a medicament, at least 80% of the powder having a particle size in the range of 0.5 to 10 .mu.m.

DISCLOSURE OF INVENTION

In accordance with the present invention, there is provided an ultrafine particle powder for inhalation comprising hydroxypropyl cellulose, and/or hydroxypropyl methyl cellulose, and a medicament, at least 80% of the powder having a particle size of 0.5 to 10 .mu.m.

It will be understood from the above description that the ultrafine particle powder for inhalation of the present inventors comprising hydroxypropyl cellulose and/or hydroxypropyl methyl cellulose and a medicament and containing particles having a particle size of 0.5 to 10 .mu.m in an amount of at least 80% is a novel technical conception which cannot be obtained even from the analogy to the conventional technical idea.

As a result of intensively carrying out research, the present inventors have discovered that when an ultrafine particle powder comprising hydroxypropyl cellulose and/or hydroxypropyl methyl cellulose, and a medicament, at least 80% of the powder having a particle size of 0.5 to 10 .mu.m, is used as an inhalant, the powder becomes an inhalant exhibiting good delivery to and good deposition at a lower airway such as a trachea and bronchi, being excellent in retaining properties and sustained releasing properties of the medicament at deposition sites, and having excellent properties such as efficient productivity, stability, safety and uniformity. The present invention has been achieved on the basis of the discovery.

Furthermore, in accordance with the present invention, there is provide a method for the production, by spray drying, of an ultrafine particle powder for inhalation comprising hydroxypropyl cellulose and/or hydroxypropyl methyl cellulose and a medicament, at least 80% of the powder having a particle size of 0.5 to 10 .mu.m.

Furthermore, in accordance with the present invention, there is provide a powder preparation for inhalation comprising such an ultrafine particle powder for inhalation. Since such an ultrafine particle powder for inhalation of the present invention has a particle size in a specific numerical range, it is capable of being delivered principally to a lower airway.

Claim 1 of 8 Claims

1. An ultrafine particle powder for administering a medicament to the lower airways by oral inhalation comprising cellulose lower alkyl ether wherein said cellulose lower alkyl ether is hydroxypropyl cellulose, wherein at least 80% of said powder has a particle size of from 0.5 to 10 .mu.m and the particle powder is capable of being delivered principally to lower airways and is obtained by spray drying, wherein said cellulose lower alkyl ether is present in an amount effective to achieve sustained release of said medicament.

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