Title:  Therapeutic preparation for inhalation

United States Patent:  6,165,976

Assignee:  Astra Aktiebolag (SE)

Filed:  May 5, 1998

A therapeutic preparation for inhalation which comprises insulin and a substance which enhances the absorption of insulin in the lower respiratory tract, is provided in the form of a powder preparation suitable for inhalation.

SUMMARY OF THE INVENTION

We have now found that insulin can be included in a dry powder preparation for inhalation also including a substance which enhances the absorption of insulin in the lung, from which preparation the insulin may be absorbed in a therapeutically acceptable rate and amount. By "enhances absorption" is meant that the amount of insulin absorbed into the systemic circulation in the presence of the enhancer is higher than the amount absorbed in the absence of enhancer.

According to this invention, there is provided a therapeutic preparation comprising active compounds (A) insulin, and (B) a substance which enhances the absorption of insulin in the lower respiratory tract, which preparation is in the form of a dry powder suitable for inhalation in which at least 50% of the total mass of active compounds consists of (a) primary particles having a diameter of less than about 10 microns, for example between 0.01 and 10 microns and preferably between 1 and 6 microns, or (b) agglomerates of said particles.

The therapeutic preparation of the present invention may contain only the said active compounds or it may contain other substances, such as a pharmaceutically acceptable carrier. This carrier may largely consist of particles having a diameter of less than about 10 microns so that at least 50% of the resultant powder as a whole consists of optionally agglomerated primary particles having a diameter of less than about 10 microns; alternatively the carrier may largely consist of much bigger particles ("coarse particles"), so that an "ordered mixture" may be formed between the active compounds and the carrier. In an ordered mixture, alternatively known as an interactive or adhesive mixture, fine drug particles (in this invention, the active compounds) are fairly evenly distributed over the surface of coarse excipient particles (in this invention, the pharmaceutically acceptable carrier). Preferably, the active compounds are not in the form of agglomerates prior to formation of the ordered mixture. The coarse particles may have a diameter of over 20 microns, such as over 60 microns. Above these lower limits, the diameter of the coarse particles is not of critical importance, so various coarse particle sizes may be used, if desired, according to the practical requirements of the particular formulation. There is no requirement for the coarse particles in the ordered mixture to be of the same size, but the coarse particles may advantageously be of similar size within the ordered mixture. Preferably, the coarse particles have a diameter of 60-800 microns.

In a particular embodiment therefore this invention provides a therapeutic preparation of insulin and a substance which enhances the absorption of insulin in the lower respiratory tract, which preparation is in the form of a dry powder preparation suitable for inhalation of which at least 50% by mass consists of (a) particles having a diameter of less than about 10 microns or (b) agglomerates of said particles; in a further particular embodiment, the invention provides a therapeutic preparation comprising insulin, a substance which enhances the absorption of insulin in the lower respiratory tract, and a pharmaceutically acceptable carrier, which preparation is in the form of a dry powder suitable for inhalation of which at least 50% by mass consists of (a) particles having a diameter of less than about 10 microns, or (b) agglomerates of said particles; and in a still further particular embodiment this invention provides a therapeutic preparation comprising active compounds (A) insulin and (B) a substance which enhances the absorption of insulin in the lower respiratory tract, wherein at least 50% of the total mass of active compounds (A) and (B) consists of particles having a diameter of less than about 10 microns, and a pharmaceutically acceptable carrier, which preparation is in the form of a dry powder preparation suitable for inhalation in which an ordered mixture may be formed between the active compounds and the pharmaceutically acceptable carrier.

Preferably at least 60% (such as at least 70% or at least 80% and more preferably at least 90%) of the total mass of active compounds (A) and (B) consists of particles having a diameter of less than about 10 microns, or of agglomerates of such particles, and, when the dry powder preparation comprises carrier other than when an ordered mixture is desired, preferably at least 60% (such as at least 70% or at least 80% and more preferably at least 90%) by mass of the total dry powder consists of particles having a diameter of less than about 10 microns, or of agglomerates of such particles.

While the dry powder for inhalation, whether with or without pharmaceutically acceptable carrier, may contain agglomerates of particles as indicated above, at the time of inhalation any agglomerates should be substantially deagglomerated yielding a powder of which at least 50% consists of particles having a diameter of up to 10 microns. The agglomerates can be the result of a controlled agglomeration process or they may simply be the result of the intimate contact of the powder particles. In either case it is essential that the agglomerates are capable of being de-agglomerated, e.g. by mechanical means in the inhaler or otherwise, into the aforesaid particles. Agglomerates are in general preferably not formed in the ordered mixture. In the case of an ordered mixture, the active compounds should be released from the large particles preferably upon inhalation, either by mechanical means in the inhaler or simply by the action of inhalation, or by other means, the active compounds then being deposited in the lower respiratory tract and the carrier particles in the mouth.

Claim 1 of 24 Claims

What is claimed is:

1. A therapeutic preparation comprising active compounds (A) insulin and (B) a substance which enhances the absorption of insulin in the lower respiratory tract, in the form of a dry powder suitable for inhalation in which at least 50% of the total mass of active compounds consists of (a) particles having a diameter of up to 10 microns or (b) agglomerates of such particles, provided that said substance is selected from the group consisting of a C₈ -C₁₆ fatty acid, a salt of such a fatty acid, an acyl carnitine, a salt of glycyrrhizine, a phospholipid, and an alkyl glycoside.

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