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|Title:||Steroidal aerosol compositions and process for the preparation thereof|
|Abstract:||An antiinflammatory steroid exhibiting a tendency to crystal growth in suspension in aerosol propellants is contacted with a halogenated hydrocarbon to form a crystalline solvate, which, after removal of some or all of the propellant from the crystals, is reduced to a particle size permitting inhalation into the human bronchial system when dispersed as an aerosol, the micronized crystalline solvate not thereafter exhibiting crystal growth in the aerosol propellant. The solvate is a new composition of matter which has been characterized by I.R. spectra and the aerosol formulation prepared therefrom has valuable therapeutic properties, particularly in the treatment of asthma.|
|Inventor(s):||Cook; Peter Barry (Standon, EN), Hunt; John Harold (Theydon Bois, EN)|
|Assignee:||Allen & Hanburys Limited (London, EN)|
|Filing Date:||Jul 09, 1976|
|Claims:||1. A method of converting an anti-inflammatory steroid selected from the group consisting of pregn-4-en-3,20-diones having at the 17.alpha.-position a hydroxy or acyloxy group, provided that when the 17.alpha.-position is substituted by a hydroxy group, the 21-position is substituted by an acyloxy group, or having a 16,17-ketonide group; having an axo group or a .beta.-chlorine or .beta. -hydroxy group at the 11-position; and having a single or double bond in the 1,2-position, the 21-position being unsubstituted or substituted by a hydroxy or acyloxy group or a halogen atom, said steroid having a hydrogen, fluorine or chlorine atom or a methyl group in the 6.alpha.-position; a hydrogen or chlorine atom in the 9.alpha.-position when there is a .beta.-chlorine atom in the 11-position; a fluorine, chlorine or hydrogen atom in the 9.alpha.-position when there is an oxygen function at the 11-position; and a hydrogen atom or a methyl or methylene group at the 16-position; said steroid exhibiting crystal growth in aerosol propellants into a form which does not exhibit such growth whereby the said steroid is contacted with a halogenated hydrocarbon to form a crystalline solvate therewith, the crystalline material so formed being, if desired after removal of some or all of the halogenated hydrocarbon therefrom, reduced to a particle size permitting inhalation into the human bronchial system when dispersed as an aerosol. |
2. A method as claimed in claim 1 in which the steroid is beclomethasone dipropionate.
3. A method as claimed in claim 1 in which the steroid is betamethasone 21-acetate-17-isobutyrate or 21-chloro-21-desoxy betamethasone-17-propionate.
4. A method as claimed in claim 1 in which the halogenated hydrocarbon is a chloro or chlorofluorohydrocarbon having 1 or 2 carbon atoms.
5. A method as claimed in claim 4 in which the halogenated hydrocarbon is trichloromonofluoromethane.
6. A method as claimed in claim 4 in which the halogenated hydrocarbon is dichlorodifluoromethane, trichlorotrifluoroethane or chloroform.
7. A method as claimed in claim 1 in which the particle size of the solvate crystals is reduced to less than 20 microns.
8. A method as claimed in claim 7 in which the particle size is reduced to from 2 to 5 microns.
9. A method as claimed in claim 8 in which the steroid is beclomethasone dipropionate and the halogenated hydrocarbon is trichloromonofluoromethane.
10. A method as claimed in claim 1 in which the solvate is formed by contacting the steriod, in solvent-free form, with the halogenated hydrocarbon.
11. A method as claimed in claim 1 in which the solvate is formed by dissolving the steroid, in unsolvated form, in a first solvent and then distilling the resulting solution with the solvating solvent until the first solvent has been driven off.
12. A method as claimed in claim 11 in which the first solvent is a methanol.
13. A method as claimed in claim 1 in which the solvate is formed by crystallization from a low-temperature mixture of a first solvent, in which the steroid in unsolvated form is initially dissolved, and the solvating solvent.
14. A method as claimed in claim 13 in which the solution of the steriod in the first solvent is added slowly to an excess of the solvating solvent.
15. A method as claimed in claim 1 in which the pregn-4-en-3,20-dione steroid is a 17-ester, a 16,17-ketonide, a 21-ester, a 21-desoxy analogue thereof, a 21-desoxy-21-halo analogue thereof, an 11.beta.-chloro and .DELTA..sup.1,4 -analogue thereof, an 11.beta.-chloro or .DELTA..sup.1,4 -analogue thereof.
16. A method as claimed in claim 15 in which the steroid carries in the 6.alpha.-position a fluorine or chlorine atom; in the 9.alpha.-position a chlorine atom or, when there is an oxygen function at the 11-position, a fluorine atom; and/or in the 16-position a methyl or methylene group.
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