Provided herein are improved processes for converting C7-amino-substituted tetracyclines to C7-fluoro-substituted tetracyclines, as well as intermediates produced by or used in these processes. In one embodiment, a thermal fluorination method is provided in which a suspension comprising a non-polar organic solvent and a C7-diazo-substituted tetracycline hexafluorophosphate, hexafluoroarsenate or hexafluorosilicate salt, or a salt, solvate or combination thereof, is heated to provide a C7-fluoro-substituted tetracycline, or salt, solvate or combination thereof. In another embodiment, a photolytic fluorination is provided in which a solution comprising an ionic liquid and a C7-diazo-substituted tetracycline tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate or hexafluorosilicate salt, or a salt, solvate or combination thereof, is irradiated to provide a C7-fluoro-substituted tetracycline, or salt, solvate or combination thereof.

A topical therapeutic hydrophobic breakable composition includes a carrier comprising (a) about 60% to about 99% by weight of at least one hydrophobic oil; (b) at least one viscosity-modifying agents selected from the group consisting of a fatty alcohol, a fatty acid and a wax; and (c) a tetracycline antibiotic, characterized in that at least part of the tetracycline antibiotic is suspended in the composition; the viscosity of the composition is at least about 30% higher than the viscosity of the carrier without the tetracycline antibiotic; and is higher than the viscosity of the hydrophobic oil and the tetracycline antibiotic without the viscosity modifying agents. The tetracycline is chemically stable in the composition for at least six months; wherein more than about 90% of the tetracycline has not broken down. The composition is packaged as a breakable foam that breaks easily upon application of shear force.

The present invention is directed to a compound represented by Structural Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof. The variables for Structural Formula (I) are defined herein. Also described is a pharmaceutical composition comprising the compound of Structural Formula (I), or a pharmaceutically acceptable salt thereof, and its therapeutic use.

The present invention is directed to a compound represented by Structural Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof. The variables for Structural Formula (I) are defined herein. Also described is a pharmaceutical composition comprising the compound of Structural Formula (I), or a pharmaceutically acceptable salt thereof, and its therapeutic use.

A tetracycline salt comprising a tetracycline and an organic acid wherein the organic acid is oxalic acid or maleic acid is provided. The tetracycline is preferably doxycycline, minocycline, sancycline, lymecycline, tetracycline or demeclocycline, and preferred salts include oxycycline maleate, minocycline oxalate, tetracycline oxalate, demeclocycline maleate, demeclocycline oxalate, sancycline maleate, lymecycline maleate, or lymecycline oxalate. A pharmaceutical formulation comprising a tetracycline salt according to the invention is also provided, as is a medical device having coated thereon a salt or pharmaceutical formulation according to the invention. A salt of the invention, or a formulation of the invention are also provided for use as medicaments, particularly for use in the treatment or prevention of an inflammation and/or an infection. There is also provided a method of preparing a tetracycline salt, which method comprises reacting a tetracycline base with an excess of an organic acid in a solvent.

A tetracycline salt comprising a tetracycline and an organic acid wherein the organic acid is oxalic acid or maleic acid is provided. The tetracycline is preferably doxycycline, minocycline, sancycline, lymecycline, tetracycline or demeclocycline, and preferred salts include oxycycline maleate, minocycline oxalate, tetracycline oxalate, demeclocycline maleate, demeclocycline oxalate, sancycline maleate, lymecycline maleate, or lymecycline oxalate. A pharmaceutical formulation comprising a tetracycline salt according to the invention is also provided, as is a medical device having coated thereon a salt or pharmaceutical formulation according to the invention. A salt of the invention, or a formulation of the invention are also provided for use as medicaments, particularly for use in the treatment or prevention of an inflammation and/or an infection. There is also provided a method of preparing a tetracycline salt, which method comprises reacting a tetracycline base with an excess of an organic acid in a solvent.

A tetracycline salt comprising a tetracycline and an organic acid wherein the organic acid is oxalic acid or maleic acid is provided. The tetracycline is preferably doxycycline, minocycline, sancycline, lymecycline, tetracycline or demeclocycline, and preferred salts include oxycycline maleate, minocycline oxalate, tetracycline oxalate, demeclocycline maleate, demeclocycline oxalate, sancycline maleate, lymecycline maleate, or lymecycline oxalate. A pharmaceutical formulation comprising a tetracycline salt according to the invention is also provided, as is a medical device having coated thereon a salt or pharmaceutical formulation according to the invention. A salt of the invention, or a formulation of the invention are also provided for use as medicaments, particularly for use in the treatment or prevention of an inflammation and/or an infection. There is also provided a method of preparing a tetracycline salt, which method comprises reacting a tetracycline base with an excess of an organic acid in a solvent.

A crystalline mono hydrochloride salt of (4S,4aS,5aR,12aS)-4-dimethylamino-3,10,12,12a-tetrahydroxy-7-[(methoxy(methyl)amino)-methyl]-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydro-naphthacene-2-carboxylic acid amide is disclosed having improved stability. In addition, a crystalline mono mesylate salt and crystalline mono sulfate salt of (4S,4aS,5aR,12aS)-4-dimethylamino-3,10,12,12a-tetrahydroxy-7-[(methoxy(methyl)amino)-methyl]-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydro-naphthacene-2-carboxylic acid amide are also disclosed having improved stability. A pharmaceutical composition containing the crystalline salts and methods of treating inflammatory skin disorders and bacterial infections comprising administering the crystalline salts are also disclosed.

A crystalline mono hydrochloride salt of (4S,4aS,5aR,12aS)-4-dimethylamino-3,10,12,12a-tetrahydroxy-7-[(methoxy(methyl)amino)-methyl]-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydro-naphthacene-2-carboxylic acid amide is disclosed having improved stability. In addition, a crystalline mono mesylate salt and crystalline mono sulfate salt of (4S,4aS,5aR,12aS)-4-dimethylamino-3,10,12,12a-tetrahydroxy-7-[(methoxy(methyl)amino)-methyl]-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydro-naphthacene-2-carboxylic acid amide are also disclosed having improved stability. A pharmaceutical composition containing the crystalline salts and methods of treating inflammatory skin disorders and bacterial infections comprising administering the crystalline salts are also disclosed.

The tetracycline class of antibiotics has played a major role in the treatment of infectious diseases for the past 50 years. However, the increased use of the tetracyclines in human and veterinary medicine has led to resistance among many organisms previously susceptible to tetracycline antibiotics. The modular synthesis of tetracyclines and tetracycline analogs described provides an efficient and enantioselective route to a variety of tetracycline analogs and polycyclines previously inaccessible via earlier tetracycline syntheses and semi-synthetic methods. These analogs may be used as anti-microbial agents or anti-proliferative agents in the treatment of diseases of humans or other animals.