Method for obtaining a stable dispersion of benzoyl peroxide

1 . A method for wetting a benzoyl peroxide powder comprising contacting the powder with a wetting fluid containing an organic fluid selected from the group consisting of a polyol, a polyol ether, and/or a low-carbon organic alcohol, wherein the organic fluid is present in the wetting fluid at a concentration that is sufficient to permit the wetting fluid to wet the benzoyl peroxide powder.

2 . The method of claim 1 wherein the benzoyl peroxide in the powder is not micronized.

3 . The method of claim 2 wherein the powder is Hydrous Benzoyl Peroxide, USP.

4 . The method of claim 1 wherein the wetting fluid contains a solvent in addition to the organic fluid.

5 . The method of claim 4 wherein the solvent is miscible with the organic fluid.

6 . The method of claim 5 wherein the solvent is water.

7 . The method of claim 1 wherein the organic fluid is a polyol.

8 . The method of claim 7 wherein the polyol is propylene glycol or hexylene glycol.

9 . The method of claim 1 wherein the organic fluid is a polyol ether.

10 . The method of claim 9 wherein the polyol ether is ethoxydiglycol.

11 . The method of claim 1 wherein the organic fluid is a low-carbon organic alcohol.

12 . The method of claim 1 which further comprises mechanically agitating the wetting fluid in contact with the powder.

13 . The method of claim 1 wherein the wetting fluid is free of surfactants.

14 . The method of claim 1 wherein the concentration of the polyol, polyol ether, and/or the low-carbon organic alcohol in the wetting fluid is about 5% w/w or higher.

15 . The method of claim 14 wherein the concentration is about 10% or higher.

16 . The method of claim of claim 14 wherein the concentration is about 15% or higher.

17 . A wetted benzoyl peroxide powder, wherein the benzoyl peroxide powder is in combination with a liquid containing one or more of a polyol, a polyol ether, and/or a low-carbon organic alcohol, wherein the concentration of the polyol, a polyol ether, and/or a low-carbon organic alcohol in the liquid is sufficient to wet the benzoyl peroxide powder.

18 . The wetted benzoyl peroxide powder of claim 17 wherein the benzoyl peroxide powder is not micronized.

19 . The wetted benzoyl peroxide powder of claim 18 wherein the powder is Hydrous Benzoyl Peroxide, USP.

20 . The wetted benzoyl peroxide powder of claim 17 wherein the liquid contains a solvent in addition to the polyol, a polyol ether, and/or a low-carbon organic alcohol.

21 . The wetted benzoyl peroxide powder of claim 20 wherein the solvent is miscible with the polyol, a polyol ether, and/or a low-carbon organic alcohol.

22 . The wetted benzoyl peroxide powder of claim 21 wherein the solvent is water.

23 . The wetted benzoyl peroxide powder of claim 17 wherein the liquid contains a polyol.

24 . The wetted benzoyl peroxide powder of claim 23 wherein the polyol is propylene glycol or hexylene glycol.

25 . The wetted benzoyl peroxide powder of claim 17 wherein the liquid contains a polyol ether.

26 . The wetted benzoyl peroxide powder of claim 25 wherein the polyol ether is ethoxydiglycol.

27 . The wetted benzoyl peroxide powder of claim 17 wherein the liquid contains a low-carbon organic alcohol.

28 . The wetted benzoyl peroxide powder of claim 17 which is free of surfactants.

29 . The wetted benzoyl peroxide powder of claim 17 wherein the concentration of the polyol, polyol ether, and/or the low-carbon organic alcohol in the liquid is about 5% w/w or higher.

30 . The wetted benzoyl peroxide powder of claim 29 wherein the concentration is about 10% or higher.

31 . The wetted benzoyl peroxide powder of claim of claim 29 wherein the concentration is about 15% or higher.

32 . A method for making a suspension of benzoyl peroxide comprising suspending a powder that contains benzoyl peroxide in a suspending fluid that comprises one or more of an organic fluid selected from the group consisting of a polyol, a polyol ether, and a low-carbon organic alcohol, wherein the concentration of the polyol, polyol ether, and low-carbon organic alcohol in the suspending fluid is sufficient, even in the absence of any other vehicle fluid that may be included in the suspending fluid, to completely and uniformly wet the benzoyl peroxide powder.

33 . The method of claim 32 wherein the benzoyl peroxide in the powder is not micronized.

34 . The method of claim 33 wherein the powder is Hydrous Benzoyl Peroxide, USP.

35 . The method of claim 32 wherein the suspending fluid contains a solvent in addition to the polyol, polyol ether, and/or low-carbon organic alcohol.

36 . The method of claim 35 wherein the solvent is miscible with the polyol, polyol ether, and/or low-carbon organic alcohol.

37 . The method of claim 36 wherein the solvent is water.

38 . The method of claim 32 wherein the organic fluid is a polyol.

39 . The method of claim 38 wherein the polyol is propylene glycol or hexylene glycol.

40 . The method of claim 32 wherein the organic fluid is a polyol ether.

41 . The method of claim 40 wherein the polyol ether is ethoxydiglycol.

42 . The method of claim 32 wherein the organic fluid is a low-carbon organic alcohol.

43 . The method of claim 43 wherein the suspending comprises mechanically agitating the suspending fluid and the powder.

44 . The method of claim 32 wherein the suspension is made without the use of a surfactant.

45 . The method of claim 32 wherein the concentration of the polyol, polyol ether, and/or the low-carbon organic alcohol in the suspending fluid is about 5% w/w or higher.

46 . The method of claim 45 wherein the concentration is about 10% or higher.

47 . The method of claim of claim 45 wherein the concentration is about 15% or higher.

48 . The method of claim 33 which further comprises subjecting the suspension to a micronization treatment and obtaining a suspension containing micronized benzoyl peroxide.

49 . A suspension comprising micronized benzoyl peroxide that is obtained by the method of claim 48 .

50 . The suspension of claim 49 which contains one or more pharmaceutically acceptable excipients.

51 . The suspension of claim 49 wherein the concentration of benzoyl peroxide in the suspension is between 1% and 10% w/w.

52 . The suspension of claim 51 wherein the concentration of benzoyl peroxide is between 2% and 5%.

53 . The suspension of claim 51 which further contains an additional pharmaceutical agent that is useful in the treatment of a dermatologic disorder.

54 . The suspension of claim 53 wherein the dermatologic disorder is acne vulgaris or acne rosacea.

55 . The suspension of claim 54 wherein the pharmaceutical agent is an antibiotic.

56 . The suspension of claim 55 wherein the antibiotic is clindamycin.

57 . The suspension of claim 51 which is in the form of a semi-solid.

58 . The suspension of claim 57 wherein the semi-solid is selected from the group consisting of a cream, a lotion, and a gel.

59 . A method for making micronized benzoyl peroxide comprising obtaining a suspension of benzoyl peroxide wherein the benzoyl peroxide is suspended in a suspending fluid that comprises one or more of an organic fluid selected from the group consisting of a polyol, a polyol ether, and a low-carbon organic alcohol, wherein the concentration of the polyol, polyol ether, and low-carbon organic alcohol in the suspending fluid is sufficient, in the absence of any other vehicle fluid that may be included in the suspending fluid, to completely and uniformly wet the benzoyl peroxide powder, and subjecting the suspension to a micronization treatment to obtain the micronized benzoyl peroxide.

60 . The method of claim 59 wherein the suspending fluid is free of surfactant.

61 . The method of claim 59 wherein the concentration of benzoyl peroxide in the suspension is between 1% and 10% w/w.

62 . The method of claim 59 wherein the concentration of benzoyl peroxide is between 2% and 5% w/w.