TOPICAL PHARMACEUTICAL FORMULATIONS CONTAINING A LOW CONCENTRATION OF BENZOYL PEROXIDE IN SUSPENSION IN WATER AND A WATER-MISCIBLE ORGANIC SOLVENT
An aqueous formulation for topical application to the skin comprising water, a water-miscible organic solvent, and benzoyl peroxide, wherein the concentration of the organic solvent is sufficient to provide a stable suspension of benzoyl peroxide in the aqueous formulation without the inclusion of a surfactant in the formulation, wherein the ratio of concentrations of water and organic solvent in the formulation is sufficient to maintain the benzoyl peroxide in saturated solubility in the formulation following application to the skin, and wherein the concentration of benzoyl peroxide in the formulation is less than 5.0% and at least 1.0% w/w. The formulation may further contain a chemical compound in addition to benzoyl peroxide that is effective in the treatment of acne. The aqueous formulations of the invention are useful in the treatment of acne and acne rosacea.
1 . A method for treating acne rosacea, comprising applying to the skin of a patient in need thereof an aqueous suspension formulation comprising 2.5% w/w to 4.5% w/w benzoyl peroxide, about 1.2% w/w clindamycin phosphate, propylene glycol, a gelling agent, and water;
wherein the combined concentration of water and propylene glycol is sufficient to provide a suspension of benzoyl peroxide in a saturated solution of benzoyl peroxide,
wherein the ratio of water to propylene glycol in the formulation ranges from 12:1 to 20:1,
wherein the concentration of the propylene glycol is one to four times the concentration of the benzoyl peroxide, and
wherein the formulation is applied once a day for up to 12 weeks to the skin of the patient.
2 . The method of claim 1 , wherein the concentration of benzoyl peroxide in the formulation ranges from 2.5% to 3.5% w/w.
3 . The method of claim 1 , wherein the concentration of benzoyl peroxide in the formulation is about 3.5% w/w.
4 . The method of claim 1 , wherein the concentration of propylene glycol in the formulation is about 5.0% w/w and the ratio of water to propylene glycol in the formulation ranges from 12:1 to 18:1.
5 . The method of claim 1 , wherein the gelling agent is selected from the group consisting of hydroxypropylcellulose, hydroxyethylcellulose, a carboxyvinyl polymer, polyvinyl alcohol, a polyethylene oxide, a propylene glycol alginate, methylcellulose, hydroxypropylmethylcellulose, xanthan gum, and carrageenan.
6 . The method of claim 5 , wherein the gelling agent is a carboxyvinyl polymer.
7 . The method of claim 1 , wherein the formulation is free of surfactant.
8 . The method of claim 1 , wherein the formulation contains a surfactant.