CLOBETASOL PROPIONATE- clobetasol propionate aerosol, foam
For Dermatologic Use Only
Not for Ophthalmic Use
Clobetasol propionate foam, 0.05% contains clobetasol propionate, USP, a synthetic corticosteroid, for topical dermatologic use. Clobetasol, an analog of prednisolone, has a high degree of glucocorticoid activity and a slight degree of mineralocorticoid activity.
Clobetasol propionate is pregna-1,4-diene-3,20-dione, 21-chloro-9-fluoro-11-hydroxy-16-methyl-17-(1-oxopropoxy)-, (11β, 16β)-, with the empirical formula C25 H32 ClFO5 , a molecular weight of 466.97. The following is the chemical structure:
Clobetasol propionate is a white or almost white, odorless, crystalline powder and is insoluble in water.
Clobetasol propionate foam, 0.05% contains 0.5 mg clobetasol propionate, USP, per gram in a thermolabile hydroethanolic foam vehicle consisting of cetyl alcohol, citric acid, ethanol (60%), polysorbate 60, potassium citrate, propylene glycol, purified water, and stearyl alcohol pressurized with a hydrocarbon (propane/butane) propellant.
Like other topical corticosteroids, clobetasol propionate foam has anti-inflammatory, antipruritic, and vasoconstrictive properties. The precise mechanism of the anti-inflammatory activity of topical steroids in the treatment of steroid-responsive dermatoses, in general, is uncertain. However, corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A2 .
Topical corticosteroids can be absorbed from intact healthy skin. The extent of percutaneous absorption of topical corticosteroids is determined by many factors, including the vehicle and the integrity of the epidermal barrier. Occlusion, inflammation and/or other disease processes in the skin may also increase percutaneous absorption.
Once absorbed through the skin, topical corticosteroids are handled through pharmacokinetic pathways similar to systemically administered corticosteroids. Due to the fact that circulating levels are well below the level of detection, the use of pharmacodynamic endpoints for assessing the systemic exposure of topical corticosteroids is necessary. They are metabolized, primarily in the liver, and are then excreted by the kidneys. In addition, some corticosteroids and their metabolites are also excreted in the bile.
A well-controlled clinical study evaluated 188 subjects with moderate to severe scalp psoriasis. Subjects were treated twice daily for 2 weeks with one of four treatments: Clobetasol propionate foam, 0.05%, Vehicle foam, a commercially available clobetasol propionate solution, or Vehicle solution. The efficacy of clobetasol propionate foam, 0.05% in treating scalp psoriasis at the end of the 2 weeks’ treatment was superior to that of Vehicle (foam and solution), and was comparable to that of the commercially available Scalp Application. See Table 1 below .
|Clobetasol Propionate Foam, 0.05% n (%)||Vehicle Foam n (%)|
|Total number of subjects||62||31|
|Subjects with Treatment Success *||39 (63)||1 (3)|
|Subjects with Parameter Clear at Endpoint (Scalp Psoriasis)|
|Scaling — Clear at Endpoint||42 (68)||3 (10)|
|Erythema — Clear at Endpoint||27 (44)||2 (6)|
|Plaque Thickness — Clear at Endpoint||41 (66)||3 (10)|
Another well-controlled clinical study evaluated 279 subjects with mild to moderate plaque-type psoriasis (mean Body Surface Area at baseline was 6.7% with a range from 1% to 20%) of non-scalp regions. Subjects were treated twice daily for 2 weeks with clobetasol propionate foam, 0.05% or Vehicle foam. The face and intertriginous areas were excluded from treatment. The efficacy of clobetasol propionate foam, 0.05% in treating non-scalp psoriasis at the end of 2 weeks’ treatment was superior to that of Vehicle foam. See Table 2 below.
|Vehicle Foam |
|Total number of subjects||139||140|
|Subjects with Treatment Success *||39 (28)||4 (3)|
|Physician’s Static Global Assessment -Clear or Almost Clear at Endpoint||94 (68)||30 (21)|
|Scaling -Clear or Almost Clear at Endpoint||101 (73)||42 (30)|
|Erythema -Clear or Almost Clear at Endpoint||88 (63)||35 (25)|
|Plaque Thickness -Clear at Endpoint||44 (32)||5 (4)|
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