Capex (Fluocinolone Acetonide Topical) - Description and Clinical Pharmacology

DESCRIPTION

Capex^® Shampoo 0.01% is supplied as a shampoo formulation with a 12 mg fluocinolone acetonide capsule which is emptied into the shampoo base by the pharmacist at the time of dispensing. After mixing, Capex^® Shampoo contains fluocinolone acetonide(6α,9-Difluoro-11β,16α, 17,21-tetrahydroxypregna-1,4-diene-3, 20-dione cyclic 16,17-acetal with acetone), a synthetic fluorinated corticosteroid for topical dermatologic use. The corticosteroids constitute a class of primarily synthetic steroids used topically as an anti-inflammatory and antipruritic agents.

Chemically, Capex^® Shampoo mixture is C₂₄H₃₀F₂O₆. It has the following structural formula:

Fluocinolone acetonide in Capex^® Shampoo has the molecular weight of 452.50. It is a white crystalline powder that is odorless, stable in light and melts at 270°F with decomposition; soluble in alcohol, acetone and methanol; slightly soluble in chloroform; insoluble in water.

Each fluocinolone capsule contains 12 mg of fluocinolone acetonide, 548 mg of dibasic calcium phosphate dihydrate USP, and 240 mg of talc USP. The shampoo base contains aluminum acetate basic, benzalkonium chloride solution, boric acid, citric acid anhydrous, cocamido-ether-sulfate complex, cocoamine oxide, lauramide DEA, magnesium aluminum silicate, methylparaben, oat flour, propylene glycol, propylparaben, purified water, and fragrances, with D&C Yellow #10 and FD&C Blue #1 as coloring.

CLINICAL PHARMACOLOGY

Like other topical corticosteroids, fluocinolone acetonide has anti-inflammatory, antipruritic and vasoconstrictive properties. The mechanism of the anti-inflammatory activity of the topical steroids, in general, is unclear. 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.

Pharmacokinetics: The extent of percutaneous absorption of topical corticosteroids is determined by many factors including the vehicle and the integrity of the epidermal barrier. Occlusive dressings with hydrocortisone for up to 24 hours have not been demonstrated to increase penetration; however, occlusion of hydrocortisone for 96 hours markedly enhances penetration. Topical corticosteroids can be absorbed from normal intact skin while inflammation and/or other disease processes in the skin increase percutaneous absorption.

Capex^® Shampoo is in the low to medium range of potency as compared with other topical corticosteroids.

CLINICAL STUDIES

In vehicle-controlled studies for the treatment of seborrheic dermatitis of the scalp, after 14 days of treatment, 84% of patients on active treatment and 29% of patients on the drug vehicle had cleared or markedly improved.