|Short description DIFFERIN (adapalene) Gel, 0.1% contains adapalene 0.1% (3 mg/g) in a topical aqueous gel for use in the treatment of acne vulgaris, consisting of carbomer 940, edetate disodium, methylparaben, poloxamer 124, propylene glycol, purified water, and sodium hydroxide. May contain hydrochloric acid for pH adjustment. The chemical name of adapalene is 6-[3-(l-adamantyl)-4-methoxyphenyl]-2-naphthoic acid. It is a white to off-white powder, which is soluble in tetrahydrofuran, very slightly soluble in ethanol, and practically insoluble in water. The molecular formula is C28H28O3 and molecular weight is 412.53. Adapalene is represented by the following structural formula.