Adapalene

Adapalene is a third-generation synthetic retinoid widely used as the active pharmaceutical ingredient in topical acne treatments, most notably marketed as Differin®. As a selective agonist of retinoic acid receptors, Adapalene binds preferentially to RARβ and RARγ, modulating gene expression involved in cell differentiation, keratinization, and inflammation. Adapalene inhibits the growth and differentiation of sebocytes in a concentration-dependent manner and exhibits potent anti-inflammatory properties by inhibiting lipoxygenase activity. Adapalene is more active than indomethacin, betamethasone valerate, tretinoin, isotretinoin, or etretinate in inhibiting lipoxygenase activity, while showing little activity against cyclo-oxygenase. For pharmaceutical quality control and analytical development, Adapalene serves as an essential reference standard for impurity profiling, method validation, and stability studies in generic manufacturing.

 

Product Parameters

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Parameter	Specification
Product Name	Adapalene
CAS Number	106685-40-9
Molecular Formula	C₂₈H₂₈O₃
Molecular Weight	412.52 g/mol
Appearance	White to off-white solid
Melting Point	319-322 °C
Boiling Point	606.3±55.0 °C
Solubility	DMSO: ≥10.31 mg/mL
Storage Condition	2-8 °C

 

Pharmacological Action

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Adapalene is a retinoid compound that has demonstrated anti-inflammatory properties in both in vivo and in vitro inflammatory models, exhibits chemical stability, and does not readily decompose under air or light exposure. Its mechanism of action is identical to that of retinoic acid, involving binding to specific retinoic acid nuclear receptors; however, adapalene does not bind to cytoplasmic receptors associated with proteins. Skin application studies conducted in mouse models have shown that adapalene can treat acne vulgaris and also exhibits efficacy against acne vulgaris and its differentiation process. The mechanism of action involves promoting normal differentiation of hair follicle epithelial cells, thereby reducing the formation of microcomedones. In standard anti-inflammatory analyses conducted in vivo and in vitro, adapalene demonstrates superior efficacy compared to retinoic acid. It inhibits the chemotactic response of human polymorphonuclear leukocytes and suppresses the metabolism of polymorphonuclear leukocytes by blocking the oxidative conversion of arachidonic acid into inflammatory mediators, thus alleviating cell-mediated inflammatory responses. Adapalene is indicated for the treatment of acne vulgaris characterized primarily by comedones, papules, and pustules, as well as for acne on the face, chest, and back.

 

Pharmacokinetics

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Adapalene exhibits very low transdermal absorption rates; in clinical trials, prolonged topical application to extensive acne lesions resulted in adapalene concentrations so low as to be undetectable. When ¹⁴C-labeled adapalene was administered to rats (intravenous, intraperitoneal, oral, and topically) and rabbits (intravenous, oral, and topically), radioactive activity was distributed throughout multiple tissues, with highest levels observed in the liver, spleen, adrenal glands, and ovaries. Adapalene is primarily metabolized in animals through oxygen demethylation, hydroxylation, and conjugation reactions, with excretion predominantly occurring via bile.

 

[Interactions]No interactions have been observed between this product and other medications that may be used concurrently on the skin. However, concomitant use with other retinoid drugs or other medications sharing similar mechanisms of action should be avoided. Adapalene exhibits stable chemical structure and does not decompose readily in air or sunlight. Extensive animal and human studies have demonstrated no phototoxicity or photosensitivity. Nevertheless, the safety of repeated exposure to sunlight or ultraviolet radiation remains uncertain; excessive sun exposure or UV exposure should be avoided when using this product. Adapalene has very low transdermal absorption, making systemic drug interactions unlikely. No evidence suggests that oral contraceptives, antibiotics, or other oral medications are affected by topical application of Dafuwen. Dafuwen may cause mild local irritation; additional irritation may occur when used concomitantly with exfoliants, astringents, or irritants. Therefore, concurrent use of other topical anti-acne agents such as erythromycin (concentration ≤4%), chloramphenicol phosphate solution (1%), or benzoyl peroxide aqueous gel (concentration ≤10%) in the morning, or Dafuwen gel at night, may prevent drug interaction-induced degradation or cumulative irritative effects.

 

[Adverse Reactions]The most common adverse reactions during the initial 2–4 weeks of treatment include erythema, dryness, scaling, pruritus, burning sensation, or stinging pain, typically mild to moderate in severity. Less frequent adverse reactions include sunburn, skin irritation, skin discomfort, burning sensations, and stinging pain (as reported in Chemicalbook). Rare adverse reactions encompass acne-related redness and swelling, dermatitis and contact dermatitis, ocular edema, conjunctivitis, erythema, pruritus, skin discoloration, rash, and eczema. In cases of severe adverse reactions, dosing frequency should be reduced or treatment discontinued.

 

Application

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Adapalene, a retinoic acid analog, is an agonist of RARβ and RARγ receptors. Adapalene inhibits cell proliferation and induces apoptosis in colorectal cancer cells in vitro. Adapalene gel is an effective therapeutic agent for acne.

 

Contact Us

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Looking for Adapalene for your topical dermatological API manufacturing campaign, impurity profiling program, or retinoid research? Cosperpharm makes it simple. Contact our team today for pricing, documentation, or technical support—we're ready to assist with your specific requirements.