Adapalene

Adapalene

Systematic (IUPAC) name
6-[3-(1-adamantyl)-4-methoxy-phenyl] naphthalene-2-carboxylic acid
Clinical data
Trade names	Differin, Teva, Pimpal, Gallet, Adelene, Adeferin
AHFS/Drugs.com	monograph
MedlinePlus	a604001
Licence data	US FDA:link
Pregnancy category	AU: D US: C (Risk not ruled out)
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Routes of administration	Topical
Pharmacokinetic data
Bioavailability	Very low
Excretion	Biliary
Identifiers
CAS Number	106685-40-9 Y
ATC code	D10AD03 (WHO)
PubChem	CID: 60164
IUPHAR/BPS	5429
DrugBank	DB00210 Y
ChemSpider	54244 Y
UNII	1L4806J2QF Y
KEGG	D01112 Y
ChEBI	CHEBI:31174 Y
ChEMBL	CHEMBL1265 Y
Chemical data
Formula	C28H28O3
Molecular mass	412.52 g/mol
SMILES O=C(O)c2ccc1cc(ccc1c2)c3cc(c(OC)cc3)C46CC5CC(CC(C4)C5)C6
InChI InChI=1S/C28H28O3/c1-31-26-7-6-23(21-2-3-22-12-24(27(29)30)5-4-20(22)11-21)13-25(26)28-14-17-8-18(15-28)10-19(9-17)16-28/h2-7,11-13,17-19H,8-10,14-16H2,1H3,(H,29,30) Y Key:LZCDAPDGXCYOEH-UHFFFAOYSA-N Y
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Adapalene is a third-generation topical retinoid primarily used in the treatment of mild-moderate acne, and is also used off-label to treat keratosis pilaris as well as other skin conditions. It is effective against acne conditions where comedones are predominant.

History

Adapalene is a research product of Galderma Laboratories, France. Adapalene was approved in 1996 by the U.S. Food and Drug Administration (FDA) for use in the treatment of acne.

Mechanism of action

Unlike tretinoin, adapalene inhibits keratinocyte differentiation. This inhibition of keratinocyte differentiation and proliferation is responsible for adapalene’s comedolytic effect. It has both exfoliating and anti-inflammatory effects. In an in vivo study, adapalene’s ability to reduce comedo formation was demonstrated by a 50–60% reduction in comedo counts compared with vehicle.

Available forms

Tube of generic adapalene

In the United States, adapalene is available under the brand name Differin in three different preparations: 0.1% cream, 0.1% gel, and 0.3% gel. The 0.1% gel is available as a generic made by Teva. It is also available combined with benzoyl peroxide under the brand name Epiduo. In Europe, only the 0.1% cream and 0.1% gel are available. Adapalene is currently marketed by Galderma under the trade names Differin in some countries, and Adaferin in India. It is mostly available in 0.1% w /w gel form.

Pharmacology

Drug interactions

Adapalene has been shown to enhance the efficacy of topical clindamycin, although adverse effects are also increased. Application of adapalene gel to the skin 3–5 minutes before application of clindamycin enhances penetration of clindamycin into the skin, which may enhance the overall efficacy of the treatment as compared to clindamycin alone.

Unlike tretinoin (Retin-A), adapalene has also been shown to retain its efficacy when applied at the same time as benzoyl peroxide due to its more stable chemical structure.

Pharmacokinetics

Absorption of adapalene through the skin is low. A study with six acne patients treated once daily for five days with two grams of adapalene cream applied to 1000 cm² of skin found no quantifiable amounts, or less than 0.35 ng/mL of the drug, in the patients' blood plasma.

External links

• Adapalene General Information, Patient Information, Contraindications and Interactions
• Epiduo Prescribing Information