Guest Post: The Chemistry of Acne Treatments- How Galderma’s Epiduo Gel Works

Staying blemish free this Friday date night? SeeArrOh guest posts about the chemistry that makes it possible. SeeArrOh is a Ph.D. chemist working in industry. Pharmaceutical marketing, like all advertising, is all about finding the right audience.  Targeting drugs to their desired demographic is, after all, a multi-billion dollar industry.  Thus, for erectile dysfunction, well-to-do 50-somethings ride horses or sit in bathtubs watching the sunset.  For smoking cessation, you’re in a bar or restaurant having a great time and chewing nicotine-enhanced gum.  So it should come as no surprise that the new acne medication Epiduo targets its desired demographic, teenagers, with catchy graphics, cool phrasing (“breakout cheerleaders”, anyone?), and even an iPhone app to track your treatment. The pharmaceutical company behind Epiduo, Galderma Laboratories, has left nothing to chance to attract the attention of flighty fifteen year olds.  The Napoleon Dynamite-style graphics evoke scribbling on the back of Mead college-rule notebooks, and suggest that pimples are caused by inky black spirals under your skin.  So what did I think was so cool about Galderma’s otherwise predictable ads?  The actual structures of the two major drug components in Epiduo, adapalene and dibenzoyl peroxide, are prominently featured in bright colors flanking a unicorn, some stars, and a tentacle (more doodles).  I recall learning the structure of DNA and amino acids in eighth-grade biology, so perhaps it’s not too unbelievable that budding young chemists might want to know what’s in their face creams.  Dibenzoyl peroxide is no stranger to organic and medicinal chemists: it’s one of our favorite radical initiators.  Perhaps best known as a promoter of radical bromination (making carbon-bromine bonds under moderate heat) and to initiate polymerizations, it’s used here to cause oxidative damage to bacteria found in acne lesions.  The peroxide breaks down in tissue to form oxygen and benzoic acid, and this combination can both kill cells and cause unwanted skin bleaching, a known side-effect of acne medication.  Adapalene, on the other hand, is a black box, as its exact mechanism of action is unknown.  It belongs to a chemical class known as the retinoids, compounds made to mimic the structure of­ Vitamin A, also known as retinol.  Vitamin A itself is thought to improve skin condition by reducing oily secretions, lessening inflammation, and reducing bacteria in skin ducts.  Whereas previous retinoids were synthesized to mimic the conjugated tail of retinol, newer-generation retinoids such as adapalene and tazarotene bear the telltale mark of the medicinal chemist: adamantyl anisoles (adapalene) and acetylenic pyridines (tazarotene) tend not to be in Nature’s usual toolbox.  Like most potent drugs, Epiduo and tazarotene are prescription-only. However, some topical treatments are natural products used for other applications that serendipitously found use as acne medications.  Salicylic acid, usually found as various esters derived from willows, birch, and wintergreen, has been used in Stridex and Clearasil for decades.  You may also recognize its acetylated cousin aspirin as a world-renowned painkiller.  Azelaic acid, a nine-carbon diacid used as a signaling molecule in plants, also works as a topical antibacterial.  Sulfacetamide, one of the sulfa “miracle drugs” originally synthesized in 1939 to treat battleground infections, fights pimples in combination with one of the most ancient natural products – elemental sulfur. Maybe the biggest advantage to the new medications?  Not smelling like a volcano on that all-important first date.

Author: Carmen Drahl

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3 Comments

  1. Oh, man. There goes that post idea. What were you watching when you saw the ad, SAO? I think I was watching He-Man, but I dunno.

  2. @CJ – Ironically, I think I was watching The Daily Show. It must do well with that 12-19 demographic…

  3. I think the adapalene mechanism of action is based on accelerated maturation and pealing of cells on the skin surface. This prevents new pimples from growing. However, if you are hypersensitive or if you are using too much, you can get a bad case of a dry flaky stuff pealing off your face (which looks far more alarming than acne) at the beginning of the therapy.

    My ex started her internship at a famous US hospital. She was very worried about her looks so she got Adapalene cream to defeat the pimples. That did not go well – she soon looked like a walking leprosy case…But the pimples disappeared