Octocrylene
Also known as: 2-Ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-Ethylhexyl 2-cyano-3,3-diphenyl-2-propenoate
Description
Octocrylene is a cyanoacrylate-based UV absorber that provides protection across the UVB and short UVA range (290–360 nm), with peak absorption around 303 nm. Approved by the FDA at up to 10%, it serves a dual role in sunscreen formulations: as a direct UV absorber and, critically, as a photostabilizer for avobenzone. Octocrylene quenches the excited triplet state of avobenzone, preventing its photodegradation and maintaining broad-spectrum UVA protection. It has a favorable safety profile, though concerns have been raised about its degradation product benzophenone, a potential endocrine disruptor and photoallergen, which may accumulate in aged formulations.
Mechanism of Action
Octocrylene absorbs UV radiation through its 2-cyano-3,3-diphenylacrylate chromophore, dissipating absorbed energy as heat via vibrational relaxation. As a photostabilizer, it acts as a triplet-state quencher for avobenzone — it accepts energy from the excited triplet state of avobenzone's diketo form via triplet–triplet energy transfer, preventing the irreversible photolysis that would otherwise destroy avobenzone's UVA-absorbing capacity. Octocrylene itself is highly photostable due to the rigidity of its acrylate backbone, making it an ideal stabilizing partner in broad-spectrum formulations.
Indications
- UVB and short UVA photoprotection
- Photostabilization of avobenzone-containing formulations
- Broad-spectrum sunscreen formulations
- SPF boosting
Available Concentrations
Side Effects
- Contact dermatitis (uncommon)
- Photoallergic contact dermatitis (rare, more common in children)
- Potential benzophenone accumulation in aged products
- Mild irritation in sensitive skin
Contraindications
- Known hypersensitivity to octocrylene or acrylate compounds
- History of photoallergic contact dermatitis to octocrylene
Pregnancy Category
Not formally classified (topical use generally considered low risk)