Organic sunscreens act by absorbing solar radiation at particular wavelengths, emitting them at different and less harmful wavelengths. Such sunscreens are categorized as UVA or UVB, depending on their absorption wavelength.
As is well-known, in order to protect across the full range of wavelengths, sunscreen compositions must include both UV-A and UV-B filters, which can increase the cost and aggravate stability problems. To mitigate these issues, stabilizers and antioxidants, such as homosalate, are often included, expanding ingredient labels and the potential for interactions among components or with the consumer.
Accordingly, there remains a need for more effective sunscreen compositions. This is especially the case for those that can protect consumers using low concentrations and without implementing multiple actives. This was the focus of the present invention, which is based on polyhydroxy fullerene.
Polyhydroxy fullerene sunscreens
WIPO Patent Application WO/2017/136809
Publication date: Aug. 10, 2017
Assignee: The Cleveland Clinic Foundation
Described in this patent application are compositions including a dermatologically acceptable carrier and a polyhydroxy fullerene (PHF) compound. According to the inventors, this novel, safe, multifunctional active absorbs both UVB and UVA, and is a powerful antioxidant.
As stated in the patent literature, PHFs are the water-soluble form of fullerenes. They are spherical "cages" made of carbon atoms with a general formula of C2n, where n can range from 10 to 270. The molecular formula for unmodified PHF is C2n(OH)x; where x is in the range of 12 to 40.
Biocompatible and biodegradable, these molecules absorb UVB and UVA, with a critical wavelength of 381 nm and UVA/UVB ratio of 1.6; exceeding the FDA minimum limit of 370 nm and 0.91, respectively. PHF has been shown to absorb UV without generating free radicals, and can catalytically neutralize different types of free radicals without changing its molecular structure. Lastly, it reportedly can be easily incorporated into model sunscreen formulations.