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Macromolecular Photosensitizers for Reduced Toxicity Sunscreen Formulations

IP.com Disclosure Number: IPCOM000247207D
Publication Date: 2016-Aug-16
Document File: 5 page(s) / 128K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed are macromolecular photosensitizers for reduced toxicity sunscreen formulations.

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Macromolecular Photosensitizers for Reduced Toxicity Sunscreen Formulations

Disclosed are macromolecular photosensitizers for reduced toxicity sunscreen formulations. The synthesis of derivitized octocrylene, oxinoxate, homosalate, and octisalate and their incorporation into macromolecular chemical structures is described. The large size and chemical compatibility of these derivatives allows for the prevention of them being absorbed into skin while still being a non-toxic sunscreen formulation. These different macromolecular photosensitizer molecules/oligomers/polymers are synthesized to possess either a hydroxyl, a bromine, or an alkyne functionality in order to undergo substitution, transition metal-catalyzed cross-coupling, or "Click" chemistry with various macromolecules such as a poly(vinylpyrrolidinone) (PVP) and poly(ethylene glycol) (PEG).

    Sunscreens are products combining several ingredients that help prevent the sun's ultraviolet (UV) radiation from reaching the skin. Two types of ultraviolet radiation, UVA and UVB, damage the skin, age it prematurely, and increase the risk of skin cancer. UVB is the chief culprit behind sunburn, while UVA rays, which penetrate the skin more deeply, are associated with wrinkling, leathering, sagging, and other light-induced effects of aging (photoaging). They also exacerbate the carcinogenic effects of UVB rays, and increasingly are being seen as a cause of skin cancer on their own. Sunscreens vary in their ability to protect against UVA and UVB. Active ingredients in sunscreens come in two forms, mineral and chemical filters. Each uses a different mechanism for protecting skin and maintaining stability in sunlight. Each may pose hazards to human health. The most common sunscreens on the market contain chemical filters. These products typically include a combination of two to six of these active ingredients: oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate. Mineral sunscreens use zinc oxide and/or titanium dioxide. A handful of products combine zinc oxide with chemical filters. All of the sunscreens that function as chemical filters are absorbed through the skin, are hormone disruptors, and/or are allergens. Consequently, the need exists to mitigate these undesirable properties while still affording the UVA/UVB protection. Chemical filters function by absorbing UVA/B sunlight and converting it to vibrational energy. For the specific case of oxybenzone, as shown in Figure 1, data suggests that its photoprotective properties can be understood in terms of an initial ultrafast excited state enol → keto tautomerization, followed by efficient internal conversion and subsequent vibrational relaxation to the ground state (enol) tautomer. The same photochemical principals also apply to octisalate and homosalate photosensitizer molecules in this disclosure.

    The photochemical reaction of octocrylene is shown below in Figure 2. This photochemical reaction takes place by...