The Effect of Emollients on the SPF of Organic Sunscreens

Skin health plays a significant role in an individual’s appearance and wellbeing. The sun’s ultraviolet rays, if exposure to them is significant, have the power to negatively impact an individual’s skin health. Conditions such as burns, premature skin aging, and skin cancer are some of the common side effects of such exposure. Fortunately, because of the ability to avoid the sun, or even protect oneself from the harmful radiation, these issues can be avoided. One product commonly found on the market is sunscreen, which uses organic UV filters due to their many benefits. However, these filters are capable of absorbing into the skin, posing a safety concern for consumers. The goal of this research project was to find solvents (emollients) for different organic UV filters. Formulating for Efficacy (FFE) was used to match Hansen Solubility Parameters (HSPs) of the UV filters and the emollients in order to enhance the sun protection factor (SPF) and prevent absorption into the skin. The first step of the process included searching online in chemical databases and supplier websites. Different solvents were entered into FFE, which selected the optimal solvents for the given sunscreens based on HSPs. The most favorable UV filter-solvent combinations were tested in vitro using an SPF tester (LabSphere, UV-2000s). Through the performance of these tests, conclusions can be drawn about how the use of solvents effects sunscreen’s SPF.
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Abstract/Description: Skin health plays a significant role in an individual’s appearance and wellbeing. The sun’s ultraviolet rays, if exposure to them is significant, have the power to negatively impact an individual’s skin health. Conditions such as burns, premature skin aging, and skin cancer are some of the common side effects of such exposure. Fortunately, because of the ability to avoid the sun, or even protect oneself from the harmful radiation, these issues can be avoided. One product commonly found on the market is sunscreen, which uses organic UV filters due to their many benefits. However, these filters are capable of absorbing into the skin, posing a safety concern for consumers. The goal of this research project was to find solvents (emollients) for different organic UV filters. Formulating for Efficacy (FFE) was used to match Hansen Solubility Parameters (HSPs) of the UV filters and the emollients in order to enhance the sun protection factor (SPF) and prevent absorption into the skin. The first step of the process included searching online in chemical databases and supplier websites. Different solvents were entered into FFE, which selected the optimal solvents for the given sunscreens based on HSPs. The most favorable UV filter-solvent combinations were tested in vitro using an SPF tester (LabSphere, UV-2000s). Through the performance of these tests, conclusions can be drawn about how the use of solvents effects sunscreen’s SPF.
Subject(s): UV filter; LabSphere UV-2000S; Formulating for Efficacy; Hansen Solubility Parameters