PHYTOSPHERIX TM as a Sun Protection Factor (SPF) Booster

Transcription

1 PHYTOSPHERIX TM as a Sun Protection Factor (SPF) Booster PHYTOSPHERIX TM provides a boost to sun protection formulations containing synthetic and mineral sunscreen agents. Because of its unique combination of properties, PHYTOSPHERIX TM and chemically modified PHYTOSPHERIX TM are very useful, natural polyfunctional additives to water-based formulations for personal care, food and industrial applications. We have demonstrated that the addition of PHYTOSPHERIX TM to sun protection formulations boosts the sun protection factor (SPF) index. This effect was observed in formulations containing physical (containing inorganic pigments) and chemical (containing UV-absorbing chemicals) sunscreen agents. Furthermore, PHYTOSPHERIX TM acts as a photostabilizer for photolabile compounds in various cosmetics, medical and food formulations, e.g. vitamins, sunscreen active ingredients, drugs, etc. Also, PHYTOSPHERIX TM provides improved emulsification and emulsion stabilization of oil in water emulsions, such as creams lotions, etc. PHYTOSPHERIX TM IMPROVES EMULSIFICATION PROTECTS SUNSCREEN ACTIVES FROM PHOTODEGRADATION SCATTERS UVA/UVB LIGHT STABILIZES EMULSIONs ENHANCES MOISTURIZATION & REDUCES GREASY FEEL LESS SUNSCREEN ACTIVES IN THE FORMULATION BETTER LONG-LASTING SUN PROTECTION SAFER CHEAPER PRODUCTS Figure 1: Useful properties of PHYTOSPHERIX TM for sunscreen applications. PHYTOSPHERIX TM improves the sun protection properties of sunscreen formulations. The damaging effects of over-exposure of human skin to sunlight are well known. Ultraviolet (UV) radiation ( nm) is the most harmful part of the solar light spectrum. To protect human skin from

2 harmful sunlight radiation, a wide variety of sunscreen preparations, based on physical and chemical agents, have been developed. To achieve adequate SPF index values, high concentrations of sunscreen actives should be used in formulations. However, regulatory agencies, e.g. FDA, limit sunscreen concentrations to 3-15% based on the available safety data. As a consequence, formulations typically contain a large number of different sunscreen actives. PHYTOSPHERIX TM and PHYTOSPHERIX TM modified with octenylsuccinic acid (OSA) were incorporated into sunscreen formulations containing homosalate or titanium dioxide. The resulting sunscreen formulations had SPF index values up to 20% higher relative to the formulation that did not contain PHYTOSPHERIX TM or OSA-modified PHYTOSPHERIX TM. Improvement of the SPF index by addition of PHYTOSPHERIX TM to sunscreen formulations is attributed to its ability to reflect and scatter UV light, or to improved emulsification and dispersion of other sunscreen actives, improved formulation rheology, or a combination thereof. The amount of PHYTOSPHERIX TM in the final formulation can vary between 1% and 20% by weight, preferably between 5% and 10%. The choice of using PHYTOSPHERIX TM or OSA-modified PHYTOSPHERIX TM will depend on the particular organic sunscreen active. PHYTOSPHERIX TM improves the photostability of organic sunscreens. Numerous recent studies have demonstrated that many sunscreen actives suffer from inadequate photostability and rapidly lose their photoprotective ability upon exposure to ultraviolet radiation. This results in marketed products that may not meet their labeled SPF index. Furthermore, photoinactivation of sunscreens may produce free radical intermediates and compounds that act as sensitizers and photoallergens. There are different ways to improve the photostability of sunscreen formulations. The most commonly employed strategies are the addition of photostabilizing agents and antioxidants, encapsulation in polymers, and complexation with hydroxypropyl-beta-cyclodextrins. Also, to mitigate this problem, some manufactures add more sunscreens actives to the product than is actually needed to achieve the SPF index value on the label. Nonetheless, sunscreen photostability is complicated by a number of factors and photostabilization of sunscreen actives constitute, to date, a problem that has not been solved in a completely satisfactory manner. Introducing PHYTOSPHERIX TM into sunscreen formulations enhanced the photostability of organic sunscreen actives: their photostability was improved at least 3-fold and as much as 10-fold, depending on the formulation parameters. Typical results are shown in Table I and Figure 2.

3 Sunscreen activity, % Sunscreen actives in the formulation Change in Sunscreen activity, % Homosalate 7% Homosalate 7% + PHYTOSPHERIX TM, 6% 0.0 OM cinnamate 7% OM cinnamate 7% + PHYTOSPHERIX TM, 6% Avobenzone 7% Avobenzone 7% + PHYTOSPHERIX TM, 6% +8.0 Table I: Change in sunscreen activity obtained after xx h of exposure to UV radiation for sunscreen formulations containing different organic sunscreen actives, with and without PHYTOSPHERIX TM Typical sunscreen, Avobenzone +PHYTOSPHERIX UV irradiation time, min Figure 2: Dependence of sunscreen activity on time of exposure to UV radiation for sunscreen formulations containing Avobenzone (with and without PHYTOSPHERIX TM ). The exact mechanism of the increase in sunscreen activity is not clear. However, we believe that this reflects both an improvement of the photostability of the sunscreen actives and an increase in the overall opacity of the film for the dehydrated formulations. To improve photostability and dispersibility, sunscreen actives can be covalently conjugated to PHYTOSPHERIX TM. It can be seen from the data shown in Figure 3 that a PHYTOSPHERIX TM -ethyl-4-

4 aminocinnamate conjugate retained 60% of its activity after 4 h of exposure to UV radiation, compared to 30% of its activity for the aminocinnamate. Figure 3: Dependence of sunscreen activity on time of exposure to UV radiation for sunscreen formulations containing aminocinnamate (with and without PHYTOSPHERIX TM ). PHYTOSPHERIX TM improves the photostabilization of vitamins and bioactives. Because PHYTOSPHERIX TM is a natural ingredient that can be produced under food grade conditions, its photostabilizing properties are useful not only in sunscreen formulations, but also in medical and food formulations, e.g. vitamins, drugs, food colorants, etc. For example, the photostability of vitamin A in a cosmetic formulation was greatly improved by addition of OSA-modified PHYTOSPHERIX TM. As can be seen from Figure 4 after 3 h of UV light irradiation, there was no measurable change in vitamin A concentration in the emulsion containing OSA-modified PHYTOSPHERIX TM, in contrast to a 56% decrease in vitamin A concentration in the emulsion that did not contain OSA-modified PHYTOSPHERIX TM.

5 Amount of active Vitamin A, % Vitamin A Vitamin A + PHYTOSPHERIX UV irradiation time, min Figure 4: Dependence of amount of active Vitamin A remaining on time of exposure to UV radiation, for Vitamin A incorporated into alcohol-based emulsions, which are suitable for spray applications, with and without the addition of 5% OSA-modified PHYTOSPHERIX TM. The decrease in the activity of Vitamin A was calculated from the measured decrease in the maximum absorption at nm.