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Studies on the effect of solvent on the efficiency of sunscreen products

OBJECTIVES: Solvents are one of the most important ingredients in the preparation of hygienic and cosmetic products. Nowadays the adverse effects of the sun light on the skin such as stinging, erythema and finally skin cancer have been known Therefore the use of anti preparations is common. In this study we tried to evaluate the effect of the solvents in altering of absorption amount and of LTVB for the chemical substance of products. METHODS: For this mean and solar materials were solved in solvents i.e. water, sorbitol, ethanol, propylene glycol and glycerin. Then spectra and absorption intensities of them were measured in 5 nm intervals using by spectrophotometer instrument. Finally according to them maximum absorption, shift amount, area under the curve and relative efficacy of the anti solar substance were calculated. RESULTS: The results showed that the type of solvent had significantly effect on Landa max It should be considered that in the formulations containing Parsoli 5000, using water and sorbitol as a solvent is not reasonable. Because these solvents will shift the Landa max of sunscreen and the efficacy of the preparation will be lost. Most of the solvents altered the Landa max of the benzophenon toward lower wave lengths. It was showed that PABA and Parsol HS had low sensitivity to the type of solvent among other sunscreens. Then it is possible to use most of the solvents in formulations as sunscreen products. It is necessary to say that the SPF of the product may be changed because of altering the Landa max and absorption intensity of the anti solar substance by the solvents. CONCLUSION: Then it is possible to choose proper solvent for the each of above anti solar materials.