Abstract
Retinlyl Palmitate, the skin normalizerm is useful to promote greater skin elasticity, to diminish lipid peroxidation and skin roughness following UV exposure, and promote a youthfulgeneral skin appearance. In manufacturing creams, Retinyl Palmitate, which is a derivative of retinol, is used since reionol is easily oxidized by heat and light. However, only a small mount of retinol, is used since using a large amount of it may be harmful to its stability. In this study, thermal stability and UV stability of W/O-, W/S-, O/W-, and MLV-type creams containing 5% of retinyl palmitate and 10% of tocopheryl acetate are measured by Chroma Meters, and the content of RP is quantitatively analyzed by HPLC at 25 $^{\circ}C$ and 45 $^{\circ}C$. Also, how RP has been changed by heat, light, etc. is measured by HPLC, and toxicity of the changed substance is studied. Particle size of each type of the cream if measured, cellular renewal is measured by using DHP and Chroma Meters in order to study their efficacy and effect, moisture content is measured by using Corneometer and Tewameter, and how much wrinkles are improved is studied by using Image Analyzer. Development of MLV-type cream containing 5% of RP and 10% of TA, and satisfying conditions for better creams has been successful.