Preparation and evaluation of alpha tocopherol/cyclodextrin complexes

Vitamin E is an oil-soluble vitamin. The alpha tocopherol (α-TC) form of vitamin E is mostly used in cosmetic products. The α-TC have antioxidant, antibacterial, skin rejuvenating and antiaging properties. It is sensitive to light and heat and can irritate the skin in high concentrations. α-TC must be in low concentration with high efficiency in an ideal cosmetic product. For this aim its tocopherol acetate form is used generally. Although stability of tocopherol acetate is higher than α-TC, it has less antioxidant properties. Cyclodextrins are cyclic oligosaccharides formed as a result of strach degredation. By forming inclusion complexes with guest molecules, they can change the physical and chemical properties of the molecules they carry. The aim of study is to increase the stability and solubility of α-TC and prepare a complex that will show higher antioxidant activity than its pure form. For this purpose, α-TC:CD complexes were prepared with hydroxypropyl beta cyclodextrin (HPBCD) and randomly methylated beta cyclodextrin (RAMEB) by freeze drying method. The characteristics of the complexes were evaluated by solubility, SEM, DSC, FT-IR, 1H-NMR, encapsulation efficacy and in-vitro dissolution rate analyses. Antioxidant activity studies on complexes carried out with DPPH tests. Compared to pure α-TC, solubility, dissolution rate and antioxidant activity were increased in the prepared complexes. α-TC:RAMEB was found to be more stable than other complex at different storage conditions (2-8 oC refrigerator, 25 oC dark, 25 oC sunlight, 40 oC etuv) during the one month of storage.