| Summary: | 碩士 === 靜宜大學 === 化粧品科學系 === 101 === The first objective of this research is to investigate the effectiveness of sunscreens in emulsions of water in oil (W/O) by optimizing the combination of commonly used emollients with different single organic UV-filters or poly(methyl methacrylate) (PMMA) encapsulated organic UV filters. By modifying the dosage of each component, we analyzed how the SPF value and UVA/UVB ratio of sunscreen lotions were affected. We also examined the effect of combination of Tegosoft TN (TTN) with 4 other emollients on the SPF value as well as UVA/UVB ratio in W/O emulsions using the UK-Boots Star rating method. The second objective is to test the photostability of PMMA encapsulated organic UV filters. The third objective is to study the transdermal diffusion efficiency of PMMA encapsulated organic UV filters.
In our results, UV filters combine with TTN to obtain the best SPF value and UVA/UVB ratio. Similar to a powder dispersant, TTN facilitates the dispersion of sunscreen powders in emulsion system and also exhibits the synergistic effect to boost SPF value. For UV filters in W/O emulsions, combination of TTN and Tegosoft DEC (TDEC) also improves the sunscreen effectiveness. For encapsulated UV filters, the SPF value has significant increase in W/O formulation up to 35%. Furthermore, after UV irradiation, the photodegradation is decreased and the improved stability can up to 60% when compared with the unencapsulated UV filters. In addition, in the cytotoxicity test, the cell viabilities of encapsulated UV filters are higher than that of unencapsulated UV filters. Moreover, we also proved that PMMA encapsulated octyl methoxycinnamate (OMC) will decrease its transdermal diffusion when compared with that of unencapsulated OMC. Diethylamino hydroxybenzoyl hexyl benzoate (DHHB) presents a higher cytotoxicity to cells and which is up to 50%. However, after encapsulation, the cytotoxicity of DHHB is decreased to only 22%. By comparing the percentage of degradation after UV irradiation, we supposed that the enhanced efficiency of encapsulated organic UV filters is through the improving of its photostability.
Finally, we have developed the safe sunscreens with an improved benefit/risk ratio, enhanced UV blocking activity and chemical stability in W/O emulsions with the best emollients combination.
|
|---|
