Glabridin 함유 나노에멀젼 제형의 피부흡수 최적화 연구

Abstract

화장품 업계에서는 미백, 주름, 항산화, 항노화 등 기능성 화장품의 신소재 개발과 더불어 실제로 피부에 적용 시 피부 흡수율을 높이는 기술이 중요하다. 이에 본 연구에서는 실험설계법인 반응표면분석법(Response Surface Methodology, RSM)을 활용하여 나노에멀젼 제형을 최적화하고자 하였다. 유용성감초추출물의 주성분인 glabridin을 활성성분으로 하여 고압유화(High-Pressure Homogenization, HPH) 방법으로 나노에멀젼을 제조하였으며, 최종적으로 최적화한 나노에멀젼의 피부 흡수율을 평가하였다. RSM 인자로 계면활성제 함량(1.0 ∼ 5.0 wt%), 콜레스테롤 함량(0.1 ∼ 0.5 wt%), 오일 함량(2.0 ∼ 10.0 wt%), 폴리올 함량(2.0 ∼ 18.0 wt%), 고압유화 압력(400 ∼ 1,000 bar), 고압유화 횟수(1 ∼ 5 pass)를 달리하여 나노에멀젼을 제조하였다. 그 중 입자 크기에 가장 큰 영향을 미치는 인자인 계면활성제 함량, 오일 함량, 고압유화 압력, 고압유화 횟수를 독립변수로 하였고, 나노에멀젼의 입자 크기와 피부 흡수율을 반응변수로 하였다. 실험은 중심점 5 회 반복을 포함하여 총 29 회 실험이 무작위로 수행되었으며, 제조된 나노에멀젼의 입자 크기와 피부 흡수율을 측정하였다. 그 결과를 바탕으로 최소 입자 크기, 최대 피부 흡수율을 갖는 제형을 최적화하였으며, 계면활성제 함량 5.0 wt%. 오일 함량 2.0 wt%, 고압유화 압력 1,000 bar, 고압유화 횟수 4 pass를 최적 조건으로 도출하였다. 최적 조건으로 제조한 나노에멀젼의 물성으로 pH는 6.90 ± 0.01, 입자 크기는 111.6 ± 0.2 nm, 다분산지수(Polydispersity Index, PDI)는 0.247 ± 0.014, 제타전위(Zeta Potential, ZP)는 -56.7 ± 1.2 mV로 측정되었다. 나노에멀젼의 피부 흡수율을 대조군인 에멀젼과 비교한 바, 24 h 후 나노에멀젼의 누적 흡수율은 79.53 ± 0.23%, 대조군으로서 에멀젼의 누적 흡수율은 66.54 ± 1.45%로 나노에멀젼이 에멀젼보다 13% 높은 누적 투과량을 보였다.|In the cosmetics industry, it is important to develop new materials for functional cosmetics such as whitening, wrinkles, anti-oxidation, and anti-aging, as well as technology to increase skin absorption rate when actually applied to the skin. Therefore, in this study, the we tried to optimize the nanoemulsion formulation using RSM, an experimental design method. A nanoemulsion was prepared by a HPH method using glabridin as an active ingredient, and finally, the optimized skin absorption rate of the nanoemulsion was evaluated. Nanoemulsions were prepared by varying the surfactant content (1.0 ~ 5.0 wt%), cholesterol content (0.1 ~ 0.5 wt%), oil content (2.0 ~ 10.0 wt%), polyol content (2.0 ~ 18.0 wt%), HPH pressure (400 ~ 1,000 bar), and the number of HPH (1 ~ 5 pass) as RSM factors. Among them, surfactant content, oil content, HPH pressure, and the number of HPH, which are factors that have the greatest influence on particle size, were used as independent variables, and particle size and skin absorption rate of nanoemulsion were used as response variables. A total of 29 experiments were randomly conducted, including 5 repetitions of the center point, and the particle size and skin absorption rate of the prepared nanoemulsion were measured. Based on the results, the formulation with the minimum particle size and maximum skin absorption rate was optimized, and the surfactant content of 5.0 wt%, oil content of 2.0 wt%, HPH pressure of 1,000 bar, and the number of HPH of 4 pass were derived as the optimal conditions. The physical properties of the nanoemulsion prepared under optimal conditions, the pH was 6.90 ± 0.01, the particle size was 111.6 ± 0.2 nm, the PDI was 0.247 ± 0.014, and the ZP was -56.7 ± 1.2 mV. The skin absorption rate of the nanoemulsion was compared with emulsion as a control. After 24h, the result of the nanoemulsion and general emulsion skin absorption test, the cumulative absorption rate of the nanoemulsion was 79.53 ± 0.23% and the emulsion was 66.54 ± 1.45%, nanoemulsion was 13% higher than the emulsion.