Abstract
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 absorption when applied to the skin. Therefore, in this study, we tried to optimize the nanoemulsion formulation by utilizing response surface methodology (RSM), an experimental design method. A nanoemulsion was prepared by a high-pressure emulsification 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, cholesterol content, oil content, polyol content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization as RSM factors. Among them, surfactant content, oil content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization, 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 conducted at random, including 5 repetitions of the center point, and the particle size and skin absorption of the prepared nanoemulsion were measured. Based on the results, the formulation with the minimum particle size and maximum skin absorption was optimized, and the surfactant content of 5.0 wt%, oil content of 2.0 wt%, high-pressure homogenization pressure of 1,000 bar, and the cycling number of high-pressure homogenization of 4 pass were derived as the optimal conditions. As the physical properties of the nanoemulsion prepared under optimal conditions, the particle size was 111.6 ± 0.2 nm, the PDI was 0.247 ± 0.014, and the zeta potential was -56.7 ± 1.2 mV. The skin absorption rate of the nanoemulsion was compared with emulsion as a control. As a result of the nanoemulsion and general emulsion skin absorption test, the cumulative absorption of the nanoemulsion was 79.53 ± 0.23%, and the cumulative absorption of the emulsion as a control was 66.54 ± 1.45% after 24 h, which was 13% higher than the emulsion.
화장품 업계에서는 미백, 주름, 항산화, 항노화 등 기능성 화장품의 신소재 개발과 더불어 실제로 피부에 적용 시 피부흡수율을 높이는 기술이 중요하다. 이에 본 연구에서는 실험설계법인 반응표면분석법(RSM)을 활용하여 나노에멀젼 제형을 최적화하고자 하였다. Glabridin을 활성성분으로 하여 고압유화 방법으로 나노에멀젼을 제조하였으며, 최종적으로 최적화한 나노에멀젼의 피부흡수율을 평가하였다. RSM 인자로서 계면활성제 함량, 콜레스테롤 함량, 오일 함량, 폴리올 함량, 고압유화 압력, 고압유화 횟수를 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 피부흡수율을 반응변수로 하였다. 중심점 5 회 반복실험을 포함하여 총 29 회 실험이 무작위로 수행되었으며, 제조된 나노에멀젼의 입자 크기와 피부흡수율을 측정하였다. 그 결과를 바탕으로 최소 입자 크기, 최대 피부흡수율을 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 입자 크기는 111.6 ± 0.2 nm, 다분산지수는 0.247 ± 0.014, 제타전위는 -56.7 ± 1.2 mV로 측정되었다. 나노에멀젼과 일반 에멀젼 피부흡수 시험 결과, 24 h 후 나노에멀젼의 누적 투과량은 79.53 ± 0.23%이며, 대조군으로서 에멀젼의 누적 투과량은 66.54 ± 1.45%로 나노에멀젼이 에멀젼보다 13% 높았다.