Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand.
Cosmetics and Natural Products Research Center, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand.
J Cosmet Dermatol. 2022 Nov;21(11):6400-6413. doi: 10.1111/jocd.15308. Epub 2022 Sep 20.
Sunscreens and catechins from grape seed extract (GSE) are sensitive to various environmental factors and undergo certain changes over time that might affect the effectiveness of the final product. To this date, effects of thermal storage conditions have not been sufficiently addressed to guarantee the long-term stability of sunscreen formulations.
To study the chemical and mechanical accelerated and long-term stability of sunscreen formulation containing GSE at the Climatic Zone IVb conditions.
Stability studies were performed for 6 months for accelerated stability study at 30°C ± 2 and 50°C ± 2, 75 ± 5% relative humidity; and long-term stability study at 5°C ± 5. The quantification of constituents of three formulations: sunscreen with GSE, cream with UV filters only, and cream with GSE only was performed by high-performance liquid chromatography. In vitro spectrophotometry was used to determine changes in sun protection effectiveness through SPF and UVAPF values. Mechanical stability was evaluated by textural and rheological analyzes.
All tested formulations were less stable at high-temperature conditions. The contents of catechin (С) and epicatechin (EC) in sunscreen with GSE were reduced to 37% and 50% at 50°C, respectively, whereas UV filters appeared to be stable. However, despite the significant reduction in catechins over time, polyphenols in GSE remained unchanged at different stored conditions. The SPF values and water resistance of sunscreen with GSE were maintained throughout the study.
A current in vitro study has shown that sunscreen with GSE is a value-added anti-aging ingredient in sunscreen formulation because its polyphenolic composition as well as SPF values and water resistance were maintained under all temperature conditions over time.
防晒霜和葡萄籽提取物（GSE）中的儿茶素对各种环境因素敏感，随着时间的推移会发生某些变化，这可能会影响最终产品的效果。迄今为止，尚未充分研究热储存条件的影响，无法保证防晒霜配方的长期稳定性。
研究含 GSE 的防晒霜配方在气候区 IVb 条件下的化学和机械加速及长期稳定性。
在 30°C±2 和 50°C±2、75±5%相对湿度的加速稳定性研究中进行了为期 6 个月的稳定性研究；在 5°C±5 的长期稳定性研究中进行了为期 6 个月的稳定性研究。通过高效液相色谱法对三种配方（含 GSE 的防晒霜、仅含紫外线滤光剂的乳膏和仅含 GSE 的乳膏）的成分进行定量。采用分光光度法测定防晒指数（SPF）和紫外线防护因子（UVAPF）值的变化，以确定防晒效果的变化。通过质构和流变分析评估机械稳定性。
所有测试配方在高温条件下都不太稳定。含 GSE 的防晒霜中儿茶素（C）和表儿茶素（EC）的含量分别在 50°C 下降至 37%和 50%，而紫外线滤光剂则保持稳定。然而，尽管儿茶素随时间显著减少，但 GSE 中的多酚在不同储存条件下保持不变。含 GSE 的防晒霜的 SPF 值和耐水性在整个研究过程中保持不变。
目前的体外研究表明，含 GSE 的防晒霜是防晒霜配方中的一种附加值抗衰老成分，因为其多酚成分以及 SPF 值和耐水性在所有温度条件下都能随着时间的推移而保持。
