Supplementary Material for: Skin Barrier Restoration and Moisturization Using Horse Oil-Loaded Dissolving Microneedle Patches

Background: Horse oil (HO) has skin barrier restoration and skin-moisturizing effects. Although cream formulations have been used widely and safely, their limited penetration through the stratum corneum is a major obstacle to maximizing the cosmetic efficacy of HO. Therefore, we aimed to encapsulate HO in a cosmetic dissolving microneedle (DMN) for efficient transdermal delivery. Methods: To overcome these limitations of skin permeation, HO-loaded DMN (HO-DMN) patches were developed and evaluated for their efficacy and safety using in vitro and clinical studies. Results: Despite the lipophilic nature of HO, the HO-DMN patches had a sharp shape and uniform array, with an average length and tip diameter of 388.36 ± 16.73 and 38.54 ± 5.29 µm, respectively. The mechanical strength of the HO-DMN patches was sufficient (fracture force of 0.29 ± 0.01 N), and they could successfully penetrate pig skin. During the 4-week clinical evaluation, HO-DMN patches caused significant improvements in skin and dermal density, skin elasticity, and moisturization. Additionally, a brief safety assessment showed that the HO-DMN patches induced negligible adverse events. Conclusion: The HO-DMNs are efficient, safe, and convenient for wide use in cosmetic applications for skin barrier restoration and moisturization.

研究背景：马油（Horse Oil, HO）具备皮肤屏障修复与保湿功效。尽管乳膏制剂已被广泛且安全地应用，但其透过角质层（stratum corneum）的渗透能力有限，这成为最大化马油美容功效的主要障碍。因此，本研究旨在将马油封装于美容级溶解型微针（dissolving microneedle, DMN）中，以实现高效的透皮递送（transdermal delivery）。
研究方法：为克服皮肤渗透的上述局限，本研究开发了负载马油的溶解型微针贴片（HO-loaded DMN, HO-DMN），并通过体外实验（in vitro）与临床研究对其功效与安全性进行评估。
研究结果：尽管马油具有亲脂性，HO-DMN贴片仍具备锐利的外形与均匀的阵列结构，其平均长度与尖端直径分别为388.36±16.73 μm与38.54±5.29 μm。该贴片的机械强度充足，断裂力（fracture force）为0.29±0.01 N，可成功穿透猪皮肤。在为期4周的临床评估中，HO-DMN贴片可显著改善皮肤与真皮密度、皮肤弹性及保湿状态。此外，简要的安全性评估显示，HO-DMN贴片仅引发可忽略不计的不良事件（adverse events）。
研究结论：HO-DMN具备高效、安全且便捷的特性，可广泛应用于皮肤屏障修复与保湿的美容领域。