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

<b><i>Background:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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. <b><i>Conclusion:</i></b> The HO-DMNs are efficient, safe, and convenient for wide use in cosmetic applications for skin barrier restoration and moisturization.

<b><i>背景：</i></b> 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，但这类制剂经角质层渗透能力有限，这成为最大化发挥马油美容功效的主要障碍。因此，本研究旨在将马油包封于美容用可溶性微针（dissolving microneedle, DMN）中，以实现高效经皮递送。<b><i>方法：</i></b> 为克服皮肤渗透局限，本研究开发了载马油可溶性微针贴片（HO-DMN），并通过体外实验与临床研究对其功效与安全性进行评估。<b><i>结果：</i></b> 尽管马油具有亲脂性，所制备的HO-DMN贴片外形尖锐、阵列均匀，其平均长度与针尖直径分别为388.36±16.73 μm与38.54±5.29 μm。该贴片的机械强度达标（断裂力为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及真皮密度、皮肤弹性与保湿状态。此外，简短的安全性评估显示，HO-DMN贴片引发的不良事件可忽略不计。<b><i>结论：</i></b> 载马油可溶性微针用于皮肤屏障修复与保湿类美容应用时，具备高效、安全、便捷的优势，适宜广泛推广使用。