(1) Background: The study systematically investigated the influence of dispersed particles within a topical formulation on the dermal penetration efficacy of active compounds that are dissolved in the water phase of this formulation. The aim was to prove or disprove if particle-assisted dermal penetration can be used for improved dermal drug delivery. (2) Methods: Fluorescein was used as a surrogate for a hydrophilic active ingredient (AI). It was dissolved in the water phase of different formulations with and without particles. Two different types of particles (titanium dioxide and nanostructured lipid carriers (NLC)) were used. The influence of particle size and number of particles and the influence of skin hydrating excipients was also investigated. (3) Results demonstrate that the addition of particles can strongly increase the dermal penetration efficacy of AI. The effect depends on the size of the particles and the number of particles in the formulation, where smaller sizes and higher numbers resulted in higher penetration parameters. Formulations with NLC that contained 20% w/w or 40% w/w particles resulted in an about 2-fold higher amount of penetrated AI and increased the penetration depth about 2.5-fold. The penetration-enhancing effect was highly significant (p < 0.001) and allowed for an efficient delivery of the AI in the viable dermis. In contrast, the penetration-enhancing effect of excipients that increase the skin hydration was found to be very limited and not significant (≤5%, p > 0.05). (4) Conclusions: Based on the results, it can be concluded that particle-assisted dermal penetration can be considered to be a simple but highly efficient and industrially feasible formulation principle for improved and tailor-made dermal drug delivery of active compounds.

中文翻译：

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粒子辅助真皮渗透——一种促进真皮渗透功效的简单配方策略

(1) 背景：该研究系统地研究了局部制剂中分散颗粒对溶解在该制剂水相中的活性化合物的真皮渗透功效的影响。目的是证明或反驳粒子辅助皮肤渗透是否可用于改善皮肤药物输送。(2) 方法：荧光素用作亲水性活性成分 (AI) 的替代物。它溶解在有和没有颗粒的不同配方的水相中。使用了两种不同类型的颗粒（二氧化钛和纳米结构脂质载体 (NLC)）。还研究了颗粒大小和颗粒数量的影响以及皮肤保湿赋形剂的影响。(3) 结果表明，添加颗粒可以显着提高 AI 的真皮渗透功效。效果取决于颗粒的大小和配方中的颗粒数量，其中较小的尺寸和较高的数量会导致较高的渗透参数。含有 20% NLC 的配方w / w或 40% w / w颗粒导致渗透的 AI 量增加约 2 倍，渗透深度增加约 2.5 倍。渗透增强效果非常显着 ( p < 0.001)，并允许 AI 在有活力的真皮中有效输送。相比之下，发现增加皮肤水合作用的赋形剂的渗透增强作用非常有限且不显着（≤5%，p> 0.05)。(4) 结论：基于结果，可以得出结论，颗粒辅助皮肤渗透可以被认为是一种简单但高效且工业上可行的制剂原理，用于改善和定制活性化合物的皮肤药物递送。