Zinc pyrithione (ZnPT) is a widely used antifungal, usually applied as a microparticle suspension to facilitate delivery into the hair follicles, where it then dissociates into a soluble monomeric form that is bioactive against yeast and other microorganisms. In this study, we use multiphoton microscopy (MPM) and fluorescence lifetime imaging microscopy (FLIM) to characterise ZnPT formulations and map the delivery of particles into follicles within human skin. To simulate real-world conditions, it was applied using a massage or no-massage technique, while simultaneously assessing the dissolution using Zinpyr-1, a zinc labile fluorescent probe. ZnPT particles can be detected in a range of shampoo formulations using both MPM and FLIM, though FLIM is optimal for detection as it allows spectral and lifetime discrimination leading to increased selectivity and sensitivity. In aqueous suspensions, the ZnPT 7.2 µm particles could be detected up to 500 µm in the follicle. The ZnPT particles in formulations were finer (1.0–3.3 µm), resulting in rapid dissolution on the skin surface and within follicles, evidenced by a reduced particle signal at 24 h but enhanced Zinpyr-1 intensity in the follicular and surface epithelium. This study shows how MPM-FLIM multimodal imaging can be used as a useful tool to assess ZnPT delivery to skin and its subsequent dissolution.

中文翻译：

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多模态成像评估吡啶硫酮锌的卵泡输送

吡啶硫酮锌 (ZnPT) 是一种广泛使用的抗真菌剂，通常用作微粒悬浮液以促进递送到毛囊中，然后在毛囊中解离成对酵母和其他微生物具有生物活性的可溶性单体形式。在这项研究中，我们使用多光子显微镜 (MPM) 和荧光寿命成像显微镜 (FLIM) 来表征 ZnPT 制剂并将颗粒递送到人体皮肤内的毛囊中。为了模拟真实世界的条件，它使用按摩或非按摩技术应用，同时使用锌不稳定荧光探针 Zinpyr-1 评估溶解度。可以使用 MPM 和 FLIM 在一系列洗发水配方中检测到 ZnPT 颗粒，尽管 FLIM 是检测的最佳选择，因为它允许光谱和寿命区分，从而提高选择性和灵敏度。在水性悬浮液中，可在毛囊中检测到高达 500 µm 的 ZnPT 7.2 µm 颗粒。制剂中的 ZnPT 颗粒更细（1.0–3.3 µm），导致在皮肤表面和毛囊内快速溶解，24 小时时颗粒信号降低但毛囊和表面上皮细胞中 Zinpyr-1 强度增强就证明了这一点。本研究显示了 MPM-FLIM 多模态成像如何用作评估 ZnPT 向皮肤的递送及其随后的溶解的有用工具。导致皮肤表面和毛囊内的快速溶解，这可以通过 24 小时时的颗粒信号降低但毛囊和表面上皮细胞中的 Zinpyr-1 强度增强来证明。本研究显示了 MPM-FLIM 多模态成像如何用作评估 ZnPT 向皮肤的递送及其随后的溶解的有用工具。导致皮肤表面和毛囊内的快速溶解，这可以通过 24 小时时的颗粒信号降低但毛囊和表面上皮细胞中的 Zinpyr-1 强度增强来证明。本研究显示了 MPM-FLIM 多模态成像如何用作评估 ZnPT 向皮肤的递送及其随后的溶解的有用工具。