Drug delivery via hair follicles has attracted much research attention due to its potential to serve for both local and systemic therapeutic purposes. Recent studies on topical application of various particulate formulations have demonstrated a great role of this delivery route for targeting numerous cell populations located in skin and transporting the encapsulated drug molecules to the bloodstream. Despite a great promise of follicle-targeting carriers, their clinical implementation is very rare, mostly because of their poorer characterization compared to conventional topical dosage forms, such as ointments and creams, which have a history spanning over a century. Gathering as complete information as possible on the intrafollicular penetration depth, storage, degradation/metabolization profiles of such carriers and the release kinetics of drugs they contain, as well as their impact on skin health would significantly contribute to understanding the pros and cons of each carrier type and facilitate the selection of the most suitable candidates for clinical trials. Optical imaging and spectroscopic techniques are extensively applied to study dermal penetration of drugs. Current paper provides the state-of-the-art overview of techniques, which are used in optical monitoring of follicular drug delivery, with a special focus on non-invasive in vivo methods. It discusses key features, advantages and limitations of their use, as well as provide expert perspectives on future directions in this field.

中文翻译：

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通过毛囊进行药物输送的光学监测的当前问题


通过毛囊递送药物因其可用于局部和全身治疗目的的潜力而引起了研究的广泛关注。最近对各种颗粒制剂局部应用的研究表明，这种递送途径在靶向位于皮肤中的众多细胞群并将包封的药物分子运输到血液中方面发挥着重要作用。尽管卵泡靶向载体前景广阔，但它们的临床应用非常罕见，这主要是因为与已有一百多年历史的常规局部剂型（如软膏和乳膏）相比，它们的特性较差。收集有关此类载体的滤泡内渗透深度、储存、降解/代谢曲线及其所含药物的释放动力学及其对皮肤健康的影响的尽可能完整的信息，将大大有助于了解每种载体类型的优缺点，并有助于选择最合适的临床试验候选者。光学成像和光谱技术广泛用于研究药物的皮肤渗透。本文提供了用于滤泡药物递送光学监测的技术的最新概述，特别关注无创体内方法。它讨论了它们使用的主要特征、优势和局限性，并就该领域的未来方向提供了专家观点。