Ultrasound-enhanced corneal drug delivery

项目总结/摘要 角膜疾病的医学治疗依赖于局部药剂有效地渗透到角膜中。在 在许多情况下，角膜上皮充当扩散的屏障，而在上皮缺损的情况下， 药物穿透基质可能是不可靠的或不充分的。本研究旨在评估 超声波技术，以提高角膜的渗透性，并促进角膜吸收选定的 局部用药-核黄素、万古霉素和伏立康唑。核黄素用于角膜交联， 用于通过核黄素与以下物质的相互作用而使组织变硬的角膜弱化疾病的治疗 紫外线能量由于通常去除上皮以实现足够的核黄素渗透到细胞中， 角膜，使患者遭受疼痛和感染的风险，需要一种创新，可以增加 基质核黄素摄取，同时避免上皮去除。由于核黄素是自发荧光的，因此它可以是 使用共聚焦显微镜在角膜中定量。万古霉素-BODIPY是一种标记的荧光形式的 高度临床相关的抗生素，也可以在角膜中检测到。它是一个更大的分子， 因此提供了优化超声参数的额外信息，以推广到其他药物。 一种独特但紧迫的临床需求涉及真菌性角膜溃疡的治疗，其经常需要 切除受感染的组织，部分原因是抗真菌剂（如伏立康唑）进入深部的效果不佳 基质。我们已经显示了一个显着增加核黄素渗透到角膜后超声 暴露而不进行上皮清创，在初步实验中，我们观察到令人印象深刻的 万古霉素-BODIPY渗透到没有上皮的基质中，以及改善的核黄素 通过优化溶液制剂的粘度并产生 微泡因此，本研究的目的是确定临床上有用的超声治疗方案， 核黄素、万古霉素和伏立康唑的递送，以改善一系列角膜病症中的患者护理。在 目的1，我们将优化超声治疗参数，包括频率，强度，占空比， 使用核黄素和万古霉素-BODIPY应用于兔角膜的体外模型的治疗时间， 用共聚焦显微镜测量药物渗透。在目标2中，我们将量化体内角膜递送 使用目标1中确定的最有效设置。在目标3中，我们将测试超声波改善 在镰刀菌角膜炎的活兔模型中，通过定量伏立康唑对角膜基质的递送， 治疗后角膜中残留的微生物。目标4：临床有效治疗方案的安全性 将在几个时间点通过角膜的临床和组织学检查进行评价， 注意内皮细胞损伤或丢失。该结果可作为患者临床试验的依据 正在进行交联或患有难治性角膜感染，并将提供概念验证以进行研究 该技术用于其他应用，例如递送用于内皮细胞功能障碍的新疗法。

Project Summary/Abstract Medical treatment of corneal disease depends upon effective penetration of topical agents into the cornea. In many instances the corneal epithelium serves as a barrier to diffusion, while in cases with epithelial defects drug penetration through the stroma can be unreliable or inadequate. This study proposes to evaluate ultrasound technology to enhance the permeability of the cornea and promote corneal uptake of selected topical medications – riboflavin, vancomycin, and voriconazole. Riboflavin is used in corneal cross-linking, a treatment for diseases of corneal weakening that stiffens the tissue through the interaction of riboflavin with ultraviolet energy. Since the epithelium is generally removed to achieve adequate riboflavin penetration in the cornea, subjecting patients to pain and the risk of infection, there is a need for an innovation that can increase stromal riboflavin uptake while avoiding epithelial removal. Since riboflavin is autofluorescent, it can be quantified in the cornea using confocal microscopy. Vancomycin-BODIPY is a labeled fluorescent version of the highly clinically relevant antibiotic and can also be detected in the cornea. It is a larger molecule and will therefore provide additional information in optimizing ultrasound parameters for generalizability to other drugs. A distinct but pressing clinical need relates to the treatment of fungal corneal ulcers, which frequently require excision of infected tissue, due in part to poor delivery of antifungal agents, such as voriconazole, into the deep stroma. We have shown a significant increase in penetration of riboflavin into the cornea following ultrasound exposure without epithelial debridement, and in preliminary experiments we observed an impressive penetration of vancomycin-BODIPY into the stroma without epithelium, as well as an improved riboflavin penetration at lower ultrasound settings by optimizing the viscosity of the solution formulation and generating microbubbles. The goal of this study therefore is to identify clinically useful ultrasound treatment regimes for riboflavin, vancomycin, and voriconazole delivery to improve patient care in a range of corneal conditions. In Aim 1, we will optimize ultrasound treatment parameters including frequency, intensity, duty cycle, and treatment time using an in vitro model of riboflavin and vancomycin-BODIPY application to the rabbit cornea, measuring drug permeation with confocal microscopy. In Aim 2, we will quantify the corneal delivery in vivo using the most effective settings identified in Aim 1. In Aim 3, we will test the ability of ultrasound to improve the delivery of voriconazole to the corneal stroma in a live rabbit model of Fusarium keratitis by quantifying the residual organisms in the cornea after treatment. In Aim 4 the safety of a clinically effective treatment regimen will be evaluated through clinical and histologic examination of the cornea at several time points with particular attention to endothelial cell damage or loss. The results can serve as the basis for clinical trials in patients undergoing cross-linking or with recalcitrant corneal infections and will provide proof of concept to investigate this technology for other applications, such as delivery of novel therapies for endothelial cell dysfunction.