Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.
Institute for Biomedical Engineering, Rostock University Medical Center, Rostock, Germany.
Sci Rep. 2017 Nov 17;7(1):15780. doi: 10.1038/s41598-017-15954-w.
Local drug delivery systems (DDS) have become a favourable approach for the treatment of numerous diseases. Biomedical imaging techniques such as ultrahigh field magnetic resonance imaging (UHF-MRI) offer unique insight into DDS biodegradation in vivo. We describe the establishment of a 7 Tesla MRI routine for longitudinal in vivo examinations of a subconjunctival DDS for the treatment of glaucoma in a rabbit model. In initial in vitro examinations the T2-relaxation times of the polymeric DDS components were assessed. Imaging of enzymatically degraded depot samples in vitro did not reveal changes in sample morphology or T2-relaxation time. Ex vivo investigations with an enucleated porcine eye showed good correlation of anatomical MRI and histological data. In longitudinal in vivo studies in rabbits, we repeatedly scanned the depot in the same animal over the course of 5 months with an in-plane resolution of 130 µm at scan times of less than 30 minutes. The degradation was quantified using volumetric analysis showing a volume reduction of 82% between 3 and 21 weeks after depot implantation. We have thereby demonstrated the feasibility of our UHF-MRI protocol as a non-invasive imaging routine for qualitative and quantitative, longitudinal evaluation of biodegradable subconjunctival DDS.
局部药物递送系统（DDS）已成为治疗多种疾病的一种有利方法。生物医学成像技术，如超高场磁共振成像（UHF-MRI），为 DDS 在体内的生物降解提供了独特的见解。我们描述了在兔模型中建立一种用于治疗青光眼的结膜下 DDS 的 7 特斯拉 MRI 常规，以进行纵向体内检查。在最初的体外检查中，评估了聚合物 DDS 成分的 T2 弛豫时间。在体外对酶降解储库样本进行成像，未显示出样品形态或 T2 弛豫时间的变化。在猪眼的离体研究中，解剖学 MRI 和组织学数据具有良好的相关性。在兔的纵向体内研究中，我们在 5 个月的时间内对同一动物的储库进行了多次扫描，在不到 30 分钟的扫描时间内，层厚分辨率为 130 µm。使用体积分析来定量降解，显示在植入储库后 3 至 21 周之间体积减少了 82％。我们已经证明了我们的 UHF-MRI 方案的可行性，作为一种非侵入性成像常规，用于对可生物降解的结膜下 DDS 进行定性和定量的纵向评估。
