基于同步辐射光源显微成像技术原位表征软胶囊结构变化及内部微粒分布

软胶囊壁不透光时,无法直接观察内容物变化。本研究旨在原位无损伤地测定软胶囊的结构及其内部微粒分布,揭示软胶囊的内在质量,发展软胶囊原研制剂剖析与物理稳定性评价的新技术。以蜂胶软胶囊为例,依托同步辐射光源X-射线显微成像(synchrotron radiation X-ray micro computed tomography, SR-μCT)原位无损伤地采集软胶囊的CT投影图像,通过三维重构计算内容物中微粒体积、个数、分布及囊壁厚度等结构参数,分别定量分析长期试验和加速试验6个月后软胶囊的结构差异。结果表明,长期试验的软胶囊内容物分布均匀,微粒数量少;加速试验后软胶囊的壳壁在压缝部位、一侧囊壁处局部变薄,内容物出现分层现象,具有相对较强X-射线吸收的微粒密集分布在囊壁边缘。本研究通过SR-μCT获取的软胶囊结构参数可用于评价储存环境对软胶囊稳定性的影响,为软胶囊质量控制与评价提供新方法。

In situ characterization of structural change and internal particle distributions of soft capsules based on synchrotron radiation X-ray micro computed tomography

It is difficult to directly observe the structural transformation inside of soft capsules if their shells are opaque. This study was designed to noninvasively in situ measure the structural characteristics of the soft capsules and internal particle distributions to reveal the intrinsic quality of the soft capsules and develop a new technique for reverse engineering and the physical stability evaluation of the soft capsules. In this research, the CT projection images of soft capsules, namely, propolis soft capsules, were collected via synchrotron radiation X-ray micro computed tomography(SR-μCT). After three-dimensional reconstruction, the structural differences of the soft capsules under long-term test and accelerated test for 6 months were quantitatively analyzed by calculating the three-dimensional structure parameters such as volume, number and distribution of the particles inside and the thickness for the wall of the capsules. There were only a small number of particles evenly distributed in the soft capsules stored under common storage condition without layering. On the other hand, the shell wall of the soft capsule turned thinner locally at the occlusal portion and the particles with strong X-ray absorption were densely distributed at the edge of the capsule wall after the accelerated test. This study revealed that the structural parameters of soft capsules obtained by SR-μCT could be used to evaluate the influence of storage environment on the physical stability of soft capsules. The technology provides a new method for quality control and evaluation for the soft capsules.