University of Hamburg, Dept. of Chemistry, Div. of Pharmaceutical Technology, Bundesstraße 45, 20146 Hamburg, Germany.
University of Cambridge, Dept. of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, Cambridge CB3 0AS, United Kingdom.
Eur J Pharm Sci. 2018 Jan 1;111:549-555. doi: 10.1016/j.ejps.2017.10.029. Epub 2017 Oct 19.
Terahertz pulsed imaging (TPI) was applied to analyse the inner structure of multiple unit pellet system (MUPS) tablets. MUPS tablets containing different amounts of theophylline pellets coated with Eudragit® NE 30 D and with microcrystalline cellulose (MCC) as cushioning agent were analysed. The tablets were imaged by TPI and the results were compared to X-ray microtomography. The terahertz pulse beam propagates through the tablets and is back-reflected at the interface between the MCC matrix and the coated pellets within the tablet causing a peak in the terahertz waveform. Cross-section images of the tablets were extracted at different depths and parallel to the tablet faces from 3D terahertz data to visualise the surface-near structure of the MUPS tablets. The images of the surface-near structure of the MUPS tablets were compared to X-ray microtomography images at the same depths. The surface-near structure could be clearly resolved by TPI at depths between 24 and 152μm below the tablet surface. An increasing amount of pellets within the MUPS tablets appears to slightly decrease the detectability of the pellets within the tablets by TPI. TPI was shown to be a non-destructive method for the detection of pellets within the tablets and could resolve structures thicker than 30μm. In conclusion, a proof-of-concept was provided for TPI as a method of quality control for MUPS tablets.
太赫兹脉冲成像（TPI）被应用于分析多单位颗粒系统（MUPS）片剂的内部结构。分析了含有不同数量茶碱颗粒的 MUPS 片剂，这些颗粒用 Eudragit® NE 30 D 包衣，并用微晶纤维素（MCC）作为缓冲剂。TPI 对片剂进行成像，并将结果与 X 射线微断层摄影术进行比较。太赫兹脉冲束穿过片剂，并在片剂内 MCC 基质和包衣颗粒之间的界面处背反射，导致太赫兹波形中出现峰值。从 3D 太赫兹数据中提取出与片剂表面平行的不同深度的片剂横截面图像，以可视化 MUPS 片剂的表面附近结构。将 MUPS 片剂的表面附近结构图像与相同深度的 X 射线微断层摄影术图像进行比较。TPI 可以在片剂表面以下 24 到 152μm 的深度范围内清晰地分辨出 MUPS 片剂的表面附近结构。MUPS 片剂中颗粒的数量增加似乎会略微降低 TPI 对片剂中颗粒的检测能力。TPI 被证明是一种用于检测片剂中颗粒的非破坏性方法，并且可以分辨出厚度大于 30μm 的结构。总之，为 TPI 作为 MUPS 片剂质量控制方法提供了概念验证。
