Porosity, one of the important quality attributes of pharmaceutical tablets, directly affects the mechanical properties, the mass transport and hence tablet disintegration, dissolution and ultimately the bioavailability of an orally administered drug. The ability to accurately and quickly monitor the porosity of tablets during manufacture or during the manufacturing process will enable a greater assurance of product quality. This tutorial systematically outlines the steps involved in the terahertz-based measurement method that can be used to quantify the porosity of a tablet within seconds in a non-destructive and non-invasive manner. The terahertz-based porosity measurement can be performed using one of the three main methods, which are (i) the zero-porosity approximation (ZPA); (ii) the traditional Bruggeman effective medium approximation (TB-EMA); and (iii) the anisotropic Bruggeman effective medium approximation (AB-EMA). By using a set of batches of flat-faced and biconvex tablets as a case study, the three main methods are compared and contrasted. Overall, frequency-domain signal processing coupled with the AB-EMA method was found to be most suitable approach in terms of accuracy and robustness when predicting the porosity of tablets over a range of complexities and geometries. This tutorial aims to concisely outline all the necessary steps, precautions and unique advantages associated with the terahertz-based porosity measurement method.

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基于太赫兹的药物片剂孔隙度测量：教程

孔隙度是药物片剂的重要质量属性之一，直接影响机械性能，质量传递，进而影响片剂的崩解，溶解以及最终口服药物的生物利用度。在制造过程中或制造过程中准确，快速地监视片剂孔隙率的能力将为产品质量提供更大的保证。本教程系统地概述了基于太赫兹测量方法的步骤，该方法可用于以无损，无创的方式在几秒钟内量化药片的孔隙率。基于太赫兹的孔隙度测量可以使用以下三种主要方法之一进行：（i）零孔隙率近似（ZPA）；（ii）传统的布鲁格曼有效媒介近似（TB-EMA）；（iii）各向异性布鲁格曼有效介质近似（AB-EMA）。通过使用一组批次的平面和双凸片剂作为案例研究，比较和对比了三种主要方法。总体而言，在预测复杂程度和几何形状范围内的片剂孔隙率时，就准确性和鲁棒性而言，频域信号处理与AB-EMA方法相结合是最合适的方法。本教程旨在简要概述与基于太赫兹的孔隙度测量方​​法相关的所有必要步骤，注意事项和独特优势。比较和对比了三种主要方法。总体而言，在预测复杂程度和几何形状范围内的片剂孔隙率时，就准确性和鲁棒性而言，频域信号处理与AB-EMA方法相结合是最合适的方法。本教程旨在简要概述与基于太赫兹的孔隙度测量方​​法相关的所有必要步骤，注意事项和独特优势。比较和对比了三种主要方法。总体而言，在预测复杂程度和几何形状范围内的片剂孔隙率时，就准确性和鲁棒性而言，频域信号处理与AB-EMA方法相结合是最合适的方法。本教程旨在简要概述与基于太赫兹的孔隙度测量方​​法相关的所有必要步骤，注意事项和独特优势。