Viana M, Jouannin P, Pontier C, Chulia D
GEFSOD EA 2631, Laboratoire de Pharmacie galénique, Faculté de Pharmacie 2, rue du Docteur Marcland, 87025 Limoges Cedex, France.
Talanta. 2002 May 24;57(3):583-93. doi: 10.1016/s0039-9140(02)00058-9.
Pycnometric density is at the moment the closest approximation of true density calculated from the molecular weight and crystalline lattice of the product. It is determined by using helium pycnometers that offer the advantage of being easy-to-use and rapid, especially fully automated apparatus. If the accuracy and the reproducibility of the technique are sufficient to reveal minute variations, this data is of interest for characterisation of crystalline structures (polymorphs, pseudopolymorphs, amorphous state), detection of defects, pores or impurities, and possible changes in crystal density during compaction. The aim of this article is to investigate on the confidence that can be expected when measuring density with an AccuPyc 1330 pycnometer. The experiments carried out on glass beads, quartz and mannitol have shown that operating parameters can affect the accuracy of pycnometric density to the nearest 0.01 g cm(-3). If measurements are performed in optimal conditions, 0.02% accuracy can be obtained, otherwise it can fail to 0.1% or less, depending on the material and the variations in the standard volume.
比重瓶密度目前是根据产品的分子量和晶格计算出的最接近真实密度的值。它是通过使用氦比重瓶来测定的，氦比重瓶具有使用方便、速度快的优点，特别是全自动仪器。如果该技术的准确性和可重复性足以揭示微小变化，那么这些数据对于晶体结构（多晶型物、假多晶型物、非晶态）的表征、缺陷、孔隙或杂质的检测以及压实过程中晶体密度的可能变化具有重要意义。本文的目的是研究使用AccuPyc 1330比重瓶测量密度时可预期的置信度。对玻璃珠、石英和甘露醇进行的实验表明，操作参数会影响比重瓶密度的准确性，精确到最接近0.01 g cm(-3)。如果在最佳条件下进行测量，可以获得0.02%的准确度，否则根据材料和标准体积的变化，准确度可能会降至0.1%或更低。
