A material-sparing simplified buoyancy method for determining the true density of solids

• Published in: International journal of pharmaceutics 2023-03, Vol.635, p.122694-122694, Article 122694
• Main Authors: Goldenberg, Merrill, Vreeman, Gerrit, Sun, David J., Moffit, Mackenzie, Li, May, Zernik, Marina, Ahuja, Saivee, Kim, Yumin, Semin, Dillon, Sun, Changquan Calvin
• Format: Article
• Language: English
• Subjects: Buoyancy; Crystal; Material-sparing; Physical Phenomena; Polymer; Powders; True density
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2023.122694

[Display omitted] True density is an important physical property of powdered materials, especially in the context of powder compaction. Currently available methods for true density determination either require a significant amount of materials or are laborious. Hence, a material-sparing and efficient method for true density determination is of value. In this work, we detail a simplified buoyancy-based method capable of fast determination of true density with accuracy comparable to helium pycnometry. This miniaturized method only uses a few milligrams of a powder with data collection process expedited by centrifugation in a laboratory centrifuge. This method can be easily adapted in a laboratory since determination of true density only requires a balance, a micropipette, a laboratory centrifuge, and standard stock liquids of low and high densities. Hence, it is a useful addition to the materials characterization tool kit critical for pharmaceutical formulation development.