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Assessing particle mechanical properties of pharmaceutical materials quickly and with little material can be very important to early stages of pharmaceutical research. In this study, a wide range of pharmaceutical materials were studied using atomic force microscopy (AFM) nanoindentation. A significant amount of particle hardness and elastic modulus data were provided. Moreover, powder compact mechanical properties of these materials were investigated in order to build correlation between the particle hardness and powder compaction performance. It was found that the materials with very low or high particle hardness most likely exhibit poor compaction performance while the materials with medium particle hardness usually have good compaction behavior. Additionally, the results from this study enriched Hiestand's special case concept on particle hardness and powder compaction performance. This study suggests that the use of AFM nanoindentation can help to screen mechanical properties of pharmaceutical materials at early development stages of pharmaceutical research. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4307–4316, 2010 [ABSTRACT FROM AUTHOR]

Abstract: Refractive index is a basic physical property of pharmaceutical solids. In this paper, the refractive index values of 424 pharmaceutical solids from the literature were surveyed. It was found that the refractive index values exhibit a normal distribution with an overall mean value of 1.603. The Eisenlohr and Vogel methods developed for organic liquids were employed to estimate the refractive index for pharmaceutical solids. The estimated results were compared with experimentally measured values determined by polarized light microscopy. Both Eisenlohr and Vogel R D methods agreed very well with the measured mean refractive index values from the literature with an average absolute percent error of 1.22% and 1.25%, respectively. The evaluation for in-house measurements for Pfizer active pharmaceutical ingredients showed larger differences between the calculated and measured values. The results indicate that the Eisenlohr and Vogel R D methods can provide fast and accurate results for predicting the refractive index of pharmaceutical solids. [Copyright &y& Elsevier]