Influence of crystal shape on the tableting performance of L-lysine monohydrochloride dihydrate

Changquan Sun, David J.W. Grant

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


The purpose of this study is to understand the influence of crystal shape on the tableting performance of L-lysine monohydrochloride (LMH) dihydrate, using the method of data analysis developed by Joiris E et al. 1998. Pharm Res 15:1122-1130. Phase-pure crystals of LMH dihydrate, prism-shaped (S) and plate-shaped (T), were prepared by adjusting the composition of the crystallization solvent. At the same compaction pressure, T always gives stronger tablets than S, (i.e.; the tabletability oft is greater). The porosity of tablets from T crystals is always greater than that of S crystals when compressed at the same pressure, (i.e.; the compressibility of T is lower). The tensile strength of T tablets, at the same porosity, is greater than that of S tablets, (i.e.; the compactibility of T is greater). Therefore, the greater tabletability of T is a result of its better compactibility that overcomes the negative effects by its lower compressibility. The greater compactibility of T is related to favorable orientation of the slip planes in the tablet, corresponding to greater plasticity under load. The yield strengths of T and S crystals are essentially the same (20 MPa). Therefore, the crystal shape influences the tableting performance but does not, in principle, affect the yield strength of LMH dihydrate.

Original languageEnglish (US)
Pages (from-to)569-579
Number of pages11
JournalJournal of Pharmaceutical Sciences
Issue number5
StatePublished - 2001

Bibliographical note

Funding Information:
We thank Pfizer Central Research for financial support and the Supercomputing Institute of the University of Minnesota for financially supporting our use of the Medicinal Chemistry/ Supercomputing Institute Visualization ‐ Workstation Laboratory.

Copyright 2017 Elsevier B.V., All rights reserved.


  • Compatibility
  • Compressibility
  • Crystal shape
  • Crystallization solvent
  • L-lysine monohydrochloride dihydrate
  • Porosity
  • Slip planes
  • Tabletability

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