Influence of crystal shape on the tableting performance of L-lysine monohydrochloride dihydrate.
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 of T 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.
Sun
C
C
Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Weaver-Densford Hall, 308 Harvard Street S.E., Minneapolis, Minnesota 55455-0343, USA.
Grant
D J
DJ
D019245:Compressive Strength; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods; D008239:Lysine / Q000737:chemistry*; D016062:Porosity; D011208:Powders; D011312:Pressure; D013607:Tablets
D011208:Powders; D013607:Tablets; D008239:Lysine