The intrinsic nature and the coherence of compacted pure pharmaceutical tablets

The paper describes methods to define the intrinsic mechanical nature, and the coherence of various pure compacted tablets using both the nanoscopic indentation and the confined die compaction results. Data for seven different kinds of pharmaceutical drugs and excipients, composing alpha lactose, microcrystalline cellulose (Avicel PH 102), acetylsalicylic acid (Aspirin), dicalcium phosphate, magnesium carbonate, acetaminophen (Paracetamol) and pre-gelatinized starch are reported. The powders were compacted to various ultimate normal stresses ranging between 25 and 246 MPa in instrumented (force/displacement) singled ended axial compression in a cylindrical die with planar punch. The planar surfaces of these compacted tablets were nano-indented. The results clearly show that the coherence and the intrinsic nature of the tablets may be defined in a more comprehensive manner using interpretations of the nano-indentation rather than the uniaxial compaction data. The various data are consistent with the magnitude of the tensile strength of the compacts. (c) 2006 Elsevier B.V. All rights reserved.