application of principal component analysis (pca) to evaluating the deformation behaviors of pharmaceutical powders

this study uses principal component analysis (pca) to investigate deformation during powder compaction, in order to classify common pharmaceutical materials according to their relative plasticity.

methods

a variety of mechanical measurements were used during pca modeling, including both applied force-dependent measurements and deformation parameters derived from various consolidation models. the applied force-dependent measurements included solid fraction, density change during elastic recovery, work of compression (w c ), work of decompression (w d ), normalized radial tensile strength (σt/σt, ε = 0), elasticity, and the work of compression and decompression (w c/d ). the models of consolidation included those proposed by heckel, walker, alderborn, gurnham, and denny’s proposed modification to the heckel model. the initial pca model was calibrated based on 12, well-characterized pharmaceutical materials with a wide span of plastic, brittle, and elastic deformation properties.

results and conclusions

it was found that the first principal component seemed to be consistent with the relative plasticity of each material predicted by traditional methods. the variables contributing most to the variance explained by the first pc were found to be the c value from gurnham model, w c , and w c/d . further analysis of five additional materials indicated that the c value, alone, provided adequate differentiation of the materials’ relative plasticities. the advantages of multivariate analysis in analyzing the mechanical data and future application of pca modeling are also discussed.