Recognition of slip or cleavage planes can expedite the essential understanding of mechanical properties of organic crystals relevant to pharmaceutical applications, such as tableting and milling. Slip/cleavage planes were frequently entrust based on attachment energy calculation. These crystallographic planes can also be determine by visualization of crystals characterized by stacking layers of high molecular density and often strengthened by two-dimensional hydrogen bonding network.. Here, the LPV and RTV have the same crystal system, orthorhombic. The crystal behavior of these drugs under mechanical such tableting process is observed in various instrument (PXRD, ATR FTIR, Raman spectroscopic) and  simulation with Mercury software.  Overall, slip/cleavage planes in LPV and RTV crystals that identified by crystal structure visualization were successfully predicted by various analysis from data of diffraction, vibration and visualization of single crystal structure from Mercury software simulation.

Keywords: slip plan, lopinavir, ritonavir, tableting