Understanding Deformation Behavior and Compression Speed Effect in Gabapentin Compacts.

Deformation mechanism and strain rate sensitivity of gabapentin powder was investigated in this work. Heckel analysis, specific surface area and indentation hardness measurements revealed an intermediate yield pressure and brittle fracture as the dominant type of deformation mechanism during consolidation. Strain rate sensitivity of gabapentin was studied by compressing it at 1 mm/min and 500 mm/min compression speeds. Gabapentin demonstrated an atypical strain rate sensitivity in compactibility profile (tensile strength vs. solid fraction). Compacts of gabapentin compressed at fast speed showed an increase in tensile strength when compared with those compressed at slow speed. To understand the effect of compression speed on gabapentin's compactibility, PXRD analysis, surface area analysis, indentation hardness measurements, and consolidation modeling were performed. PXRD analysis carried out on compacts revealed no effect of speed on the physical solid-state stability of gabapentin. Specific surface area of compacts made at fast speed was higher than that of compacts made at slow speed. Indentation measurements performed on gabapentin compacts showed higher values of hardness in the case compacts made at fast speed. It was identified that at the fast compression speed, gabapentin shows greater particle fragmentation and form compacts with smaller pores.