Compressibility and compactibility properties of ethylcellulose

Abstract

Compaction characteristics of various viscosity grades of ethylcellulose were examined using an instrumented tablet press. Four different data analysis techniques were employed to characterize the compactibility and compressibility data: tablet hardness-compression force profiles, ejected tablet Heckel analysis, work calculations from force-displacement data and force-time profile analysis. The calculated parameters derived from these approaches included the following: mean yield pressure from the Heckel analysis, net work and elastic work from the force-displacement data and the area to height ( A H ) ratio from force-time data. Lower viscosity grades of ethylcellulose were found to be more compactible as described by tablet hardness-compression force profiles. Lower viscosity grades also exhibited a lower mean yield pressure from the Heckel analysis, indicating greater compressibility. Higher viscosity grades exhibited a decrease in net work and an increase in elastic work. Higher viscosity grades also exhibited greater values for the A H ratio derived from force-time analysis, indicating lower compressibility. Higher viscosity grades of ethylcellulose showed increases in true density, melting point, and heat of fusion. The variation in compactibility and compressibility properties of different viscosity grades of ethylcellulose can be attributed to changes in the polymer's degree of order.