Compactibility assessment of direct compression excipients: Prosolv Easytab

Objective: The aim of this work is to put side-by-side different methods to set up Prosolv EasyTab compactibility as a parameter to define the surrogate and the relative surrogate functionality of this ready-to-use direct compression excipient. Methods: The evaluated parameters included the tablet crushing strength, D; tablet tensile strength, σ; specific crushing strength, SCS and compactibility coefficients, Cp. Results: The defined parameters do not allow the identification of an all-purpose compactibility magnitude for Easytab. All parameters show a trend as the tablet weight changes although those using normalized values of tablet hardness display the smaller trend. Parameters considering the experimental values of the maximal compactibility have as disadvantage the requirement of equipment capabilities in a width span. Parameters considering the relative density have the disadvantage of calculating compactibility at a relative density of 1.0 that in some cases are not attainable due to compression problems. The compactibility parameters show an average of 26% lesser compactibility of Easytab compared to Helmcel 200. Conclusion: All calculated parameters allow the reduction of compactibility to a numerical value that characterizes the surrogate functionality of materials as an absolute number and as a relative value referred to microcrystalline cellulose. Compactibility can be described through the potential to form a coherent compact, defined as D_max, σ_max or SCS_max, and the capability of a material to attain the maximal extent of interparticle bonds given by the slope of a linear relationship from a compactibility profile.