Changes in the specific surface area of tablets composed of pharmaceutical materials with various deformation behaviors

Abstract

Objective: The aim of this work is to study the effect of compaction on the specific surface area of tablets composed of various pharmaceutical materials (microcrystalline cellulose, lactose, and anhydrous calcium phosphate) compacted under seven degrees of compaction pressure. Methods: In a first part, the influence of the deformation behavior of the compacted materials on the evolution of the specific surface area is observed. In a second part, the brittle and ductile abilities of the materials are calculated using the specific surface area values. The experimental results are used to calculate the number and the force of interparticulate bonds inside the tablet.Results and Discussion: Tablets made of microcrystalline cellulose, which deform plastically, have specific surface areas that fall under pressure. In the case of lactose, the tablet specific surface area first increases to reach a maximum value at a pressure of 150 MPa. At higher pressure, however, the specific surface area decreases. The specific surface area of tablets composed of anhydrous calcium phosphate consistently increases, whatever the compaction pressure applied. Moreover, the evolution of the specific surface area is correlated with the tensile strength of the corresponding tablets. The number and the force of interparticulate bonds make it possible to classify the materials according to their deformation behavior and to quantify their ability to form cohesive tablets.

• Compaction
• deformation behavior
• excipients
• specific surface area
• tensile strength