Mechanical characterization of pharmaceutical powders and correlation with their behavior during grinding

TL;DR

This study links the mechanical properties of pharmaceutical powders, measured through nano-indentation, with their grinding behavior during milling, aiming to develop predictive models for powder grindability.

Contribution

It introduces a method to characterize pharmaceutical powders' mechanical properties and correlates these with milling performance, proposing a basis for predictive grindability models.

Findings

Mechanical properties vary among powders and influence milling efficiency.

Nano-indentation data can predict powder grindability.

Correlation between mechanical properties and milling outcomes is demonstrated.

Abstract

Controlling the size of powder particles is pivotal in the design of many pharmaceutical forms and the related manufacturing processes and plants. One of the most common techniques for particle size reduction in process industry is powder milling, whose efficiency relates to the mechanical properties of powder particles themselves. In this work, we first characterize the elastic and plastic response of different pharmaceutical powders by measuring their Young modulus, the hardness and the brittleness index via nano-indentation. Subsequently, we analyze the behavior of those powder samples during comminution via jet-mill at different process conditions. Finally, the correlation between single particle mechanical properties and milling process results is illustrated; the possibility to build a predictive model for powder grindability, based on nano-indentation data, is critically discussed