Assessment of Powder Surface Caking by Ball Indentation Method

Researcher: Qinqin Chen
Principal Investigator: Prof. Mojtaba Ghadiri

Sponsor: CSC (China Scholarship Council)
Status: Ongoing (2016 – ) Abstract Caking of powders during processing and storage is a ubiquitous problem in many industries, which could significantly decrease products quality and lead to economic losses. It is hence important to know the conditions under which powders caking occurs. Caking of powders is significantly influenced by a large number of factors: particle size, shape, relative humidity, temperature, applied force, hygroscopicity, deliquency and possible solid state transformations. Ball indentation, a novel method developed at University of Leeds, is used to test the surface caking of powders. Three pharmaceutical powders with different hygroscopicities are used in this study. The tests are done by exposing a compacted powder bed in a die to certain environment with different relative humidities and temperatures for different periods of time. Results obtained by ball indentation method is used to establish a relationship between surface caking and relative humidity, temperature, time and applied force. To avoid excessive powder caking, different concentrations of magnesium stearate are added as a lubricant to the samples using a high shear mixer and the optimum amount is quantified. Publications