Comminution-amorphisation relationships during ball milling of lactose at different stress energies
(English)Manuscript (preprint) (Other academic)
The purpose of the study was to investigate the relationship between comminution and amorphisation of α-lactose monohydrate particles during ball milling under different milling conditions, including ball-to-powder mass ratio, milling time and ball diameter.
The results revealed that at a constant ball filling ratio, ball-to-powder mass ratio of 25:1 resulted in the lowest minimum particle size of ~5 μm and the highest degree of apparent amorphous content of 82%. The rate of comminution was high during early stage of milling whereas the degree of apparent amorphous content increased gradually at a slow rate. An increased ball-to-powder mass ratio during milling increased both the rate of comminution and the rate of amorphisation. Using a given ball-to-powder mass ratio, the ball size affected the degree of apparent amorphous content of the particles while the particle diameter remained unchanged.
The relationship between comminution and amorphisation could be described as consisting of two regimes, i.e. comminution dominated and amorphisation dominated regime. It was proposed that the rate constant of comminution and amorphisation are controlled by stress energy distribution in the milling jar and the stress energy distribution is regulated by the ball motion pattern that can be affected by the process parameter used.
Ball milling, process-induced disordering, amorphisation, comminution, comminution rate constant, α-lactose monohydrate, stress energy distribution
Research subject Pharmaceutical Science
IdentifiersURN: urn:nbn:se:uu:diva-317797OAI: oai:DiVA.org:uu-317797DiVA: diva2:1082881