Impact of stressing conditions and polymer–surfactant interactions on product characteristics of organic nanoparticles produced by media milling

Scaling Wet Fine Grinding Processes of Organic Particles Using Stirred Media Mills

“…In contrast to the mill size the influence of stirrer tip speed was less pronounced, the increase of stress energy by increasing tip speeds do not show an influence on the energetic efficiency. Similar observations were made by Konnerth et al during grinding experiments of pyrene . It was noticed that all grinding experiments trended towards a steady state particle size.…”

“…It might be assumed that also the structure of micron sized crystals influences the particle breakage. Anthraquinone crystals are needle like shaped, in contrast pyrene crystals have a cubic structure , . This might influence the preferred direction of breakage and with it the required breakage energy.…”

Formation of Mefenamic Acid Nanocrystals with Improved Dissolution Characteristics

“…However, irrespective of the applied stirrer tip speed a limiting particle size around x 50,3 ≈ 180 nm and x 90,3 ≈ 350 nm, could be observed, indicating that final product particle sizes of MA are not linked to this operating parameter. This result is in good agreement with comparable studies discussed in literature , , , supporting general observations that in particular high stress numbers at moderate stress energies are advantageous with respect to a fast and energy efficient media milling process of APIs and organic crystals, respectively.…”

“…During collisions the kinetic energy of the beads is transferred to internal stress and strain in the feed particles and, consequently, product formation occurs by fracture. However, also liquid phase and formulation mediated growth effects, induced by dissolution, precipitation, and ripening phenomena may influence product particle size and shape of APIs during wet comminution . Furthermore, mechanical activation of the organic crystal during the milling process may cause surface near alterations of the solid (e.g., crystal defects, local amorphization) resulting in an activated state of the solid with different physicochemical properties .…”

Mechanism of interaction between hydroxypropyl cellulose and water in aqueous solutions: Importance of polymer chain length

“…[ 11 ] The results obtained herein are consistent and complement the previous studies on HPC, which shows that solubility is enhanced for short‐chain grades. [ 1–3 ] In this work, we find that the water retention of HPC, and therefore its drug solubility, is modulated primarily by the polymer chain length ( M w ) and the aliphatic chain content. Evidently, HPCs with the lowest molecular weights (UL and SSL) exhibit an association with the fact that they comprise the lowest amount of water molecules around their polymer chains; this is probably because they do not allow significant vesicle formation and consequently, exhibit substantially low agglomeration.…”