Chapter 26 Morphology and strength development in solid and solidifying interparticle bridges in granules of pharmaceutical powders

Effect of Biodegradable Binder Properties and Operating Conditions on Growth of Urea Particles in a Fluidized Bed Granulator

“…Our results are in line with studies of Morl et al [20] and Saleh and Guigon [22] on effect of wetting degree on agglomeration of particles. This undesired phenomenon of premature drying of the droplet surface at high temperature and subsequent relinquishment of the liquid bridge can be avoided by decreasing the binder concentration (see Figure 12) [52].…”

Effect of Physical States of Binders on High-Shear Wet Granulation and Granule Properties: A Mechanistic Approach Toward Understanding High-Shear wet Granulation Process, Part 3: Effect of Binder Rheological Properties

“…If the dissolved solid is recrystallized during liquid evaporation, the Griffith model can be used to express the bridge tensile strength 21. In the absence of dissolved solid and recrystallization, the dry granules are held together by auto‐adhesive forces, and in this case, porosity and interfacial fracture energy play a significant role (JKR) 21,22. For the blends studied in this paper, binders are in the viscous state and JKR theory does not apply very well.…”

“…Theoretical investigation on granule strength is still lacking in many ways. However, there are a few models being proposed: crush strength model, recrystallization bridge model, and the auto‐adhesion model [Johnson–Kendall–Robert (JKR) theory] 21. The former two models are typically referred to the systems in which binders are dissolved in solution and added into powder bed.…”

“…The quantities ρ p and d p are the primary particle density and diameter; b and c are numerical coefficients and σ sb is the “neck” strength. If the dissolved solid is recrystallized during liquid evaporation, the Griffith model can be used to express the bridge tensile strength 21. In the absence of dissolved solid and recrystallization, the dry granules are held together by auto‐adhesive forces, and in this case, porosity and interfacial fracture energy play a significant role (JKR) 21,22.…”

Design, Optimization, and Correlation of In Vitro/In Vivo Disintegration of Novel Fast Orally Disintegrating Tablet of High Dose Metformin Hydrochloride Using Moisture Activated Dry Granulation Process and Quality by Design Approach

“…To overcome this challenge, the formulator has to use the wet granulation process to get agglomerates of drug and excipients with adequate compression characteristics [ 15 ]. This may lead to formation of solid bridges ”necks” among metformin particles that impart mechanical strength, lack powder flow, and sticking issues through the tableting process owing to consequent moisture migration or desorption during the wet granulation process [ 16 , 17 ]. In addition, from an industrial perspective, the wet granulation method is inferior to a direct compression and dry granulation methods because an additional drying step in a separate equipment like fluidized-bed dryer and tray dryer is necessary after the agglomeration phase [ 18 , 19 ].…”