Spheronization of micronized theophylline anhydrate and monohydrate using a mechanical powder processor

Exploring conventional and emerging dehydration technologies for slurry/liquid food matrices and their impact on porosity of powders: A comprehensive review

The contribution of dehydration to the growing market of food powders from slurry/liquid matrices is inevitable. To overcome the challenges posed by conventional drying technologies, several innovative approaches have emerged. However, industrial implementation is limited due to insufficient information on the best-suited drying technologies for targeted products. Therefore, this review aimed to compare various conventional and emerging dehydration technologies (such as active freeze, supercritical, agitated thin-film, and vortex chamber drying) based on their fundamental principles, potential applications, and limitations. Additionally, this article reviewed the effects of drying technologies on porosity, which greatly influence the solubility, rehydration, and stability of powder. The comparison between different drying technologies enables informed decision-making in selecting the appropriate one. It was found that active freeze drying is effective in producing free-flowing powders, unlike conventional freeze drying. Vortex chamber drying could be considered a viable alternative to spray drying, requiring a compact chamber than the large tower needed for spray drying. Freeze-dried, spray freeze-dried, and foam mat-dried powders exhibit higher porosity than spray-dried ones, whereas supercritical drying produces nano-porous interconnected powders. Notably, several factors like glass transition temperature, drying technologies, particle aggregation, agglomeration, and sintering impact powder porosity. However, some binders, such as maltodextrin, sucrose, and lactose, could be applied in controlled agglomeration to enhance powder porosity. Further investigation on the effect of emerging technologies on powder properties and their commercial feasibility is required to discover their potential in liquid drying. Moreover, utilizing clean-label drying ingredients like dietary fibers, derived from agricultural waste, presents promising opportunities.

Solventless amorphization and pelletization using a high shear granulator. Part I; feasibility study using indomethacin

The aim of the current study was to investigate the feasibility of solventless amorphization and pelletization using a high shear granulator, to produce amorphous drug-layered pellets by simply mixing drug crystals and inactive spheres without using solvent and heating. Indomethacin crystals were mixed with microcrystalline cellulose spheres at a weight ratio of 1:10 using the granulator and the resulting particles were then characterized using solid-state and particle analytical techniques as well as pharmaceutically relevant tests. Amorphization of indomethacin crystals progressed with increasing processing time and decreasing jacket temperature. The amorphization rate increased as the spheres became larger and full amorphization was achieved using spheres of 414 and 649 μm in diameter. Indomethacin crystals were pulverized due to mechanical activation by the spheres and the resulting amorphous microparticles were then deposited on the spheres, yielding pellets with an amorphous layer. The pellets exhibited supersaturation characteristics and the dissolution rate was faster than that of quench-cooled indomethacin powder. However, the amorphous drug deposited on the pellets exhibited a lower physical stability than quench-cooled amorphous indomethacin, but recrystallization could be inhibited by co-processing with polyvinylpyrrolidone K-25 stabilizing the amorphous form. The findings suggest the feasibility of the solventless amorphization and pelletization technique.

Solventless granulation and spheronization of indomethacin crystals using a mechanical powder processor: Effects of mechanically induced amorphization on particle formation

Our aim was to reveal the effects of mechanically-induced amorphization on the solventless agglomeration and spheronization of drug crystals using a mechanical powder processor. This process can provide spherical particles comprising 100% drug. Indomethacin crystals were mechanically treated using various jacket temperatures and the resulting particles were characterized using particle and crystalline analyses. Also, the adhesive and mechanical properties of amorphous indomethacin were examined. At 20 °C, the indomethacin crystals fragmented and amorphized during processing, indicating that glassy-state indomethacin with no adhesiveness does not contribute to agglomeration or spheronization. At 40 °C, agglomeration occurred due to the transformation of mechanically-induced amorphous phases from non-adhesive glass to an adhesive supercooled liquid at around the glass transition temperature. However, at higher temperatures, the formation of agglomerates was suppressed by recrystallization of the amorphous surface. At 60 °C, the indomethacin crystals compacted and spheronized due to deformation of the particle surface, consistent with results showing that the stiffness of amorphous indomethacin decreased suddenly above 60 °C. The lifespan of the amorphous phase decreased due to enhanced recrystallization as the temperature increased, thereby reducing the degree of spheronization. In conclusion, agglomeration and spheronization are affected by the glass transition temperature and recrystallization of the mechanically-induced amorphous phase.