Spheronization mechanism of pharmaceutical material crystals processed by extremely high shearing force using a mechanical powder processor

Kondo, Kazunori; Kido, Kansuke; Niwa, Toshiyuki

doi:10.1016/j.ejpb.2016.06.021

Cited by 15 publications

(7 citation statements)

References 27 publications

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“…One process of particle morphology modification is the rounding of irregular-shaped particles (also called spheronization). This process has been employed for the production of spherical particles of metals [7][8][9][10][11], ceramics [12], polymers [5,6,[13][14][15][16][17] and pharmaceutical products [18]. Depending on the mechanical and thermal properties of the particles, rounding can be achieved by mechanical and thermal approaches.…”

Section: Introductionmentioning

confidence: 99%

“…Depending on the mechanical and thermal properties of the particles, rounding can be achieved by mechanical and thermal approaches. Mechanical approaches use the effect of particle abrasion and deformation upon impact to achieve spherical particles using e.g., dry impact comminution devices [7,[18][19][20]. Thermal approaches involve the melting of particles dispersed in a fluid and the consequent rounding of the produced droplets driven by their surface tension.…”

Section: Introductionmentioning

confidence: 99%

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Particle Lagrangian CFD Simulation and Experimental Characterization of the Rounding of Polymer Particles in a Downer Reactor with Direct Heating

et al. 2021

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Polypropylene (PP) powders are rounded at different conditions in a downer reactor with direct heating. The particles are fed through a single central tube, while the preheated sheath gas is fed coaxially surrounding the central aerosol jet. The influence of the process parameters on the quality of the powder product in terms of particle shape and size is analyzed by correlating the experimental results with the flow pattern, residence time distribution of the particles and temperature distribution predicted by computational fluid dynamics (CFD) simulations. An Eulerian–Lagrangian numerical approach is used to capture the effect of the particle size distribution on the particle dynamics and the degree of rounding. The simulation results reveal that inlet effects lead to inhomogeneous particle radial distributions along the total length of the downer. The configuration of particle/gas injection also leads to fast dispersion of the particles in direction of the wall and to particle segregation by size. Broad particle residence time distributions are obtained due to broad particle size distribution of the powders and the particles dispersion towards the wall. Lower mass flow ratios of aerosol to sheath gas are useful to reduce the particle dispersion and produce more homogenous residence time distributions. The particles’ residence time at temperatures above the polymer’s melting onset is determined from the simulations. This time accounts for the effective treatment (rounding) time of the particles. Clear correlations are observed between the numerically determined effective rounding time distributions and the progress of shape modification on the particles determined experimentally.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Particle Lagrangian CFD Simulation and Experimental Characterization of the Rounding of Polymer Particles in a Downer Reactor with Direct Heating

et al. 2021

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“…With respect to the mechanical properties, the higher the ductility of the material, the faster is the shape transformation kinetics (Otani et al , 1996). Mechanical rounding can be applied to materials with moderate strength, ductile material such as metals and even to hard materials (Kondo et al , 2016). Brittle materials are likely to be comminuted rather than rounded.…”

Section: Introductionmentioning

confidence: 99%

“…Brittle materials are likely to be comminuted rather than rounded. The mechanical rounding of toner particles (Otani et al , 1994), stainless steel particles (Otani et al , 1996), graphite (Ohzeki et al , 2005; Mundszinger et al , 2017) and various pharmaceutical organic crystals (Kondo et al , 2016) have been reported. In the field of additive manufacturing, mechanical rounding has been employed for the production of micro-sized polysulfone (Mys et al , 2016a) and polystyrene (Mys et al , 2016b) particles for SLS.…”

Section: Introductionmentioning

confidence: 99%

Thermal rounding of micron-sized polymer particles in a downer reactor: direct vs indirect heating

Bonilla

Dechet

Schmidt

et al. 2020

RPJ

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Purpose The purpose of this paper is to investigate the effect of different heating approaches during thermal rounding of polymer powders on powder bulk properties such as particle size, shape and flowability, as well as on the yield of process. Design/methodology/approach This study focuses on the rounding of commercial high-density polyethylene polymer particles in two different downer reactor designs using heated walls (indirect heating) and preheated carrier gas (direct heating). Powder bulk properties of the product obtained from both designs are characterized and compared. Findings Particle rounding with direct heating leads to a considerable increase in process yield and a reduction in powder agglomeration compared to the design with indirect heating. This subsequently leads to higher powder flowability. In terms of shape, indirect heating yields not only particles with higher sphericity but also entails substantial agglomeration of the rounded particles. Originality/value Shape modification via thermal rounding is the decisive step for the success of a top-down process chain for selective laser sintering powders with excellent flowability, starting with polymer particles from comminution. This report provides new information on the influence of the heating mode (direct/indirect) on the performance of the rounding process and particle properties.

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“…This is accompanied by a higher state of free energy, enabling faster extent and rate of drug dissolution. 10 , 11 Another well-known strategy for decreasing drug crystallinity is particle spheronization which was achieved in literature via different techniques and mechanisms; 12 thus, enabling dissolution enhancement of poorly soluble drugs. 13 …”

Section: Introductionmentioning

confidence: 99%

The Impact of Amorphisation and Spheronization Techniques on the Improved in Vitro & in Vivo Performance of Glimepiride Tablets

et al. 2017

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Purpose: Triple solid dispersion adsorbates (TSDads) and spherical agglomerates (SA) present new techniques that extensively enhance dissolution of poorly soluble drugs. The aim of the present study is to hasten the onset of hypoglycemic effect of glimepiride through enhancing its rate of release from tablet formulation prepared from either technique.Methods: Drug release from TSDads or SA tablets with different added excipients was explored. Scanning electron microscopy (SEM) and effect of compression on dissolution were illustrated. Pharmacodynamic evaluation was performed on optimized tablets.Results: TSDads & SA tablets with Cross Povidone showed least disintegration times of 1.48 and 0.5 min. respectively. Kinetics of drug release recorded least half-lives (54.13 and 59.83min for both techniques respectively). Cross section in tablets displayed an organized interconnected matrix under SEM, accounting for the rapid access of dissolution media to the tablet core. Components of tablets filled into capsules showed a similar release profile to that of tablets after compression as indicated by similarity factor. The onset time of maximum reduction in blood glucose in male albino rabbits was hastened to 2h instead of 3h for commercial tablets.Conclusion: After optimization of tablet excipients that interacted differently with respect to their effect on drug release, we could conclude that both amorphisation and spheronization were equally successful in promoting in vitro dissolution enhancement as well as providing a more rapid onset time for drug action in vivo.

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Spheronization mechanism of pharmaceutical material crystals processed by extremely high shearing force using a mechanical powder processor

Cited by 15 publications

References 27 publications

Particle Lagrangian CFD Simulation and Experimental Characterization of the Rounding of Polymer Particles in a Downer Reactor with Direct Heating

Particle Lagrangian CFD Simulation and Experimental Characterization of the Rounding of Polymer Particles in a Downer Reactor with Direct Heating

Thermal rounding of micron-sized polymer particles in a downer reactor: direct vs indirect heating

The Impact of Amorphisation and Spheronization Techniques on the Improved in Vitro & in Vivo Performance of Glimepiride Tablets

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