Effects of true density, compacted mass, compression speed, and punch deformation on the mean yield pressure

Gabaude, C. M. D.; Guillot, Micael A.; Gautier, Jean‐Claude; Saudemon, Philippe; Chulia, Dominique

doi:10.1021/js9803050

Cited by 56 publications

(28 citation statements)

References 14 publications

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“…The parameters can be related to the mechanisms involved and the aptitude of the powders, or the granules, to be ductile or brittle. However, this interpretation of Heckel parameters is very sensitive to the errors introduced when measuring the true density of a product [12].…”

Section: Densification Under Loadmentioning

confidence: 99%

Binder granulation and compaction of coloured powders

N'Dri-Stempfer¹,

Oulahna²,

Eterradossi³

et al. 2003

Powder Technology

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This paper gives results of a study of compacts made from both a free powder mixture and granules made from this same mixture, and produced by two binder granulation techniques: high shear granulation and fluidised bed granulation. The characteristics of the compacts are analysed in terms of colour and aspect derived from their reflectance spectra and related to the flow properties and bulk density of the components forming the compacts.

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Section: Densification Under Loadmentioning

confidence: 99%

Binder granulation and compaction of coloured powders

N'Dri-Stempfer¹,

Oulahna²,

Eterradossi³

et al. 2003

Powder Technology

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“…For this reason, excipients need to be added to a drug formulation to compensate for intrinsic undesirable properties of the drug. 2,3) At the onset of compression, particles within the powder bed are expected to undergo some rearrangement in their packing condition reducing their particle-particle contact distances in which bigger holes between particles are filled with small particles. This process is influenced by surface characteristics, frictional properties and particle size.…”

mentioning

confidence: 99%

Effect of the Compaction Platform on the Densification Parameters of Tableting Excipients with Different Deformation Mechanisms

Rojas

Hernández

2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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Several compaction models have been attempted to explain the compression and compaction phenomena of excipients. However, the resulting parameters could be influenced by the compaction platform such as dwell time, compact mass, geometry and type of material. The goal of this study is to assess the effect of these variables on the densification parameters obtained from key models such as Heckel, non-linear Heckel, Kawakita, Carstensen, and Leuenberger. The relationship among the parameters derived was determined by employing a Principal Component Analysis. Results indicated that factors such as compact geometry, consolidation time and compact mass had a negligible impact on parameters such as tensile strength, yield pressure and compressibility. On the contrary, the excipient type had the largest influence on these parameters. Further, the Leuenberger (γ) and Carstensen ( f ) parameters were highly correlated and related to the excipient deformation mechanism. Sorbitol and PVP-k30 were the most highly compactable excipients and were characterized for having a low yield pressure (P y ), compressibility (a), and critical porosity (ε c ). The magnitude of these parameters was highly dependent on the consolidation behavior of each material.Key words deformation mechanism; compaction behavior; compression model; compactibility; tableting performanceThe consolidation phenomenon of compressing materials into a cohesive mass during compact formation is a complex process. The pressure applied to bulk pharmaceutical powders give rise to a change in bed density, gradually reducing its volume until a complete tablet is formed. During this process, powders undergo complex transitions and structural changes to form a porous solid. Thus, a final porosity reduction represents a transformation to a new physical irreversible structure where the solid constitute a continuous phase. 1)It is commonly accepted that powder consolidation happens by cohesive forces acting at the areas of true interparticle contact points including van der Waals forces, solid bridges and mechanical interlocking. However, only van der Waals forces are significant for tableting of pharmaceutical materials. Hydrogen bonds and electrostatic forces are other examples of forces that act over a distance between particles. Nevertheless, if too much energy is stored elastically at compression, the elastic recovery during decompression could break most of the bonds formed rendering a flaky tablet. For this reason, excipients need to be added to a drug formulation to compensate for intrinsic undesirable properties of the drug. 2,3)At the onset of compression, particles within the powder bed are expected to undergo some rearrangement in their packing condition reducing their particle-particle contact distances in which bigger holes between particles are filled with small particles. This process is influenced by surface characteristics, frictional properties and particle size. The smaller the particles, the greater the number of contact points per unit volume. 4) As t...

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“…Owing to poor stress transmission through the solids, the volume-averaged bulk density determined in this manner is generally not an isotropic value for the material. 19 A variant of the compaction cell was proposed by Butters et al, 20 who found that the compacting piston had a smaller diameter than the bore of the cylindrical housing. In this device, shear stresses are formed within the compacting bed of solids along a plane parallel to the side wall of the moving piston.…”

Section: Review Of Testing Apparatusesmentioning

confidence: 99%

Cohesive‐driven particle circulation in the solids conveying zone of a single‐screw extruder

2008

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ABSTRACT:Aspects of heat transfer within the solids conveying zone of a single-screw extruder were studied by using a specially constructed drum testing apparatus. Experiments were conducted with linear low-density polyethylene, polystyrene (PS), and polypropylene (PP) samples by examining their transient temperature profile while the heated drum was stationary or moving. In accordance with classic solids conveying theory, the granular beds of PP and PS remained as plugs while the drum rotated. In such cases, the dominant modes of heat transfer for these systems are conduction through the contact area of a particle and conduction through the interstitial gas. An exception to this behavior was found with PE, in which the bed temperature increased more rapidly while the drum rotated. Visual observations of the bed showed that the particles circulated in the presence of shear and that this complex flow pattern increased in velocity as the drum temperature approached the onset temperature for melting the PE material. With strong correlation between the rate of circulation and the temperature rise in the bed, the movement of particles was assumed to act in a convective heat transfer

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Effects of true density, compacted mass, compression speed, and punch deformation on the mean yield pressure

Cited by 56 publications

References 14 publications

Binder granulation and compaction of coloured powders

Binder granulation and compaction of coloured powders

Effect of the Compaction Platform on the Densification Parameters of Tableting Excipients with Different Deformation Mechanisms

Cohesive‐driven particle circulation in the solids conveying zone of a single‐screw extruder

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