Measurement of the Repose Angle of aTablet Granulation
01 Jul 1955-Journal of the American Pharmaceutical Association (Elsevier)-Vol. 44, Iss: 7, pp 435-437
TL;DR: The response angle of a sulfathiazole granulation was studied as a function of average particle size, presence of lubricants, and admixture of fines to find that the repose angle increased with decreasing particle size.
Abstract: In order to study the problem of granulation flow in tableting as it is related to interparticle friction, the response angle of a sulfathiazole granulation was studied as a function of average particle size, presence of lubricants, and admixture of fines.In general, the repose angle increased with decreasing particle size.Talc added to granules in small concentrations decreased the repose angle but tended to increase the angle at higher concentrations.Magnesium stearate had little or no effect on the repose angle of the granulation samples studied.Addition of fines to coarse granules caused a striking increase in repose angle.
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TL;DR: In this paper, an extensive review about the angle of repose angle theory, its definitions, method of measurements, appropriate applications and the influencing factors are presented. But, the authors do not consider the effect of the inter-particle properties of granular materials.
441 citations
Cites background or methods from "Measurement of the Repose Angle of ..."
...Using the fixed funnel method, Nelson [38] measured the angle of repose of sulfathiazole materials for a pharmacology application....
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...These restrictions are ascribed to the fact that the granular material has a uniform density and moisture content and that the particles have a uniform size [38]....
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TL;DR: In this paper, the effect of particle size variation on tablet tensile strength for spray-dried lactose, Sta-Rx 1500 and Avicel PH-101 was investigated.
Abstract: The effect of particle size variation on tablet tensile strength for spray-dried lactose, Sta-Rx 1500 and Avicel PH-101 was investigated. Decreasing the particle size of spray-dried lactose and Sta-Rx 1500 resulted in stronger compacts whereas the tablet tensile strength of Avicel PH-101 was unaffected by particle size variation. The Heckel relationship, at two different contact times, was used to examine the predominant compaction mechanism. This was independent of the size fractions studied for all three materials. Angle of repose and Hausner ratio measurements indicated a correlation between the internal forces of friction and cohesion of the sized powders and the tensile strength of compacts formed from them.
170 citations
TL;DR: Four methods of determining the angle of repose of free flowing powders have been critically compared using graded samples of glass balls, lead shot and silver sand and it was found that results for spheres could be correlated on one graph, irrespective of type of material.
Abstract: Four methods of determining the angle of repose of free flowing powders have been critically compared using graded samples of glass balls, lead shot and silver sand. The method used influenced the result. Results of all methods have been correlated graphically and values for static and dynamic interparticulate friction have been assessed for the materials used. It was found that results for spheres could be correlated on one graph, irrespective of type of material and an explanation is given to account for this.
143 citations
TL;DR: The proposed series of analytical approaches to the evaluation of powders for inclusion in aerosol products has merit and may be the basis for screening and ultimately predicting particle performance with a view to formulation optimization.
111 citations
01 Jan 2009
TL;DR: In this paper, the authors provide a background in particle, powder, and compact characterization that can generate the information needed to develop a robust understanding of the impact of material and processes on product performance.
Abstract: Particle, powder, and compact characterization is critically important to the rational and scientific development of solid dosage forms. As development timelines are compressed and active pharmaceutical ingredient supplies for product development are reduced, scientific and predictive product development procedures are necessary to replace the guided empiricism and trial-and-error approaches that have driven formulation development for much of the 20th century. Within the framework of quality by design, efficient product development requires an understanding of material properties (critical material attributes) and processes (critical process parameters) and their impact on final product performance (critical quality attributes). With the implementation of material-sparing development strategies, thorough characterization and understanding are paramount. This chapter provides a background in methods of particle, powder, and compact characterization that can generate the information needed to develop a robust understanding of the impact of material and processes on product performance.
75 citations
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