The intrinsic nature and the coherence of compacted pure pharmaceutical tablets

Mohammed, Hamdi; Briscoe, B.J.; Pitt, Kendal

doi:10.1016/j.powtec.2006.03.010

Cited by 18 publications

(8 citation statements)

References 13 publications

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“…A similar force/displacement behaviour is seen with many semi brittle pharmaceutical compacts (60% theoretical density) such as acetaminophen (Paracetamol) where discontinuous almost linear interrelationships are found. More ductile compacts, such as those formed from microcrystalline cellulose, show a smooth and hardening force displacement response [15]. The deviations observed in a semi-static indent response can be correlated to inhomogeneities in the surface and subsurface structures of the material and these are initially marked by events where the indenter progressively encounters less resistance than that found for a fully dense coherent material.…”

Section: Nano-indentation-contact Compliancementioning

confidence: 99%

Nano-indentation of scratched poly(methyl methacrylate) surfaces

et al. 2005

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The paper describes an experimental study of the nano-indentation hardness profiling of scratches, of various depths, produced upon the surface of a poly(methyl methacrylate). The method has limited spatial resolution and typically the indent size, and hence the volume of deformed material sensed, was in the worst cases one-tenth of the scratch width; in exceptional cases the resolution was ten times better than this figure. Additionally, the various topographical and morphological features are evaluated using laser profilometry and optical and scanning electron microscopy. The data described indicate that the scratching process introduces damage in subsurface regions, which may be tentatively ascribed to the formation of subsurface crazing or voidage in certain regions of the scratch damage area; in particular within the base of the scratch formation. Such structures could potentially develop in the substrate tensile fields developed at the rear of the indenter. In addition, there is evidence for densification of the polymer adjacent to the primary damage zone-on the ''shoulder'' areas adjacent to the main scratch path. An analysis of the periodic fluctuations of the nanohardness data, in certain zones, allows a speculative description of the topology of the subsurface damage in terms of the induced voidage and its distribution. Such features would naturally lead to a ''positive'' deformation volume; an analysis of an orthogonal topographical trace of a scratch allows a simulation of volume with respect to the unpurturbed surface-a ''positive'' comparison infers an additional volume and vice versa. In the current study, such ''positive'' volume deformation regions were not unequivocally identified with the proposed craze zones using the topographical estimation procedures employed.

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Section: Nano-indentation-contact Compliancementioning

confidence: 99%

Nano-indentation of scratched poly(methyl methacrylate) surfaces

et al. 2005

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“…The plastic work component E n-r can be obtained by subtracting the elastic component from the total work. The magnitude of the plastic component is an indication of the material's ductility (Mohammed et al, 2006;Wang, Fang, & Lin, 2007). For a fully plastically deformed material E r ¼ 0.…”

Section: Unconfined Compression E Procedures and Parameter Selectionmentioning

confidence: 99%

“…The energy stored in such materials is transformed into permanent deformations, causing lower local stress intensity and protecting such materials from brittle and massive fracture (Drucker & Rice, 1970). In terms of energy dispersal, elastic strain energy recovery during pelleting is not desirable, although some elasticity preventing die clogging may be advantageous (Mohammed, Briscoe, & Pitt, 2006).…”

Section: Introductionmentioning

confidence: 99%

Prediction of pelleting outcomes based on moisture versus strain hysteresis during the loading of individual pea seeds

Kulig

Łysiak

Skonecki

2015

Biosystems Engineering

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“…Being metastable in all the temperature range at ambient pressure (1,9), it transforms spontaneously into the stable form I on grinding (10) or on storage (1,8). For the tabletting of form I of paracetamol, the existing technologies use either wet granulation (11), compression of the mixtures of paracetamol-I with various excipients (12)(13)(14)(15)(16)(17)(18), or obtaining co-crystals with other compounds (19). An attempt to obtain directly compressible form I by a hemisolvate decomposition to produce sintered-like particles has been described in (20).…”

Section: Introductionmentioning

confidence: 99%