Auflistung nach Autor:in "Šklubalová, Zdenka"

Gerade angezeigt 1 - 3 von 3

Corrigendum to “Powder cohesion and energy to break an avalanche. Can we address surface heterogeneity?” [Int. J. Pharm. 626 (2022) 122198]
(Elsevier, 2023) Brokešová, Jana; Niederquell, Andreas; Kuentz, Martin; Zámostný, Petr; Vraníková, Barbora; Šklubalová, Zdenka
01A - Beitrag in wissenschaftlicher Zeitschrift
Evaluation of gravitational consolidation of binary powder mixtures by modified Heckel equation
(Elsevier, 2022) Svačinová, Petra; Macho, Oliver; Jarolímová, Žofie; Gabrišová, Ľudmila; Šklubalová, Zdenka; Kuentz, Martin
Consolidation of powders by tapping is an important quality test but it is time and material consuming, which encourages the use of mathematical modelling. This article aims to study this gravitational consolidation dynamics by using nine binary mixtures consisting of cellets and powdered microcrystalline cellulose (MCC102), differing in size, shape, and consolidation properties. To describe the correlation between number of taps and powder bed density/ porosity, the modified Heckel equation. (MH) was newly introduced and compared to the models by Kawakita (KW) and Varthalis & Pilpel (VP). High coefficients of determination were observed by applying the traditional KW model up to 80% of cellets, while a comparable fitting adequacy was obtained with the MH equation up to 50% of cellets in the mixtures. An increased content of MCC102 increased fitting adequacy in the MH and KW model, whereas a nearly opposite mixture trend was observed for the VP model.
01A - Beitrag in wissenschaftlicher Zeitschrift
Fractal Aspects of Static and Dynamic Flow Properties of Pharmaceutical Excipients
(Springer, 11/2017) Hurychová, Hana; Šklubalová, Zdenka; Kuentz, Martin
Purpose Characterisation of powder flow is important for pharmaceutical processing and manufacturing. This work aims at a better understanding of how fractal particle and bulk properties affect the static and dynamic flow of excipients. Methods Traditional methods of flowability testing, e.g. the angle of repose or the flow through an orifice, were complemented by avalanching in a rotational drum. Dynamic image analysis provided a fractal contour line dimension of the powder bulk in the drum (bD F ). This was compared to the contour line fractal dimension of particles (pD F ) as obtained from the box-counting method. Avalanche testing was able to measure also cohesive materials that were otherwise difficult or not measurable at all using the classical methods. Results The values of the avalanche energy were in good agreement with the different flow properties of the samples. These flow properties showed good correlations with bD F in that poor flow properties were associated with a more rugged contour line of the bulk and hence higher bD F . Conclusions Interestingly, there was no correlation observed between pD F and bD F , which may suggest that a distinct bulk structure typically emerges from the particles under dynamic flow. Future research should further clarify how fractal powder aspects affect pharmaceutical manufacturing processes.
01A - Beitrag in wissenschaftlicher Zeitschrift