Water transport and absorption in pharmaceutical tablets – a numerical study

Vaitukaitis, Povilas; Maggiolo, Dario; Remmelgas, Johan; Abrahmsén-Alami, Susanna; Bernin, Diana; Siiskonen, Maria Daniela Irene; Malmqvist, Johan; Sasic, Srdjan; Sardina, Gaetano

doi:10.1007/s11012-019-01103-2

Cited by 10 publications

(4 citation statements)

References 46 publications

(67 reference statements)

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“…We anticipate similar but possibly more complex invasion patterns in three-dimensional anisotropic materials. Having in mind that transverse invasion would then take place on a two-dimensional plane, we can expect an even slower invasion dynamics along such a direction [32]. Future simulations should investigate the impact of threedimensional invasion dynamics on the extent of the asymmetric functioning range currently observed.…”

Section: Discussionmentioning

confidence: 98%

Asymmetric invasion in anisotropic porous media

Maggiolo,

Picano,

Toschi

2021

Preprint

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We report and discuss, by means of pore-scale numerical simulations, the possibility of achieving a directional-dependent two-phase flow behaviour during the process of invasion of a viscous fluid into anisotropic porous media with controlled design. By customising the pore-scale morphology and heterogeneities with the adoption of anisotropic triangular pillars distributed with quenched disorder, we observe a substantially different invasion dynamics according to the direction of fluid injection relative to the medium orientation, that is depending if the triangular pillars have their apex oriented (flow-aligned) or opposed (flow-opposing) to the main flow direction. Three flow regimes can be observed: (i) for low values of the ratio between the macroscopic pressure drop and the characteristic pore-scale capillary threshold, i.e. for ∆p0/pc ≤ 1, the fluid invasion dynamics is strongly impeded and the viscous fluid is unable to reach the outlet of the medium, irrespective of the direction of injection; (ii) for intermediate values, 1 < ∆p0/pc ≤ 2, the viscous fluid reaches the outlet only when the triangular pillars are flow-opposing oriented; (iii) for larger values, i.e for ∆p0/pc > 2, the outlet is again reached irrespective of the direction of injection. The porous medium anisotropy induces a lower effective resistance when the pillars are flow-opposing oriented, suppressing front roughening and capillary fingering. We thus argue that the invasion process occurs as long as the pressure drop is larger then the macroscopic capillary pressure determined by the front roughness, which in the case of flow-opposing pillars is halved. We present a simple approximated model, based on Darcy's assumptions, that links the macroscopic effective permeability with the directional-dependent front roughening , to predict the asymmetric invasion dynamics. This peculiar behaviour opens up the possibility of fabrication of porous capillary valves to control the flow along certain specific directions.

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Section: Discussionmentioning

confidence: 98%

Asymmetric invasion in anisotropic porous media

Maggiolo,

Picano,

Toschi

2021

Preprint

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“…The particles in contact with the fluid starts to dissolve. At the same time the fluid enters the tablet through the pores and its network resulting in the disintegration of the tablet into smaller pieces and this stage is effectively controlled by the concentration of pores [ 242 , 243 , 244 , 245 , 246 , 293 , 345 , 346 , 347 ]. By extracting the information of the pore network and its permeability from a SEM image, Zhang et al [ 348 ] has shown that one can estimate the drug release rate by computational fluid dynamic simulation.…”

Section: Tablet Characterizationmentioning

confidence: 99%

Characterization of Pharmaceutical Tablets by X-ray Tomography

et al. 2023

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Solid dosage forms such as tablets are extensively used in drug administration for their simplicity and large-scale manufacturing capabilities. High-resolution X-ray tomography is one of the most valuable non-destructive techniques to investigate the internal structure of the tablets for drug product development as well as for a cost effective production process. In this work, we review the recent developments in high-resolution X-ray microtomography and its application towards different tablet characterizations. The increased availability of powerful laboratory instrumentation, as well as the advent of high brilliance and coherent 3rd generation synchrotron light sources, combined with advanced data processing techniques, are driving the application of X-ray microtomography forward as an indispensable tool in the pharmaceutical industry.

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“…To further explore the evolution of droplet The power-law dependency of the penetration mass is in line with the previous findings for a droplet impacting a porous medium. 52,53 In the following, we will propose a new model to describe the evolution of droplet penetration mass. As the analysis of Fig.…”

Section: Articlementioning

confidence: 99%

Lattice Boltzmann simulation of a water droplet penetrating a micropillar array in a microchannel

2021

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Water droplets penetrating a microchannel equipped with an array of micropillars are commonly seen in engineering applications, ranging from micro-electro-mechanical systems to macro-heat-transfer facilities. Understanding the detailed droplet dynamics in this process is therefore beneficial to the advancement of many fields of industry. In this study, we adopt a nonorthogonal multiple-relaxation-time lattice Boltzmann model to simulate a water droplet penetrating a micropillar array in a microchannel. We first validate our model against the experimental results of (a) off-center impact of a water droplet on a ridged superhydrophobic surface and (b) impact of a water droplet on a curved superhydrophobic surface. Then a comprehensive parametric study is carried out by changing the droplet initial velocity, opening fraction of the micropillar array, and wettability of the micropillar surface. It is found that when the droplet penetrates the micropillar array, its fingering dynamics in the longitudinal direction is governed by the competition between the dynamic and capillary pressures, while the permeation process in the lateral and vertical directions is dominated by the capillary effect. The change of the droplet initial velocity and configuration setup can significantly influence the droplet penetration velocity, maximum wetted surface area, and penetration rate. Finally, a theoretical model is proposed to describe the transient evolution of the droplet penetration mass for a variety of Weber numbers, opening fractions, and static contact angles.

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Water transport and absorption in pharmaceutical tablets – a numerical study

Cited by 10 publications

References 46 publications

Asymmetric invasion in anisotropic porous media

Asymmetric invasion in anisotropic porous media

Characterization of Pharmaceutical Tablets by X-ray Tomography

Lattice Boltzmann simulation of a water droplet penetrating a micropillar array in a microchannel

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