Simulations of dissolution of spherical particles in laminar shear flow

Derksen, J. J.; Reynolds, Gavin K.; Crampton, Alex; Huang, Zhaohui; Booth, Jonathan

doi:10.1016/j.cherd.2014.06.027

Cited by 12 publications

(11 citation statements)

References 29 publications

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“…Computational models have been built to predict optimal processing conditions (e.g., temperature, residence time, drug loading), but they are limited by the lack of supporting data for key mass transport parameters. A common omission is the lack of experimental data on the API diffusion coefficient at conditions relevant to HME, 11 and currently molecular diffusivities are extracted from complex and timeconsuming molecular dynamic simulations. 12 Diffusion coefficient measurements are not straightforward, and there is no standard or universally acceptable method.…”

Section: ■ Introductionmentioning

confidence: 99%

NMR and Thermal Studies for the Characterization of Mass Transport and Phase Separation in Paracetamol/Copovidone Hot-Melt Extrusion Formulations

et al. 2020

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The formulation of drug/polymer amorphous solid dispersions (ASDs) is one of the most successful strategies for improving the oral bioavailability of poorly soluble active pharmaceutical ingredients (APIs). Hot-melt extrusion (HME) is one method for preparing ASDs that is growing in importance in the pharmaceutical industry, but there are still substantial gaps in our understanding regarding the dynamics of drug dissolution and dispersion in viscous polymers and the physical stability of the final formulations. Furthermore, computational models have been built to predict optimal processing conditions, but they are limited by the lack of experimental data for key mass transport parameters, such as the diffusion coefficient. The work presented here reports direct measurements of API diffusion in pharmaceutical polymer melts, using high-temperature pulsed-field gradient NMR. The diffusion coefficient of a model drug/polymer system (paracetamol/copovidone) was determined for different drug loadings and at temperatures relevant to the HME process. The mechanisms of the diffusion process are also explored with the Stokes–Einstein and Arrhenius models. The results show that diffusivity is linked exponentially to temperature. Furthermore, this study includes rheological characterization, differential scanning calorimetry (DSC), and 1H ssNMR T 1 and T 1ρ measurements to give additional insights into the physical state, phase separation, and API/polymer interactions in paracetamol/copovidone ASD formulations.

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Section: ■ Introductionmentioning

confidence: 99%

NMR and Thermal Studies for the Characterization of Mass Transport and Phase Separation in Paracetamol/Copovidone Hot-Melt Extrusion Formulations

et al. 2020

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“…Computational dissolution models have been developed by researchers using particle size distributions [19,59,60], porosity [61,62], and real particle geometries scanned from XRT [63,64]. A few enable the simulation of particle disintegration in their codes, for example Štěpánek and his group simulated dissolution process of pharmaceutical particles focusing on API release while abrupt break-upof particle was least investigated [19].…”

Section: Discussion: Limitations Of the Modelmentioning

confidence: 99%

Abrupt disintegration of highly porous particles in early stage dissolution

Karampalis

Caragay

et al. 2018

Powder Technology

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Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.

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“…However, most of the studies regarding wall effects in fluid-particle systems are devoted to the study of packed beds in cylindrical containments. In contrast, investigations on suspensions bounded by one or more flat walls were performed only recently [6,7,8,3,9]. This is despite the obvious importance of near-wall treatment when modeling suspension flows: For example, it was shown that (in dilute suspensions under turbulent flow conditions) particles tend to migrate towards (flat) walls due to a phenomenon named turbophoresis [10].…”

Section: Introductionmentioning

confidence: 87%

“…The use of an immersed boundary approach allows to solve the governing equations in a global domain Ω with simple shape (which can be efficiently meshed using a simple Cartesian grid) rather than the highly complex fluid domain Ω f . This is why immersed boundary methods are frequently used in the field of suspension flows, even in case particles are arrested (see, for example in [8] or [32,33,34,35,36,37]). The HFD-IB approach ensures that no errors arise due to highly skewed cells and, most important, it eliminates the effort to build a body-fitted mesh.…”

Section: Mesh Generation and Cfd Solutionmentioning

confidence: 99%

Momentum, heat and mass transfer simulations of bounded dense mono-dispersed gas-particle systems

Municchi

Radl

2018

International Journal of Heat and Mass Transfer

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Particle Resolved Direct Numerical Simulation (PR-DNS) is employed to study momentum, heat and mass transfer in confined gas-particle suspensions. In this work, we show that the presence of wall boundaries induces an inhomogeneous particle distribution, and as a consequence continuous phase fields exhibit peculiar profiles in the wall-normal direction. Therefore, we first propose a correlation for the particle volume fraction as a function of the distance from the wall and the bulk particle concentration. Secondly, we quantify wall effects on flow field and interphase transfer coefficients (i.e., the flow field, a scalar field, as well as the Nusselt number and drag coefficient). We show that these effects do not depend significantly on the Reynolds number in case an appropriate scaling is applied. Finally, we propose correlations to reconstruct the continuous phase fields in the proximity of adiabatic walls. Also, we provide interpolation tables for the correction to the drag force and the Nusselt number that are helpful in unresolved Euler-Lagrange simulations.

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Simulations of dissolution of spherical particles in laminar shear flow

Cited by 12 publications

References 29 publications

NMR and Thermal Studies for the Characterization of Mass Transport and Phase Separation in Paracetamol/Copovidone Hot-Melt Extrusion Formulations

NMR and Thermal Studies for the Characterization of Mass Transport and Phase Separation in Paracetamol/Copovidone Hot-Melt Extrusion Formulations

Abrupt disintegration of highly porous particles in early stage dissolution

Momentum, heat and mass transfer simulations of bounded dense mono-dispersed gas-particle systems

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