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A Non-Isothermal Pore Network Model of Primary Freeze Drying

In this work, a non-isothermal pore network (PN) model with quasi-steady vapor transport and transient heat transfer is presented for the first time for the application of primary freeze drying. The pore-scale resolved model is physically based and allows for the investigation of correlations betwee...

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Autores principales: Thomik, Maximilian, Faber, Felix, Gruber, Sebastian, Foerst, Petra, Tsotsas, Evangelos, Vorhauer-Huget, Nicole
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10458176/
https://www.ncbi.nlm.nih.gov/pubmed/37631345
http://dx.doi.org/10.3390/pharmaceutics15082131
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author Thomik, Maximilian
Faber, Felix
Gruber, Sebastian
Foerst, Petra
Tsotsas, Evangelos
Vorhauer-Huget, Nicole
author_facet Thomik, Maximilian
Faber, Felix
Gruber, Sebastian
Foerst, Petra
Tsotsas, Evangelos
Vorhauer-Huget, Nicole
author_sort Thomik, Maximilian
collection PubMed
description In this work, a non-isothermal pore network (PN) model with quasi-steady vapor transport and transient heat transfer is presented for the first time for the application of primary freeze drying. The pore-scale resolved model is physically based and allows for the investigation of correlations between spatially distributed structure and transport conditions. The studied examples were regular PN lattices with a significantly different structure, namely a spatially homogeneous PN, also denoted as monomodal PN, and a PN with significant structure variation, referred to as bimodal PN because of its bimodal pore size distribution. The material properties selected for the solid skeleton in this study are equivalent to those of maltodextrin. The temperature ranges applied here were −28 °C to −18 °C in the PN and −42 °C in the surrounding environment. The environmental vapor pressure was 10 Pa. The PNs were dried with constant temperature boundary conditions, and heat was transferred at the top side by the vapor leaving the PN. It is shown how the structural peculiarities affect the local heat and mass transfer conditions and result in a significant widening of the sublimation front in the case of the bimodal PN. The possibility of spatially and temporally resolved front structures is a unique feature of the PN model and allows the study of situations that are not yet described by classical continuum approaches, namely heterogeneous frozen porous materials. As demonstrated by the thin layers studied here, the pore-scale simulations are of particular interest for such situations, such as in lyomicroscopes or collagen scaffolds, where a length-scale separation between dry and ice-saturated regions is not possible.
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spelling pubmed-104581762023-08-27 A Non-Isothermal Pore Network Model of Primary Freeze Drying Thomik, Maximilian Faber, Felix Gruber, Sebastian Foerst, Petra Tsotsas, Evangelos Vorhauer-Huget, Nicole Pharmaceutics Article In this work, a non-isothermal pore network (PN) model with quasi-steady vapor transport and transient heat transfer is presented for the first time for the application of primary freeze drying. The pore-scale resolved model is physically based and allows for the investigation of correlations between spatially distributed structure and transport conditions. The studied examples were regular PN lattices with a significantly different structure, namely a spatially homogeneous PN, also denoted as monomodal PN, and a PN with significant structure variation, referred to as bimodal PN because of its bimodal pore size distribution. The material properties selected for the solid skeleton in this study are equivalent to those of maltodextrin. The temperature ranges applied here were −28 °C to −18 °C in the PN and −42 °C in the surrounding environment. The environmental vapor pressure was 10 Pa. The PNs were dried with constant temperature boundary conditions, and heat was transferred at the top side by the vapor leaving the PN. It is shown how the structural peculiarities affect the local heat and mass transfer conditions and result in a significant widening of the sublimation front in the case of the bimodal PN. The possibility of spatially and temporally resolved front structures is a unique feature of the PN model and allows the study of situations that are not yet described by classical continuum approaches, namely heterogeneous frozen porous materials. As demonstrated by the thin layers studied here, the pore-scale simulations are of particular interest for such situations, such as in lyomicroscopes or collagen scaffolds, where a length-scale separation between dry and ice-saturated regions is not possible. MDPI 2023-08-14 /pmc/articles/PMC10458176/ /pubmed/37631345 http://dx.doi.org/10.3390/pharmaceutics15082131 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Thomik, Maximilian
Faber, Felix
Gruber, Sebastian
Foerst, Petra
Tsotsas, Evangelos
Vorhauer-Huget, Nicole
A Non-Isothermal Pore Network Model of Primary Freeze Drying
title A Non-Isothermal Pore Network Model of Primary Freeze Drying
title_full A Non-Isothermal Pore Network Model of Primary Freeze Drying
title_fullStr A Non-Isothermal Pore Network Model of Primary Freeze Drying
title_full_unstemmed A Non-Isothermal Pore Network Model of Primary Freeze Drying
title_short A Non-Isothermal Pore Network Model of Primary Freeze Drying
title_sort non-isothermal pore network model of primary freeze drying
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10458176/
https://www.ncbi.nlm.nih.gov/pubmed/37631345
http://dx.doi.org/10.3390/pharmaceutics15082131
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