Sucrose solution freezing studied by magnetic resonance imaging

Mahdjoub, Rachid; Chouvenc, Pierre; Seurin, Marie José; Andrieu, Julien; Briguet, A.

doi:10.1016/j.carres.2006.01.005

Cited by 17 publications

(9 citation statements)

References 19 publications

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“…Visualization of the freezing process following the spatial distribution of non-frozen water Images of the freezing process and final microstructure after the solution becomes opaque due to ice formation 70,71 Indirect methods: freeze substitution, freeze fixation, and freeze drying…”

Section: Freeze Dryingmentioning

confidence: 99%

“…68,69 Nondestructive MRI techniques allow the visualization of the freezing process and generation of 3D images by following the spatial distribution of non-frozen water. 70,71 In MachZender optical interferometry, small relative changes in refractive index are accurately measured and subsequently related to changes in the solution concentration and in the morphology of the ice-solution interface. 72 This optical method has been employed to obtain the 3D morphology and the solute concentration field around the dendritic tip for various solutes at different concentration 73 as well as to study the ice crystal growth in supercooled pure water.…”

Section: Observing and Measuring Ice Morphologymentioning

confidence: 99%

See 1 more Smart Citation

Ice Morphology: Fundamentals and Technological Applications in Foods

2009

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Freezing is the process of ice crystallization from supercooled water. Ice crystal morphology plays an important role in the textural and physical properties of frozen and frozen-thawed foods and in processes such as freeze drying, freeze concentration, and freeze texturization. Size and location of ice crystals are key in the quality of thawed tissue products. In ice cream, smaller ice crystals are preferred because large crystals results in an icy texture. In freeze drying, ice morphology influences the rate of sublimation and several morphological characteristics of the freeze-dried matrix as well as the biological activity of components (e.g., in pharmaceuticals). In freeze concentration, ice morphology influences the efficiency of separation of ice crystals from the concentrated solution. The cooling rate has been the most common variable controlling ice morphology in frozen and partly frozen systems. However, several new approaches show promise in controlling nucleation (consequently, ice morphology), among them are the use of ice nucleation agents, antifreeze proteins, ultrasound, and high pressure. This paper summarizes the fundamentals of freezing, methods of observation and measurement of ice morphology, and the role of ice morphology in technological applications.

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Section: Freeze Dryingmentioning

confidence: 99%

Section: Observing and Measuring Ice Morphologymentioning

confidence: 99%

Ice Morphology: Fundamentals and Technological Applications in Foods

2009

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“…This quite uniform intrasyringe ice crystal morphology was quite different from what was observed with glass vials systems, for which the ice crystal structure was finer and more thin at the vial bottom than at the vial top. [2,6,8] This positive behavior regarding freeze-dried cake homogeneity, different from what was observed with glass vials, can be explained by the fact that syringes are cooled simultaneously on three surfaces (top, bottom, wall) and that the solution volumes in syringe configuration were smaller-the interior syringe diameter was equal to one half of the interior diameter of a vial-which certainly reduced the heterogeneity of the supercooling degrees and the local thermal gradients and, consequently, decreased the dispersion on local nucleation rates. Many images were recorded and typical ice crystal size distributions were obtained and plotted as shown in Fig.…”

Section: Sample Observationsmentioning

confidence: 99%

“…Annealing treatments are often carried out to improve the ice crystal homogeneity by applying to the frozen product, at the end of the freezing step, an isothermal treatment above the T g temperature. [2,[7][8][9][10] While cylindrical glass vials are presently the most common packaging containers for chemical drugs and vaccines freeze-drying, prefilled syringes for injectable formulations are presently becoming more common because of improved compliance and convenience for the user. This is why, in the present article (Part I), we report original data concerning the ice morphology experimental characterization and the validation of a fine physical model of the freezing step in syringe configuration by using an aqueous model sucrose formulation.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Modeling of Freeze-Drying in Syringe Configuration. Part I: Freezing Step

et al. 2009

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This article concerns the experimental study and the modeling of the freezing step during freeze-drying of a model lyoprotectant formulation in syringe configuration. First, ice crystal morphology observations were carried out in a cold chamber equipped with stereomicroscopy to determine the ice crystal size distribution. We observed that the ice crystal morphology was homogeneous as a function of the radial position and that, contrary to our previous observations in glass vial configuration, no significant ice morphology differences existed between the bottom and the top of syringes. Thus, it seems that the gas cooling by free convection at the walls of the syringe during the freezing step led to higher homogeneity in the ice crystal morphology. These data allowed calculation of the mean ice crystal diameter (which was supposed to represent the mean porous diameter) and then the permeability of the freeze-dried cake. Moreover, a two-dimensional axisymmetric (2D) mathematical model in cylindrical geometry of the freezing step for aqueous sucrose solution was elaborated. It has been proved that this model was able to simulate quite precisely the whole temperature profiles during the freezing step, except the exothermic peak of nucleation. In the last part of this work on syringe geometry, the impact of annealing treatments on the freeze-dried matrix morphology was investigated. Some heterogeneity of sublimation rates was observed, with significant variation of residual humidity. Additionally, the water vapor mass transfer resistance values decreased if a convenient annealing treatment (shelf temperature at -10 C) was applied. INTRODUCTIONThe freezing step, which is the first step of the freezedrying process, is generally a crucial step to set up the morphological properties of the final freeze-dried product. For example, recent publications demonstrated that ice nucleation temperature is a critical parameter which fixes the ice morphology and, by the way, the rate of ice

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“…4. Two halves of a 2-L bottle glued with silicone to a 2-mm transparent acrylic plate whereas white areas correspond to the viscous phase where the hydrogen nuclei have motility (9). The structure of the ice on the top is clearly influenced by the cover (Fig.…”

Section: Internal Structure Of Frozen Solutionsmentioning

confidence: 99%

Interfacial Stress and Container Failure During Freezing of Bulk Protein Solutions Can Be Prevented by Local Heating

Duarte¹,

Rego²,

Ferreira

et al. 2020

AAPS PharmSciTech

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Bottles and carboys are used for frozen storage and transport of biopharmaceutical formulations under a wide range of conditions. The quality of freezing and thawing in these systems has been questioned due to the formation of heterogeneous ice structures and deformation of containers. This work shows that during freezing of bulk protein solutions, the liquid at the air-liquid interface freezes first, forming an ice crust and enclosing the liquid phase. As the enclosed liquid freezes, internal pressure rises, pushing the liquid phase through the porous ice crust towards the air interface, leading to interfacial stress and protein aggregation. The aggregation of bovine serum albumin was more intense in the foamlike ice mound that was formed at the top, where bubbles were entrapped. This was characterized experimentally with the assistance of magnetic resonance imaging (MRI). An isothermal cover is proposed to prevent the early freezing of the liquid at the air interface, attenuating substantially interfacial stress to proteins and releasing hydrostatic pressure, preserving the shape and integrity of the containers.

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Sucrose solution freezing studied by magnetic resonance imaging

Cited by 17 publications

References 19 publications

Ice Morphology: Fundamentals and Technological Applications in Foods

Ice Morphology: Fundamentals and Technological Applications in Foods

Experimental Study and Modeling of Freeze-Drying in Syringe Configuration. Part I: Freezing Step

Interfacial Stress and Container Failure During Freezing of Bulk Protein Solutions Can Be Prevented by Local Heating

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