Sedimentation of a starch microsphere: What is usually missed and why?

Argatov, Ivan; Krcic, Nedim; Kocherbitov, Vitaly

doi:10.1016/j.heliyon.2023.e20257

Cited by 1 publication

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“…To obtain an accurate measure of time it was necessary to divide the movie obtained from the cell phone into frames; as the video recorded was high definition at Gels 2024, 10, 277 4 of 15 1080p HD/30 fps, this means that every 30 frames corresponded to 1 s. Based on the number of frames obtained it was therefore possible to have an accurate measure of the time it takes for the particle to travel a certain distance. A discussion of the method's accuracy is provided in [14] and Appendix A.…”

Section: Sedimentation Experimentsmentioning

confidence: 99%

Determination of Density of Starch Hydrogel Microspheres from Sedimentation Experiments Using Non-Stokes Drag Coefficient

Cretella,

Fazilati,

Krcic

et al. 2024

Gels

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Sedimentation is an important property of colloidal systems that should be considered when designing pharmaceutical formulations. In pharmaceutical applications, sedimentation is normally described using Stokes’ law, which assumes laminar flow of fluid. In this work we studied swelling and hydration of spherical cross-linked amorphous starch microspheres in pure water, solutions of sodium chloride, and in pH-adjusted aqueous solutions. We demonstrated that Reynolds numbers obtained in these experiments correspond to the transition regime between the laminar flow and the turbulent flow and, hence, expressions based on the non-Stokes drag coefficient should be used for calculations of sedimentation velocity from known density or for assessment of density from observed sedimentation velocity. The density of starch microparticles hydrated in water was about 1050 kg/m3, while densities obtained from experiment with other liquids were dependent on the liquids’ densities. The data indicate that the swelling of the cross-linked starch microparticles as characterized by their densities is not sensitive to pH and salt concentration in the studied range of these parameters.

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Section: Sedimentation Experimentsmentioning

confidence: 99%