Measurement of the Kinetics of Protein Unfolding in Viscous Systems and Implications for Protein Stability in Freeze-Drying

2005 ◽  
Vol 22 (7) ◽  
pp. 1176-1185 ◽  
Author(s):  
Xiaolin (Charlie) Tang ◽  
Michael J. Pikal
Keyword(s):  
Protein Stability ◽  
Freeze Drying ◽  
Protein Unfolding ◽  
Kinetics Of

scholarly journals Morphology and Release Kinetics of Protein-Loaded Porous Poly(L-Lactic Acid) Spheres Prepared by Freeze-Drying Technique

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Sasaki ◽  
Kazuki Tanaka ◽  
Daisuke Morino ◽  
Kensuke Sakurai
Keyword(s):  
Lactic Acid ◽  
Freeze Drying ◽  
Release Kinetics ◽  
Particle Surface ◽  
Spherical Particles ◽  
Freeze Dried ◽  
Model Drug ◽  
Drug Compound ◽  
Kinetics Of ◽  
Step Mechanism

Freeze-drying a biodegradable polymer, poly(L-lactic acid) (PLLA), from 1,4-dioxane solutions provided very porous spherical particles of ca. 3 mm in radius with specific surface area of 8–13 m2 g−1. The surface of the particle was found to be less porous compared with its interior. To apply the freeze-dried PLLA (FDPLLA) to drug delivery system, its morphology and drug releasing kinetics were investigated, bovine serum albumin (BSA) being used as a model drug compound. Immersion of FDPLLA into a BSA aqueous solution gave BSA-loaded FDPLLA, where mass fraction of the adsorbed BSA reached up to 79%. Time-dependent release profile of BSA in water suggested a two-step mechanism: (1) very rapid release of BSA deposited on and near the particle surface, which results in an initial burst, and (2) leaching of BSA from the interior of the particle by the diffusion process. It was suggested that the latter process is largely governed by the surface porosity. The porosity of both the interior and surface was found to decrease remarkably as the concentration of the original PLLA/1,4-dioxane solution increases, C0. Thus, C0 is a key parameter that controls the loading and releasing of BSA.

scholarly journals Vacuum-Induced Surface Freezing for the Freeze-Drying of the Human Growth Hormone: How Does Nucleation Control Affect Protein Stability?

2020 ◽  
Vol 109 (1) ◽  
pp. 254-263 ◽  
Author(s):  
Irene Oddone ◽  
Andrea Arsiccio ◽  
Chinwe Duru ◽  
Kiran Malik ◽  
Jackie Ferguson ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Protein Stability ◽  
Human Growth Hormone ◽  
Freeze Drying ◽  
Human Growth ◽  
Surface Freezing

Freeze Drying Kinetics of Sucrose-NaCl-Protein Aqueous Mixtures

1998 ◽  
Vol 51 (3) ◽  
pp. 905-911 ◽  
Author(s):  
J. M. Saiter ◽  
N. Delahaye ◽  
A. Bardat ◽  
E. Chatenet
Keyword(s):  
Freeze Drying ◽  
Drying Kinetics ◽  
Aqueous Mixtures ◽  
Kinetics Of

Kinetics of atmospheric freeze-drying of apple

2007 ◽  
pp. 159-172 ◽  
Author(s):  
Jan Stawczyk ◽  
Sheng Li ◽  
Dorota Witrowa-Rajchert ◽  
Anna Fabisiak
Keyword(s):  
Freeze Drying ◽  
Kinetics Of

scholarly journals A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

2019 ◽  
Vol 116 (38) ◽  
pp. 18822-18826 ◽  
Author(s):  
Runze Li ◽  
Dinesh Dhankhar ◽  
Jie Chen ◽  
Thomas C. Cesario ◽  
Peter M. Rentzepis
Keyword(s):  
Fluorescence Intensity ◽  
Protein Unfolding ◽  
Uv Light ◽  
Quantum Yields ◽  
Continuous Irradiation ◽  
Minute Period ◽  
Bacteria Inactivation ◽  
Tryptophan Residues ◽  
Inactivation Mechanism ◽  
Kinetics Of

The UV photodissociation kinetics of tryptophan amino acid, Trp, attached to the membrane of bacteria, Escherichia coli and Bacillus subtilis, have been studied by means of normal and synchronous fluorescence. Our experimental data suggest that the fluorescence intensity of Trp increases during the first minute of irradiation with 250 nm to ∼ 280 nm, 7 mW/cm2 UV light, and subsequently decreases with continuous irradiation. During this short, less than a minute, period of time, 70% of the 107 cell per milliliter bacteria are inactivated. This increase in fluorescence intensity is not observed when tryptophan is in the free state, namely, not attached to a protein, but dissolved in water or saline solution. This increase in fluorescence is attributed to the additional fluorescence of tryptophan molecules formed by protein unfolding, the breakage of the bond that attaches Trp to the bacterial protein membrane, or possibly caused by the irradiation of 2 types of tryptophan residues that photolyze with different quantum yields.

The role of kinetics of water and amide bonding in protein stability

Soft Matter ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 328-336 ◽  
Author(s):  
D. Porter ◽  
F. Vollrath
Keyword(s):  
Protein Stability ◽  
Kinetics Of

Kinetics of breaking a salt-bridge critical in protein unfolding

2004 ◽  
Vol 385 (5-6) ◽  
pp. 337-340 ◽  
Author(s):  
Andreea D. Gruia ◽  
Stefan Fischer ◽  
Jeremy C. Smith
Keyword(s):  
Protein Unfolding ◽  
Salt Bridge ◽  
Kinetics Of

Near-Infrared Spectroscopy for In-Line Monitoring of Protein Unfolding and Its Interactions with Lyoprotectants during Freeze-Drying

2011 ◽  
Vol 84 (2) ◽  
pp. 947-955 ◽  
Author(s):  
Sigrid Pieters ◽  
Thomas De Beer ◽  
Julia Christina Kasper ◽  
Dorien Boulpaep ◽  
Oliwia Waszkiewicz ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Freeze Drying ◽  
Protein Unfolding ◽  
Near Infrared

Analysis of Freeze-Drying and Rehydration of Açai (Euterpe oleracea Martius)

2015 ◽  
Vol 365 ◽  
pp. 11-16
Author(s):  
R.J. Brandão ◽  
M.M. Prado ◽  
L.G. Marques
Keyword(s):  
Mass Transfer ◽  
Energy Demand ◽  
Freeze Drying ◽  
Moisture Diffusion ◽  
Euterpe Oleracea ◽  
Power Ultrasound ◽  
Ultrasound Waves ◽  
Freeze Dried ◽  
Peleg’S Equation ◽  
Kinetics Of

The freeze-drying rate is essentially low, since it is controlled by internal moisture diffusion. In addition, the application of vacuum and low temperature during the process presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during freeze-drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve freeze-drying characteristics of açai, quantifying the influence of the applied power on both the drying and rehydration kinetics of the material. Açai (Euterpe oleracea Martius) samples were sonicated with two different frequency levels, 20 kHz and 40 kHz, and two sonication times, 3 min and 10 min. Page’s equation considering internal and external resistances to mass transfer provided a good fit of freeze-drying kinetics, while the Peleg’s equation was found to be suitable for describing the rehydration kinetics of freeze-dried açai. Pretreatment of açai with ultrasound waves was not effective. Ultrasound-induced structural disruption in the açai skin hindered the mass transfer during both freeze-drying and rehydration processes.

Sign in / Sign up

Export Citation Format

Share Document