The role of microsphere fabrication methods on the stability and release kinetics of ovalbumin encapsulated in polyanhydride microspheres

2006 ◽  
Vol 23 (8) ◽  
pp. 832-843 ◽  
Author(s):  
Amy S. Determan ◽  
Jennifer R. Graham ◽  
Katherine A. Pfeiffer ◽  
Balaji Narasimhan
Keyword(s):  
Release Kinetics ◽  
The Stability ◽  
Kinetics Of

scholarly journals Halloysite nanotubes filled with salicylic acid and sodium diclofenac: effects of vacuum pumping on loading and release properties

2021 ◽  
Author(s):  
Lorenzo Lisuzzo ◽  
Giuseppe Cavallaro ◽  
Stefana Milioto ◽  
Giuseppe Lazzara
Keyword(s):  
Salicylic Acid ◽  
Release Kinetics ◽  
Halloysite Nanotubes ◽  
Drug Molecules ◽  
Sodium Diclofenac ◽  
Tunable Release ◽  
Feature Based ◽  
Kinetics Of ◽  
Filling Mechanism

AbstractIn this work, we investigated the effects of the vacuum pumping on both the loading efficiencies and the release kinetics of halloysite nanotubes filled with drug molecules dissolved in ethanol. As model drugs, salicylic acid and sodium diclofenac were selected. For comparison, the loading of the drug molecules was conducted on platy kaolinite to explore the key role of the hollow tubular morphology on the filling mechanism of halloysite. The effects of the pressure conditions used in the loading protocol were interpreted and discussed on the basis of the thermodynamic results provided by Knudsen thermogravimetry, which demonstrated the ethanol confinement inside the halloysite cavity. Several techniques (TEM, FTIR spectroscopy, DLS and $$\zeta$$ ζ -potential experiments) were employed to characterize the drug filled nanoclays. Besides, release kinetics of the drugs were studied and interpreted according to the loading mechanism. This work represents a further step for the development of nanotubular carriers with tunable release feature based on the loading protocol and drug localization into the carrier. Graphic abstract The filling efficiency of halloysite nanotubes is enhanced by the reduction of the pressure conditions used in the loading protocol.

scholarly journals Investigation of the Role of Cholesterol Superlattice in Release Kinetics of Drugs from Stealth Liposomes

2012 ◽  
Vol 102 (3) ◽  
pp. 83a ◽  
Author(s):  
Nicole Haloupek ◽  
Justin Rafferty ◽  
Kayla Haloupek ◽  
Emmanuel Tejada ◽  
Tamara Mamistvalova ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Stealth Liposomes ◽  
Kinetics Of

The role of divalent cations in the activation of the NADP+-specific isocitrate dehydrogenase from Pisum sativum L.

1977 ◽  
Vol 55 (9) ◽  
pp. 928-934 ◽  
Author(s):  
Robert J. Maloney ◽  
David T. Dennis
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Isocitrate Dehydrogenase ◽  
Divalent Cations ◽  
Free Form ◽  
Saturation Kinetics ◽  
The Difference ◽  
The Stability ◽  
Kinetics Of

A divalent cation electrode was used to measure the stability constants (association constants) for the magnesium and manganese complexes of the substrates for the NADP+-specific isocitrate dehydrogenase (EC 1.1.1.42) from pea stems. At an ionic strength of 26.5 mM and at pH 7.4 the stability constants for the Mg2+–isocitrate and Mg2+–NADP+ complexes were 0.85 ± 0.2 and 0.43 ± 0.04 mM−1 respectively and for the Mn2+–isocitrate and Mn2+–NADP+ complexes they were 1.25 ± 0.07 and 0.75 ± 0.09 mM−1 respectively. At the same ionic strength but at pH 6.0 the Mg2+–NADPH and Mn2+–NADPH complexes had stability constants of 0.95 ± 0.23 and 1.79 ± 0.34 mM−1 respectively. Oxalosuccinate and α-ketoglutarate do not form measureable complexes under these conditions. Saturation kinetics of the enzyme with respect to isocitrate and metal ions are consistent with the metal–isocitrate complex being the substrate for the enzyme. NADP+ binds to the enzyme in the free form. Saturation kinetics of NADPH and Mn2+ indicate that the metal–NADPH complex is the substrate in the reverse reaction. In contrast the pig heart enzyme appears to bind free NADPH and Mn2+. A scheme for the reaction mechanism is presented and the difference between the reversibility of the NAD+ and NADP+ enzyme is discussed in relation to the stability of the NADH and NADPH metal complexes.

Electrostatic effects control the stability and iron release kinetics of ovotransferrin

2014 ◽  
Vol 19 (6) ◽  
pp. 1009-1024 ◽  
Author(s):  
Sandeep Kumar ◽  
Deepak Sharma ◽  
Rajesh Kumar ◽  
Rajesh Kumar
Keyword(s):  
Release Kinetics ◽  
Iron Release ◽  
Electrostatic Effects ◽  
The Stability ◽  
Kinetics Of

scholarly journals Preparation, Characterization, and Release Kinetics of Chitosan-Coated Nanoliposomes Encapsulating Curcumin in Simulated Environments

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 2023 ◽  
Author(s):  
Mahmoud Hasan ◽  
Kamil Elkhoury ◽  
Cyril J. F. Kahn ◽  
Elmira Arab-Tehrany ◽  
Michel Linder
Keyword(s):  
Release Kinetics ◽  
Physicochemical Characteristics ◽  
Biological Properties ◽  
Lipophilic Compounds ◽  
Simulated Environments ◽  
Natural Polyphenol ◽  
Poorly Soluble ◽  
The Stability ◽  
Kinetics Of ◽  
Low Solubility

Curcumin, a natural polyphenol, has many biological properties, such as anti-inflammatory, antioxidant, and anti-carcinogenic properties, yet, its sensitivity to light, oxygen, and heat, and its low solubility in water renders its preservation and bioavailability challenging. To increase its bioaccessibility, we fabricated nanoliposomes and chitosan-coated nanoliposomes encapsulating curcumin, and we evaluated the systems in terms of their physicochemical characteristics and release profiles in simulated gastrointestinal mediums. Chitosan-coating enhanced the stability of nanoliposomes and slowed the release of curcumin in the simulated gastrointestinal (GI) environment. This study demonstrates that nanoliposomes and chitosan-coated nanoliposomes are promising carriers for poorly soluble lipophilic compounds with low oral bioavailability, such as curcumin.

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