On the synthesis of layered double hydroxides (LDHs) by reconstruction method based on the “ memory effect ”

2015 ◽  
Vol 214 ◽  
pp. 246-248 ◽  
Author(s):  
G. Mascolo ◽  
M.C. Mascolo
Keyword(s):  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Reconstruction Method ◽  
Double Hydroxides

scholarly journals Luminescent Layered Double Hydroxides Intercalated with an Anionic Photosensitizer via the Memory Effect

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 153 ◽  
Author(s):  
Alexandre Teixeira ◽  
Alysson Morais ◽  
Ivan Silva ◽  
Eric Breynaert ◽  
Danilo Mustafa
Keyword(s):  
Aqueous Solution ◽  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Efficient Energy Transfer ◽  
Efficient Energy ◽  
Calcination Temperatures ◽  
Anionic Species ◽  
Benzenetricarboxylic Acid ◽  
Double Hydroxides ◽  
Rehydration Process

Layered double hydroxides (LDHs) containing Eu3+ activators were synthesized by coprecipitation of Zn2+, Al3+, and Eu3+ in alkaline NO3−-rich aqueous solution. Upon calcination, these materials transform into a crystalline ZnO solid solution containing Al and Eu. For suitably low calcination temperatures, this phase can be restored to LDH by rehydration in water, a feature known as the memory effect. During rehydration of an LDH, new anionic species can be intercalated and functionalized, obtaining desired physicochemical properties. This work explores the memory effect as a route to produce luminescent LDHs intercalated with 1,3,5-benzenetricarboxylic acid (BTC), a known anionic photosensitizer for Eu3+. Time-dependent hydration of calcined LDHs in a BTC-rich aqueous solution resulted in the recovery of the lamellar phase and in the intercalation with BTC. The interaction of this photosensitizer with Eu3+ in the recovered hydroxide layers gave rise to efficient energy transfer from the BTC antennae to the Eu3+ ions, providing a useful tool to monitor the rehydration process of the calcined LDHs.

scholarly journals Synthesis and release behavior of layered double hydroxides–carbamazepine composites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ma. F. Peralta ◽  
S. N. Mendieta ◽  
I. R. Scolari ◽  
G. E. Granero ◽  
M. E. Crivello
Keyword(s):  
Layered Double Hydroxides ◽  
Release Kinetics ◽  
Sodium Cholate ◽  
Basal Spacing ◽  
Reconstruction Method ◽  
Formal Charge ◽  
Axis Parallel ◽  
Double Hydroxides ◽  
Ray Patterns ◽  
Kinetics Of

AbstractCarbamazepine (CBZ) was incorporated into layered double hydroxides (LDH) to be used as a controlled drug system in solid tumors. CBZ has a formal charge of zero, so its incorporation in the anionic clay implies a challenge. Aiming to overcome this problem, CBZ was loaded into LDH with sodium cholate (SC), a surfactant with negative charge and, for comparison, without SC by the reconstruction method. Surprisingly, it was found that both resultant nanocomposites had similar CBZ encapsulation efficiency, around 75%, and the LDH-CBZ system without SC showed a better performance in relation to the release kinetics of CBZ in simulated body fluid (pH 7.4) and acetate buffer simulating the cellular cytoplasm (pH 4.8) than the system with SC. The CBZ dimensions were measured with Chem3D and, according to the basal spacing obtained from X-ray patterns, it can be arranged in the LDH-CBZ system as a monolayer with the long axis parallel to the LDH layers. Fourier transform infrared spectroscopy and solid state NMR measurements confirmed the presence of the drug, and thermogravimetric analyses showed an enhanced thermal stability for CBZ. These results have interesting implications since they increase the spectrum of LDH application as a controlled drug system to a large number of nonionic drugs, without the addition of other components.

scholarly journals Synthesis and release behavior of layered double hydroxides – carbamazepine composites

2020 ◽  
Author(s):  
Maria Peralta ◽  
Silvia Mendieta ◽  
Ivana Scolari ◽  
Gladys Granero ◽  
Monica Crivello
Keyword(s):  
Drug Delivery ◽  
Layered Double Hydroxides ◽  
Controlled Drug Delivery ◽  
Sodium Cholate ◽  
Basal Spacing ◽  
Reconstruction Method ◽  
X Rays ◽  
Formal Charge ◽  
Axis Parallel ◽  
Double Hydroxides

Abstract Carbamazepine (CBZ) was incorporated into Layered Double Hydroxides (LDH) to be used as controlled drug delivery in solid tumors. CBZ has a formal charge of 0, which implies a challenge to be incorporated in the anionic clay. Aiming to overcome this problem, CBZ was first incorporated in micelles of sodium cholate (SC), a surfactant with negative charge. CBZ in SC micelles and, for comparison, free CBZ were incorporated in LDH by reconstruction method. It was found that resultant nano-composites had similar CBZ encapsulation efficiency, around 75 %, but drug release in simulated body fluid (pH 7.4) and acetate buffer (pH 4.8) was efficient only with the LDH-CBZ sample. CBZ dimensions were measured with Chem3D and, according to the basal spacing obtained from X rays patterns, it can arrange as monolayer with the long axis parallel to the LDH layers. Fourier Transform Infrared Spectroscopy confirmed the incorporation of the drug. Thermogravimetric analyses showed and enhanced thermal stability for CBZ. These results have interesting implications since they increase the spectrum of LDH application as controlled drug delivery to a large number of non-ionic drugs, without the addition of other components.

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