scholarly journals Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Stephen Majoni ◽  
Jeanne M. Hossenlopp
Keyword(s):  
Controlled Release ◽  
Dipole Moments ◽  
Release Kinetics ◽  
Strong Dependence ◽  
Exchange Reactions ◽  
Metal Hydroxides ◽  
Double Salts ◽  
Rate Of Reaction ◽  
Hydroxy Double Salts ◽  
Double Hydroxides

Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs) and hydroxy double salts (HDSs) can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release. The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers. The orthoisomer showed a more sustained and complete release as compared to the other isomers.

Preparation of hydroxy double salts exchanged by organic compounds

1998 ◽  
Vol 13 (4) ◽  
pp. 848-851 ◽  
Author(s):  
Hiroyuki Morioka ◽  
Hideyuki Tagaya ◽  
Masa Karasu ◽  
Jun-ichi Kadokawa ◽  
Koji Chiba
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Layered Double Hydroxides ◽  
Interlayer Spacing ◽  
Layered Materials ◽  
Exchange Reactions ◽  
Double Salts ◽  
Hydroxy Double Salts ◽  
Double Hydroxides ◽  
Positively Charged

Hydroxy double salts (HDS's) comprise a class of layered materials that are similar to layered double hydroxides (LDH's) and show a comparable intracrystalline reactivity. Their anion exchange reactions occur with preincorporated anions in the hydroxide layer and with anions bound as gegenions of the positively charged layers, respectively. In this study, nitrate and acetate anions of HDS's were exchanged with anionic monoand di-carboxylic acids, and we confirmed that interlayer spacing of HDS's increased depending on the size of mono- and di-carboxylic acids. Moreover, we have prepared photofunctional materials by exchange reaction with azobenzene-p-carboxylic acid and 4–4′-azobenzenedicarboxylic acid.

Preparation of Sodium Paeonolsilate Intercalated into Layered Double Hydroxides and its Release Properties

2015 ◽  
Vol 1095 ◽  
pp. 349-354 ◽  
Author(s):  
Liang Hua Gu ◽  
Hong Qing Song ◽  
Zhi Yong Sun ◽  
Ji Yong Zheng ◽  
Jin Wei Zhang ◽  
...  
Keyword(s):  
Controlled Release ◽  
Release Kinetics ◽  
Molar Ratio ◽  
Burst Release ◽  
X Ray Diffraction ◽  
Release Process ◽  
Rate Determining Step ◽  
Release Ratio ◽  
Double Hydroxide ◽  
Double Hydroxides

A controlled release composite has been prepared by intercalation of sodium paeonolsilate (PAS) into Mg/Al layered double hydroxide (LDH) with the molar ratio (M2+/M3+) of 2:1. The powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) confirm the intercalation of PAS into the galleries of LDH. The chemical composites of PAS-LDH were revealed by elemental analysis. Release tests of the PAS-LDH composite showed that no burst release phenomenon occurred at the beginning stage and a high release ratio of PAS (89.8%) was obtained, exhibiting controlled release behavior. Furthermore, the parabolic diffusion model was used to simulate the release kinetics of PAS from the LDH carrier, indicating that the intraparticle diffusion via ion-exchange is the rate-determining step in the release process. It is significance in this work for introducing the PAS-LDH composite to develop antifouling materials with long-term activity.

ChemInform Abstract: Anion-Exchange Reactions of Hydroxy Double Salts.

ChemInform ◽  
2010 ◽  
Vol 24 (28) ◽  
pp. no-no
Author(s):  
M. MEYN ◽  
K. BENEKE ◽  
G. LAGALY
Keyword(s):  
Anion Exchange ◽  
Exchange Reactions ◽  
Double Salts ◽  
Hydroxy Double Salts

Anion-exchange reactions of hydroxy double salts

1993 ◽  
Vol 32 (7) ◽  
pp. 1209-1215 ◽  
Author(s):  
Martina Meyn ◽  
Klaus Beneke ◽  
Gerhard Lagaly
Keyword(s):  
Anion Exchange ◽  
Exchange Reactions ◽  
Double Salts ◽  
Hydroxy Double Salts

scholarly journals Simultaneous Intercalation of 1-Naphthylacetic Acid and Indole-3-butyric Acid into Layered Double Hydroxides and Controlled Release Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shifeng Li ◽  
Yanming Shen ◽  
Min Xiao ◽  
Dongbin Liu ◽  
Lihui Fan ◽  
...  
Keyword(s):  
Controlled Release ◽  
Butyric Acid ◽  
Layered Double Hydroxides ◽  
Ph Value ◽  
Release Kinetics ◽  
Release Formulation ◽  
Pseudo Second Order ◽  
Controlled Release Formulations ◽  
Naphthylacetic Acid ◽  
Double Hydroxides

Controlled release formulations have been shown to have potential in overcoming the drawbacks of conventional plant growth regulators formulations. A controlled-release formulation of 1-naphthylacetic acid (NAA) and indole-3-butyric acid (IBA) simultaneous intercalated MgAl-layered double hydroxides (LDHs) was prepared. The synthetic nanohybrid material was characterized by various techniques, and release kinetics was studied. NAA and IBA anions located in the gallery of MgAl-LDHs with bilayer arrangement, and the nanohybrids particles were of typical plate-like shape with the lateral size of 50–100 nm. The results revealed that NAA and IBA have been intercalated into the interlayer spaces of MgAl-LDHs. The release of NAA and IBA fits pseudo-second-order model and is dependent on temperature, pH value, and release medium. The nanohybrids of NAA and IBA simultaneously intercalated in LDHs possessed good controlled release properties.

Optimization Study to Develop Once-a-day Controlled Release Formulation of Metoclopramide with Predictable Design Space

1970 ◽  
Vol 1 (1) ◽  
pp. 71-76
Author(s):  
Rajesh Dubey ◽  
Udaya K. Chowdary ◽  
Venkateswarlu V.
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Design Space ◽  
Release Kinetics ◽  
Release Profile ◽  
Release Formulation ◽  
Linear Effect ◽  
Controlled Release Formulation ◽  
The Difference ◽  
Face Centered

A controlled release formulation of metoclopramide was developed using a combination of hypromellose (HPMC) and hydrogenated castor oil (HCO). Developed formulations released the drug over 20 hr with release kinetics following Higuchi model. Compared to HCO, HPMC showed significantly higher influence in controlling the drug release at initial as well as later phase. The difference in the influence can be explained by the different swelling and erosion behaviour of the polymers. Effect of the polymers on release was optimized using a face-centered central composite design to generate a predictable design space. Statistical analysis of the drug release at various levels indicated a linear effect of the polymers’ levels on the drug release. The release profile of formulations containing the polymer levels at extremes of their ranges in design space was found to be similar to the predicted release profile

Antibiotic-anionic Clay Matrix Used for Drug Controlled Release

2018 ◽  
Vol 69 (2) ◽  
pp. 321-323
Author(s):  
Georgeta Zegan ◽  
Elena Mihaela Carausu ◽  
Loredana Golovcencu ◽  
Alina Sodor Botezatu ◽  
Eduard Radu Cernei ◽  
...  
Keyword(s):  
Controlled Release ◽  
Layered Double Hydroxides ◽  
Bioactive Molecules ◽  
Drug Controlled Release ◽  
Anionic Clays ◽  
Anionic Clay ◽  
Toxicological Studies ◽  
High Efficient ◽  
Clay Matrix ◽  
Double Hydroxides

Anionic clay matrix acting as drug controlled release system have shown in last years a great potential for delivery of bioactive molecules and chemical therapeutics. This organic-inorganic nanohybrid system is high efficient offering an excellent protection of intercalated compounds from degradation. Compared to other nanoparticles used in medical area, anionic clays type layered double hydroxides have found to be biocompatible according to toxicological studies. Ampicillin containing MgAlLDHs and ZnAlLDH samples have been prepared following two routes: anion-exchange procedure and reconstruction from calcined layered double hydroxides. Solid samples have been characterized by FTIR and SEM-EDX highlighting the alteration of pristine LDHs structure when the antibiotic is introduced in the interlayer gallery.

scholarly journals Polymer/Iron-Based Layered Double Hydroxides as Multifunctional Wound Dressings

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1130
Author(s):  
Mariana Pires Figueiredo ◽  
Ana Borrego-Sánchez ◽  
Fátima García-Villén ◽  
Dalila Miele ◽  
Silvia Rossi ◽  
...  
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Mechanical Performance ◽  
Release Kinetics ◽  
Wound Dressings ◽  
In Vitro Drug Release ◽  
Improved Performance ◽  
Double Hydroxide ◽  
Double Hydroxides

This work presents the development of multifunctional therapeutic membranes based on a high-performance block copolymer scaffold formed by polyether (PE) and polyamide (PA) units (known as PEBA) and layered double hydroxide (LDH) biomaterials, with the aim to study their uses as wound dressings. Two LDH layer compositions were employed containing Mg2+ or Zn2+, Fe3+ and Al3+ cations, intercalated with chloride anions, abbreviated as Mg-Cl or Zn-Cl, or intercalated with naproxenate (NAP) anions, abbreviated as Mg-NAP or Zn-NAP. Membranes were structurally and physically characterized, and the in vitro drug release kinetics and cytotoxicity assessed. PEBA-loading NaNAP salt particles were also prepared for comparison. Intercalated NAP anions improved LDH–polymer interaction, resulting in membranes with greater mechanical performance compared to the polymer only or to the membranes containing the Cl-LDHs. Drug release (in saline solution) was sustained for at least 8 h for all samples and release kinetics could be modulated: a slower, an intermediate and a faster NAP release were observed from membranes containing Zn-NAP, NaNAP and Mg-NAP particles, respectively. In general, cell viability was higher in the presence of Mg-LDH and the membranes presented improved performance in comparison with the powdered samples. PEBA containing Mg-NAP sample stood out among all membranes in all the evaluated aspects, thus being considered a great candidate for application as multifunctional therapeutic dressings.

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