Intercalation and grafting of hydrogen phosphates and phosphonates into synthetic hydrotalcites and a.c.-conductivity of the compounds thereby obtained

Costantino, U.; Casciola, Mario; Massinelli, L.; Nocchetti, Morena; Vivani, Riccardo

doi:10.1016/s0167-2738(97)00043-x

Cited by 115 publications

(69 citation statements)

References 11 publications

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“…The interlayer distance of this residue was 1.07 nm. This value is relative to HTlc containing phosphates as intercalated ions [13]. The disappearance of the peak at 2.36 nm relative to HTlc-DIK was also observed.…”

Section: In Vitro Drug Releasementioning

confidence: 70%

“…In the case of another hydrotalcite containing Zn and Al (Zn -Al-HTlc), the acidic H 2 PO 4 -anions, once exchanged, react with the hydroxyls of the layer to form a layered Zn and Al hydroxyphosphate [13] (grafting reaction). In this strongly bound form, phosphates are no longer movable and can obstruct the exit of the intercalated anions.…”

Section: In Vitro Drug Releasementioning

confidence: 99%

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Intercalation compounds of hydrotalcite-like anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation

et al. 2002

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ABASTRACT The purpose of this study was to investigate whether hydrotalcite is able to intercalate diclofenac, a nonsteroidal anti-inflammatory drug, and release it in a controlled manner. Layered Mg-Al hydrotalcite in the chloride form was used as a host, and the intercalation compound was prepared by Cl -/diclofenac anionic exchange. Drug release from the intercalation compound was performed in vitro in simulated intestinal fluid at pH 7.5 according to USP 24 and in a pH 7.0 solution designed to mimic the ionic conditions of the small intestine. Results from the intercalation process show that hydrotalcite is able to intercalate diclofenac with a simple procedure and with a good drug loading (55% wt/wt). The in vitro drug release was remarkably lower than that from the corresponding physical mixture at both pH 7.5 and pH 7.0. In the latter case, the release was not complete at 24 hours. The kinetic analysis shows the importance of the diffusion through the particle in controlling the drug release rate. The obtained results show that hydrotalcite may be used to prepare modified release formulations.

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Section: In Vitro Drug Releasementioning

confidence: 70%

Section: In Vitro Drug Releasementioning

confidence: 99%

Intercalation compounds of hydrotalcite-like anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation

et al. 2002

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“…HTlcs may be widely utilized in many fields such as catalysts and catalyst precursors, antacids, the preparation of pigments, the treatment of waste water, sunscreen agents, anionic exchangers, sorbents and rheology modifiers for both aqueous and nonaqueous system. [18][19][20][21][22] Cationic starch (CS) is a positively charged polymer, and a large-scale commercial product that has widespread uses in many fields such as papermaking chemical, topical drug delivery systems and oilfield applications. [23][24][25] The rheology of aqueous suspension containing Mg-Al HTlc and high-substituted cationic starch (HCS) (the mass ratio of HTlc to HCS was not more than 0.08) was investigated recently and the thixotropic type of the suspension could transform from negative through complex to positive thixotropy with the increase of HTlc content.…”

Section: Introductionmentioning

confidence: 99%

Thixotropy of Aqueous Suspensions Containing Mg-Al Hydrotalcite-like Compound and Low-substituted Cationic Starch: Comparison between Oscillatory Shear and Thixotropic Loop Measurements

Shen

2011

Chin. J. Chem.

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The rheological properties of aqueous suspensions consisting of positively charged aluminum magnesium hydrotalcite-like compound (HTlc) and low-substituted cationic starch (LCS) were investigated. Special emphasis was placed on the thixotropic phenomenon. Thixotropic behavior was investigated by two thixotropic methods: thixotropic loop and oscillatory shear measurements. LCS molecules could be adsorbed onto HTlc particles due to the hydrogen bonding between ether groups or hydroxyl groups of LCS and hydroxyl groups of HTlc. The elastic dynamic response of the HTlc/LCS suspension increased with increasing mass ratio (R) of HTlc and a three-dimensional network structure could be formed in the suspension with higher R value. The thixotropic type of the HTlc/LCS suspension transformed from negative to positive and then to complex thixotropy when R changed from 0 to 0.5. By comparing between the thixotropic results obtained by thixotropic loop and oscillatory shear measurements, it was validated that the thixotropic loop for the suspension showing complex thixotropy had a crossover point.

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“…[3][4][5] The fields of real and potential industrial application of HTlc range widely from oil fields to agriculture. Among numerous uses of HTlc, the drilling fluids, which are composed of HTlc and sodium montmorillonite (MT), are of major importance.…”

Section: Introductionmentioning

confidence: 99%

“…The chemical composition was found with a 3080E2 type automatic X-ray fluorescent spectrometer (Japan), and the XRD pattern obtained by a D/max-llrA model instrument shows the HTlc particles have a well crystallized hydrotalcite-type structure. 5 The clay obtained from Jiangyin Montmorillonite Co. was first suspended in deionized water by stirring and then decanted leaving the deposit, to which some H 2 O 2 was added to remove the organic matter. The dispersion was heated to ca.…”

Section: Introductionmentioning

confidence: 99%

Thixotropic and Viscoelastic Properties of Hydrotalcite Like Compound‐Montmorillonite Suspensions

Zhu

2009

Chin. J. Chem.

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The thixotropic and viscoelastic properties of the complex suspension made up of hydrotalcite-like compound (HTlc)-sodium montmorillonite (MT) suspensions have been studied carefully. Two kinds of Fe-Mg-Al-HTlc systems have been examined, and from sample 1 to sample 2, the content of Mg 2＋ enhances gradually while the molar ratio of Al to Fe remains constant. With increasing the content of Mg 2＋ in the HTlc samples, the results of the creep tests and the stress sweep experiments all indicate that the structure strength of the HTlc/MT suspension increases. Moreover, the hysterisis loops have been detected carefully, showing that the thixotropic degree increases with increasing the Mg 2＋ content. It was concluded that the rheological properties could be adjusted by the change of the metal content.

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Intercalation and grafting of hydrogen phosphates and phosphonates into synthetic hydrotalcites and a.c.-conductivity of the compounds thereby obtained

Cited by 115 publications

References 11 publications

Intercalation compounds of hydrotalcite-like anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation

Intercalation compounds of hydrotalcite-like anionic clays with anti-inflammatory agents, II: Uptake of diclofenac for a controlled release formulation

Thixotropy of Aqueous Suspensions Containing Mg-Al Hydrotalcite-like Compound and Low-substituted Cationic Starch: Comparison between Oscillatory Shear and Thixotropic Loop Measurements

Thixotropic and Viscoelastic Properties of Hydrotalcite Like Compound‐Montmorillonite Suspensions

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