Use of coated microtubular halloysite for the sustained release of diltiazem hydrochloride and propranolol hydrochloride

Levis, S.R.; Deasy, P. B.

doi:10.1016/s0378-5173(02)00702-0

Cited by 183 publications

(113 citation statements)

References 11 publications

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“…Some sources claim that molecules can penetrate also into the interlamellar space . The majority of the groups using halloysite as carrier material for active molecules assume that these latter are located within the tubes and released from there to achieve prolonged effect [2][3][4][5][6][7][8][9][10][11][12][13][14]. Unfortunately, usually not much proof is supplied for this assumption and further study and model calculations must be carried out to define the location and distribution of quercetin molecules on the surface of the halloysite unambiguously.…”

Section: Discussion Consequencesmentioning

confidence: 99%

“…Halloysite is a naturally occurring mineral, which is available both in platelet like and tubular form. Numerous attempts have been made to use halloysite nanotubes as carriers for all kinds of bioactive molecules including drugs [2][3][4][5][6][7][8][9][10][11][12][13][14]. However, besides medical applications, halloysite nanotubes are used as supports in other areas as well.…”

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confidence: 99%

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Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes

Hári

Gyürki

Sárközi

et al. 2016

Journal of Colloid and Interface Science

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Halloysite nanotubes used as potential carrier material for a controlled release stabilizer in polyethylene were thoroughly characterized with several techniques including the measurement of specific surface area, pore volume and surface energy. The high surface energy of the halloysite results in the strong bonding of the additive to the surface.Dissolution experiments carried out with eight different solvents for the determination of the effect of solvent characteristics on the amount of irreversibly bonded quercetin proved that adsorption and dissolution depend on competitive interactions prevailing in the system. Solvents with low polarity dissolve only surplus quercetin adsorbed in multilayers.Polyethylene is a very apolar polymer forming weak interactions with every substance; quercetin dissolves into it only above a critical concentration. Stabilization experiments confirmed that strong adhesion prevents dissolution and results in limited stabilization efficiency. At larger adsorbed amounts better stability and extended effect were measured indicating dissolution and controlled release.

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Section: Discussion Consequencesmentioning

confidence: 99%

mentioning

confidence: 99%

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes

Hári

Gyürki

Sárközi

et al. 2016

Journal of Colloid and Interface Science

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“…As concerns the size, HNTs are quite polydisperse with a length ranging between 0.1 and 2 mm while the outer and inner diameters are ca. 30e50 nm and 1e30 nm, respectively [7]. The internal surface consists of gibbsite octahedral sheet (AleOH) groups whereas the external surface is composed of siloxane groups (SieOeSi) [8].…”

Section: Introductionmentioning

confidence: 99%

“…The negative charge on the outer surface was used in the production of halloysite multilayer films by layer-by-layer nanoassembly [10]. The functionalization of the lumen with anionic macromolecules, such as biocides, pharmaceuticals, enzymes and other chemically active agents, is an efficient strategy to obtain smart nanomaterials attractive for anticorrosion protective coating, drug immobilization and controlled release, water purification [7,11,12]. Inorganic micelles with high affinity towards hydrophobic compounds were successfully prepared by selective modification of HNT lumen [2a,13].…”

mentioning

confidence: 99%

Eco-friendly functionalization of natural halloysite clay nanotube with ionic liquids by microwave irradiation for Suzuki coupling reaction

Massaro

Riela

Cavallaro

et al. 2014

Journal of Organometallic Chemistry

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“…Besides titanium dioxide and carbon nanotubes, halloysite nanotubes are also good potential carriers for active molecules, and were claimed to offer controlled release function as well [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. As a consequence, numerous attempts were made to use them for controlled drug delivery, but also in other applications.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of an active molecule on the surface of halloysite for controlled release application: Interaction, orientation, consequences

Hári

Polyák

Mester

et al. 2016

Applied Clay Science

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The goal of the study was to check the possible use of halloysite nanotubes as a controlled release natural antioxidant device with quercetin as the active component. The mineral was thoroughly characterized by various techniques including the determination of particle and tube morphology, specific surface area, pore size and volume, as well as surface energy. The high surface energy of halloysite predicted strong adsorption of active molecules on its surface and consequently difficult release. FTIR spectroscopy confirmed the existence of strong interactions, energetically heterogeneous halloysite surface and multilayer coverage at large loadings. FTIR and XRD experiments proved the complete lack of intercalation and showed that below 3.5 wt% quercetin loading, most of the molecules are located within the halloysite tubes. Molecular modelling indicated the parallel orientation of quercetin molecules with the surface. Critical concentrations derived from various measurements agreed well with each other further confirming that up to about 4.0 wt% loading, quercetin is bonded very strongly to the halloysite surface. As a consequence, the dissolution of active molecules is very difficult or impossible, especially into apolar media, thus neither stabilization nor controlled release effect can be expected below that concentration.

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Use of coated microtubular halloysite for the sustained release of diltiazem hydrochloride and propranolol hydrochloride

Cited by 183 publications

References 11 publications

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes

Eco-friendly functionalization of natural halloysite clay nanotube with ionic liquids by microwave irradiation for Suzuki coupling reaction

Adsorption of an active molecule on the surface of halloysite for controlled release application: Interaction, orientation, consequences

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