Some Factors Affecting the Release of a Water-Soluble Drug from a Compressed Hydrophilic Matrix

Lapidus, H.; Lordi, Nicholas G.

doi:10.1002/jps.2600550818

Cited by 180 publications

(49 citation statements)

References 5 publications

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“…At the beginning it was thought to be applicable to planar systems, and then it was extended to include various geometries and porous matrices (Desai et al, 1965;Higuchi, 1963;Lapidus & Lordi, 1966). In his first contribution Higuchi imagined the drug release as being modelled by the release of a cytotoxic agent from a thin ointment base, according to the following conditions:…”

Section: Resultsmentioning

confidence: 99%

Maghemite Functionalization for Antitumor Drug Vehiculization

2012

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In this paper we describe the preparation and characterization of magnetic nanocomposites designed for applications in targeted drug delivery. Combining superparamagnetic behavior with proper surface functionalization in a single entity makes it possible to have altogether controlled location and drug loading, and release capabilities. The colloidal vehicles consist of maghemite (γ-Fe2O3) cores surrounded by a gold shell through an intermediate silica coating. The external Au layer confers the particles a high degree of biocompatibility and reactive sites for the transported drug binding. In addition, it permits to take advantage of the strong optical resonance, making it easy to visualize the particles or even control their payload release through temperature changes. The results of the analysis of relaxivity demonstrate that these nanostructures can be used as T 2 contrast agents in magnetic resonance imaging (MRI), but the magnetic cores will be mainly useful in manipulating the particles using external magnetic fields. We describe how optical absorbance and electrokinetic data provide a followup of the progress of the nanostructure formation. Additionally, these techniques, together with confocal microscopy, are employed to demonstrate that the component nanoparticles are capable of loading significant amounts of the antitumor drug doxorubicin, very efficient in the chemotherapy of a wide range of tumors. Colon adenocarcinoma cells were used to test the in vitro release capabilities of the drug-loaded nanocomposites.

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Section: Resultsmentioning

confidence: 99%

Maghemite Functionalization for Antitumor Drug Vehiculization

2012

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“…Gum-or HPMC-containing tablets take up water on contact with the release medium (16,28,54), thus allowing dissolution of a certain percent of the drug found at and near the tablet surface prior to gel or viscous medium formation. This is followed by hydration and swelling of the polymer, Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The second causes a reduction in the diffusion pathlength and evidence of erosion, which increase the release rate. Interestingly, first-order kinetics is evident at HPMC levels greater than 10% w/w of the tablet (8,24,27,28); only at 5% w/w HPMC was erosion observed (25).…”

Section: Introductionmentioning

confidence: 98%

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Guar Gum, Xanthan Gum, and HPMC Can Define Release Mechanisms and Sustain Release of Propranolol Hydrochloride

2010

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Abstract. The objectives were to characterize propranolol hydrochloride-loaded matrix tablets using guar gum, xanthan gum, and hydroxypropylmethylcellulose (HPMC) as rate-retarding polymers. Tablets were prepared by wet granulation using these polymers alone and in combination, and physical properties of the granules and tablets were studied. Drug release was evaluated in simulated gastric and intestinal media. Rugged tablets with appropriate physical properties were obtained. Empirical and semi-empirical models were fit to release data to elucidate release mechanisms. Guar gum alone was unable to control drug release until a 1:3 drug/gum ratio, where the release pattern matched a Higuchi profile. Matrix tablets incorporating HPMC provided near zero-order release over 12 h and erosion was a contributing mechanism. Combinations of HPMC with guar or xanthan gum resulted in a Higuchi release profile, revealing the dominance of the high viscosity gel formed by HPMC. As the single rate-retarding polymer, xanthan gum retarded release over 24 h and the Higuchi model best fit the data. When mixed with guar gum, at 10% or 20% xanthan levels, xanthan gum was unable to control release. However, tablets containing 30% guar gum and 30% xanthan gum behaved as if xanthan gum was the sole rate-retarding gum and drug was released by Fickian diffusion. Release profiles from certain tablets match 12-h literature profiles and the 24-h profile of Inderal ® LA. The results confirm that guar gum, xanthan gum, and HPMC can be used for the successful preparation of sustained release oral propranolol hydrochoride tablets.

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“…In recent review articles, mathematical models have been reviewed, which describe drug release from tablets with HPMC matrix (3,4). The diffusion equations for a semi-infinite medium were also proposed (5,6). Later, a model accounting for both the volume change of the swellable tablet upon contact with the aqueous medium and the countercurrent diffusion of the solute was also developed (7).…”

Section: Introductionmentioning

confidence: 99%

Quantification of Swelling and Erosion in the Controlled Release of a Poorly Water-Soluble Drug Using Synchrotron X-ray Computed Microtomography

Yin

Guo

et al. 2013

AAPS J

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Abstract. The hydration layer plays a key role in the controlled drug release of gel-forming matrix tablets. For poorly water-soluble drugs, matrix erosion is considered as the rate limiting step for drug release. However, few investigations have reported on the quantification of the relative importance of swelling and erosion in the release of poorly soluble drugs, and three-dimensional (3D) structures of the hydration layer are poorly understood. Here, we employed synchrotron radiation X-ray computed microtomography with 9-μm resolution to investigate the hydration dynamics and to quantify the relative importance of swelling and erosion on felodipine release by a statistical model. The 3D structures of the hydration layer were revealed by the reconstructed 3D rendering of tablets. Twenty-three structural parameters related to the volume, the surface area (SA), and the specific surface area (SSA) for the hydration layer and the tablet core were calculated. Three dominating parameters, including SA and SSA of the hydration layer (SA hydration layer and SSA hydration layer ) and SA of the glassy core (SA glassy core ), were identified to establish the statistical model. The significance order of independent variables was SA hydration layer > SSA hydration layer > SA glassy core , which quantitatively indicated that the release of felodipine was dominated by a combination of erosion and swelling. The 3D reconstruction and structural parameter calculation methods in our study, which are not available from conventional methods, are efficient tools to quantify the relative importance of swelling and erosion in the controlled release of poorly soluble drugs from a structural point of view.

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Some Factors Affecting the Release of a Water-Soluble Drug from a Compressed Hydrophilic Matrix

Cited by 180 publications

References 5 publications

Maghemite Functionalization for Antitumor Drug Vehiculization

Maghemite Functionalization for Antitumor Drug Vehiculization

Guar Gum, Xanthan Gum, and HPMC Can Define Release Mechanisms and Sustain Release of Propranolol Hydrochloride

Quantification of Swelling and Erosion in the Controlled Release of a Poorly Water-Soluble Drug Using Synchrotron X-ray Computed Microtomography

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