Polymer mobilization and drug release during tablet swelling. A 1H NMR and NMR microimaging study

Dahlberg, Carina; Fureby, Anna; Schuleit, Michael; Dvinskikh, Sergey V.; Furó, István

doi:10.1016/j.jconrel.2007.07.007

Cited by 52 publications

(25 citation statements)

References 30 publications

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“…However, since such measurements involve observations at a macroscopic level, little information has been obtained relating the properties of the solvent inside the polymer matrix to the mechanisms of the process that control the swelling. Consequently, in order to understand the mechanism in controlled release systems new and more effective methods, such as magnetic resonance imaging (MRI), are reported (Fyfe and Blazek 1997; Fyfe and Blazek‐Welsh 2000; Fyfe and others 2000; Knorgen and others 2000; Tritt‐Goc and Pis'lewski 2002; Kowalczuk and others 2004; Cranitch and others 2007; Dahlberg and others 2007; Karakosta and McDonald 2007). …”

Section: Introductionmentioning

confidence: 99%

“…Relevant to this study, MRI has been used to monitor diffusion of solvents into synthetic polymers and to track the penetration of water into swelling tablets, most commonly hydroxypropylmethylcellulose (HPMC) (Fyfe and Blazek 1998, 2000; Fyfe and others 2000; Tritt‐Goc and Pis'lewski 2002; Kowalczuk and others 2004; Dahlberg and others 2007), poly(glycolic acid‐co‐DL‐lactic acid) (Hyde and others 1995), polyethylene oxide (Hyde and Gladden 1998), and high‐amylose starch tablets (Baille and others 2002; Russo and others 2007; Therién‐Aubin and others 2008). In these studies, qualitative and quantitative descriptions of the swelling process were obtained, and solvent uptake was quantified by kinetic and diffusion expressions.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Resonance Imaging (MRI) and Relaxation Spectrum Analysis as Methods to Investigate Swelling in Whey Protein Gels

Öztop¹,

Rosenberg²,

Rosenberg³

et al. 2010

Journal of Food Science

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Effective means for controlled delivery of nutrients and nutraceuticals are needed. Whey protein-based gels, as a model system and as a potential delivery system, exhibit pH-dependent swelling when placed in aqueous solutions. Understanding the physics that govern gel swelling is thus important when designing gel-based delivery platforms. The extent of swelling over time was monitored gravimetrically. In addition to gravimetric measurements, magnetic resonance imaging (MRI) a real-time noninvasive imaging technique that quantified changes in geometry and water content of these gels was utilized. Heat-set whey protein gels were prepared at pH 7 and swelling was monitored in aqueous solutions with pH values of 2.5, 7, and 10. Changes in dimension over time, as characterized by the number of voxels in an image, were correlated to gravimetric measurements. Excellent correlations between mass uptake and volume change (R(2)= 0.99) were obtained for the gels in aqueous solutions at pH 7 and 10, but not for gels in the aqueous solution at pH 2.5. To provide insight into the mechanisms for water uptake, nuclear magnetic resonance (NMR) relaxation times were measured in independent experiments. The relaxation spectrum for the spin-spin relaxation time (T(2)) showed the presence of 3 proton pools for pH 7 and 10 trials and 4 proton pools for pH 2.5 trials. Results demonstrate that MRI and NMR relaxation measurements provided information about swelling in whey protein gels that can constitute a new means for investigating and developing effective delivery systems for foods.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetic Resonance Imaging (MRI) and Relaxation Spectrum Analysis as Methods to Investigate Swelling in Whey Protein Gels

Öztop¹,

Rosenberg²,

Rosenberg³

et al. 2010

Journal of Food Science

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show abstract

“…The measurements can be performed on any conventional NMR probe equipped with pulsed field gradients (PFG), since it requires only low gradient strengths. Similar NMR studies have been performed earlier with the aim to study diffusion in multi-component systems [2,3], but without the chemical shift resolution.…”

Section: Introductionmentioning

confidence: 86%

Chemical shift imaging NMR to track gel formation

Östlund

Bernin

Nordstierna

et al. 2010

Journal of Colloid and Interface Science

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“…Therefore, based on the fast exchange of water molecules between the bound state on the polymer chains and the free state in the rest of the hydrogel water, the amount of bound water per polymer repeating unit can be determined. Moreover, through these MRI and NMR techniques, drug release behaviors can be investigated together during the swelling process (169,170). For the physical characterization of tablets, other parameters are usually evaluated, such as hardness, friability, weight variation, and content uniformity.…”

Section: Evaluation Of the Physicochemical Properties Of Cr-sdmentioning

confidence: 99%

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

Tran

Park

et al. 2011

Pharm Res

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In addition to a number of highly soluble drugs, most new chemical entities under development are poorly water-soluble drugs generally characterized by an insufficient dissolution rate and a small absorption window, leading to the low bioavailability. Controlled-release (CR) formulations have several potential advantages over conventional dosage forms, such as providing a uniform and prolonged therapeutic effect to improve patient compliance, reducing the frequency of dosing, minimizing the number of side effects, and reducing the strength of the required dose while increasing the effectiveness of the drug. Solid dispersions (SD) can be used to enhance the dissolution rate of poorly water-soluble drugs and to sustain the drug release by choosing an appropriate carrier. Thus, a CR-SD comprises both functions of SD and CR for poorly water-soluble drugs. Such CR dosage forms containing SD provide an immediately available dose for an immediate action followed by a gradual and continuous release of subsequent doses to maintain the plasma concentration of poorly water-soluble drugs over an extended period of time. This review aims to summarize all currently known aspects of controlled release systems containing solid dispersions, focusing on the preparation methods, mechanisms of action and characterization of physicochemical properties of the system.

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Polymer mobilization and drug release during tablet swelling. A 1H NMR and NMR microimaging study

Cited by 52 publications

References 30 publications

Magnetic Resonance Imaging (MRI) and Relaxation Spectrum Analysis as Methods to Investigate Swelling in Whey Protein Gels

Magnetic Resonance Imaging (MRI) and Relaxation Spectrum Analysis as Methods to Investigate Swelling in Whey Protein Gels

Chemical shift imaging NMR to track gel formation

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

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