Nuclear magnetic imaging of an osmotic water uptake and delivery process

Riggs, P.D.; Kinchesh, Paul; Braden, M.; Patel, Mukesh R.

doi:10.1016/s0142-9612(00)00093-4

Cited by 17 publications

(6 citation statements)

References 19 publications

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“…Because inorganic salts are a group of chemicals that can cause the osmotic influx of water in hydrophobic systems, their transport properties in SR systems have been studied. Examples include the works of Golomb et al,18 Sutinen et al,19 and Riggs et al,20 who studied the release of K 2 Cr 2 O 7 , NaCl, and NH 4 F, respectively, from SR systems along with the measurement of the concurrent water uptake, taking into account the particle sizes and the initial salt load.…”

Section: Introductionmentioning

confidence: 99%

“…The Π that builds up inside these cavities may be large enough to create microscopic cracks around them. These microscopic cracks progressively grow and percolate, creating small pathways 20, 21, 24. Although in all of the studies the formation of microscopic cracks was a prerequisite, Amsden and coworkers22, 23 also proposed that the release kinetics of osmotically active excipients from monolithic matrices is also load dependent.…”

Section: Introductionmentioning

confidence: 99%

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Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

Soulas

Sanopoulou

Papadokostaki

2009

J of Applied Polymer Sci

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ABSTRACT:The release process of three osmotically active solutes with various solubilities in water (NaCl, CsNO 3 , and CsCl) from silicone rubber matrices is presented. The kinetics of release for different initial loads of the salts were supplemented by measurements of the kinetics of concurrent water uptake. To gain insight on the relevant non-Fickian transport mechanisms, the morphology, the diffusion and sorption properties and the physicochemical state of water in the salt-depleted matrices were studied. In addition, both salt-loaded and saltdepleted matrices were characterized with respect to their mechanical properties. The combined information, derived from these techniques, supported the operation of a release mechanism carried out through the formation of microscopic cracks, interconnecting the permanently formed cavities inside the matrices. The results indicate that these microscopic cracks may have healed upon drying.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

Soulas

Sanopoulou

Papadokostaki

2009

J of Applied Polymer Sci

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“…2 The technique can provide information on either the penetrant sorption or drug release processes at the molecular level. 2 For example, MRI has recently been used to observe the ingress of penetrants into solid systems [3][4][5][6][7][8][9] and to provide two-or three-dimensional, time-dependent images of the density of these highly mobile components in a material. Because it provides direct information on the nature of the penetrant diffusion front during sorption, it provides direct information on the penetrant diffusion mechanism.…”

Section: Introductionmentioning

confidence: 99%

NMR Imaging of the Diffusion of Water at 37 °C into Poly(2-hydroxyethyl methacrylate) Containing Aspirin or Vitamin B₁₂

2004

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The ingress of water into poly(2-hydroxyethyl methacrylate), PHEMA, loaded with either one of two model drugs, vitamin B(12) or aspirin, was studied at 37 degrees C using three-dimensional NMR imaging. PHEMA was loaded with 5 and 10 wt % of the drugs. From the imaging profiles, it was observed that incorporation of vitamin B(12) into PHEMA resulted in enhanced crack formation on sorption of water and the crack healing behind the diffusion front was slower than for PHEMA without added drug. This was accounted for by the anti-plasticization of PHEMA by vitamin B(12). Crack formation was inhibited in the PHEMA-aspirin systems because of the plasticizing effect of the aspirin on the PHEMA matrix. All of the polymers were found to absorb water according to an underlying Fickian diffusion mechanism. For PHEMA loaded with 5 wt % of aspirin or vitamin B(12), the best values of the water diffusion coefficients were both found to be 1.3 +/- 0.1 x 10(-11) m(2) s(-1) at 37 degrees C, while the values for the polymer loaded with 10 wt % of the drugs were slightly higher, 1.5 +/- 0.1 x 10(-11) m(2) s(-1).

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“…Osmosis-based substance release mechanisms were found to act for water in a silicon matrix containing NH 4 F. 68 In the presence of salt the T 1 and T 2 times of water are shortened and the ability of the cylindrical polymer sample to absorb water is enhanced considerably. Water diffusion in the matrix was accompanied by the formation of concentrated brine droplets that grew under the action of osmotic pressure.…”

Section: Swelling Of Polymers and Coalmentioning

confidence: 99%

Applications of NMR tomography to mass transfer studies

Koptyug¹,

Sagdeev²

2002

Russ. Chem. Rev.

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Nuclear magnetic imaging of an osmotic water uptake and delivery process

Cited by 17 publications

References 19 publications

Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

NMR Imaging of the Diffusion of Water at 37 °C into Poly(2-hydroxyethyl methacrylate) Containing Aspirin or Vitamin B₁₂

Applications of NMR tomography to mass transfer studies

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Nuclear magnetic imaging of an osmotic water uptake and delivery process

Cited by 17 publications

References 19 publications

Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

Comparative study of the release kinetics of osmotically active solutes from hydrophobic elastomeric matrices combined with the characterization of the depleted matrices

NMR Imaging of the Diffusion of Water at 37 °C into Poly(2-hydroxyethyl methacrylate) Containing Aspirin or Vitamin B12

Applications of NMR tomography to mass transfer studies

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Product

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NMR Imaging of the Diffusion of Water at 37 °C into Poly(2-hydroxyethyl methacrylate) Containing Aspirin or Vitamin B₁₂