The Role of Polymer Permeability in the Control of Drug Release

Richards, John H.

doi:10.1007/978-94-009-4858-7_6

Cited by 17 publications

(12 citation statements)

References 119 publications

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“…During the early phase of phenanthrene partitioning from several solids, the increase in concentration in the aqueous phase was observed to be linear with the square root of time. Similar results have been observed during the partitioning of organic solutes from polymers [25,26] and waxes [27] to aqueous solution. Therefore, to estimate the maximum rates of partitioning from the solids, a linear regression analysis was conducted of the points that constituted the initial linear phase of partitioning when the concentration of phenanthrene in solution was plotted as a function of the square root of time.…”

Section: Methodssupporting

confidence: 84%

Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

Hatzinger

Alexander

1997

Enviro Toxic and Chemistry

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A study was conducted using model solids to determine whether the time‐dependent decline in availability for biodegradation of organic pollutants in soil might result from the entrapment of these compounds in porous or nonporous solids. A strain of Pseudomonas mineralized phenanthrene in solid alkanes containing 18 to 32 carbons, three waxes, and low‐molecular‐weight polycaprolactone, polyethylene, and polypropylene. The rates were appreciably slower than when the substrate was not initially present within these nonporous solids. From 1.4 to 63.4% of the polycyclic aromatic hydrocarbon added to the solids was mineralized in 90 d. The rates and extents of partitioning of phenanthrene varied markedly among the solids. The rates of partitioning and biodegradation of phenanthrene initially present in the alkanes were positively correlated. The bacterium rapidly and extensively mineralized phenanthrene provided in calcium alginate beads containing varying amounts of soluble soil organic matter. The rates and extents of phenanthrene mineralization declined as the percentage of the substrate in the nanopores within silica particles increased, but the reductions in rate, extent, or both were less pronounced than with nonporous solids. The rate of 4‐nitrophenol biodegradation also declined with increasing percentages of the compound in these nanopores. The data are consistent with hypotheses that the sequestration and consequent decrease in bioavailability of organic compounds that persist in soil result from their partitioning into organic matter or their presence within nanopores in soil.

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Section: Methodssupporting

confidence: 84%

Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

Hatzinger

Alexander

1997

Enviro Toxic and Chemistry

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“…When considering a microcapsule shell, acting as a barrier for diffusion outside the microcapsule, permeation is dependent upon the active partition into the shell and its diffusion through it. 20,21 It is also a function of the chemical potential imbalance in the system as a result of concentration differences of the active between the core and the continuous phase, the total exposed surface area and thickness of the shell (more details about relating the properties of the microcapsule shells to the release characteristics can be found elsewhere [22][23][24] ). The latter two parameters can be manipulated easily for a set microcapsule system and provide some degree of permeation control.…”

Section: Introduction: Microencapsulation Of Functional Materials Andmentioning

confidence: 99%

Encapsulation of Emulsion Droplets with Metal Shells for Subsequent Remote, Triggered Release

Stark

Hitchcock

Fiaz

et al. 2019

ACS Appl. Mater. Interfaces

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“…2) is due to the lag effect, which represents the time it takes for the membrane to get saturated and to reach steady state (zero-order) diffusion. 18,19 The initial nonlinearity of diffusion in a membrane may also exhibit a burst effect, i.e., when diffusion is initially fast and then it slows down as it approaches the steady state.…”

Section: Diffusion Studiesmentioning

confidence: 99%

“…The last two columns in Table II indicate the diffu-sion coefficients (diffusivities) of glucose and insulin determined from the time to reach steady state and using the equation 18,19 :…”

Section: Diffusion Studiesmentioning

confidence: 99%

Amphiphilic networks. X. Diffusion of glucose and insulin (and nondiffusion of albumin) through amphiphilic membranes

Shamlou

Kennedy

Levy

1997

J. Biomed. Mater. Res.

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Select semipermeable amphiphilic membranes have been prepared and their diffusional characteristics for glucose, insulin, and albumin investigated. The membranes were prepared by cast copolymerization of a hydrophilic monomer (i.e., N,N-dimethyl acrylamide, or N,N-dimethylaminoethyl methacrylate) with the hydrophobic crosslinker methacrylate-ditelechelic polyisobutylene. The products have sufficient mechanical properties for the fabrication of swollen membranes, sheets, tubes, etc. Membranes have been identified which allowed the rapid simultaneous countercurrent diffusion of glucose (Mn = 180 Da) and insulin (Mn = 5733 Da) but did not allow albumin (Mn approximately 60,000 Da) to pass. Evidently, the effective molecular weight cutoff point of these membranes is in the 6-60-KDa range.

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The Role of Polymer Permeability in the Control of Drug Release

Cited by 17 publications

References 119 publications

Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

Encapsulation of Emulsion Droplets with Metal Shells for Subsequent Remote, Triggered Release

Amphiphilic networks. X. Diffusion of glucose and insulin (and nondiffusion of albumin) through amphiphilic membranes

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