Heterogeneous interpenetrating polymer networks for drug delivery

Bae, You Han; Okano, Teruo; Ebert, Charles S.; Heiber, S. J.; Chandra, Dave, Sirish; Kim, Sung Wan

doi:10.1016/0168-3659(91)90042-c

Cited by 30 publications

(2 citation statements)

References 17 publications

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“…By knowing n mer (α) we can further approximate the polymer volume fraction, which allows us to identify physically meaningful values of α and K. Using the water profile (Fig. 3) we extract the excluded volume per monomer as V ex,mer = 0.167 nm 3 and assume the BIS' volume to scale with the number of heavy atoms (without hydrogens) compared to a PNIPAM monomer (11. vs. 8), yielding V ex,xlink = 0.230 nm 3 . The excluded volume in one unit cell is then v ex = 8V ex,xlink + n mer (α)V ex,mer and the 2.…”

Section: A Force Field Parametersmentioning

confidence: 99%

“…Responsive polymers have increasingly gained attention in many research fields due to their ability to reversibly adapt to external stimuli such as temperature, osmotic pressure, or pH. Various types and shapes at different length scales have been designed, providing various possibilities for applications, 1,2 such as solute uptake, transport 3 and release, 4,5 sensors, 6 intelligent coatings, switchable catalysis, 7,8 etc. To structurally stabilize and fine-tune properties and function, polymer architectures are often E-mail: joachim.dzubiella@physik.uni-freiburg.de equipped with chemical cross-linkers covalently interconnecting the chains, 9 which are then referred to as hydrogels.…”

Section: Introductionmentioning

confidence: 99%

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Cross-linker effect on solute adsorption in swollen thermoresponsive polymer networks

Milster

Chudoba

Kanduč

et al. 2019

Phys. Chem. Chem. Phys.

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The selective solute partitioning within a polymeric network is of key importance to applications in which controlled release or uptake of solutes in a responsive hydrogel is required. In this work we investigate the impact of cross-links on solute adsorption in a swollen polymer network by means of all-atom, explicit-water molecular dynamics simulations. We focus on a representative network subunit consisting of poly(N -isopropylacrylamide) (PNIPAM) and N ,N -methylenebisacrylamide (BIS/MBA) cross-linker types. Our studied system consists of one BIS-linker with four atactic PNIPAM chains attached in a tetrahedral geometry. The adsorption of several representative solutes of different polarity in the low concentration limit at the linker region is examined. We subdivide the solute adsorption regions and distinguish between contributions stemming from polymer chains and cross-link parts. In comparison to a single polymer chain, we observe that the adsorption of the solutes to the cross-link region can significantly differ, with details depending on the specific compounds' size and polarity. In particular, for solutes that have already a relatively large affinity to PNIPAM chains the dense cross-link region (where many-body attractions are at play) amplifies the local adsorption by an order of magnitude. We also find that the cross-link region can serve as a seed for the aggregation of mutually attractive solutes at higher solute concentrations. Utilizing the microscopic adsorption coefficients in a mean-field model of an idealized macroscopic polymer network, we extrapolate these results to the global solute partitioning in a swollen hydrogel and predict that these adsorption features may lead to non-monotonic partition ratios as a function of the cross-link density.

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Section: A Force Field Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cross-linker effect on solute adsorption in swollen thermoresponsive polymer networks

Milster

Chudoba

Kanduč

et al. 2019

Phys. Chem. Chem. Phys.

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Preparation, characterization and degradation characteristics of polyanhydrides containing poly(ethylene glycol)

Jiang

Zhu

1999

Polym. Int.

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Poly(ethylene glycol) (PEG) segments were introduced into a polyanhydride main chain by copolymerization of terminal‐carboxylated poly(ethylene glycol) with diacidic monomers (sebacic acid and trimellitylimidoglycine). IR and 1H NMR spectroscopy confirmed the copolymer structures. DSC analysis showed that these polyanhydrides have low Tg and low crystallinity. In vitro degradation tests indicated that introducing PEG segments accelerated the degradation rate of these polymers and the degradation duration could be manipulated from 3 days to 3 weeks. The pH of the environment caused by the polymer degradation was lower than 5.0; therefore, the polyanhydrides could be used as components of a newly designed pulsed‐release device for peptide and protein delivery. © 1999 Society of Chemical Industry

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Combined experimental and computer simulation study of the kinetics of solute release from a relaxing swellable polymer matrix. II. Release of an osmotically active solute

Papadokostaki

2004

J of Applied Polymer Sci

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ABSTRACT:The performance of a model monolithic controlled release device, consisting of a swellable polymeric matrix subject to structural relaxation (cellulose acetate), loaded with a simple osmotically active solute (NaCl) and activated by the ingress of solvent (water), was studied experimentally and by computer simulation. The former study involved detailed monitoring of the kinetics of both solute release and solvent absorption (followed in due course by desorption of osmotically imbibed excess solvent). The computer simulation study was based on extensive previous modeling work. Values of the relevant input model parameters were derived from independent experimental measurements of the sorption and diffusion properties of solvent (cf. Part I) and solute (reported in the present article). The resulting simulation was highly successful, considering that it proved possible to simulate closely and consistently the kinetics of both solute release (over practically the whole experimental range) and concurrent solvent absorption (including correct prediction of the magnitude of the osmotically induced excess swelling of the polymeric matrix). Simulation of the final desorption of osmotically imbibed water was facilitated by the realization that this process actually reflects the kinetics of a long-term deswelling relaxation of the polymer structure back to the state of normal hydration, the rate of which could be measured to a good approximation on the pure deswelling polymer. The results presented here are of obvious practical significance in relation to progress toward computer-assisted design of monolithic controlled release devices exhibiting relatively complex kinetic behavior. They should also prove useful by calling attention to an important caveat when desorption into water is used as a method for the straightforward determination of solute diffusivity in hydrated polymers, in cases of osmotically active solutes diffusing in nonhydrophilic polymers.

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Heterogeneous interpenetrating polymer networks for drug delivery

Cited by 30 publications

References 17 publications

Cross-linker effect on solute adsorption in swollen thermoresponsive polymer networks

Cross-linker effect on solute adsorption in swollen thermoresponsive polymer networks

Preparation, characterization and degradation characteristics of polyanhydrides containing poly(ethylene glycol)

Combined experimental and computer simulation study of the kinetics of solute release from a relaxing swellable polymer matrix. II. Release of an osmotically active solute

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