• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.65.1-65.1
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• 2007

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.169-174
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• 1988

The release of heparin from monolithic devices composed of different ratios of polyethylene oxide-polypropylene oxide (PEO-PPO) and hydrophobic polyurethane was investigated. The release rate of heparin could be controlled by varying the PEO-PPO content. The heparin release rate from the devices increased as the content of PEO-PPO in the devices increased. The release mechanism may be associated with creation of micro-channels and pores through the devices following the change in the physical structure of the polymer network. Hydrophobic polyurethane containing PEO-PPO can provide an antithrombogenic material for prolonged release of heparin from a heparin blended system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.423-428
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• 1999

Potato starches were hydroxypropylated with 2.5, 5.0, 7.5, and 10.0% propylene oxide(PO) to improve mechanical properties of starch polyethylene film. Starch polyethylene cast films were prepared that contained 5% or 10% of the hydroxypropylated potato starch. Mechanical properties of these films were measured and compared to those of the films containing native potato starch. DS(degree of substitution) increased proportionally as propylene oxide concentration increased. Relative crystallinity in X ray diffraction patterns was decreased and starch granule observed by scanning electron micro scopy was destroyed by severe hydroxypropylation. In color properties of films, b value was not significantly different in the films but 5% starch polyethylene films with 2.5 PO starch showed the lowest L and a value. Tensile strength and strain energy of the films except the film containing 10.0 PO starch were higher than those of the containing native starch.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3834-3837
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• 2010

• Journal of Pharmaceutical Investigation
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• v.29 no.1
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• pp.7-12
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• 1999

The captopril matrix tablets composed of polyethylene oxide(PEO) was prepared and administered to beagle dogs. Captopril matrix tablets were prepared using direct compressed method and wet granulation compressed method with various ratios of drug to PEO. The diffusion rate of captopril matrix tablets followed on the Higuchi's diffusion model. With increasing hardness of captopril matrix tablets, release rate was decreased. Each formulation was evaluated by the area under the curve (AUC) and time course of plasma captopril concentration after oral administration to beagle dogs. The $AUC_{0-12}$ were $9.126\;{\mu}g\;h/ml$ and $6.417\;{\mu}g\;h/ml$ for the matrix tablets and conventional tablets, respectively. Therefore, the bioavailability of captopril matrix tablets was greater than that of commercial product. It is suggested that captopril matrix tablets using PEO is a useful sustained release formulation.

• Archives of Pharmacal Research
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• v.12 no.3
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• pp.191-195
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• 1989

The release of progesterone from monolithic devices composed of different ratios of polyethylene oxide (PEO; mw 20, 000) and hydrophobic polydimethylsiloxane was investigated. Water soluble PEO soaked into the polymer provided controlled release of progesterone. The release rate of progesterone could be controlled by varying the contents of PEO and progesterone in soaking solution. The progesterone release rate from silicone devices increased as the content of PEO in devices increased, while it decreased as the content of PEO in soaking solution increased. The release rate may be made by simple alterations of geometry of devices controlled swelling and the change in the physical structure of polymer network. Hydrophobic polydimethylsiloxane containing PEO and progesterone can provide a contraceptive material for prolonged release of progesterone.

• Macromolecular Research
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• v.11 no.6
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• pp.444-450
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• 2003

Hydrophobically End-capped polyethylene oxide Urethane Resin(HEUR)-associating polymers, HEUR 35(8), HEUR 35(12), and HEUR 35(18), comprise a polyethylene oxide (PEO) having a molecular weight of 35,000 that is end capped with two C$\_$8/H$\_$17/, C$\_$12/H$\_$25/, and C$\_$18/H$\_$37/ alkyl chains, respectively. These associating polymers were synthesized by condensation reactions with polyethylene oxides and alkyl isocyanates. The self-diffusion coefficients of HEUR-associating polymers were measured in aqueous solution by pulsed-gradient spin-echo (PGSE) nuclear magnetic resonance (NMR) spectroscopy. All polymers underwent a decrease in their mean diffusion coefficients as the concentration was increased. However, the dispersion of the diffusion coefficients, ${\beta}$, about the mean fluctuated with changes in concentration. The large dispersion at low concentrations of HEUR 35(8) and HEUR 35(12) is related to the interaction between hydrophobic end groups, and the large dispersion at high concentrations of HEUR 35(18) is correlated with transient network formation. These results are valuable for predicting the associating mechanism of the large aggregates before and after their critical micelle concentration.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.245-248
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• 1992

Polyethylene oxide (PEO) surfaces are recognized as having an effective steric stabilization character. A theoretical scaling analysis involves the osmotic and elastic coefficients of the polymer as a function of molecular weight, in a good solvent. The calculated results show that PEO in water may exhibit the greatest flexibility among water soluble polymers, probably due to its lowest elastic contribution.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.149-153
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• 1991

Polyethylene oxide (PEO)-polymethacrylic acid (PMAA) interpenetrating polymer networks (IPN) were synthesized via radical polymerization of PMAA and simultaneous crosslinking of PEO using triisocyanate. The equilibrium swelling of PEO-PMAA IPN was determined at different pHs. The swelling of PEO-PMAA IPN, ranged from 20% to 90%, was more sensitive than that of homo polymer PMAA gel This is probably due to protonation and deprotonation of the PMAA network and interpolymer complex formation between PEO and PMAA. Several model drugs were loaded into the IPN matrices and the release mechanisms were investigated. The release of nonionizable drugs such as ftorafur and prednisolone was controlled by swelling of the matrices. However, he release of propranolol, positively charged drug, was more affected by the ionic interaction between the drug and PMAA newtork, and the interpolymer complexation.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.527-531
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• 2009

Periodic mesoporous organosilicas (PMO) were synthesized using bis(triethoxy silyl) benzene as the precursor and dodecyl trimethyl ammonium bromide (DTMA) as the templating agent. From these results of XRD, TEM, and NMR, the pore structure of the material was confirmed to have a well-organized hexagonal structure. Poly(ethylene oxide) (PEO) was penetrated into PMO. From the DSC and XRD experiments, the polymer melting transition of crystalline polyethylene oxide (PEO) decreased then finally disappeared. These results prove that the polymer chains penetrate into the PMO channels, and penetrated polymer chains are constrained inside channels of PMO.