• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.173-179
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• 2002

Solid dispersions of ipriflavone with PVP were prepared by a spray-drying method in order to improve the bioavailability. They were measured with scanning electron microscopy, differential scanning calorimetry, x-ray powder diffraction, and Fourier transform infrared spectroscopy to evaluate the physicochemical interaction between ipriflavone and PVP and study the correlation between these physicochemical characteristics and bioavailability. Ipriflavone exhibited crystallinity, whereas PVP was almost amorphous. The area of the endotherm $({\Delta}H)$ of freezer milled ipriflavone, freezer milled ipriflavone physically mixed with freezer milled PVP, and physically mixed ipriflavone with PVP was almost the same, whereas ${\Delta}H$ of the solid dispersed ipriflavone with PVP was much smaller than that of the other preparation types. Also, the crystallinity and the crystal size of ipriflavone in the solid dispersed ipriflavone with PVP were much smaller than those of the other preparation types. From the in vivo test, the AUC of the solid dispersed ipriflavone with PVP was approximately 10 times higher than that of the physically mixed ipriflavone with PVP. The solid dispersion using the spray-drying method with a water-soluble polymer, PVP, may be effective for the improvement of the bioavailability.

• Macromolecular Research
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• v.15 no.4
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• pp.330-336
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• 2007

Luminescent CdSe/ZnS QDs, with emission in the red region of the spectrum, were synthesized and encapsulated in poly(ethylene glycol)-poly(D,L-lactide) diblock copolymer micelles, to prepare water-soluble, bio-compatible QD micelles. PEG-PLA diblock copolymers were synthesized by ring opening polymerization of D,L-lactide, in the presence of methoxy PEG as a macro initiator. QDs were encapsulated with PEG-PLA polymers using a solid dispersion method in chloroform. The resultant polymer micelles, with encapsulated QDs, were characterized using various analytical techniques, such as UV- Vis measurement, light scattering, fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic forced microscopy (AFM). The polymer micelles, with encapsulated QDs, were spherical and showed diameters in the range of 20-150 nm. The encapsulated QDs were highly luminescent, and have high potential for applications in biomedical imaging and detection.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.35-41
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• 2014

Poly(g-glutamic acid) (g-PGA) is a very promising biodegradable polymer that is produced by microorganism of Bacillus subtilis. Because g-PGA is water-soluble, anionic, biodegradable, and even edible, its potential applications have been studied from an industrial standpoint. In this study, we fabricated porous g-PGA foams by means of a freeze-solvent extraction method for tissue-engineering applications. Porous g-PGA foams were chemically cross-linked using a hexamethylene diisocyanate solution. An aqueous basic solution was used to neutralize g-PGA foam for cell culturing. During an in vitro cell culture study, it was observed that primary rabbit ear chondrocytes were well at tached and spread over the surface oft hree-dimensional cross-linkedg-PGA foam. From these results, it is concluded that cross-linkedg-PGA foam is aprom is in gmaterial for tissue-engineering applications, especially those pertaining to the regeneration of human cartilage.

• Macromolecular Research
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• v.12 no.2
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• pp.246-250
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• 2004

We have classified a number of aqueous ternary systems containing two different polymers into three types by focusing on the deviation of the Huggins constant k'from the additivity line. Systems of type I have negative deviations of k'; the repulsive interaction between the two different polymers dominates. In systems of type II, k' almost follows the additivity relation; the repulsive and attractive interactions between the two different polymers are balancing. Type III systems have positive deviations of k'; the attractive interactions are relatively dominant. This classification of systems is supported by the fact that the positive and negative deviations of k' from the additivity line also correspond to the sign of interaction parameter between polymer 2 and 3, Δb$\_$23/. Furthermore, we have verified the relatively high compatibility between dextran and poly(vinyl alcohol) by determining the binodal concentration of a liquid-liquid phase separation for a water/dextran/poly(vinyl alcohol) system, which is classified as type III. Thus, we found that the compositional dependence of k' closely relates to the compatibility of binary polymer mixtures in aqueous ternary systems.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.229-235
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• 2007

Multi-layered granules were prepared by a fluidized-bed coater and uniformed granules were obtained with a size range between $950{\sim}1000{\mu}m$ in diameter. The granule system was composed of three layers, i.e. seed layer with sugar sphere bead and a water-swellable polymer, middle layer with a drug, solubilizer and polymer, and the top layer of porous membrane with a polymeric binder. The aim of this work is to find out the dependence of a drug dissolution rate on the amount of a water-soluble binder and a solubilizer in the granule system. The results showed that the higher amount of hydrophilic binder in the porous membrane, gave the bigger pore size and porosity and made faster dissolution rate and also the higher amount of solubilizer in drug layer enhanced the dissolution rate of drug.

• Journal of Conservation Science
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• v.25 no.2
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• pp.171-178
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• 2009

When we considered the superior ability of the semi-water soluble urethane 1st transcription and final epoxy products, the stability for moving historic sites depend on physical properties and the peel off state of separation media. In this paper, we synthesised three type of water-borne epoxy solution without using a surfactant, and investigated the peel off state, physical properties, and the state between urethane surface and epoxy surface after exfoliation. The life time of water-borne separation media is over the 60 days. When it is used the 30% solution of water-borne separation media, it made good separation of urethane pre-products surface and epoxy final product surface and no color change. The separation tension pressure is about 15~50 kg/$cm^2$ and there is no surface whitewash phenomenon. We suggest that this water-borne epoxy will be best material as separation media of low viscosity type.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.135-140
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• 1998

Drag reduction produced by dilute solution of water soluble ionic polymer-surfactant complex under turbulent flow in a rotating disk apparatus(RDA) was investigated in this study. Three different molecular weights of polyacrylic acid(PAA) were adopted as drag reducing additives, and distilled water was used as a solvent. Experiments were undertaken to observe the dependence of drag reduction on various factors such as polymer molecular weight, molecular expansions and flexibility, rotating speed of the disk and polymer concentration. Specific considerations were put on conformational difference between surfactant and polymer, and effect of pH on ionic polymer possessing various molecular conformation through pH. The complex of ionic polymer and surfactant(Sodium Dodecyl Sulfate) behaves like a large polyelectrolyte. Surfactant changes the polymer conformation and then increases the dimension of the polymer. The radius of gyration, hydrodynamic volume and relative viscosity of the polymer-surfactant system are observed to be greater than those of polymer itself. Such surfactant-polymer complex has enhanced drag reduction properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.524-528
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• 2002

Green layer, Enteromorpha prolifera, is regarded as one of important materials for food processing in Korea. The acidic water-soluble polysaccharide (CPC-PS) isolated from the alga with hot water and cetylpyridium chloride was mainly constituted of rhamnose, xylose, uronic acid and sulfate. To determine the glycosyl-linkages and positions of sulfate by methylation, the CPC-PS was reduced and/or sulfates. A marked increase of glucose content in the reduced polysaccharide indicated that glucuronic acid was a major sugar in the polymer and sulfation was deduced to occur on O-3 of rhamnose and O-2 of xylose. According to the methylation analysis of the native, reduced, desulfated and reduced-desulfated polymers, CPC-PS mainly composed of 1,4- and 1,2,3-linked rhamnose 3-sulfate, 1,4-linked xylose 2-sulfate, 1,4-linked xylose and 1,4-linked glucuronic acid. Minor 1,4-linked rhamnose and 1,4,6-linked galactose residues were also detected.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.866-874
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• 2005

The objective of this study was to elucidate the feasibility to improve the solubility and bioavailability of poorly water-soluble itraconazole via solid dispersions by using supercritical fluid (SCF). Solid dispersions of itraconazole with hydrophilic polymer, HPMC 2910, were prepared by the aerosol solvent extraction system (ASES) under different process conditions of temperature/pressure. The particle size of solid dispersions ranged from 100 to 500 nm. The equilibrium solubility increased with decrease (15 to 10 MPa) in pressure and increase (40 to $60^{\circ}C$) in temperature. The solid dispersions prepared at $60^{\circ}C$/15 MPa showed a slight increase in equilibrium solubility (approximately 27-fold increase) when compared to pure itraconazole, while those prepared at $60^{\circ}C$/10MPa showed approximately 610-fold increase and no endothermic peaks corresponding to pure itraconazole were observed, indicating that itraconazole might be molecularly dispersed in HPMC 2910 in the amorphous form. The amorphous state of itraconazole was confirmed by DSC/XRD data. The pharmacokinetic parameters of the ASES-processed solid dispersions, such as $T_{max},\;C_{max},\;and\;AUC_{0-24h}$ were almost similar to $Sporanox_{\circledR}$ capsule which shows high bioavailability. Hence, it was concluded that the ASES process could be a promising technique to reduce particle size and/or prepare amorphous solid dispersion of drugs in order to improve the solubility and bioavailability of poorly water-soluble drugs.

• Journal of Pharmaceutical Investigation
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• v.38 no.2
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• pp.119-126
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• 2008

Solid dispersions of poorly water-soluble drug, sibutramine, were prepared with hydrophilic polymer, poly-N-vinylpyrrolidone (PVP), hydroxypropylmethylcellulose (HPMC) and organic acid, citric acid, to improve the solubility of drug. Physicochemical variation and shape of microsphere were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and Fourier-transform infrared spectroscopy (FT-IR). Microspheres containing additives showed more spherical shape than non additive microspheres. In vitro release behavior of microspheres presented at simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8). The solid dispersion form transformed the drug into an amorphous state and dramatically improved its dissolution rate. These data suggest that the solid dispersion technique is an effective approach for developing the appetite depressant drug products and various pharmaceutical excipients are able to control the release behaviors.