• Journal of Powder Materials
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• v.15 no.2
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• pp.114-118
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• 2008

Functional nanomaterial is expected to have improved capacities on various fields. Especially, metal nanoparticles dispersed in polymer matrix and metal nanofiber, one of the functional nanomaterials, are able to achieve improvement of property in the electric and other related fields. In this study, the fabrication of metal (Ag) nanoparticle dispersed nanofibers were attempted. The Ag nanoparticle dispersed polymer nanofiber and Ag nanofiber were fabricated by electrospinning method using electric force. First, PVP/$AgNO_3$ nanofibers were synthesized by electrospinning in $18{\sim}22kV$ voltage with the starting materials (Ag-nitrate) added polymer (PVP; poly (vinylpyrrolidone)). Then Ag nanoparticle dispersed polymer nanofibers were fabricated to reduce hydrogen reduction at $150^{\circ}C$ for 3hr. And Ag nanofibers were synthesized by the decomposited of PVP at $300{\sim}500^{\circ}C$ for 3hr. The nanofibers were analyzed by XRD, TGA, FE-SEM and TEM. The experimental results showed that the Ag nanofibers could be applied in many fields as an advanced material.

• 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.

• Analytical Science and Technology
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• v.20 no.5
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• pp.413-418
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• 2007

Poly(vinylpyrrolidone) stabilized cadmium sulfide (CdS) nanoparticles were loaded onto the surface of silica ($SiO_2$) nanoparticles by using ${\gamma}$-irradiation. TEM micrograph reveals the presence of ~20nm sized CdS nanoparticles on the surface of $SiO_2$ nanoparticles. XRD patterns confirm the crystalline. PL spectra of the simple PVP-stabilized CdS nanoparticle and $SiO_2$@CdS composite confirm the differences in the emission characteristics between them. Two prominent emission peaks were noted around 550 nm and 600 nm for PVP-stabilized CdS nanoparticles). The emission peaks noted for the PVP-stabilized CdS nanoparticles were found to be blue shifted for $SiO_2$@CdS composites. Besides, an additional emission peak around 450 nm was noticed for the $SiO_2$@CdS composite. The presence of CdS nanoparticles influence the emission characteristics and induce quantum confinement effect.

• Polymer(Korea)
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• v.27 no.3
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• pp.217-225
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• 2003

We fabricated the 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine)-loaded PLGA wafers containing poly(N-vinylpyrrolidone) (PVP) or tedium chloride (NaCl) in order to control the release profile of drug in special shape (3 in diameter, 1 mm in thickness) by direct compression method. In vitro release profiles of BCNU could be controlled by additives contained in the wafers. Initial release amount, release rate and duration of BCNU could be controlled with presence of PVP or NaCl. In vitro antitumor activity accessed using 9L gliosarcoma cell line has been evaluated by assaying the viability of cells treated with BCNU released from the wafers containing additives resulting in continuous growth inhibition of 9L gliosarcoma tumor cells. Specially, the continuous growth inhibition of BCNU-loaded PLGA wafers containing additives was more effective than that of non-additive BCNU-loaded PLGA wafers. The cytotoxic effect of the drug from the wafers containing NaCl as compared to wafers containing PVP was more enhanced.

• Resources Recycling
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• v.19 no.5
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• pp.58-67
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• 2010

Platy silver powders with varied size and thickness were prepared by polyol process with $PdCl_2$ in ethylene glycol and characterized its properties and investigated the effects of reaction time, $NH_4OH$, PVP(poly-vinylpyrrolidone) and $PdCl_2$. The characteristics of the products were verified by scanning electron microscopy(SEM), high resolution transmitted electron microscopy(HR-TEM), X-ray diffraction(XRD) and particle size analyzer(PSA) and image analyzer. Platy silver powder was prepared about $5.5\;{\mu}m$ of size and $0.2\;{\mu}m$ at 120minute. It was found that the size of powders increased by the increasing of $NH_4OH$ and $PdCl_2$ concentrations, and the thickness of powders was decreased by increasing of PVP concentration.

• Polymer(Korea)
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• v.26 no.5
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• pp.691-700
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• 2002

Interstitial therapy using biodegradable polymeric device loaded with anticancer agent can deliver the drug to the tumor site at high concentration, resulting in an increase of therapeutic efficacy. 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) is most commonly used as chemotherapeutic agent for brain tumors. The design of implantable device is regarded as an important factor lot the efficient delivery of antitumor agent to targeting site. In order to control the release profile of drug, the release pattern of BCNU with the changes of various dimension and additives was investigated. The PLGA wafers containing 3.85, 10, 20 and 30% of BCNU were prepared in various shape (diameter of 3, 5 and 10 mm, thickness of 0.5, 1 and 2 mm) by direct compression method. In vitro drug release profile of BCNU-loaded PLGA wafers could be controlled by changing the dimension of wafers such as initial drug content, weight, diameter, thickness, volume and surface area of wafers, as well as PLGA molecular weight and additives. Drug release from BCNU-loaded PLGA wafers was facilitated with an increase of BCNU-loading amount or presence of poly(N-vinylpyrrolidone)(PVP) or sodium chloride (NaCl). The effects of various geometric factors and additives on the BCNU release pattern were confirmed by the investigation of mass loss and morphology of BCNU-loaded PLGA wafers.