• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.15-22
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• 2007

An oil-in-water solvent evaporation method was used to prepare the cyclosporin A (CyA)-loaded nanoparticles varying in poly (D,L-lactide-co-glycolide) (PLGA) polymer (RG 502H, RG 503H) and the amount of additive ethyl myristate (EM) or chitosan (CS). The particles were characterized for drug loading and entrapment efficiency by HPLC, surface morphology by scanning electron microscopy, particle size by dynamic light scattering and surface charge by Zetapotential. The results showed drug loadings ranging from 10.9% to 15.8% with high encapsulation efficiency (82.0-97.8%). SEM and DLS studies showed discrete and spherical particles with smooth surfaces and mean size ranging 257.6-721.7 nm. The additive EM or CS did not change the mean sizes of the nanoparticles, whereas by the coating effect of CS, the Zetapotential values of the CS-added nanoparticles were moved to the more positive direction as the amount of CS was increased. From the pharmacokinetic analysis, the nanoparticles formulations showed the higher bioavailability and MRT than $Neoral^{\circledR}$ While little adding effect of EM or CS was detected in pharmacokinetic profile when RG 503H was used as polymer carrier, more noticeable different pharmacokinetic behaviors could be observed in case of RC 502H. EM incorporation was found to elevate the $K_{el}$, whereas CS coating resulted in the decrease of F and $K_{el}$, which seems to be due to the function of CS as a barrier and a mucoadhesive coating.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.4
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• pp.323-332
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• 2008

Aim of the study: Scaffolds are crucial to tissue engineering/regeneration. Biodegradable polymer/ceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. In this study, poly(L-lactide)/hydroxyapatite(PLLA/HA) composite scaffolds were fabricated for in vivo bone tissue engineering. Material & methods: In this study, PLLA/HA composite microspheres were prepared by double emulsion-solvent evaporation method, and were evaluated in vivo bone tissue engineering. Bone marrow mesenchymal stem cell from rat iliac crest was differentiated to osteoblast by adding osteogenic medium, and was mixed with PLLA/HA composite scaffold in fibrin gel and was injected immediately into rat cranial bone critical size defect(CSD:8mm in diameter). At 1. 2, 4, 8 weeks after implantation, histological analysis by H-E staining, histomorphometric analysis and radiolographic analysis were done. Results: BMP-2 loaded PLLA/HA composite scaffolds in fibrin gel delivered with osteoblasts differentiated from bone marrow mesenchymal stem cells showed rapid and much more bone regeneration in rat cranial bone defects than control group. Conclusion: This results suggest the feasibility and usefulness of this type of scaffold in bone tissue engineering.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.11-19
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• 1992

$SrTiO_3$powders were synthesized from the chloride and the nitrate aqueous solution by spray pyrolysis method using ultrasonic vibrator. The concentration of mother solution was prepared 0.05M and O.lM. The carrier gas flow rate was 0.5cm/sec and 1.5cm/sec, respectively. The formation processing was investigated in the 0.05M and 0.05cm/sec. The $SrTiO_3$powders could not be synthesized from chloride aqueous solution. The prepared powders from nitrate aqueous solution was SrTi03 with cubic structure and nearly sphere particle for all samples. Mean particle size was increased from $0.49{\mu}m$ to $0.67{\mu}m$ by changing the carrier gas flow rate from O.5cm/sec to 1.5cm/sec. Also, mean particle size increased from $0.49{\mu}m$to $0.55{\mu}m$by changing the concentration of mother solution from O.05M to O.1M. Atomizing droplet size was $14.3{\mu}m$. The shape of particles was very porous by evaporation of solvent at the initial step. But through the each step upwards, shape of particles was formed themselves into a nearly roundish.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.46-49
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• 2005

Curdlan, a natural $\beta-1,3-glucan,$ has been studied as drug carrier due to its unique properties including its thermal gelling characters. In this study, curdlan was chemically acetylated for pH-sensitive drug delivery. Curdlan acetate microspheres(CAMs) were prepared by the solvent evaporation method. The size of the CAMs was below $200{\mu}m.$ The drug loading efficiency of microspheres was approximately $58.44\%$. In the swelling test, the CAMs showed pH-sensitive behavior. The swelling capacity of microspheres at pH 7.4 was much greater than at pH 1.4. Also, release rate of indomethacin(IND) at pH 7.4 from the CAMs was faster than that at pH 1.4. Therefore the CAMs have potential for the controlled release of IND over an extended period of time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.169-170
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• 2006

In this study, ultra thin films of ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer were fabricated on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE=70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000~5000rpm for 30 seconds. After annealing in a vacuum ambient at $200^{\circ}C$ for 60 min, upper gold electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on $n^+$-Si(100) wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the dielectric films have ferroelectric properties. The typical measured remnant polarization (2Pr) and coercive filed (EC) values measured using a computer controlled a RT-66A standardized ferroelectric test system (Radiant Technologies) were about $0.54\;C/cm^2$ and 172 kV/cm, respectively, in an applied electric field of ${\pm}0.75\;MV/cm$.

• Membrane Journal
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• v.13 no.3
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• pp.200-209
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• 2003

Polymer-metal complexed membranes were prepared by solvent evaporation method using ethylcellulose, platinum(II)acetylacetonate, and rhodium(III)acetylacetonate. The various composition of metal salt(0.3-4.0 wt%) were employed to obtain the optimum performance of final membrane. EC-metal complexed membranes were characterized by FTIR and scanning electron microscopy(SEM) to observe the morphology and the performance of oxygen, nitrogen, carbon dioxide, and methane gases was tested. It was shown that the metal salts enhanced the permeability of all gases without decrease of selectivity. However, it was found that Pt had more effects on the permeability of oxygen and nitrogen gases while Rh had more effects on the permeability of carbon dioxide and methane gases. EC-Pt complexed membrane(Pt 1.0 wt%) even showed the enhanced selectivity of oxygen/nitrogen(37%) due to the affinity characteristic of Pt to oxygen.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.440-447
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• 2000

Microspheres of felodipine, which is one of the calcium channel blocker using a mixture of Eudragi $t^{R}$ RL, L, E, and cellulose on the base of Eudragi $t^{R}$ RS were investigated. Cremopho $r^{R}$ was added to each preparation of polymers in order to increase the release of felodipine from microspheres. Felodipine-loaded microspheres were prepared by a solvent evaporation method, which is based on dispersion of methylene chloride containing felodipine and polymers in 0.5 w/v % polyvinyl alcohol solution. The average diameter based on the size distribution of the felodipine-loaded microspheres was observed to be ca. 40-55 ${\mu}{\textrm}{m}$. A good and smooth surface were showed in all types of the microspheres. The amount of felodipine loaded was over 90 w/w % in all types of microspheres. The dissolution profiles of felodipine from microspheres were similar with each type of polymer, and about a 60 w/w % of the total amount of felodipine loaded to microsphere was released within 7 hours. Dissolution rate of felodipine from the microsphere was increased by addition of Cremophor. After oral administration of the felodipine-loaded microspheres in PVA solution and felodipine alone in PEG solution to rats, respectively, the pharmacokinetic study revealed that the Tmax values of the microspheres were observed in the range of 0.67~l.0 hr while that of the felodipine solution was obtained 0.33 hr. In addition, the AUC of the microspheres at 0 to 7 hr was remarkably increased in comparison to that of felodipine solution. These results revealed that the microspheres based on Eudragit RS could be a good candidate for the controlled release drug delivery system for felodipine.e.e.e.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.7-14
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• 2019

The microencapsulation of nifedipine (NF) with 4 wt% of poly(${\varepsilon}-caprolactone$) (PCL)/polyvinylpyrollidone (PVP) or PCL/polyethylene glycol (PEG) was carried out by solvent evaporation method in oil in water emulsion system to investigate the effect of PVP and PEG addition on drug release behavior of the microcapsules. The PVA (emulsifier) concentration of 1.0 wt% was chosen for the formation of PCL capsule having an average size of $154{\pm}25{\mu}m$ due to nearly spherical shape with a narrow size distribution. As PCL/PVP and PCL/PEG ratios were raised from 10/0 to 6/4, the capsule size increased gradually from $154{\pm}25{\mu}m$ to $236{\pm}32{\mu}m$ and $248{\pm}56{\mu}m$, respectively. The drug release rate of PCL/PVP and PCL/PEG capsules increased dramatically from 0 to 4 h at the beginning and then reached the plateau region from 20 h. As the concentration of PVP or PEG increased, the amount of drug release increased, suggesting that the larger capsule size was attributed to the higher drug content. However, the drug release behavior remained almost constant. The PCL capsules exhibited no evidence of causing cell lysis or toxicity regardless of NF loading, implying that the microcapsules are clinically suitable for use as drug delivery systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.10-15
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• 2020

Ultraviolet rays, which have wavelengths smaller than 400 nm, are very harmful to the eyes. Recently, high-energy visible light was also revealed to be harmful to retinal cells. Therefore, polymer eyeglass lenses that can block UV and high-energy visible light are needed for eye health. In this study, high-refractive-index polymer eyeglass lens, n=1.67, were manufactured using the injection-mold method with the m-xylene diisocyanate monomer, 2,3-bis((2-mercaptoethyl)thio)-1-propanethiol monomer, benzotriazole UV absorber, release of alkyl phosphoric ester, dye mixture of CI solvent violet 13, and catalyst of dibutyltin dichloride mixture. A multi-layer anti-reflection coating was applied to manufactured polymer eyeglass lenses for both sides using an E-beam evaporation system. The optical properties of the manufactured lenses with the UV and high-energy visible light-blocking function were analyzed by UV-visible spectrophotometry. As a result, the polymer eyeglass lens with a UV absorber of 0.5 wt. % blocked 99% of UV and high-energy visible light shorter than 411 nm. The average transmittance of the polymer eyeglass lens with a UV absorber of 0.5wt.% was 97.9% in the range of 460 ~ 660 nm for photopic eye sensitivity higher than 10%. Therefore, clear image acquisition in photopic vision is possible.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.464-473
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• 2018

The objective of the current study was to evaluate the effects of roasting methods on volatile flavor compounds of boricha using solvent-assisted flavor evaporation-gas chromatography (GC)-mass spectrometry and GC-olfactometry. The barley roasting methods tested were air roasting (AR), drum roasting (DR), and air/drum roasting (ADR). Twenty, twenty-one, and eighteen aroma-active compounds were detected in the products of AR, DR, and ADR, respectively. Guaiacol (smoky), 2-acetylpyrazine (almond-like), and furfuryl alcohol (burnt sugar-like) were detected as high intensity aroma-active compounds. Intensities of most aroma-active compounds produced by the DR method were higher. On the other hand, aroma intensities of phenols produced by the AR method, such as guaiacol and 2-methoxy-4-vinylphenol (curry-like), tended to be stronger. Aroma characteristics of phenols are not considered to be desirable for boricha. Although roasting time for DR was longer than that for AR, DR may be an effective barley roasting method for enhancing desirable aroma characteristics of boricha.