• Title/Summary/Keyword: cyclodextrins

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The Effect of Methylated Cyclodextrins on the Morphological Change of Poly(3-hydroxybutyrate) with and without the Formation of Inclusion Complex

  • Shin, Kyung-Moo;Dong, Tungalag;Inoue, Yoshio
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.351-351
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    • 2006
  • The possible interactions between cyclodextrins and biodegradable polyesters were investigated. The hydrophobicity of cyclodextrin could be varied with the methyl substitution of host CD, and the possibility of IC formation and the types of interaction between respective CDs and polyesters were subsequently changed. Further, the effect of cyclodextrins on the morphological change of biodegradable polymer was shown to depend on the degree of IC formation between cyclodextrin and biodegradable polymer as well as on the type of interaction between respective CDs and polyesters. That is, the enhancement and/or the restriction of the crystallization of P(3HB) were observed by the incorporation of various kind of cyclodextrins with different cavity size and hydrophobicity.

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Ionic Cluster Mimic Membranes Using Ionized Cyclodextrin

  • Won Jong-Ok;Yoo Ji-Young;Kang Moon-Sung;Kang Yong-Soo
    • Macromolecular Research
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    • v.14 no.4
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    • pp.449-455
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    • 2006
  • Ionic cluster mimic, polymer electrolyte membranes were prepared using polymer composites of crosslinked poly(vinyl alcohol) (PVA) with sulfated-${\beta}$-cyclodextrins (${\beta}-CDSO_3H$) or phosphated-${\beta}$-cyclodextrins (${\beta}-CDPO(OH)_2$). When Nafion, developed for a fuel cell using low temperature, polymer electrolyte membranes, is used in a direct methanol fuel cell, it has a methanol crossover problem. The ionic inverted micellar structure formed by micro-segregation in Nafion, known as ionic cluster, is distorted in methanol aqueous solution, resulting in the significant transport of methanol through the membrane. While the ionic structure formed by the ionic sites in either ${\beta}-CDSO_3H$ or ${\beta}-CDPO(OH)_2$ in this composite membrane is maintained in methanol solution, it is expected to reduce methanol transport. Proton conductivity was found to increase in PVA membranes upon addition of ionized cyclodextrins. Methanol permeability through the PVA composite membrane containing cyclodextrins was lower than that of Nafion. It is thus concluded that the structure and fixation of ionic clusters are significant barriers to methanol crossover in direct methanol fuel cells.

Bioavailability Studies on Suspension of Inclusion Complexes of Piroxicam with Cyclodextrins (Piroxicam-Cyclodextrin 포접화합물의 현탁제에 대한 생체내 이용율의 연구)

  • Park, Sun Hee;Lee, Chang Hoon;Choi, Young Wook;Park, Gee Bae;Kim, Johng Kap
    • Korean Journal of Clinical Pharmacy
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    • v.1 no.1
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    • pp.9-14
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    • 1991
  • Inclusion complexes of piroxicam with $\alpha,\;\beta\;and\;\gamma- cyclodextrins$ were prepared and suspended to enhance the bioavailability of piroxicam. A quantitative analysis was employed HPLC for the determination of piroxicam in the rabbit serum after a single oral dose in suspension of piroxicam and each of inclusion complexes of piroxicam with $\alpha,\;\beta\;and\;\gamma- cyclodextrins$, respectively. The bioavailability and serum level of piroxicam exhibited the highest in piroxicam clathrated $\beta-cyclodextrin$ than both piroxicam and the other complexes administered. and the total area under the curve of serum concentration versus time for their inclusion complexes were larger than that of piroxicam.

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Effect of Cyclodextrins on the Solubility and Stability of Aspalatone in Aqueous Solutions (수용액중 시클로덱스트린류가 아스팔라톤의 용해성과 안정성에 미치는 영향)

  • Gwak, Hye-Sun;Chun, In-Koo
    • Journal of Pharmaceutical Investigation
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    • v.30 no.4
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    • pp.267-271
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    • 2000
  • The effect of cyclodextrins on the solubility and stability of aspalatone (acetylsalicylic acid maltol ester, AM, CAS 147249-33-0), which has been recently found to have an antithrombotic effect, was investigated. The addition of ${\beta}-cyclodextrin\;({\beta}-CD),\;dimethyl-{\beta}-cyclodextrin\;(DMCD)\;or\;2-hydroxypropyl-{\beta}-cyclodextrin\;(HPCD)$ to the aqueous solution increased the solubility of AM concentration-dependently. From the phase solubility diagram, stability constants for $AM-{\beta}-CD$, -DMCD or -HPCD complexes were calculated to be 43.1, 78.3 and $53.0\;M^{-1}$. The addition of ${\beta}-CD$, DMCD or HPCD to AM solution retarded the degradation rate of AM in the acidic region. However, ${\beta}-CD$ and HPCD rather acted as an accelerator of degradation in the neutral and alkaline regions. DMCD had a stabilizing effect at all pHs studied.

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Inclusion Complexation of Clonixin with Cyclodextrins (클로닉신과 시클로덱스트린과의 포접복합체 형성)

  • Park, Sun-Joo;Kim, Kil-Soo
    • Journal of Pharmaceutical Investigation
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    • v.25 no.4
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    • pp.283-289
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    • 1995
  • The aim of this study is to increase the solubility and dissolution rate of clonixin by inclusion complex formation. Inclusion complexes of clonixin, a non-steroidal antiinflammatory drug, with ${\beta]-cyclodextrin$ were $2-hydrolrypropyl-{\beta]-cyclodextrin$ were prepared by freeze drying method. Inclusion complex formation of clonixin with cyclodextrins was determined by UV, IR and DSC. The apparent stability constants were calculated from the phase solubility diagrams. Dissolution rate and solubility of clonixin in water markedly increased by the complex formation.

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Conformational Analysis of Cyclodextrins and Their Methylated Analogs (시클로 덱스티린과 그 메틸유도체의 구조분석)

  • Hee-Sook Choi
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.324-328
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    • 1992
  • The $^1H$ NMR chemical shifts and coupling constants for ${\alpha}$-, permethyl-${\alpha}$-, ${\beta}$-and permethyl-${\beta}$-cyclodextrins in neutral aqueous media were assigned based on the 470MHz spectra. In order to obtain accurate chemical shifts and coupling constants the experimental spectra were analyzed with the Raccoon spin simulation program. The rotamer distribution around the$C_{5-}C_6$ bond of the cyclodextrins evaluated from the coupling constants of $J_{56a}$ and $J_{56b}$. In our calculation of the ${\alpha}$-, and ${\beta}$-cycliodextrin showed that gg conformers were most favorable form and tg conformers were least favorable form. It is very interesting to note the changes in $J_{56a}$, $J_{56b}$ coupling constants of permethylated ${\alpha}$- and ${\beta}$-cyclodextrins from unmodified one. The gg conformers were more increased than unmodified one and instead of tg conformers gt conformers were least favorable one upon methylation.

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Influence of Various Cyclodextrins on the Stability of Hydrocortisone 17-Butyrate in Aqueous Solution

  • Chun, In-Koo;Kim, Bo-Young
    • Archives of Pharmacal Research
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    • v.15 no.2
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    • pp.176-183
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    • 1992
  • The stabilizing effects of $\alpha$-$\beta$-$\gamma$- and dimethyl-$\beta$-cyclodextrins $(\alpha$-, $\beta$-, $\gamma$- and DM-$\beta-$-CyDs) on the degradation of hydrocortisone 17-butyrate (HC-17B) in aqueous solution was investigated. Hc-17B underwent a facile hydroxide ion-catalyzed rearrangement to the less active 21-butyrate ester by the apparent first-order kinetics, and maximum stability of HC-17B was obtained at around pH 4.0. The stability of HC-17B was increased by inclusion complexation with $\alpha$-, $\gamma$- and DM-$\beta$-CyD in the pH range of 2.0-8.0 examined, whereas $\beta$-CyD accelerated the degradation of HC-17B at the pH higher than 5.0. The effects of ionic strength, solvent, temperature and CyD concentration were also investigated. Stability constants and apparent degradation rate constants of HC-17B-$\gamma$-CyD and HC-17B-DM-$\beta$-CyD complexes were determined kinetically on the basis of 1:1 complexation. The results suggested that the inclusion complexation with $\gamma$-CyD or DM-$\beta$-CyD was most useful means to enhance the stability of the steroid.

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