• Bulletin of the Korean Chemical Society
• /
• v.26 no.10
• /
• pp.1549-1554
• /
• 2005

Chiral separation of arylalcohols such as 1-phenyl-1-propanol, 1-phenyl-2-propanol, and 2-phenyl-1-propanol by capillary electrophoresis was studied using sulfonated $\beta$-cyclodextrin (CD) as a chiral selector and Ag colloids as an additive. The optimum separation condition of arylalcohols was found to be the chiral selector concentration of 6.5 mM, applied voltage of 15 kV, and pH of 7.0. In order to improve chiral separation, an Ag colloid was mixed with a running buffer. The resolution in the Ag colloid-mixed running buffer was considerably superior to that obtained with the sulfonated $\beta$-CD alone. The molar ratio of sulfonated $\beta$-CD to Ag colloid, which is one of critical parameters affecting resolution, was found to be optimum at 65 : 1. In order to elucidate the resolution mechanism, an inclusion-complex of the arylalcohols with sulfonated $\beta$-CD was prepared by mixing and shaking in solution, and then characterized by cyclic voltammetry (CV). The inclusion mechanism was also discussed using experimental results.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.11
• /
• pp.1627-1631
• /
• 2003

Molecular modeling was performed to comprehend the chiral recognition of ${\alpha}$-methoxy-${\alpha}$-trifluoromethylphenylacetic acid (MTPA) enantiomers by cyclomaltoheptaose (${\beta}$-cyclodextrin,${\beta}$-CD) and 6-amino-6-deoxy-cyclomaltoheptaose (am-${\beta}$-CD). Monte Carlo (MC) docking coupled to constant temperature molecular dynamics (MD) simulations was applied to the investigation for the ${\alpha}$-methoxy-${\alpha}$-trifluoromethylphenylacetic acid complexation with two different CDs in terms of the relative distribution of the interaction energies. The calculated results are finely correlated with the experimental observations in chiral recognition thermodynamics. Am-${\beta}$-CD as a host showed the superior enantio-discrimination ability to the native ${\beta}$-CD where the amino group of am-${\beta}$-CD was critically involved in enhancing the ability of chiral discrimination via the Coulombic interaction with MTPA.

• Archives of Pharmacal Research
• /
• v.24 no.4
• /
• pp.281-285
• /
• 2001

Enantiomers of five racemic ${\beta}_2$-agonists were investigated by capillary electrophoresis employing a hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD). The effects of the concentration of HP-${\beta}$-CD added to the background electrolyte and of the pH of the buffer on the effective mobility and resolution of the studied compounds were examined. Very good resolution was achieved for terbutaline and clenbuterol; salbutamol and bambuterol was able to be partially resolved. Enantioselectivity and resolution were influenced by the concentration of the HP-7-CD, buffer composition and pH.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.3 no.2
• /
• pp.78-81
• /
• 1998

Cyclodextrin glucanotransferase [CGTase, E.C.2.4.1.19] is an extracellular enzyme, which catalyzes he formation of ${\alpha}$-, ${\beta}$-, ${\gamma}$- CDs from starch. Their proportions of formations depend on enzyme sources and reaction conditions. To understand what determines the product specificity of CGTases, we examined the alteration of product specificity of CGTase from Bacillus macerans by organic solvent sand pH. At acidic pH range less than pH 6 where the enzyme was unstable, the ratio of ${\alpha}$-/ ${\beta}$-CD production was increased 4 times more than that at neutral pH range. As we increased the concentration of 2-butanol, ${\alpha}$-/ ${\beta}$-CD ratio was proportionally increased but / ratio remained constant. The ${\alpha}$-/ ${\beta}$-CD ratio of products was increased in the reaction media which yielded low products.

• Journal of Pharmaceutical Investigation
• /
• v.27 no.3
• /
• pp.165-171
• /
• 1997

Ibuprofen, a nonsteroidal antiinflammatory, analgesic and antipyretic drug, has several limitations in clinical application because of low solubility in water and gastrointestinal irritation. Effect of ibuprofen/$2-Hydroxypropyl-{\beta}-cyclodextrin\;(HP{\beta}CD)$ inclusion compound on release of suppository was investigated. Complex formation was confirmed by $^{1}H-\;and\;^{13}C-NMR$ spectroscopy. The release of ibuprofen from suppository base in vitro was significantly increased by the complexation with $HP{\beta}CD$. The release of ibuprofen from hydrophilic base was faster than that from hydrophobic base. In vivo studies, the release rate of ibuprofen from suppository was accelerated after rectal administration in complex form. This results suggested that ibuprofen/$HP{\beta}CD$ complex can be practically used for suppository to have faster effect of ibuprofen with reduced side effect.

• Journal of Pharmaceutical Investigation
• /
• v.23 no.1
• /
• pp.11-18
• /
• 1993

Inclusion complex of ibuprofen with $2-Hydroxypropyl-{\beta}-cyclodextrin\;(HP-{\beta}-CD)$ in aqueous solution and in the solid state was evaluated by the solubility method and the instrumental analysis such as infrared spectroscopy, thermal analysis and x-ray diffractometry. The aqueous solubility of ibuprofen was increased linearly with the increase in the concentration of $HP-{\beta}-CD$, showing an $A_L$ type phase solubility diagram. The results showed that the dissolution rate of ibuprofen was significantly increased by complexation with $HP-{\beta}-CD$. $Ibuprofen-HP-{\beta}-CD$ complex enhanced the mean plasma concentration levels and the area under plasma concentration-time curve after oral administration compared to those of the drug alone. It is concluded that the complex of ibuprofen with $HP-{\beta}-CD$ increases the dissolution rate and improves the bioavailability of the ibuprofen by the formation of a water-soluble complex.

• Applied Biological Chemistry
• /
• v.47 no.1
• /
• pp.41-48
• /
• 2004

Cyclodextrin glucanotransferase (CGTase) of Bacillus sp. isolated from soil was purified and its enzymological characteristics were investigated. It was found that the production of CGTase reached to the maximum when the strain was cultured in the broth containing 0.1 % albumin, 2% $NH_4Cl$, 2% soluble starch and 0.2% $NH_2PO_4$ for 72 hrs at $37^{\circ}C$. The purity of CGTase was increased by 9.7 folds through purification procedures by the following column chromatography DEAE-cellulose ion exchange chromatography and Sephadex G-100, G-150 gel filtration and its specific activity was 528.0 unit/mg. The optimum pH and temperature for the CGTase activity were 8.0 and $80^{\circ}C$, respectively. The enzyme was stable in pH $8.0{\sim}11.0$ at $60{\sim}80^{\circ}C$. The activity of purified enzyme was inhibited by $Pb^{2+},\;Hg^{2+}$ and $Zn^{2+}$. When CGTase was treated with each 20.5 unit, 41 unit, 205 unit and 410 unit to investigate the transglucosylation to stevioside by purified cyclodextrin glucanotransferase, transglucosylation rate to stevioside was 74.9%, 75.7%, 68.7% and 57.9%. Brown effect was observed above the concentration amounting to 205 unit of our CGTase.

• KSBB Journal
• /
• v.19 no.4
• /
• pp.321-326
• /
• 2004

Microparticles of an inclusion complex between itraconazole and 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) were prepared using an environmentally-benign supercritical anti-solvent (SAS) process. In order to evaluate the degree of complexation, the thermal behavior of solid micro particulate complexes was investigated using differential scanning calorimetry. The experimental results obatined for the solubility and dissolution rate of the microparticulate inclusion complexes in a buffer solution of pH 1.2 showed that the complexation of itraconazole with HP-${\beta}$-CD results in a significant increase in the solubility and dissolution rate of itraconazole. For the microparticulate itraconazole/Hp-${\beta}$-CD inclusion complexes prepared by the SAS process, about 80% of itraconazole was found to dissolve in the buffer solution. Our experimental results confirmed that the SAS process is a promising method for the preparation of microparticles of water-insoluble drug/cyclodextrin inclusion complexes.

• Journal of Life Science
• /
• v.12 no.6
• /
• pp.688-693
• /
• 2002

Molecular chaperones prevent the misfolding of newly synthesized polypeptides in the cell. The coexpression of molecular chaperones could be expected to improve the production of soluble and active recombinant proteins. In this study, the effect of coexpression of E. coli GroEL/ES chaperone on the active production of Bacillus macerans cyclodextrin glucanotransferase (CGTase) in E. coli was investigated. Two plasmids, pTCGT1 and pGro7 in which the cgt and the groEL/ES genes are under the control of 77 promoter and araB promoter, respectively, were co-transformed into E. coli. With a series of cultures of recombinant E. coli cells, the optimal concentrations of IPTG and L-arabinose were found be 1 mM and 0.3 mg/$m\ell$, respectively. When IPTG and L-arabinose were added at 0.8~1.0 $OD_{600}$ and 0.4~0.5 $OD_{600}$, active CGTase production was increased significantly. This coexpression condition resulted in 1.5-fold increased level of soluble CGTase (0.7~0.73 unit/$m\ell$), compared to the level of CGTase in the single expression (0.36~0.56 unit/$m\ell$). An SDS-PACE analysis revealed that about 33.6% of CGTase in the total CGTase protein was found in the soluble fraction by coexpression of GroEL/ES chaperone.

• Applied Biological Chemistry
• /
• v.38 no.1
• /
• pp.42-48
• /
• 1995

The experiment was carried out to purify and to investigate the properties of the cyclodextrinase produced from Bacillus megaterium KFCC 11855. The enzyme was partially purified with $(NH_4)_2SO_4$ and chromatography on DEAE-trisacryl, Ultrogel AcA 34, DEAE-trisacryl and Ultrogel HA. The optimum temperature and pH of the purified enzyme were $60^{\circ}C$ and 6.0, respectively. The enzyme was stable at the temperature of $45^{\circ}C$ below and at the pH range of $6.0{\sim}9.0$, respectively. The Km value for ${\gamma}-cyclodextrin$ was 0.903 mM. The enzyme activity was increased by $Mg^{2+}$ and $Mn^{2+}$, but decreased by $Hg^{2+}$ and $Cu^{2+}$. The enzyme degraded ${\gamma}-cyclodextrin$ but not ${\alpha}-cyclodextrin$. The degree of ${\beta}-CD$ degradation by the enzyme was very low. The decomposed products of ${\gamma}-cyclodextrin$ by the enzyme were mainly glucose, maltose and a little amount of maltotriose.