• Journal of Pharmaceutical Investigation
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• v.12 no.3
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• pp.55-63
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• 1982

The dissolution kinetics for polymorphs of sulpiride, the effect of polyethylene glycol 4000 on the dissolution kinetics of sulpiride polymorphs and the dissolution rate difference between the tablets of polymorph form I and form II were investigated. The results could be summerized as followings: 1. The dissolution rates of two polymorphs of sulpiride were significantly different and the thermodynamic parameters calculated from dissolution kinetics were as follows; transition temperature $98^{\circ}C$, enthalpy change, -2.108 kcal/mole, free energy change, -783 cal/mole $(31.0^{\circ}C)$. 2. The dissolution rates of the two polymorphs of sulpiride containing polyethylene glycol 4000 were significantly diefferent in 0.01N HCl but the effect of polyethylene glycol on the dissolution rates of two polymorphs was not significant at low concentration of polyethylene glycol 4000. The study on the effect by stirring speed showed that at lower stirring speed the promotion rate of dissolution of polymorph form I is greater than that of form II. 3. In the case of tablets the dissolution rates of polymorph form I of sulpiride was two fold as compared with the results obtained from form II.

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.200-206
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• 1993

Structures of two polymorphs of ${\alpha},{\alpha}$-trehalose octaacetate monohydrate, $C_{28}H_{38}O_{19}\;{\cdot}\;H_2O$, have been studied by X-ray diffraction method. ${\alpha},{\alpha}$-trehalose (${\alpha}$-D-glucopyranosyl ${\alpha}$-D-glucopyranoside) is a nonreducing disaccharide. The polymorph I belongs to the monoclinic $P2_1$, and has unit cell parameters of a=10.725(l), b=15.110(4), c=11.199(5) ${\AA}$, ${\beta}=108.16(2)^{\circ}$ and Z=2. The polymorph II is orthorhombic $P2_12_12_1$, with a=13.684(4), b=15.802(4), c=17.990(9) ${\AA}$ and Z=4. The final R and R$_w$ values for monoclinic polymorph I are 0.043 and 0.048 and for orthorhombic polymorph II are 0.116 and 0.118, respectively. Those R values of polymorph II are high because the large thermal motions of acetyl groups and the poor quality of the crystal. The molecular conformations in the two polymorphs are similar. Both D-glucopyranosyl rings have chair $^4C_1$ conformations and atoms of glycosidic chain ${\alpha}(1{\rightarrow}1)$ linkage are coplanar. The primary acetate groups of the pyranose residues assume both gauche-trans conformations. The molecules of two polymorphs have pseudo-C$_2$ symmetry at glycosidic O(1) atom. The bond lengths and angles are normal compared with those in other acetylated sugar compounds. The molecules in the monoclinic crystal are held by the hydrogen bonds with the water molecules and by van der Waals forces.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.11a
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• pp.13-19
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• 2006

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.786-790
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• 2005

A new ternary strontium germanium nitride, ${\beta}-Sr_2GeN_2$, was obtained as single crystal from constituent elements in molten Na. It crystallizes in space group Cmca (No. 64) with a = 5.441(1) $\AA$, b = 11.377(2) $\AA$, c = 12.229(2) $\AA$, and Z = 8. Its crystal structure is closely related to that of polymorphic companion, ${\alpha}-Sr_2GeN_2$, both of which contain isolated bent anions of ${GeN_2}^{4-}$.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1568-1571
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• 2005

We have evaluated thermal stability of a $BaAl_2Si_2O_8:Eu^{2+}$ $(BAS:Eu^{2+})$, which have polymorph property such as hexagonal, monoclinic structure depending upon firing temperature. When both polymorph $BAS:Eu^{2+}$ were baked in air at 500 $^{\circ}C$ for 30 min, the photoluminescence (PL) intensity of $monoclinic-BAS:Eu^{2+}$ was maintained of the initial intensity. However, the PL intensity of $hexagonal-BAS:Eu^{2+}$ decreased significantly, corresponding to about 34 %. From analyses of Rietveld refinement, the difference of thermal stability of both $BAS:Eu^{2+}$ can be ascribed to both crystal structure of host materials and the average interatomic distances between $Eu^{2+}$ ion and oxygen their crystal structure which plays a key role of shield for Eu2+ ions against oxidation atmosphere.

• Toxicological Research
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• v.20 no.4
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• pp.299-305
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• 2004

Adult periodontitis (AP) is a chronic inflammatory disease whose etiology is not well defined. Some studies suggested that the clinical characteristics of this disease may be in part explained by genetic factors, and some attempts to find genetic markers for this disease were successful. The interleukin-1 (IL-1) gene family as one of genetic factors may influence the expression of adult periodontitis. The aim of present study is to investigate the frequencies of genetic polymorphisms in the IL-1 gene family encoding three genes (IL-1A, IL-1B and IL-1RN) in Korean AP patients and periodontically healthy controls. There were no significant differences in genotype and allele frequencies of these polymorph isms between two groups, respectively. However, -511 polymorphism of IL-1 B gene was significantly associated with mean pocket depth (MPD, mm) value in AP patients (P<0.05). Therefore, our results suggest that -511 polymorphism in the IL-1B gene may be useful as a genetic marker for the severity of AP in Koreans.

• YAKHAK HOEJI
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• v.26 no.4
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• pp.231-237
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• 1982

The transformation kinetics between polymorphs of sulpiride and the effect of additives on the transformation kinetics were studied. The results could be summarized as follows. 1. Transformation kinetics of the polymorph form I to form II in water suspenion was first order type and transformation rate constant at $25^{\circ}C$ is $2.61{\times}10^{-2}min^{-1}$, the half life of form I was about 27 minutes and the activation energy for transformation was 21.35 Kcal/mole. 2. Glycerine and coloring agents increased the rate of transformation., In the case of polysorbate 80, the rate constant increased in proportion to the concentration of polyserbate 80. Simple syrup showed no effect 3n transformation kinetics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.11a
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• pp.13-13
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• 1997

1980년대 후반 미국 China Lake의 Naval Weapon Center에서 개발된 hexanitrohexa-azaisowurzitane(HNIW;CL-20)은 nitro group의 배향에 따라 $\alpha$, $\beta$,$\gamma$,$\varepsilon$형으로 불리우는 네 가지의 분리가능 한 polymorph가 존재하는 것으로 알려져 있다. 이중에서 $\varepsilon$형은 다른 polymorph보다 더 안정한 상으로서 고체추진제의 산화제로 사용하기에 적당한 구형에 가까운 결정모양을 가지고 있으며 밀도가 가장 크다. 제조된 HNIW 결정 중에는 소량의 $\beta$형을 함유할 수 있으므로 이의 함량을 측정하는 일은 매우 중요한 것이라 할 수 있다. 본 연구에서는 FT-IR을 이용하여 $\beta$형과 $\varepsilon$형을 가장 명확하게 구분할 수 있는 영역을 선택하고 $\varepsilon$함량에 따라 변화하는 흡광도를 plotting하여 검정곡선을 작성한 후 상호 관계를 수식으로 나타내어 HNIW 결정중의 $\varepsilon$형 함량을 결정할 수 있는 방법을 개발하였다.

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.14-15
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• 2002

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3609-3614
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• 2013

Orthorhombic and hexagonal lanthanum(III) hydroxycarbonate ($LaCO_3OH$) and $Ln^{3+}$-doped $LaCO_3OH$ ($LaCO_3OH:Ln^{3+}$, where Ln = Ce, Eu, Tb, and Ho) powders were prepared by a hydrothermal reaction under ambient pressure and characterized by thermogravimetry, powder X-ray diffraction, infrared and luminescence spectroscopy, and field-emission scanning electron microscopy. The polymorph of $LaCO_3OH$ depended on the reaction temperature, inorganic salt additive, species of $Ln^{3+}$ dopant, and solvent. The calcination of orthorhombic $LaCO_3OH:Ln^{3+}$ (2 mol %) powers at $600^{\circ}C$ yielded a mixture of hexagonal and monoclinic $La_2O_2CO_3:Ln^{3+}$ powders. The relative quantity of the latter increased with decreasing ionic radius of the $Ln^{3+}$ dopant ion and increasing doping concentrations. On the other hand, the calcination of hexagonal $LaCO_3OH:Ln^{3+}$ (2 mol %) powders at $600^{\circ}C$ resulted in a pure hexagonal $La_2O_2CO_3:Ln^{3+}$ powder, regardless of the species of $Ln^{3+}$ ions (Ln = Ce, Eu, and Tb). The luminescence spectra of $LaCO_3OH:Ln^{3+}$ and $La_2O_2CO_3:Ln^{3+}$ were measured to examine the effect of their polymorph on the spectra.