• Archives of Pharmacal Research
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• 제27권3호
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• pp.357-360
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• 2004

Four crystal forms of ketorolac have been obtained by recrystallization in organic solvents under variable conditions. Different ketorolac polymorphs and pseudo polymorph were characterized by X-ray powder diffraction crystallography (XRD), Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In the dissolution studies in water at $37{\pm}0.5^{\circ}C$ four crystal forms showed different patterns. The solubility of Form I were the highest. The solubility decreased in rank order: Form I> Form II > Form III > Form IV. Form land Form III were shown to have a good physical stability at room temperature for 60 days. However, Form II is converted to Form III and Form IV is converted to Form I after 60 days storage. Therefore, these observations indicate that crystalline polymorphism for ketorolac is readily inter-convertible and the relationship may have to taken into consideration in the formulation of the drug.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.846-848
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• 2009

Two modifications of the ${\alpha}\;and\;{\beta}$ forms of propyl mercaptan nickel(II) cluster, [$Ni_6(SCH_2CH_2CH_3)_{12}$], have been synthesized and their crystal structures have been determined by single-crystal X-ray diffraction. The alkyl groups are away from $Ni_6$ ring in $\alpha$ form whereas they are near to the Ni atom in $\beta$ form. The distance of Ni-H in $\beta$ form [2.576(5) $\AA$] is much shorter than that in $\alpha$ form [3.101(2) $\AA$]. In the crystal lattice of $\beta$ form, the whole structure forms a flower shape.

• Journal of Pharmaceutical Investigation
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• 제26권3호
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• pp.193-199
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• 1996

The polymorphism of biphenyl dimethyl dicarboxylate was investigated by DSC. From product five crystal forms. Form 1, Form 2, Form 3, Form 4, and Form 5, were characterized and three crystal forms. Form 6, Form 7, and Form 8, were prepared with the recrystallization method. The dissolution patterns of these eight crystal farms were also studied, but there was practically no difference in dissolution rate.

• 공업화학
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• 제24권2호
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• pp.132-137
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• 2013

포스파티딜콜린이 다량 함유된 수첨레시틴을 이용한 실험에서 액정구조가 잘 형성됨을 알 수 있었다. 액정구조를 형성하는 물질로는 포스포리피드, 에탄올, 물로 이루어짐을 알 수 있었고 로즈마린산을 지표물질로 캡슐화하였다. 액정의 평균입자크기는 480 nm ~ $3{\mu}m$로 이는 액의 구성물질과 물리적인 힘에 따라 다양한 크기의 형태로 존재하였다. 리포좀과 비교했을 때 액정구조는 매우 높은 캡슐화 효율을 보였다. 수첨레시틴의 함량이 증가하면 많은 액정을 형성하였고, 수첨레시틴의 함량이 적으면 액정의 양도 적게 나타났다. 로즈마린산을 함유한 액정구조의 방출실험결과 리포좀으로 형성된 베지클보다 훨씬 적은 양이 방출됨을 알 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제33권2호
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• pp.99-103
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• 2003

Four different crystal forms of prednisolone, two polymorphic forms and two pseudopolymorphic forms, were obtained by the recrystallization from different organic solvents under varying conditions. The isolated crystal forms were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD). Form 1 was the most stable form that had the highest melting point and melt at $250.1^{\circ}C$. Form 2 was a monohydrate and Form 3 was a methanol solvate. The endothermic peak of Form 4 was shown at $230.2^{\circ}C$. When stored at different relative humidity over the period of 3 months, all of the modifications did not undergo transformation. The dissolution patterns of these four modifications were also checked in distilled water at $37{\pm}0.5^{\circ}C$, for 120 minutes. The dissolution rate of Form 4 was highest and those of Form 3, Form 2, Form 1 followed. Form 2, Form 3 and Form 4 had higher dissolution rate than Form 1.

• Journal of Pharmaceutical Investigation
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• 제37권1호
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• pp.23-26
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• 2007

Two crystal forms of cefuroxime axetil were obtained by the recrystallization from different organic solvents and characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD). It was confirmed that two crystal forms are identical. The dissolution patterns of these two forms were also checked in 0.07 N HCl at $37{\pm}0.5^{\circ}C$, 100 rpm for 180 minutes. The transformation during storage was also studied.

• Journal of Pharmaceutical Investigation
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• 제20권2호
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• pp.65-71
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• 1990

Some studies reported physicochemical factors of drugs affecting solubility and dissolution rate. However, few have been reported about pharmaceutical application of crystal forms (habits). Therefore, using acetylsalicylic acid and phenacetin as model substances, we monitored the effects of crystal forms on the dissolution rates.

• 한국결정성장학회지
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• 제33권4호
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• pp.158-164
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• 2023

다이아몬드 결정구조가 갖는 의미와 결정형태의 조형적 아름다움을 새로운 관점에서 디자인하여 주얼리로 표현하고자 하였다. 본 연구에서는 다이아몬드의 결정구조에 대한 문헌 조사와 다이아몬드 결정구조의 조형적 특징을 모티브로 한 주얼리 디자인 사례를 분석하였다. 다이아몬드 결정구조의 의미와 가치를 새롭게 해석하고, 다이아몬드의 결정구조를 주얼리로 디자인함으로써 결정구조가 갖는 미적 효과를 나타낼 수 있는 조형적 디자인을 연구하였다. 다이아몬드 결정구조가 주는 대칭의 효과와 조형미가 주는 반복의 특징을 살려 주얼리 디자인을 제시함으로써 보석이 주는 근원적인 아름다움, 문화적 의미가 새롭게 재인식되길 기대해 본다.

• Archives of Pharmacal Research
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• 제23권4호
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• pp.381-384
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• 2000

It is well recognized that physicochemical properties of drugs are affected by the type of polymorphic crystalline form of drugs. Clarithromycin is known to exist in at least three polymorphic crystalline forms. Since conventional means to obtain the most thermodynamically stable form (Form II) for the antibiotics is known to be associated with a low purity of the stable form, we developed a novel method to improve the purity of the crystalline form by a modification of the preparation process. The new method involved a simple recrystallization of clarithromycin in solvents having 5-12 carbon atoms (e.g., hexane and heptane) or ethers with 4-10 carbon atoms (e.g., isopropyl ether) and, thus, less likely to be associated with the problem in purity of resulting crystal. Differential scanning calorimetry and powder X-ray diffraction were used to compare the crystalline form of the resultant powder with Form IIcrystal prepared by the conventional method. The crystal prepared by the new method was identical to Form IIcrystal of the conventional method as evidenced by the lack of the exothermic peak near 11$0^{\circ}C$ in differential calorimetry scan, indicating that Form IIcrystal could be readily prepared by the new process. Therefore, these data indicated that the improvement in the purity of the Form IIcrystal for clarithromycin as well as a significant cost reduction is likely by the novel method.

• Journal of Pharmaceutical Investigation
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• 제30권4호
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• pp.289-293
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• 2000

Three polymorphic modifications and one amorphous form were prepared by recrystallization under various conditions and characterized by DSC and X-ray crystallography. At $37{\pm}0.5^{\circ}C$, the polymorphic modifications showed significant differences in the dissolution rate. The dissolution rate of Mod. 4, amorphous form, was faster than that of other polymorphic modifications. When all modifications were stored at 52% RH, 95% RH, and in silica gel desiccator, amorphous form was transformed at 95% humidity condition.