• Journal of Pharmaceutical Investigation
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• 제34권4호
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• pp.289-297
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• 2004

Acyclovir (ACV) is one of the most effective and selective agents against viruses of the herpes group. Because of low solubility, bioavailability of ACV has shown below 30% with oral dosage form. In our previous study, we reported that the fabrication of solid dispersion of ACV was possible and the solid dispersion of ACV and PVP was the most useful in all samples. In this study, we examined the effect of mixture ratio of polymers (PEG and PVP) to ACV. Solubility of ACV was dramatically increased up to 25 mg/ml in $80^{\circ}C$ distilled water. So water was used as a solvent to eliminate problem of residual solvent. Spray drying method was used for the solid dispersion of ACV as solvent extraction. Different scanning calorimeter was used to check degradation of drug. Polymer carriers were PEG 6,000 and PVP. In summary, ACV-PVP (1:3) showed the best solubility in distilled water.

• Journal of Pharmaceutical Investigation
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• 제41권4호
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• pp.217-225
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• 2011

The aim of this work was to prepare porous osmotic pump tablets for controlled delivery of Aceclofenac. Aceclofenac solid dispersion was prepared to improve the solubility by using the drug - carrier (Mannitol) ratio of 1:1. The osmotic pump tablets were prepared using the solid dispersed product of Aceclofenac. The formulation contains potassium chloride as osmotic agent, cellulose acetate as semipermeable membrane, poly ethylene glycol (PEG 4000) as pore former and sodium lauryl sulphate (SLS) as solubility enhancer. The formulations were designed by the general factors such as osmotic agent and pore former. All formulations were evaluated for various physical parameters and, the in vitro release studies were conducted as per USP. The drug release kinetic studies such as zero order, first order, and Higuchi and Korsmeyer peppas were determined and compared. All the formulations gave more controlled release compared to the marketed tablet studied. Numerical optimization techniques were applied to found out the best formulation by considering the parameter of in vitro drug release kinetics and dissolution profile standards. It was concluded that the porous osmotic pump tablets (F7) composed of Aceclofenac solid dispersion/Potassium chloride/Lactose/Sodium lauryl sulphate/Magnesium Stearate (400/40/95/10/5, mg/tab) and coating composition with Cellulose acetate/ PEG 4000 (60/40 %w/w) is the most satisfactory formulation. The porous osmotic pump tablets provide prolonged, controlled, and gastrointestinal environment-independent drug release.

• Journal of Pharmaceutical Investigation
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• 제31권3호
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• pp.151-160
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• 2001

The purpose of this study is to investigate the interaction of progesterone with various cyclodextrins (CDs) in the aqueous solution and in solid state, and finally to formulate a parenteral aqueous formulation. CDs used were ${\alpha}-$, ${\beta}-$, and ${\gamma}-CD$, $2-hydroxypropyl-{\beta}-CD$ (HPCD), sulfobutyl $ether-{\beta}-CD$ (SBCD), $dimethyl-{\beta}-CD$ (DMCD) and $trimethyl-{\beta}-CD$ (TMCD). The solubility studies of progesterone were performed in the presence of various CDs as a function of concentration or temperature. The solubility of progesterone increased in the rank order of ${\alpha}-CD$ < ${\beta}-CD$ < ${\gamma}-CD$ < TMCD$ < HPCD < DMCD < SBCD. Addition of SBCD (200 mg/ml) in water increased the aqueous solubility $(9.36\;{\mu}g/ml)$ about 3,200 times, and lowering the temperature facilitated the solubilization of progesterone. However, the addition of HPCD and SBCD in 20:80 (v/v) polyethylene glycol 300-water and propylene glycol-water cosolvents markedly decreased the solubility of progesterone, compared with solubilizing effects in water. Physical mixtures and solid dispersions of progesterone with HPCD or SBCD were prepared, and evaluated by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), near IR spectroscopy and dissolution studies. By DSC and IR studies, it was found that progesterone was dispersed in HPCD in monotectic state and dissolved rapidly from both solid dispersions. Based on solubility studies, new aqueous progesterone fonnulations (5 mg/ml) containing SBCD (200 mg/ml) could be prepared and did not form precipitates even after 2 months at $4^{\circ}C$. The solution was transparent when mixed with normal saline and 5% dextrose injection at 1: 1, 1:10 and 1:20 (v/v) even after 7 days. Permeation rates of progesterone through a cellulose membrane from 20% PEG 300 solution $(50\;{\mu}g/ml)$ containing HPCD or SBCD were compared with oily formulation. Permeation of progesterone from oily formulation did not occur up to 8 hr, but aqueous formulations showed fast permeation rates from early stage of permeation study. The addition of HPCD or SBCD retarded the permeation rates of progesterone with the increase of CD concentrations, suggesting the possibility of a controlled absorption from the site administered intramuscularly. These results demonstrate that it is feasible to develop a new progesterone parenteral aqueous injection (5 mg/ml) using SBCD.

• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.194-200
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• 2020

Perylene bisimide derivatives are developed for red organic phosphor because of their advantages, such as excellent luminous efficiency and high thermal stability. Despite these advantages, they have poor solubility characteristics in organic solvents and short emission wavelength as red organic phosphor for hybrid light-emitting diodes (LEDs). In this study, we prepared terrylene bisimide using a coupling reaction and swallow-tail imide group, which has excellent solubility. The structures and properties of swallow-tail terrylene bisimide (9C) were analyzed using ¹H-nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared (FT-IR), UV/Vis spectroscopy, and thermal gravimetric analysis (TGA). The maximum absorption wavelength of (9C) in the UV/Vis spectrum was 647 nm, and the maximum emission wavelength was 676 nm. In the TGA, (9C) demonstrated good thermal stability with less than 5 wt% weight loss up to 415℃. In the solubility test, (9C) has a good solubility of more than 5 wt% in chloroform and dichloromethane. When the compounds (9C) were mixed with PMMA (polymethly methacrylate), the films showed peaks at 680 nm in the PL spectra. The results verify the suitability of (9C) as a red organic phosphor for hybrid LEDs.

• 대한토목학회논문집
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• 제29권2B호
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• pp.207-212
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• 2009

광물촉매에 의한 Fenton 산화에서 모래에 흡착된 phenanthrene을 대표적인 계면활성제인 SDS와 Tween 80을 사용하여 물질이동 영향을 조사하였다. 계면활성제 주입에 따라 액상과 고체상 사이 또는 산화물 표면으로 phenanthrene이 물질이동하였으며, 계면활성제 농도가 증가할수록 phenanthrene의 apparent solubility는 증가하는 경향을 나타내었다. Tween 80은 apparent solubility가 증가 하더라도, 계면활성제가 분해에 scavenger 작용을 하여 모래에 흡착된 phenanthrene 산화에는 영향을 주지 않았다. SDS를 주입하였을 때, Fenton-like 반응에서 SDS와 goethite가 착물을 형성하여 과산화수소 소모량을 지연시켰의며, 계면활성제를 주입 하지 않았을 때 보다 SDS 32 mM를 주입하였을 때 phenanthrene 처리효율이 증가하였다. 그러므로 최적농도의 SDS 주입은 액상과 고체상 사이 또는 산화물 표면에 phenanthrene 산화를 위한 적당한 조건을 제공 해주며, 과산화수소 소모량을 줄이고, phenanthrene 처리효율을 개선시킬 것이다.

• Journal of Pharmaceutical Investigation
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• 제28권4호
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• pp.257-266
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• 1998

To improve the solubility and dissolution rate of acyclovir (ACV), which is low oral bioavailability due to its properties of slight solubility in water and incomplete gastrointestinal absorption, the solid inclusion complexes of ACV with ${\alpha}CD$, ${\beta}CD$, $DM{\beta}CD$ in molar ratio of 1:1 were prepared by the freeze-drying method. The inclusion complexes were investigated by solubility study, UV, IR and DSC. The dissolution rate of ACV was significantly increased by ACV-CDs inclusion complex formation in artificial intestinal fluid at pH 6.8. The enhanced dissolution rate of ACV could be due to an increase of solubility and the formation of an amorphous structures through inclusion complexation with CDs. Especially, $ACV-DM{\beta}CD$ inclusion complex enhanced the maximum plasma concentration levels and AUC following oral administration compared to those of ACV alone. The present results suggest that $ACV-DM{\beta}CD$ inclusion complex serves as a potential carrier for improving the solubility, the dissolution rate and the bioavailability of ACV.

• 폴리머
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• 제38권4호
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• pp.434-440
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• 2014

셀레콕시브는 높은 결정성을 갖는 난용성 약물로서 이러한 난용성 약물의 용해도를 증진시키기 위해 고체분산법을 바탕으로 한 분무건조기를 이용하여 고체분산체를 제조하였다. PVP K30과 Eudragit EPO를 수용성 담체로 사용하였고 폴록사머 407은 계면활성제로 사용하였다. 제조된 셀레콕시브 고체분산체의 특성을 SEM, DSC, XRD 그리고 FTIR을 이용하여 확인하였다. SEM과 DSC 그리고 XRD를 통하여 셀레콕시브 고체분산체가 무정형임을 알 수 있었다. 제조된 고체분산체는 pH 1.2에서 용출을 실시하였으며 시판제인 Celebres$^{(R)}$ 용출률을 비교하였으며 분무건조를 통해 제조한 고체분산체가 Celebres$^{(R)}$보다 용출률이 크다는 것을 확인하였다.

• 폴리머
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• 제33권6호
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• pp.596-601
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• 2009

아세클로페낙은 높은 결정성을 갖는 난용성 약물이다. 이러한 난용성 약물의 용해도를 증진시키기 위해서 고체분산법을 바탕으로 한 분무건조기를 이용하여 미립구를 제조하였다. PVP-K30을 수용성 담체로 사용하였고 폴록사머는 계면활성화제로 사용하였다. 제조된 아세클로페낙 고체분산체의 특성을 SEM, DSC, XRD 그리고 FT-IR을 이용하여 확인하였다. SEM, DSC, XRD을 통하여 아세클로페낙 고체분산체가 무정형임을 알 수 있었고 FT-IR을 통하여 아세클로페낙과 PVP-K30간에 수소결합을 통해 염을 형성하고 있다는 것을 확인할 수 있었다. 제조된 미립구는 pH 6.8에서 방출을 실시하였으며 시판제인 $Airtal^{(R)}$과 용출률을 비교하였으며 분무건조를 통해 제조한 미립구가 시판제인 $Airtal^{(R)}$ 보다 용출률이 크다는 것을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.699-708
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• 2004

Natural gas hydrate typically contains 85 wt.% water and 15 wt.% natural gas, and commonly belongs to cubic structure I and II. When referred to standard conditions, 1 ㎤ solid hydrate contains up to 200㎥ of natural gas depending on pressure and temperature. Such the large volume of natural gas hydrate can be utilized to store and transport a large quantity of natural gas in a stable condition. In the present investigation, experiments were carried out for the formation of natural gas hydrate governed by pressure, temperature, gas compositions, etc. The results show that the equilibrium pressure of structure II is approximately 65% lower and the solubility is approximately 3 times higher than structure I. It is also found that for the sub-cooling of structure I and II of more than 9 and 11 K respectively, the hydrates are rapidly being formed. It is noted that utilizing nozzles for spraying water in the form of droplets into the natural gas dramatically reduces the hydrate formation time and increases its solubility at the same time.

• 한국세라믹학회지
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• 제37권8호
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• pp.787-791
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• 2000

Samples with the nominal composition, Bi2-xGexSr2CaCu2O8＋$\delta$ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by the solid-state reaction method. We have studied the effect of substitution Ge for Bi and investigated the superconducting properties by changing oxygen content with Ge substitution. It was found that temperature difference, ΔK, between TCon and TCzero was considerably smaller in the samples prepared by the intermediate pressing method than that in the samples by the solid-state reaction method. We found the solubility limit of Ge to the 80 K single phase was around x=0.3. Within the solubility limit, lattice constant c decreased with the increase of x. In the region of the 80K single phase, the onset critical temperature TCon increased and excess oxygen content decreased with increase of x.