• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.205-210
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• 1999

To formulate the parenteral delivery of a new cephalosporin derivative, 7-${\beta}$-[(2)-2-(2-arninothiazol-4-yl)-2methoxyiminoacetamido]- 3- [(2,3-cyclopenteno-4-carbamoyl-l-pyridinium)methyl]- 3-cephem-4-carboxylate sulfate( CKD604), the stability and solubility of CKD-604 in various aqueous media were investigated. The degradation kinetics of CKD-604 in aqueous solutions (ionic strength 0.1, pH 1-8) were studied at $37^{\circ}C$. The observed degradation rates followed pseudo first order kinetics. The pH-rate profile exhibited a minimum degradation rate at pH 5. The Arrhenius activation energy was 14.2 kcal/mol in pH 5 buffer solution. Excellent agreement between the cephalosporins' theoretical pH-rate profile and the experimental data indicated that the degradation pathway of CKD-604 could be predicted according to the general pathway of cephalosporins. The solubility of CKD-604 was 8.16 mg/ml at $25^{\circ}C$. To enhance the solubility and adjust the suitable pH, CKD-604 was solubilized by using sodium ascorbate, ascorbic acid and urea. The compositions were obtained to satisfy optimum pH and concentration, and the total amount of additives was several times of the active ingredient, CKD-604.

• YAKHAK HOEJI
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• v.37 no.3
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• pp.216-227
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• 1993

Complex formations of practically insoluble antelmintic drugs such as mebendazole (MBZ), albendazole (ABZ) and flubendazole (FBZ) with dimethyl-$\beta$-cyclodextrin (DM-$\beta$-CyD) and 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CyD) together with $\alpha$-, $\beta$- and $\gamma$-cyclodextrins(CyDs) in duffered solutions were investigated by solubility method. $A_{L}$ type phase solubility diagrams were obtained in all cases except for the complexation (B$_{s}$, type) of FBZ with $\gamma$-CyD. The highest stability constants were obtained with DM-$\beta$-CyD, followed by $\alpha$-CyD > $\beta$-CyD > HP-$\beta$-CyD > $\gamma$-CyD for ABZ, and HP-$\beta$-CyD > $\gamma$-CyD > $\beta$-CyD > $\alpha$-CyD for FBZ at pH 1.2. On the other hand, solid dispersion systems of ABZ and FBZ with $\beta$- and DM-$\beta$-CyDs were prepared by solvent evaporation method and evaluated by dissolution, differential thermal analysis and powder x-ray diffractometry. The dissolution rates of ABZ- and FBZ-DM-$\beta$-CyD solid dispersions were much faster than those of drugs alone, corresponding physical mixtures and tablets on market both at pH 1.2 and 6.8. Although dissolution rates of all samples at pH 6.8 were by far lower than those obtained at pH 1.2, as explained by pH-solubility profiles for ABZ and FBZ, the dissolution rates at pH 6.8 of ABZ from $\beta$- and DM-$\beta$-CyD solid dispersions exceeded the respective equilibrium solubility (23.9 $\mu\textrm{g}$/ml). Fast dissolution of ABZ from solid dispersions with CyDs was attributed to the reduction of drug crystallinity and particle size which was supported by DTA and powder x-ray diffractometry. Consequently these results suggest that solid dispersion systems with CyDs may provide useful means to markedly enhance the solubility and dissolution of benzimidazole antelmintic drugs.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.287-293
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• 1997

To make a stable o/w emulsion, the effects of egg lecithin as an emulsifier and polyvinylpyrrolidone (PVP) as an auxiliary emulsifier on the physical stability of emulsion were investigated. The oil-in-water emulsion system was manufactured by microfluidizer and evaluated the physical stability. Average particle size and size distribution of emulsion was measured by dynamic light scattering analyzer and interfacial tension was measured. From the interfacial tension tested, critical micelle concentration of the egg lecithin was 0.1 %w/v and optimal concentration for the preparation of emulsion was 1.0 %w/v. The mean particle size was about $0.2\;{\mu}m$ which was suitable for injections. The short-term accelerated stability studies were conducted by centrifugation, freeze-thaw method and shaking of the emulsion samples. The addition of PVP was caused the reduction in the particle size and improved the physical stability of emulsion. These results suggested that a mixed interfacial film comprising the egg lecithin and PVP was formed at the o/w interface and it was effective in preventing phase separation under thermic or mechanical stress. We used antineoplaston A10 (A10) as a model drug which is peptide and amino acid derivative having a action to the living organism against the development of neoplastic growth by a nonimmunological progress. It has a poor solubility in water and there may be a difficulty in formulation of A10. Emulsion formulation study about A10 was performed. Solubility of A10 in emulsion was about five times as high as that in water. From the results of solubility and partition coefficient, almost A10 molecules in o/w emulsion exist in the interface between oil and water.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.161-167
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• 2011

Recent popularity in mobile electronics requires higher standard on the mechanical strength of electronic packaging. Thus, the method of soldering between chip and substrate in electronic packaging process is changing from conventional method using intermetallic compound to a new method using organic solderability preservatives (OSP) in order to improve the stability and the reliability of final product. Since current OSPs have several serious problems like thermo-stability during packaging process, however, it is necessary to develop new OSPs having thermo-stability. The main purpose of this study is to develop various thermo-stable OSPs based upon poly(vinyl pyridine-co- methylmethacrylate) and to evaluate their anti-oxidation property protecting Cu pad, thermo-stability and solubility to acid- or alcohol-containing aqueous solution during pos-fluxing. All OSPs showed not only good anti-oxidation property, thermo-stability and solubility but also more advantages like low cost, less odor, and less hygroscopic.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.259-264
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• 2020

PURPOSE. The aim of this study was to investigate and compare the color stability of provisional restorative materials fabricated by 3D printing, dental milling, and conventional materials. MATERIALS AND METHODS. For the experimental groups, two commercially available 3D-printing provisional resins (E-Dent 100; EnvisionTEC GmbH, Germany & VeroGlaze™; Stratasys^®, USA), two dental milling blocks (PMMA Disk; Yamahachi Dental Co., Japan & Telio^®CAD; Ivoclar Vivadent AG, Liechtenstein), and two conventional materials (Alike™; GC Co., Japan & Luxatemp automix plus; DMG, Germany) were used. The water sorption and solubility test were (n=10, respectively) carried out according to ISO4049:2000 (International Standards Organization, Geneva, Switzerland). For the color stability test (n=10), coffee and black tea were used as staining solutions, and the specimens were stored for 12 weeks. Data were analyzed by one-way ANOVA and Tukey's HSD using SPSS version 22.0 (SPSS Inc. Chicago, IL, USA) (P<.05). RESULTS. Alike and Veroglaze showed the highest values and Luxatemp showed the lowest water sorption. In the color stability test, the ΔE of conventional materials varied depending on the staining solution. PMMA milling blocks showed a relatively low ΔE up to 4 weeks, and then significantly increased after 8 weeks (P<.05). 3D-printed materials exhibited a high ΔE or a significant increase over time (P<.05). CONCLUSION. The degree of discoloration increased with time, and a visually perceptible color difference value (ΔE) was shown regardless of the materials and solutions. PMMA milled and 3D-printed materials showed more rapid change in discoloration after 8 weeks.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.659-662
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• 2014

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.32-40
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• 2019

PURPOSE. The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS. In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS. For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P<.05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION. Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.243-250
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• 1996

In order to formulate aqueous multivitamin solutions containing both oil-soluble (A, D, E) and water-soluble vitmains ($B_1,\;B_2,\;B_6,\;B_{12}$, C and niacinamide) in 1ml-dose, the effects of various additives such as cosolvents (propylene glycol, polyethylene glycol, glycerin), a sweetener (sorbitol) and a surfactant (Cremophor$^{\circledR}$ RH40) on the solubility of oil-soluble vitamins in water were evaluated. Cremophor$^{\circledR}$ RH40 showed the excellent capacity on the solubilization of oil-soluble vitamins, and the simultaneous addition of cosolvents and surfactant resulted in synergetic effects on the solubilization of oil-soluble vitamins. The effects of the combination of the cosolvents and sweetener on the stability of multivitamin solutions were also evaluated by determining the amount of vitmain A and $B_1$ remained in the solutions after storing at $40^{\circ}C$ for 9 weeks. The formulation consisting of Cremophor$^{\circledR}$ RH40 15%, PG 20%, and sorbitol 20% resulted in the best stability of vitamin A and $B_1$. The stability of vitamin A and $B_1$ in this formulation was evaluated at 50, 60, and $70^{\circ}C$ up to 40 days. The shelf-lives of vitamin A and $B_1$ in the formulation, calculated using the Arrhenius equation, were 1,521 days and 475 days at $20^{\circ}C$, respectively.

• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.73-80
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• 2002

Cefuroxime axetil is a cephalosporin antibiotic having a high activity against a wide spectrum of Grampositive and Gram-negative microorganisms. It is a cephalosporin antibiotic which exist as 2 diastereoisomers: diastereoisomer A and B. It shows polymorphism of three forms: a crystalline form having a melting point of about $180^{\circ}C$, a substantially amorphous form having a high melting point of about $135^{\circ}C$ and a substantially amorphous form having a low melting point of about 70^{\circ}C$. The crystalline form of cefuroxime axetil is slightly soluble in water because diastereoisomer A has lower solubility than B in water. Substantially amorphous form of which there are no difference in solubility between diastereoisomer A and B has better solubility than crystalline form, but it forms a thicker gel than crystalline form upon contact with an aqueous medium. Based on this reason, cefuroxime axetil is not readily absorbable in the gastrointestinal tract, rendering its bioavailability on oral administration very low. The object of this study was to develop an improved non-crystalline cefuroxime axetil composition having a high physicochemical stability and bioavailability. A non-crystalline cefuroxime axetil solid dispersant showing no peak on a Differential Scanning Calorimetry (DSC) scan is prepared by dissolving cefuroxime axetil and a surfactant in an organic solvent; suspending a water-insoluble inorganic carrier in the resulting solution; and spray drying the resulting suspension to remove the organic solvent, said solid dispersant having an enhanced dissolution and stability of cefuroxime axetil and being useful for the preparation of a pharmaceutical composition for oral administration. Tablet was formulated with this cefuroxime axetil solid dispersant, disintegrants and other ingredients. It disintegrated and dissolved easily and dynamically in dissolution medium, so showed a good dissolution profile.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.410-422
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• 1989

Soybean protein isolates were acylated with succinic anhydride and partially hydrolyzed with trypsin. Chemical modification decreased protein contents of samples and, in amino acid composition, tyrosine was increased comparatively. And lysine was increased remarkably by partial proteolysis. Succinylation and trypsin treatment increased the aqueous solubility and shifted the isoelectric potint that showed high pH-dependence of protein solubility. Protein solubility was influenced by salt concentration such as $NaCl,\;CaCl_2,\;NaNO_3$ and $NaH_2PO_4$. Chemical modification increased the absorption of oil and water, emulsification properties and foam capacity, but decreased foam stability, ultraviolet absorbance and bulk density. Protein-protein Interaction between soybean protein isolates and beef protein increased the emulsifying activity, emulsifying activity index and foaming properties, but it didn't have any influence on emulsion stability.