• Journal of Pharmaceutical Investigation
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• 제33권1호
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• pp.7-14
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• 2003

The PVP-based solid dispersion systems (SDs) containing lovastatin (LOS) and solubilizers (sodium lauryl sulfate, tween 80 and oleic acid) were prepared to enhance dissolution rate of practically water insoluble LOS using solvent evaporation method. Two different organic cosolvents either acetone/ethanol or acetonitrile/ethanol were used for the preparation of SDs. The LOS contents were highly decreased when acetone/ethanol cosolvents were used. The decrease of LOS contents was not caused by acetonitrile or acetone, based on HPLC data. The surface morphology as investigated by scanning electron microscope (SEM) and angle of repose as an index of flowability of SDs were highly dependent on the type and amount of solubilizers used. Based on differential scanning calorimetry (DSC) and X-ray powder diffraction data, the SDs made crystalline LOS into amorphous structure or partially eutectic mixtures. The simultaneous use of the solubilizers in SDs was also useful to increase dissolution rate of LOS in gastric or intestinal fluid. The SDs containing solubilizers reached 76% and 60% in gastric and intestinal fluid, respectively but the commercial tablet gave only less than 4%. These solubilizers in SDs could be also applicable for enhancing dissolution and bioavailability of poorly water-soluble drugs.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.412.1-412.1
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• 2002

Purpose. To prepare PVP-based solid dispersions containing lovastatin (LOS) and solubilizers (sodium lauryl sulfate. Tween80. oleic acid) to enhance dissolution of practically insoluble LOS. Methods. Solid dispersions containing LOS were prepared by dissolving two different organic solvent systems (acetone/ethanol or acetonitrile/ethanol). Results. The stickiness and flowability of solid dispersion powders were dependent on the composition and ratio of the solubilizers. (omitted)

• Journal of Pharmaceutical Investigation
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• 제29권3호
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• pp.185-191
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• 1999

The polymeric films containing drug and various excipients were fabricated using aqueous-based $Eudragit^{\circledR}$ RS 30D dispersions. The diffusional behaviors and mechanism of the fabricated polymeric film were investigated using Keshary-Chien diffusion cell. The melatonin was used as a model drug. The diffusion behaviors of drug through the fabricated polymeric films were highly dependent on drug concentration in donor part, polymer contents and drug concentration, and the types of plasticizers and solubilizers. The fabricated polymeric films containing excipients and solubilizers could be applied for the controlled release of poorly water-soluble drug and for the preparation of drug-containing latex films for topical or oral drug delivery.

• 약학회지
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• 제28권3호
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• pp.161-167
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• 1984

To improve the solubility properties of indomethacin, a poorly water-soluble drug, some attempts were made with surfactants, such as sodium deoxycholate, sodium laurylsulfate and polysorbate-80. The enhancement effect in solubility was found to be due to the micellar solubilization and dependent on the concentration of surfactants, pH and temperature. The mechanism of interaction was suggested to be attributed to the formation of mixed micelles between the drug and solubilizers.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.352-359
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• 2012

One hundred thirty-four putative Bacillus isolates were recovered from soybean rhizosphere soils of Nimar region to select effective zinc solubilizers for increased assimilation of zinc (Zn) in soybean seeds. These isolates were screened in vitro for zinc-solubilization ability on Tris-minimal agar medium supplemented separately with 0.1% zinc in the form of zinc oxide, zinc phosphate, and zinc carbonate. Of all, 9 isolates and a reference Bacillus cereus ATCC 13061 were characterized and identified as Bacillus species based on Gram-positive reaction, endospore-forming cells, and the presence of iso-$C_{15:0}$ and anteiso-$C_{15:0}$ as predominant fatty acids. On plate assay, two isolates KHBD-6 and KHBAR-1 showed a greater diameter of solubilization halo and colony diameter on all the three zinc compounds. The isolates KHBD-6, KHBAR-1, BDSD-2-2C, and KHTH-4-1 and the reference strain ATCC 13061 had higher soluble zinc concentration in liquid medium supplemented with zinc phosphate and zinc carbonate compounds as compared with the other isolates and uninoculated control. Evaluation under microcosm conditions showed that inoculation of isolates KHBD-6 (57.34 ${\mu}g/g$), KHBAR-1 (55.67 ${\mu}g/g$), and strain ATCC 13061 (53.10 ${\mu}g/g$) significantly increased the Zn concentration in soybean seeds as compared with the other isolates and uninoculated control (47.14 ${\mu}g/g$). This study suggests the occurrence of zinc-solubilizing Bacillus in soils of Nimar region and isolates KHBD-6 and KHBAR-1 were found to be promising zinc solubilizers for increased assimilation of Zn in soybean seeds.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2577-2580
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• 2014

• 대한화장품학회지
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• 제24권3호
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• pp.111-115
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• 1998

We investigated the stability of all-trans-retinol on the liquid crystalline O/W emulsion composed of mainly alkyl polyglycerine, alkyl polyglucose and glycerine, and compared the activity of all-trans-retinol in the various forms of liquid crystal. Under certain conditions, novel liquid crystalline gel was formed around oil droplets, and layers of this liquid crystalline gel were very wide and rigid. (SWLC; Super Wide Liquid Crystal) SWLC was very helpful to stabilize retinol in O/W emulsion. After storage at 45 C for 4 weeks, all-trans-retinol in O/W emulsion composed of SWLC retained above 85% of the activity upon HPLC analysis, whereas those within no liquid crystalline emulsion gave 47% and normal liquid crystalline emulsion composed of fatty alcohols gave 40 60%. Retinol in oil phase is nealy insoluble in pure water, but in cosmetic emulsion systems can be slightly solubilized into water because emulsifiers and polyols in emulsion systems function as solubilizers. In this case, water in outer phase acts as a media for oxygen transporation$.$and thus destabilizes retinol. As a result, retinol in O/W emulsion has a tendency to become unstable. SWLC surrounding oil droplet which contains retinol is wide and rigid, therefore reduces contact between inner phase and outer phase To make SWLC, properties of emulsifiers are very important phase transition temperature should be high, and the structure of surfactants should be bulky, and their ratio should be suitable to make rigid and wide liquid crystalline gel layer in order to reduce contact between retinol in inner phase and water in outer phase.

• 약학회지
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• 제45권4호
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• pp.357-365
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• 2001

The purpose of this study is to investigate the influence of cyclodextrins (CDs) and different acids on the solubility of fluconazole, and o formulate its more concentrated parenteral aqueous solution. Solubility studies of fluconazole with 7-CD, 2-hydroxypropyl-$\beta$-CD (HPCD), sulfobutyl ether $\beta$-CD (SBCD) and dimethyl-$\beta$-CD(DMCD) were performed. The aqueous solubility of fluconazole was measured in different concentrations of different acids with or without addition of CDs. Solubility of fluconazole increased in the rank order of $\beta$-CD$^1$H-NMR studies confirmed the formation of an inclusion complex of fluconazole with HPCD. It was also shown by the NMR studies that the complex formed was a 1:1 complex. Among the different acids used, maleic acid and phosphoric acid increased solubility of fluconazole. The lower the pH of solution is, the more fluconazole dissolved, regardless of acids. Addition of HPCD (50 mM) to acid solutions increased the solubility about two times. New fluconazole injections at a dose of 10 mg/ml could be prepared in aqueous solutions containing 10% HPCD or 15% SBCD. These parenteral solutions did not form any precipitates at 4$^{\circ}C$ and was very stable at elevated temperatures. These results demonstrate that it is possible to develop a parenteral aqueous solution of fluconazole with a smaller injection volume using HPCD or SBCD.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2731-2736
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• 2012

The use of pyrimethamine as antibacterial drug is limited by the poor solubility. To enhance its solubility, we prepared complexes of pyrimethamine with low-molecular-weight succinoglycan isolated from Sinorhizobium meliloti. Low-molecular-weight succinoglycans are monomers, dimers, and trimers of the succinoglycan repeating unit. The monomers and dimers were separated into their three species (M1, M2, and M3) and four fractions (D1 to D4) using chromatographic techniques, which were shown to be nontoxic. The solubility of pyrimethamine was markedly increased up to 42 fold by succinoglycan D3, where the level of its solubility enhancement was even 8-20 fold higher comparing with cyclodextrin or its derivatives. The complex formation of succinoglycan D3 with pyrimethamine was confirmed by $^1H$ nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and molecular modeling studies. Herein, we suggest that the low-molecular-weight succinoglycans may be utilized as highly effective solubilizers of pyrimethamine for pharmaceutical purposes.

• Journal of Pharmaceutical Investigation
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• 제40권2호
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• pp.85-90
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• 2010

Docetaxel-loaded liposomes were prepared by emulsion-solvent evaporation method, then coated with chitosan at room temperature and lyophilized. This system was designed in order to improve solubility and stability of docetaxel in the GI tract for oral drug delivery. The solubilizing effect of some frequently used solubilizers and/or liposome was determined. Among the results docetaxel-loaded liposomes prepared with 0.5% TPGS as a solubilizer showed 100-fold higher solubility than docetaxel. In a stability test, mean particle size of different liposome formulations was measured by a particle size analyzer in simulated gastric fluid (SGF) and in simulated intestinal fluid (SIF). The particle size of uncoated liposomes was significantly increased compared with that of chitosan-coated liposomes in SGF, however, there was no significant difference between coated and uncoated liposome in SIF. It is evident that chitosan-coated liposomes were more stable in GI conditions. The release characteristics of docetaxel-loaded liposomes were also investigated in three buffer solutions (pH 1.2, 4.0, 6.8). Docetaxel release did not occur in pH 1.2 for 4 hrs. However, in pH 4.0 and 6.8 conditions, docetaxel was gradually released over 24 hrs as a sustained release. It seems that aggregation and precipitation of particles by electrostatic interaction might protect docetaxel from being released. In Conclusion, the results from this study show that the chitosan-coated liposomes may be useful in enhancing solubility and GI stability of docetaxel.