• YAKHAK HOEJI
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• v.27 no.1
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• pp.11-19
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• 1983

Rifampicin-arginine complex was prepared to increase the solubility and dissolution rate of rifampicin. Solvation method was applied to make the complex and its formation was identified by the solubility method, powder x-ray diffractometry, differential thermal analysis and spectroscopic determination. The complex was formed in the molar ratio of 1 : 1 which was proved by the slope ratio method and continuous variation method. The complex was a non-crystalline form determined by the x-ray powder diffractometric analysis. The solubility of complex in water was significantly higher than that of rifampicin itself. The stability constant and thermodynamical properties of the complex were determined to investigate the solubilization phenomena. The thermodynamic data showed that the complexation between rifampicin and arginine was an exothermic and spontaneous reaction. Simulated absorption studies carried out through the artificial lipid barrier in artificial gastric and intestinal juices. The results showed that the complex had an enhanced absorption rate of rifampicin nearly twice compared with that of rifampicin itself.

• Journal of Energy Engineering
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• v.23 no.1
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• pp.33-39
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• 2014

This study was performed with electrolysis treatment method for improving anaerobic digestion gas production efficiency in a sewage sludge, thereby confirmed in anaerobic digestion production and denitrification effect. As a result, solubilization was increased by increasing treatment time of electrolysis and current density, also showed to be 9.02% with 10 mA/cm2 of current density in 4 mm electrode distance. Based on the results of BMP test used the above experiment, methane production was 0.49 L CH4/g VS, and increased by 88.4% compared with control groups. As for the results of denitrification using the sewage sludge treated with the same conditions, denitrification rate appeared $19.2mg\;NO_3{^{-}}N/g\;MLVSS{\cdot}hr$, and through the sewage sludge treated with electrolysis, it can be applied to anaerobic digestion and denitrification process by increasing biodegradation.

• Environmental Engineering Research
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• v.19 no.1
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• pp.83-89
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• 2014

The effects of initial solid concentration and microwave irradiation (MWI) time on the hydrolysis of waste activated sludge (WAS) were investigated. MWI time strongly influenced WAS hydrolysis for all initial solid concentrations of 8.20, 31.51, and 52.88 g VSS/L. For all WAS, the volatile suspended solids (VSS) solubilization degree ranged from 35.6% to 38.4% during a total MWI time of 10 min. Soluble chemical oxygen demand (SCOD) concentration increased at a rate proportional to the decrease of VSS during the MWI. However, the clearly different VSS solubilization patterns that were observed during the MWI were explained by the 2-step hydrolysis of WAS, consisting of the initial disintegration of the easily degradable part of the sludge, followed by the subsequent disintegration of the hardly degradable part of the sludge. WAS hydrolysis rates for 3 to 6 min of MWI were significantly lower than those for less than 3 min, or more than 6 min. From these results, 3 min MWI time and WAS of 31.51 g VSS/L (centrifugal thickener WAS) showed the most efficient hydrolysis of WAS at 36.0%. The profiles of total nitrogen (T-N) concentrations corresponded well to the SCOD increases in terms of the empirical formula of bacterial cell mass ($C_5H_7O_2N$). The negligible T-N increase and pH decrease during WAS hydrolysis by MWI will allow the application of this process to subsequent biological processes, such as anaerobic digestion.

• Journal of Environmental Science International
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• v.17 no.9
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• pp.1033-1037
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• 2008

The effects of inorganic salts, inoculum concentration, aeration rate and shaking speed on insoluble phosphate solubilization by Pseudomonas fluorescens RAF15 were investigated. Soluble phosphate production was dependent on the presence of $MgCl_2{\cdot}6H_2O$ and $MgSO_4{\cdot}7H_2O$ in the medium. Supplementation of medium with 0.01% $CaCl_2{\cdot}2H_2O$ and 0.01% NaCl slightly increased soluble phosphate production. The optimal medium compositions for the solubilization of insoluble phosphate by P. fluorescens RAF15 were 1.5% glucose, 0.005% urea, 0.3% $MgCl_2{\cdot}6H_2O$, 0.01% $MgSO_4{\cdot}7H_2O$, 0.01% $CaCl_2{\cdot}2H_2O$ and 0.01% NaCl, respectively. Optimal inoculum concentration was 2.0%(v/v). Maximum soluble phosphate production was obtained with 20-50 ml/250-ml flask and 200 rpm of shaking speed, respectively. The addition of EDTA decreased cell growth and soluble phosphate production.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.475-481
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• 2006

The major problem in closing water like lakes and ponds in Korea is that because they are exposed to surrounding, so easily polluted. The pollution in closing water can be caused by not only artificial factor like sewage but also natural factor like elution from sediment. For insurance of safe and satisfied water source, lots of studies and projects are now going on. In this study, we examined the behavior and effect of microbubble ($3{\sim}10{\mu}m$) produced by device called O.S.D (Oxygen Solubillization Device) in small size pond. The value of oxygen transfer coefficient ($K_La$) was 0.68/min independently of air flow rate, 6.5 times higher than commercial aeration stone and the variation of nitrogen concentration was $0.008NO_3/O_2$, DO concentration was potentially saturated for 24 hr. From the results of pilot plant, SOD of experiment (O.S.D) and control were $12.18gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ and $47.95gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ respectively. In conclusion, because O.S.D has extraordinary physico-chemical characteristics, it can contribute to improvement of both the waterbody and the sediment environment.

• Journal of Pharmaceutical Investigation
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• v.25 no.1
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• pp.31-36
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• 1995

Solid dispersions and inclusion complex were prepared for the enhancement of solubility and dissolution rate of poorly water-soluble ibuprofen(IPF) as a model drug. Polyethylene glycol 4000(PEG4000) and polyvinylpyrrolidone(PVP) were used for the preparation of solid dispersion. $2-Hydroxypropyl-{\beta}-cyclodextrin(2-HP{\beta}CD)$ was also used for the preparation of inclusion complex. The solubility of IPF increased as the concentration of PEG4000, PVP and $2-HP{\beta}CD$ increased. Solubilization capacity of $2-HP{\beta}CD$ was increased about 10 times when compared to PEG 4000 and PVP. The dissolution rate of drug from solid dispersions and inclusion complex in the simulated gastric fluid was enhanced when compared to pure IPF and commercial $BR4^{\circledR}$ tablet as a result of improvement of solubility. In case of solid dispersions, dissolution rate of drug was proportional to polymer concentration in the formulation. The marked enhancement of dissolution rate of drug by inclusion complexation with $2-HP{\beta}CD$ was noted. However, dissolution rate of drug from solid dispersions and inclusion complex in the simulated intestinal fluid was not significant because IPF was readily soluble in that condition. From these findings, water-soluble polymers and cyclodextrin were useful to improve solubility and dissolution rate of poorly water-soluble drugs. However, easiness and reliability of preparation method, scale-up and cost of raw materials must be considered for the practical application of solid dispersion and inclusion complex in pharmaceutical industry.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.334-335
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• 2006

• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.263-267
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• 2010

Nanoemulsions have been widely investigated for many years because of their attractive and unique characteristics. Nanoemulsions are composed of oil, surfactant, co-surfactant and water. Especially, cosurfactant plays a critical role in formation of nanoemulsions. In pharmaceutical area, a pre-concentrate form of nanoemulsions which is known as self-nanoemulsifying drug delivery systems (SNEDDS) was available for some water-insoluble drugs. In this study, we investigated the functional behaviors of cosurfactant in design of SNEDDS and nanoemulsions. Cremophor RH 40$^{(R)}$, Propylene carbonate and medium chain triglyceride were selected for surfactant, cosurfactant and oil, respectively. Cyclosporine was employed as a drug. Phase diagrams showed the area of isotropic o/w region which forms o/w nanoemulsions was not significantly affected by the compositional ratio of cosurfactant. But, drug solubilization capacity, droplet size of nanoemulsions and drug release rate were greatly affected by the cosurfactant.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.781-785
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• 2012

This study was carried out to treat the thermal elutriated acids of piggery wastewater using UASB process. The UASB reactor was operated at an organic loading rate (OLR) of $7.4\;kgCOD/m^3-day$ (6.5 ~ 9.0). During the start-up period, the low COD removal efficiency (20%) was caused by shock loading and instability in the reactor. It was mainly due to the high concentration amounts of ammonia nitrogen, which caused inhibitory and toxic effects to toward the anaerobic bacteria. In steady state, the UASB reactor showed a SCOD removal efficiency of 71% and a VS removal efficiency of 39%. The gas production and methane content were 1.3 L/day $(0.21\;m^3\;CH^4/kg$ COD removed) and 77%, respectively.

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.181-185
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• 2010

The objective of this study was to improve the extent of drug release as well as the dissolution rate of TD49, a novel algicidal agent, via the preparation of solid dispersion (SD). Among the various carriers tested, $Solutol^{(R)}$ HS15 was most effective to enhance the solubility of TD49. Subsequently, SDs of TD49 were prepared by using $Solutol^{(R)}$ HS15 and their solubility, dissolution characteristics and drug crystallinity were examined at various drug-carrier ratios. Solubili ty of TD49 was increased significantly in accordance with increasing the ratio of $Solutol^{(R)}$ HS15 in SDs. Compared to untreated powders and physical mixtures (PMs), SDs facilitated the faster and greater extent of drug release in water. Particularly, SD having the drug-carrier ratio of 1:20 exhibited approximately 90% of drug release within 1 hr. Differential scanning calorimetry (DSC) thermograms and X-ray diffraction (XRD) patterns suggested that SDs might enhance the dissolution of TD49 by changing the drug crystallinity to an amorphous form in addition to the increased solubilization of drug in the presence of $Solutol^{(R)}$ HS15. In conclusion, SD using $Solutol^{(R)}$ HS15 appeared to be effective to improve the extent of drug release and the dissolution rate of poorly water soluble TD49.