• Journal of Pharmaceutical Investigation
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• v.26 no.1
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• pp.1-11
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• 1996

Biphenyldimethyldicarboxylate (PMC), which has been used to treat hepatitis, is insoluble in water, therefore it has low bioavailability after oral administration. For the purpose of increasing the dissolution rate of PMC, the physical mixtures and inclusion complexes of PMC and $dimethyl-{\beta}-cyclodextrin\;(DM\;{\beta}CD)\;or\;hydroxypropyl-{\beta}-cyclodextrin\;(HP{\beta}CD)$ in molar ratio of 1 : 1 and 1 : 2 were prepared by solvent evaporation method. Mixed micelles of PMC were prepared by reacting PMC with bile salts [sodium cholate(NaC), sodium glycocholate (NaGC)] and oleic acid (OA) or palmitoylcarnitine chloride(PCC). Chloroform/water partition coefficient (PC) of PMC was 36.14 in artificial gastric juice (AGJ) and 33.47 in artificial intestinal juice (AIJ), respectively, on the other hand octanol/water PC was 63.36. PMC formulation was prepared by reacting PMC with PEG400-glycerin system(95 : 5, 90 : 10, respectively) and PEG400-PEG4000-glycerin system (70 : 25 : 5, 65 : 25 : 10, respectively). Dissolution test was performed in AGJ and AIJ by paddle method at $37{\pm}0.5^{\circ}C$. The dissolution rates of PMC tablets on the market were 5.74% and 8.26% at AGJ and AIJ, respectively and marketed PMC capsules were 22.14% and 28.64% at AGJ and AIJ, respectively. The dissolution rates of inclusion complexes of PMC with $DM{\beta}CD$ and $HP{\beta}CD$ in a molar ratio of 1 : 1 were more fast than those of corresponding physical mixtures. The decreasing order of dissolution rates was as follows; PMC-PEG400-PEG4000-glycerin formulation > PMC-PEG400-glycerin formulation > mixed micelles > CD inclusion complexes. The dissolution rates of PMC-PEG400-glycerin and PMC-PEG400-PEG4000-glycerin formulation were most fast and the percentage of dissolution was almost 100% within 20 minutes. And their dissolution rates after 120 minutes were markedly increased as compared with capsules on the market (4.0-fold and 3.2-fold in PMC-PEG400-glycerin formulation at AGJ and AIJ, respectively, and 4.8-fold and 3.7-fold in PMC-PEG400-PEG4000-glycerin formulation at AGJ and AIJ, respectively).

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.108-118
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• 2001

This study was performed to investigate the bioconcentration of IBP, methidathion and piperophos. The BCFs(bioconcentration factor), depuration rate constants for three pesticides in zebrafish(Brachydanio rerio) were measured by OECD guideline 305. The concentration of test pesicides were one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ in accordance with OECD guideline 305. The results obtained are summarized as follows: The average BCF values of IBP were 5.31(n=4) and 7.30(n=4) at one-hundredth and one-thousandth concentration of 96-hrs L $C_{50}$ . The average BCF values of methidathion were 8.72(n=4) and 11.25(n=4), the average BCF values of piperophos were 34.30(n=4) and 42.60(n=4). Depuration rate constants of IBP were 0.09( $h^{-1}$ ) and 0.08( $h^{-1}$ ), half-life of IBP were 7.70 and 8.66 at each tested concentration. The concentrations of IBP in zebrafish at low and high concentrations rapidly decreased after 12(0.243$\mu\textrm{g}$/g) and 12 hours(0.040$\mu\textrm{g}$/g). Depuration rate constants of methidathion were 0.40( $h^{-1}$ ), half-life of methidathion were 1.73 at one-hunderdth and of 96-hrs L $C_{50}$ , repectively. The concentrations of methidathion in zebrafish at high concentrations rapidly decreased after 6 hours(0.18 $\mu\textrm{g}$/g). Depuration rate constant of low concentration was no measured because methidathion in zebrafish was depurated in 6 hours. Depuration rate constants of piperophos sere 0.15( $h^{-1}$ ) and 0.44( $h^{-1}$ ), half-life of piperophos were 4.62 and 1.58 at each tested concentration. The concentrations of piperophos in zebrafish at los and high concentrations rapidly decreased after 12(0.26$\mu\textrm{g}$/g) and 6 hours(0.015 $\mu\textrm{g}$/g). It was suggested that high BCF of piperophos was due to high Kow(octanol-water partition coefficient). The possibility of bioconcenration was not likely to be high because of its $K_{DEP}$(depuration rate constant) in the evniroment. It was suggested that low BCF of methidathion showed lowest Kow as well as the most rapid $K_{DEP}$. Therefore, the possibility of bioconcentration was not occured in the enviroment. It was suggested that the BCF dtermined for IBP was lower than that of other pesticides due to high Sw(water solubility), show $K_{DEP}$. Therefore, IBP revealed little bioconcentration effect on in aquatic ecosystem.ystem.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.625-630
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• 2002

Raw pine-mushrooms (Tricholoma matsutake Sing.) of four grades and those frozen were analyzed for proximate composition, smell pattern, volatile flavor compounds, and sensory evaluation. Proximate compositions of raw pine-mushrooms (A-C, regular grade) were $89.48{\sim}90.77%$ moisture, 6.81% ash excluding D (below regular grade) sample, $2.24{\sim}2.52%$ crude lipid, and $16.19{\sim}20.01%$ crude protein. Proximate compositions of frozen pine-mushrooms preserved for 6 months at -20 and $-70^{\circ}C$ showed no difference compared with raw pine-mushrooms. Results of smell pattern and multidimensional analysis revealed raw pine-mushrooms showed no differences among samples, but frozen pine-mushrooms differed significantly depending on the grade. Volatile flavor compounds of pine-mushrooms were analyzed using a purge and trap method with GC/MSD. Twenty-nine volatile compounds were identified, among which alcohols such as 1-octen-3-ol, 2-octen-1-ol, 3-methyl-butanol, and n-octanol were commonly found in all pine-mushroom samples. In sensory attributes, raw pine-mushrooms were not significantly different at 5% level, and sample D of frozen pine-mushrooms scored lower than samples $A{\sim}C$.

• Food Science and Preservation
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• v.30 no.3
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• pp.492-501
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• 2023

In this study, we wanted to understand the impact of different decaffeination processes on aroma compounds of coffee. Therefore, we analyzed differences in physical characteristics and volatile aroma compounds profiles of regular coffee (RC), Swiss water process decaffeinated coffee (SWDC), and supercritical CO₂ decaffeinated coffee (SCDC) after roasting the coffee beans. The electronic nose analysis identified RC and SCDC as different groups which indicates that these groups volatile aroma compound compositions were different. The principal component analysis of volatile compound patterns identified using an electronic nose indicated that there was a large difference in volatile compounds between RC, which was not decaffeinated, and both decaffeinated SWDC and SCDC. The major aroma compounds of RC, SWDC and SCDC were propan-2-one and hexan-2-one which are ketone, and hexanal and (E)-2-pentenal which are aldehyde and 3-methyl-1-butanol which is an alcohol. After roasting, the composition of major volatile compounds appearing in the beans was similar, but the relative odor intensity was different. We identified 28 volatile aroma compounds from RC, SWDC, and SCDC using headspace-solid phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS), and analyzed 10 major compounds that were present in high abundance, including furfural, 2-furanmethanol, 2,5-dimethylpyrazine, and 2-ethyl-3-methylpyrazine.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.45-57
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• 2015

Objectives: This study aims to compare the physicochemical characteristics, toxicological data with Occupational Exposure Limits (OELs) of chemicals under the Occupational Safety and Health Act(OSHA) regulated by the Ministry of Employment and Labor of Korea. Methods: Information on chemicals which have OELs on physicochemical characteristics and toxicological data was collected using Material Safety Data Sheet(MSDS) from Korea Occupational Safety and Health Agency(KOSHA) and the Korea Information System for Chemical Safety Management(KISChem) in 2014. Statistical analyses including correlation and simple regression were performed to compare the OELs with chemical characteristics including molecular weight, boiling point, odor threshold, vapor pressure, vapor density, solubility and octanol-water partition coefficient(OWPC) and toxicological data such as median lethal dose($LD_{50}$) and median lethal concentration($LC_{50}$). Results: A total of 656 chemicals have OELs under OSHA in Korea. The numbers of chemicals which have eight-hour time weighted average(TWA) and short term exposure limits(STEL) are 618 and 190, respectively. TWA was significantly correlated with boiling point and STEL was only correlated with vapor pressure among physicochemical characteristics. Solubility and OWPC between "skin" and "no skin" substances which indicate skin penetration were not significantly different. Both $LD_{50}$ and $LC_{50}$ were correlated with TWA, while the $LC_{50}$ was not with STEL. As health indicators, health rating and Emergency Response Planning Guidelines(ERPG) rating as recommended by the National Fire Protection Association(NFPA) and American Industrial Hygiene Association(AIHA) were associated with OELs and reflect the chemical hazards. Conclusions: We found relationships between OEL and chemical information including physicochemical characteristics and toxicological data. The study has an important meaning for understanding present regulatory OELs.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1021-1026
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• 2012

The transient mass transfer in a single droplet system consisting of 1-octanol (continuous phase)/aqueous succinic acid solution (dispersed phase) was investigated in the presence of chemical reaction, which is acid/anion exchange reaction of succinic acid and tri-n-octylamine (TOA). This succinic acid extraction by TOA can be considered to occur at the interface between organic and aqueous phase, that is, heterogeneous reaction system. The basic properties of the system such as viscosity, density, distribution coefficient, terminal velocity of droplet, and diffusion coefficient were measured experimentally or calculated theoretically, and used for theoretical calculation of characteristic parameters of mass transfer later. The effects of succinic acid concentration on the terminal velocity was negligible in the existence of TOA, although the terminal velocity increases with succinic acid concentration in the absence of TOA. On the contrary, the terminal velocity decreases with TOA concentration. While droplets falls through organic phase, the trajectory of droplets is observed to oscillate around its vertical path. A mass trnasfer cell was prepared to monitor the mass transfer behavior in a single droplet and used to measure the mean concentration of succinic acid inside droplet. The results are expressed with dimensionless parameters. Under 50 g/L succinic acid condition, the system with 0.1 mol/kg TOA showed that the molar flux decreases in proportion to the decrease of concentration gradient, while in the case of 0.5 mol/kg TOA Sh increases rapidly with time indicating the molar flux of succinic acid decreases relatively slowly compared to the decrease in concentration gradient.

• Journal of the Korean Chemical Society
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• v.35 no.3
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• pp.226-232
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• 1991

Adsorption and oxidation of polychlorinated phenols by suspended ${\sigma}-MnO_2$ in aqueous solution have been studied. Of the proposed mechanism, adsorption reaction of chlorophenols onto ${\sigma}-MnO_2$(s) depended upon the pH of the solution and the concentration of chlorophenol. Adsorption isotherms showed a reasonably good fit to the Langmuir isotherm. From the pH dependence of adsorption partition coefficient and the linear relationship between octanol-water partition coefficient and adsorption partiton coefficient of chlorophenol, it is estimated that adsorption is dominated by its hydrophobicity. The rate of electron transfer reaction evaluated from the rate of reductive dissolution of ${\sigma}-MnO_2$(s) depended linearly upon the concentration of chlorophenol and the pH of medium. Observed rate constants ($K_0$) of the meta-substituted chlorophenol were lower than that of the ortho-or para-chlorophenol because of resonance effect of chlorophenoxy radical. It is indicated that this radical is produced in the adsorption process and the electron transfer reaction is rate determining.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.11-17
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• 2019

Strawberries are one of the main commodities in Korea and have been exported over 40 million dollar. Because the strawberry cultivation using hydroponics has increased, treatment of pesticide by drenching draw interest recently. However, detailed researches for drenching treatment of pesticide are limited, which results in difficulties in proper pesticide applications in agricultural fields. To activate use of drenching and improve safety in agricultural products, In this study, time-dependent residual characteristic of pesticides were compared with between different applications of pesticides in strawberries. The characteristics of azoxystrobin, prochloraz and thiamethoxam were investigated with drenching treatment at different applications: the time of treatment, concentration etc. at hydroponic cultivation for 40 days. Azoxystrobin and prochloraz were not detected at 14 day after application. Thiamethoxam was detected from 0.02 to 0.85 mg/kg. Crop uptake of pesticides was strongly affected with octanol-water partition coefficient and solubility in water. Residual amount in crops are highly dependent on the concentration of active ingredient of pesticides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.242-250
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• 2016

Although rice has been cultivated as a major food crop for approximately 5,000 years, the interest of customers in 'scented rice' is a recent trend in the Korean market. As a part of developing a germinated scented rice variety, the newly bred scented rice variety 'Cheonjihyang-1 se' was germinated for 24 h, and changes in profiles of flavor-related volatiles, lipophilic phytonutrients, and fatty acids were investigated. The profiling of volatile compounds by using a headspace-gas chromatography-mass spectrometry (HS-GC-MS) revealed a total of 56 odor-active flavoring compounds; 52 at the pre-germination stage, 51 at the post-germination stage, and 47 common at both stages. The major flavoring compounds were nonanol and benzene, which constituted 11.5% and 6.6%, respectively, of the total peak area in pre-germinated rice, and 19.4% and 6.5%, respectively, in post-germinated rice. Germination induced an increase in 13 flavoring compounds, including 3,3,5-trimethylheptane and 1-pentadecene, which increased by 763 and 513%, respectively by germination. However, we observed a germination-induced decrease in most of the other flavoring compounds. Especially, the most important scented rice-specific popcorn-flavoring compound, 2-acetyl-1-pyrroline, showed 89% decrease due to germination. Furthermore, the germination of scented rice induced a decrease in the content of various phytonutrients. For example, the total contents of phytosterols, squalene, and tocols decreased from 207.97, 31.74, and $25.32{\mu}g\;g^{-1}$ at pre-germination stage down to 136.66, 25.12, and $17.76{\mu}g\;g^{-1}$, respectively at post-germination stage. The fatty acid compositions were also affected by germination. The composition of three major fatty acids, linoleic, oleic, and palmitic acids, increased from 36.6, 34.2, and 24.4%, respectively, at the pre-germination stage to 37.9, 36.9, and 20.7%, respectively, at the post-germination stage. All these results suggested significant changes in the flavor-related compounds and phytonutrients of the scented rice variety 'Cheonjihyang-1 se' during the process of germination, and subsequently the need for developing a more precise process of germination to enhance the flavor and nutritional quality of the germinated scented rice products.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.285-292
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• 2013

This study was carried out to validate the safety of ametoctradin residues in agricultural commodities by developing an official analysis method. An analytical method was developed and validated using HPLC-PDA detectors. The samples were extracted with methanol, subsequently partitioned with dichloromethane and purified with florisil column chromatograph using acetone/hexane (30/70, v/v) as solvent. The method was validated by using grape, hulled rice, mandarin, and potato spiked with ametoctradin at 0.05 and 5.0 mg/kg, and pepper at 0.05 and 2.0 mg/kg. Average recoveries were 76-114.8% with relative standard deviation less than 10%, and the limit of detection and limit of quantification were 0.0125 and 0.05 mg/kg, respectively. The result of recoveries and overall coefficient of variation of the laboratory results from Gwangju regional Food and Drug Administration (FDA) and Daejeon regional FDA was accorded with Codex Alimentarius Commission Guideline (CAC/GL 40). Based on these results, this method was found to be appropriate for ametoctradin residue determination and can be used as the official method of analysis.