• Journal of Pharmacopuncture
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• v.21 no.2
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• pp.48-60
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• 2018

Objective: The aim of this study is to optimize the extraction of beneficial substance from Cudrania tricuspidata leaves grown at Jirisan Mountain in South Korea by three different solvents depending on extraction time and at different temperature. Methods: The total phenolic contents were determined by the method reported by $S{\acute{a}}nchez$-Moreno et al. The total flavonoid contents were analyzed by Slinkard and Singleton. The DPPH radical scavenging activity was determined according to the method reported by Blois Results: The extraction yield for each solvent is 9.05-14.1%, 2.17-5.67%, and 2.3-3.9% for D.W., ethanol, and hexane, respectively. The overall results were maximized for the extract obtained with D.W. for 5 min at $100^{\circ}C$. The average phenol contents were 77.11, 45.64, and 0.343 mg/g at $100^{\circ}C$ in water, $78^{\circ}C$ in ethanol, and $68^{\circ}C$ in hexane, respectively. The flavonoid contents were the highest in the materials extracted with D.W., and were increased with increasing temperature, regardless of the extraction solvents, whether water (green), polar organic ethanol, or nonpolar organic hexane. In the ethanol extract, the flavonoid contents are increased gradually from 5.66 mg/g to 7.73 mg/g. The total flavonoid contents were proportional to the concentrations of the water extracts, ranging from 4.14 mg/g to 48.89 mg/g. The antioxidative activities of the water-extracted compounds are generally increased with increasing temperature from 42.5% to 85.5%. Those of the hexane extracts are increased slowly from 3.79% to 8.8%, while those of ethanol extracts are increased from 29.8% to 47.4%. Conclusion: The extraction yields were dependent upon solvents for extraction as well as extraction time and the temperature. The optimal extraction time was 5 min and the extraction yields were increased with increasing temperature excepted hexane. Of the three tested extraction solvents, the greenest solvent of water shows excellent results, suggesting that water is among the most effective solvents for natural sample extractions for general medicinal, pharmaceutical, and food applications.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.796-801
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• 1992

An empirical Lewis basicity, DN, for eight mixed methanol solvents has been measured by the solvatochromic behavior of the [Cu(tmen)(acac)]$CIO_4$. The change of DN in mixed methanol solvents is not correlated with composition of the mixtures and divided into three groups: (1) dipolar aprotic solvents contribute mainly to the solvation of solute (MeOH-DMSO, MeOH-PY, MeOH-DMF), (2) two components of mixture contribute equally to the solvation of solute (MeOH-MeCN, MeOH-dioxane, MeOH-AC) and (3) methanol contributes entirely to the solvation of solute (MeOH-DCE, MeOH-TCE). The relationship between DN and Kamlet-Taft's $B_{KT}$ for mixed methanol solvents was found to agree well. These DN values also were a useful factor to analysis of reactivity for mixed methanol solvents.

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.493-501
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• 2005

Effect of solvents on physical characteristics and release characteristics of monolithic acetaminophen (APAP) hydroxypropylmethylcellulose (HPMC) matrix granules and tablets were examined. Various types and amounts of solvents were employed for granulation and coating. APAP and other excipients were mixed and were then wet-granulated in a high-speed mixer. The dried granules were then directly compressed and film-coated with low viscosity grade HPMC. As the amount of water increased, the size of granules also increased, showing more spherical and regular shape. However, manufacturing problems such as capping and lamination in tableting occurred when water was used alone as a granulating solvent. The physical properties of HPMC matrix granules were not affected by the batch size. The initial release rate as well as the amount of APAP dissolved had a tendency to decrease as the water level increased. Addition of nonaqueous solvent like ethanol to water resulted in good physical properties of granules. When compared to water/ethanol as a coating solvent, the release rate of film-coated HPMC matrix tablets was more sensitive to the conditions of coating and drying in methylene chloride/ethanol. Most of all, monolithic HPMC matrix tablet when granulated in ethanol/water showed dual release with about $50\%$ drug release immediately within few minutes followed by extended release. It was evident that the type and amount of solvents (mainly water and ethanol) were very important for wet granulation and film-coating of monolithic HPMC matrix tablet, because the plastic deforming and fragmenting properties of material were changed by the different strengths of the different solvents.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.255-264
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• 1989

The minimum concentrations of organic solvents inducing phytotoxicity were investigated after spraying or flooding solvent solutions to annual plants. In the foliar treatment of upland test, solvents with high-boiling point or low-polarity induced severe phytotoxicity. Especially, aromatic solvents induced severe phytotoxicity. The most sensitive plant to phytotoxicity was soybean. In the pre-emergence treatment of upland test, the solvents with high-boiling point only induced phytotoxicity at high concentration. The degree of phytotoxicity induced by foliar spray in the condition of paddy field was similiar to that of upland test, but in the pre-emergence test, the former was more severe than the latter. Among 6 treatments, phytotoxicity induced by solvents was most severe in the pre-emergence test under the condition of flooding paddy field. Generally, alcohols induced severe phytotoxicity, especially, ethanol at 0.001%.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.147-164
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• 1993

A study has been conducted on developing questionnaires to serve as on site diagnostic tools for the early detection of neuropsychiatric impairment among workers chronically exposed to low-level organic solvents. Two drafts of tentative questionnaires have been developed as follows; several question items were selected from questionnaires which were administered to workers exposed to organic solvents in previous studios and were grouped into each symptom category based on the presence of its association using Guttman scaling method, then these selected items were reviewed by neuropsychiatry specialists. The final draft of the questionnaire (total symptom score=36) was developed by selecting 33 question items which had more than a 0.88 Guttman coefficient of reproducibility in each symptom category from a pilot study in which these tentative questionnaires were administered to workers manufacturing soles. Three plants using organic solvents and one plant never using organic solvents as a control group were selected to test the reliability and validity of the developed questionnaires. The major organic solvent in the workplace environment detected by a personal air sampler and GC/MSD nab toluene. The concentration of toluene in air from the department using organic solvent was statistically different from that of the department never using organic solvent. The concentration of toluene from almost all of the workplace did not exceed the allowable level. There was no statistically significant difference between the concentration of urinary hippuric acid from the workers of the department using organic solvent and that of the department never using it. Total symptom score of the plant never using organic solvents was 9.8 and those of the three plants using organic solvents were 15.6, 14.7, and 13,7 respectively. In order to evaluate the validity of the questionnaires, the workers from two different departments of the plant in which usage of organic solvents are totally dofferemt were compared. The total symptom score was 17.8 for workers of the department using organic solvent and 13.5 for the department never using organic solvent and scores of each symptom group between exposure and non-exposure group also showed statistically significant difference. The finding that total symptom score of the exposure group increased as the duration of employment increased indirectly suggests the usefulness of the developed questionnaire to assess the health effects of chronic exposure to organic solvents. The correlation coefficient, which was calculated to evaluate the test-retest reliability, was 0.581 (p=0.001). The coefficient of Crohnbach which reflects the internal consistency of the questionnaire was 0.91. In conclusion, the reliabilty of the questionnaire was well maintained over the time lapse between the two administrations of the questionnaire and despite the seasonal difference.

• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.61-67
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• 1997

This study was performed to evaluate the effects on hearing of video tape manufacturing workers exposed to organic solvents. The experimental groups included solvents exposed group 51 and unexposed group 57 workers. All workers was examined air and bone conduction sensitivity by pure tone audiometer. The mean age of solvents exposed group was 34.1 and nonexposed group was 35.8. The mean duration of solvents exposed group was 7.3years. High frequency hearing loss prevalence of both groups was 23.5% in the group exposed to organic solvents and 17.5% in nonexposed group. There is no statistical significants in the prevalence of high frequency hearing loss. According to comparison of mean auditory threshold value by frequencies, on the air conduction test, right was statistically significant in the 250, 500, 1000, 2000, 4000Hz, except 8000Hz. Left 250, 500, 1000Hz was statistically significant. On the bone conduction test, left 250, both 500, 1000, 2000, 4000Hz, except right 250Hz, was statistically significant difference. Generally, auditory sensitivity threshold of the exposed group was higher than the nonexposed group.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.163-170
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• 2014

Lipid membranes composed of phosphatidylcholine (PC) are used in biophysical study to mimic cellular membranes and interactions between the membrane and chemicals, where organics solvents are used in dissolving lipids or chemicals. Later, solvents are removed from the solution under nitrogen gas at room temperature, followed by the further removal of the solvent at vacuum condition for several hours. In this process, some solvents are easily removed under described conditions above and others are required more severe conditions. In this study, $^{31}P$ solid-state nuclear magnetic resonance (SSNMR) techniques and differential scanning calorimetry (DSC) were used to see any changes in the line shapes of $^{31}P$ NMR spectra of multilamellar vesicles (MLVs) samples of POPC and in the phase change temperature of multilamellar vesicles (MLVs) of DPPC in DSC thermogram with or without any residual solvents. The thermodynamic parameters associated with the solvents did exhibit noticeable changes depending on solvent types. Thus, it is concluded that solvents should be carefully chosen and removed completely and experimental results should also be interpreted with caution particularly for the experiments investigating lipid phase changes and related topics.

• Membrane Journal
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• v.25 no.1
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• pp.48-59
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• 2015

This paper reports a fabrication of poly(L-lactic acid) (PLLA) scaffold membranes through phase separation process using pure and mixed solvents. Chloroform and 1,4-dioxane were used as pure solvents and mixed solvents were obtained by mixing the pure solvents together. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. Scaffold membranes from the solution with pure chloroform showed solid-wall pore structure. In contrast, nano-fibrous membranes were fabricated from the solution with pure 1,4-dioxane. In case of mixed solvents, the scaffold membranes showed various structures with changing composition of the solvents. When 1,4-dioxane content was lower than 20 wt% in the solvent, scaffold membrane showed solid-wall pore structure. When the content was 20 wt%, scaffold membranes with macropores with the maximum size of $100{\mu}m$ was obtained. In the concentration range of 1,4-dioxane over 25 wt%, the scaffold membranes showed nano-fibrous structures. In this range, the fibers showed different diameters with changing composition of the solvent. The minimum fiber diameter was about $15{\mu}m$, when 1,4-dioxane composition was 80 wt%. These results indicate that the composition of the solvent showed a significant effect on the structure of scaffold membrane.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.751-756
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• 2003

We have investigated the solvent effects on Δlog $K_s$ (the difference of stability constant of binding) and the relative free energies of binding of $La^{3+} and Nd^{3+}$ ions to 18-crown-6 by a Monte Carlo simulation of statistical perturbation theory (SPT) in diverse solvents. We compared relative binding Gibbs free energies and the differences in stability constant (Δlog $K_s$) of binding of $La^{3+} and Nd^{3+}$ ions to 18-crown-6 in $CH_3OH$ in this study with the experimental. There is a good agreement between our study and the experimental. We noted that Borns function of the solvents, the electron pair donor properties of the solvent, the radii of host and guest and the differences in solvation dominate the differences in the stability constant (Δlog $K_s$) as well as the relative free energies of binding of TEX>$La^{3+} to Nd^{3+}$ ions to 18-crown-6. The results of this study appear promising for providing the association properties of crown ethers with alkaline earth metals among polar solvents and the less polar or non-polar solvents.

• KSBB Journal
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• v.16 no.3
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• pp.233-236
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• 2001

Because of casehardenign effect of amorphous paclitaxel, residual solvents, methylene chloride and emthanol could not be reduced to the maximum value allowed, 600 ppm and 3,000 ppm, in accord with the guidelines issued by the International Conference on Harmonization (ICH, 1997), using rotary evaporation and successive drying in a vacuum oven. However, methylene chloride and methanol were reduced to 486 ppm and 403 ppm, respectively using supercritical $CO_2$ on purified paclitaxel. The optimum pressure and operating time were 80 bar and 30 min at fixed operating temperature ($40^{circ}C$). This approach serves as a novel application of supercritical fluid extraction to remove residual solvents from active pharmaceutical ingredients.