• Journal of Pharmaceutical Investigation
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• v.29 no.1
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• pp.29-36
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• 1999

Aceclofenac is an non-steroidal antiinflammatory drug which has been used in the treatment of rheumatoidal rthritis and osteo-arthritis. In order to decrease the gastric ulcerogenic effects and contol the plasma level of aceclofenac, we have developed the transdermal delivery system of aceclofenac plaster, which were formulated employing matrix polymers of acrylates and penetration-enhancers such as $Lauroglycol^{\circledR}$, $Transcutol^{\circledR}$, oleic acid and linoleic acid. Using Franz diffusion cells mounted with a rat skin, transdermal penetration characteristics of the formulations were evaluated by the HPLC assay of aceclofenac and diclofenac, an active metabolite, in the receptor compartment of pH 7.2 phosphate buffered solution. Skin penetration was increased when the content of aceclofenac increased, showing the flux $(J,\;{\mu}g/cm^2/hr)$ of 0.37 and 2.50 for 2% and 6.75% of the content, respectively. The flux$(J,\;{\mu}g/cm^2/hr)$ from plasters made of $Durotak^{\circledR}$ 87-2074, $Durotak^{\circledR}$ 87-2510 and $Durotak^{\circledR}$ 87-2097 were 2.50, 2.77 and 4.39, respectively. $Durotak^{\circledR}$ 87-2074 showed the lowest penetration due to the carboxylic acid group in the polymer, which might form a strong hydrogen bonding with a secondary amine of aceclofenac. Although both $Durotak^{\circledR}$ 87-2510 and $Durotak^{\circledR}$ 87-2097 are amine-resistant adhesives, $Durotak^{\circledR}$ 872510 showed lower penetration than $Durotak^{\circledR}$ 87-2097 because of the hydroxyl group in $Durotak^{\circledR}$ 87-2510, which might form a weak hydrogen bonding with aceclofenac. These results reveal that the functional group in acrylic polymers would greatly affect the release of aceclofenac from the matrix, which is the rate-limiting step in the penetration of aceclofenac through rat skins. The penetration of aceclofenac from plasters using different penetration-enhancers increased in the following order: Transcutol < linoleic acid < oleic acid. And the flux from the plasters containing oleic acid as a penetrationenhancer was 2.22 times greater than that of creams, which suggest that a newly deveolped aceclofenac plaster could be used in the treatment of rheumatoidal arthritis and osteo-arthritis as an advanced transdermal delivery system.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.152-158
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• 2010

Biosorption is considered to be an alternative method to replace the present adsorbent systems for the treatment of metal contaminated wastewater. In this study, by-product which was abandoned from brewing factory was used to remove metal component in aqueous solution. The experimental results showed that the range of the removal efficiency is 60~91% and adsorption equilibrium was reached in about 3 hr. FT-IR and stereo microscope has been used to observe the surface conditions and changes in functional groups by calcination. At the end of elution, the amount of nitrogen and phosphorus in water was increased 11 and 7 times compare raw sample to calcinated samples. The Langmuir isotherm adequately described the adsorption of waste materials and the maximum adsorption capacity was 28.17 mg/g for Cd. The overall results suggested that waste material might can be used for biosorption of Cd.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.883-892
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• 2009

We evaluated the degradation properties of various alkanolamine absorbents (MEA, AMP, DEA, and MDEA) having different chemical structures for $CO_2$ capture. The degradation of $CO_2$ absorbent in general was known to be caused by oxygen which is in flue gas and by heat source, respectively. To analyze the effect of $CO_2$ and $O_2$ on degree of degradation, we conducted a variety of experiments at $30^{\circ}C$ and $60^{\circ}C$ (oxidative degradation) and $130^{\circ}C$ and $150^{\circ}C$ (thermal degradation), respectively. DEA showed the worst property for oxidative degradation in the presence of oxygen among the alkanolamine absorbents. In the case of thermal degradation, the degradation of absorbent was occurred for most of absorbents at $150^{\circ}C$. Among these absorbents, MEA and DEA gave the worst results. As a result, AMP which is a primary amine and having a steric hindrance showed the best result through the degradation test. But, the degradation of absorbent proceeded easily in the case of DEA which is a secondary amine and having 2 OH groups in terminal position. Consequently, we have evaluated the degree of degradation of various absorbents having different chemical structures to give the basic data for the development of alkanolamine absorbent.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2971-2975
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• 2012

Second-order rate constants $k_N$ have been measured spectrophotometrically for nucleophilic substitution reactions of t-butyl 4-pyridyl carbonate 8 with a series of alicyclic secondary amines in $H_2O$ at $25.0{\pm}0.1^{\circ}C$. The Br${\emptyset}$nsted-type plot for the reactions of 8 is linear with ${\beta}_{nuc}$ = 0.84. The ${\beta}_{nuc}$ value obtained for the reactions of 8 is much larger than that reported for the corresponding reactions of t-butyl 2-pyridyl carbonate 6 (i.e., ${\beta}_{nuc}$ = 0.44), which was proposed to proceed through a forced concerted mechanism. Thus, the aminolysis of 8 has been concluded to proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate $T^{\pm}$, in which expulsion of the leaving-group from $T^{\pm}$ occurs at the rate-determining step (RDS). In contrast, aminolysis of benzyl 4-pyridyl carbonate 7 has been reported to proceed through two intermediates, $T^{\pm}$ and its deprotonated form $T^-$ on the basis of the fact that the plots of pseudo-first-order rate constant $k_{obsd}$ vs. amine concentration curve upward. The current study has demonstrated convincingly that the nature of the leaving and nonleaving groups governs the reaction mechanism. The contrasting reaction mechanisms have been rationalized in terms of an intramolecular H-bonding interaction, steric acceleration, and steric inhibition.

• Polymer(Korea)
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• v.38 no.3
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• pp.386-390
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• 2014

Efficient stitching methods for the synthesis of tripodal Fr$\acute{e}$chet-type dendrimers containing secondary amine as a connector were elaborated. The synthetic strategy involved Staudinger/aza-Wittig reactions (new click reaction) between tripodal tris(azides) and aldehyde-dendrons in toluene in the presence of triphenylphosphine and followed by the reduction of imine intermediates. The tripodal core (1,3,5-tris-(3-azido-propoxy)-benzene) was chosen to serve as the azide functionalities for dendrimer growth. 1,3,5-Tris-(3-azido-propoxy)-benzene was stitched with the aldehyde-functionalized Fr$\acute{e}$chet-type dendrons via Staudinger/aza-Wittig reactions leading to the formation of the corresponding Fr$\acute{e}$chet-type dendrimers in high yields.

• Polymer(Korea)
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• v.25 no.6
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• pp.789-795
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• 2001

In order to recover nickel ion from waste water containing heavy metals, the PAN fibrous ion-exchanger with primary, secondary amine groups and carboxyl group was synthesized by acid and base hydrolysis. The hydrolysis yield of PAN fiber in acid solution was higher than base solution. The swelling ratio and ion-exchange capacity of PAN fiber which was synthesized in 1N $H_2SO_4$ solution at $80^{\circ}C$ for 7 hrs appeared 71.2% and 1.95 meq/g respectively. We investigated that the adsorption of nickel ion was approached 1.44 meq/g at 50 min and the maximum adsorption capacity of ion-exchanger was 2.48 meq/g. We confirmed that the $Ni^{+2}$ adsorption ability of the synthesized PAN fibrous ion-exchanger in this study is excellent.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.917-921
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• 2013

A simple, quick and reliable analytical method for the confirmation and quantification of propisochlor was developed. The propisochlor was extracted from water, soil and rice (stalks, rice and hull) matrices using acetonitrile, and cleaned up with primary secondary amine and determined by UPLC-MS/MS. The LODs of propisochlor ranged from 0.03 ${\mu}g/kg$ to 0.12 ${\mu}g/kg$, while the LOQs ranged from 0.1 ${\mu}g/kg$ to 0.4 ${\mu}g/kg$ in different matrixes. The mean recoveries of propisochlor at three levels (0.005, 0.01 and 0.05 mg/kg) were in the range of 73.7-94.9% with intra-day relative standard deviations (RSD) of 1.1-13.9% and inter-day $RSD_R$ of 3.3-12.7%. This method is suitable for routine analysis of propisochlor under field conditions. The half-lives of propisochlor in rice stalks, water and soil were 1.7, 1.5 and 2.3 days in Hunan, 5.7, 1.0 and 1.9 days in Anhui and 4.8, 1.0 and 3.1 days in Guangxi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.3
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• pp.260-265
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• 1991

The effective method to detect the mutagenicity of N-nitrosodimethylamineI (NDMA) by using Salmonella/microsome assay was studied. The Effect of vitamin C on the mutagenicity of the formed NDMA and during the formation of NDMA from nitrite and secondary amine was also investigated. Aroclor 1254-induced hamster S9 mix was more effective in activation NDMA than rat S9 mix induced by Aroclor 1254 or phenobarbital. Dimethyl sulfoxide and ethanol suppressed the mutagenic effect of NDMA, however, phosphate butter (pH 7.4), distilled water, 95% methanol and Tween 80 + water (1 : 4) were the appropriate dissolving system in the mutagenicity test of NDMA. Vitamin C did not show any inhibitory effect on the mutagenicity of the formed NDMA. However, the revertants of Salmonella typhinutrium TA 100 were significntly reduced (p<0.05) when vitamin C was added to the reaction mixture of nitrite and dimethylamine during the formation of NDMA. The amount of the formed NDMA was analyzed using HPLC and the level was decreased by about 95%. Thus it was concluded that vitamin C inhibited greatly the formation of NDMA from nitrite and dimethylamine.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.687-700
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• 2011

A new $N_3-O_2$ pentadentate ligand, H-BHPT, was synthesized. Hydrochloric acid salts of Br-BHPT, Cl-BHPT, $CH_3O$-BHPT and $CH_3$-BHPT, having Br-, Cl-, $CH_{3-}$ and $CH_3O-$ substituents at the para position of the phenol hydroxyl group of H-BHPT were synthesized. Hydrochloric acid salts of 3OH-BHPT and 4OH-BHPT, having different position of the phenol hydroxyl group of H-BHPT were also synthesized. The synthesis of each ligand was confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible, and mass spectra. The calculated proton dissociation constants ($log{K_n}^H$) of the phenol hydroxyl group and secondary amine group of the synthesized $N_3-O_2$ ligands showed five steps of the proton dissociations. The order of the overall proton dissociation constants ($log{\beta}_p$) of the ligands was Br-BHPT < Cl-BHPT < H-BHPT < $CH_3O$-BHPT < $CH_3$-BHPT. The order agreed with that of Hammett substituent constants (${\delta}_p$). However, dissociation steps of 3OH-BHPT were four and that of 4OH-BHPT was three. The calculated stability constants ($logK_{ML}$) between the ligands and transition metal ions agreed with the order of $log{\beta}_p$ values of the ligands. The order of the stability constants between the transition metal ions with the synthesized ligands was Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II). The order agreed well with that of the Iriving-Williams.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.421-435
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• 2012

Novel $N_2O_2$ tetradentate ligands, H-3BPD and H-2BPD were synthesized. Hydrochloric acid salts of Br-3BPD, Cl-3BPD, Br-2BPD and Cl-2BPD having Br and Cl substituents at the $para$ position of the phenol hydroxyl group, were synthesized. The ligands were characterized by C. H. N atomic analysis, $^1H$ NMR, $^{13}C$ NMR, UV-visible, and mass spectra. The proton dissociation constants ($logK_n{^H}$) of the phenol hydroxyl group and secondary amine of the synthesized $N_2O_2$ ligands were shown by four step wise values. The orders of the calculated overall proton dissociation constants ($log{\beta}_p$) were Br-3BPD < Cl-3BPD < H-3BPD in case of 3BPD and Br-2BPD < Cl-2BPD < H-2BPD in case of 2BPD respectively. The order agreed well with that of $para$ Hammett substituent constants(${\delta}_p$). The stability constants($logK_{ML}$) of the complexes between the synthesized ligands and transition metal(II) ions agreed with the order of $log{\beta}_p$ of the ligands. The order of the $logK_{ML}$ value of the each transition metal (II) ion was Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II), which agreed well with that of Iriving-Williams series.