• Archives of Pharmacal Research
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• v.25 no.5
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• pp.704-708
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• 2002

A fast and sensitive protein staining method in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using both an acidic dye, Coomassie Brilliant Blue R-250 (CBBR) and a basic dye, Neutral Red (NR) is described. It is based on a counter ion-dye staining technique that employs oppositely charged two dyes to form an ion-pair complex. The selective binding of the free dye molecules to proteins in an acidic solution enhances the staining effect of CBBR on protein bands, and also reduces gel background. It is a rapid staining procedure, involving fixing and staining steps with short destaining that are completed in about 1 h. As the result, it showed two to fourfold increase in sensitivity comparing with CBBR staining. The stained protein bands can be visualized at the same time of staining.

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.285-289
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• 1991

A convenient spectrophotometric method was examined for the determination of amantadine sulfate (AMTS) which has no UV-VIS chromopohores. AMTS was ion-paired quantitatively with methyl orange (MO) at $70^{\circ}C$ for 30 min. The ion-paired complex was extracted with dichloromethane and the absorbance was measured at 421.5 nm. A linear relationship was observed in the range of $2.5{\times}10^{-7}\;M$ to $3.75{\times}10^{-6}\;M$ and the correlation coefficient was 0.999 (n=3). This assay method was applied to the quantification of AMTS in commercial tablet form with good recovery and high precision.

• Archives of Pharmacal Research
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• v.29 no.4
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• pp.323-327
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• 2006

The objective of this study was to examine the pharmacokinetics of organic cations in intrahepatic cholestatic rats. A pretreatment with $17{\alpha}$-ethynylestradiol was used to induce intrahepatic cholestasis, and tributylmethylammonium (TBuMA) was used as a representative model organic cation. When $[^3H]$TBuMA was intravenously administered, the AUC value for TBuMA was significantly increased by $79\%$ in cholestasis, and its total systemic clearance was consequently decreased by $46\%$. In addition, the in vivo hepatic uptake clearance of TBuMA from the plasma to the liver was decreased by $50\%$ in cholestasis. The concentration of bile salts in plasma was increased by 2.1 fold in cholestatic rats. Since TBuMA forms ion-pair complexes with anionic components such as bile salts, the decreased hepatic uptake of TBuMA in cholestasis may be due to a change in endogenous components, e.g., bile salts in the plasma. In isolated normal hepatocytes, the uptake clearance for TBuMA in the presence of cholestatic plasma was decreased by $20\%$ compared with normal plasma. Therefore, we conclude that the inhibition of the hepatic uptake process by the cholestasis may be in part due to the increased formation of ion-pair complexes of TBuMA with bile salts in the plasma.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.179-179
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• 1993

1. PS및 CP의 flux는 전류의 새기 및 donor의 약물농도에 비래하였다. 2. pH의 flux는 pH가 증가할수록 증가하였으나, CP(pKa=9.2)의 flux는 pH=2에서 최대치를 보였다. 이는 약물의 해리 정도와 H$^{＋}$이온의 mobility, 또 피부의 permselectivity의 balance에 의해 결정된 것으로 생각된다. 3. donor cell에 NaCl을 첨가하면 두 약물 공히, 그러나 특히 PS의 flux가 저하되었다. 이는 두 약물의 이온과 $Na^{＋}$의 mobility차이에 기인한다고 생각된다. 4. PS의 경우 taurodeoxycholate(TDC)같은 음이온을 donor cell에 공존시키면 flux가 감소하였다. 이는 PS와 TDC가 전기적으로 중성인 ion-pair complex를 형성함으로써 PS이온의 유효농도가 감소하기 때문으로 생각된다.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.415-419
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• 1994

A simple nad rapid colorimetric method for the assay of amodiaquine hydrochloride, chloroquine phosphate and primaquine phosphate is described. The method is based on the interaction of the drug base with bromophenol blue to give a ion-pair complex. The spectra of the complex shows a maxima at 415-420 nm with high apparent molar absorptivities. Beer's law was obeyed in the concentration range 1-8, 2-10 and $2-12{\;}{\mu}{\cdot}ml^{-1}$ for amodiaquine hydrochloride, primaquine phosphate and chloroquine phosphate respectively. The proposed method was applied to the determination of these drugs in certain formulations and the results were favourably comparable to the official methods.

• Macromolecular Research
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• v.11 no.5
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• pp.375-381
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• 2003

Silver salt complex membranes with glassy poly(methyl methacrylate) (PMMA) unexpectedly showed higher propylene permeance than those with rubbery poly(butyl methacrylate) (PBMA) where as neat PMMA is much less permeable to propylene than that of neat PBMA. Such unusual facilitated olefin transport has been systematically investigated by changing the side chain length of polymethacrylates (PMAs) from methyl, ethyl to butyl. The ab initio calculation showed almost the same electron densities of the carbonyl oxygens in the three PMAs, expecting very similar intensity of the interaction between carbonyl oxygen and silver ion. However, the interaction intensity decreases with the length of the alkyl side chain: PMMA > PEMA > PBMA according to wide angle X-ray scattering and FT-Raman spectroscopy. The difference in the interaction intensity may arise from the difference in the hydrophilicity of the three PMAs, as confirmed by the contact angle of water, which determines the concentrations of the ionic constituents of silver salts: free ion, contact ion pair and higher order ionic aggregate. However, propylene solubilities and facilitated propylene transport vary with the side chain length significantly even at the same concentration of the free ion, the most active olefin carrier, suggesting possible difference in the prohibition of the molecular access of propylene to silver ion by the side chains: the steric hindrance. Therefore, it may be concluded that both the hydrophilicity and the steric hindrance associated with the side chain length in the three PMAs are of pivotal importance in determining facilitated olefin transport through polymer/silver salt complex membranes.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.155-158
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• 1989

The rates of complexation of the 18-C-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) with $K^+,\;Ca^{2+},\;Sr^{2+},\;and\;Ba^{2+}$ in methanol solution have been determined at 25$^{\circ}C$ by a pressure-jump technique. The Eigen Winkler mechanism has been applied to interprete the kinetic data. The results suggest that the rate determining step of the complexation in methanol is the rearrangement of the ligand in the outer sphere ion-dipole pair to form a stable encapsulated complex of the metal ion by the crown ether.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.3
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• pp.422-428
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• 2000

At present, analytical methods available for determining the amount of cationic surfactants(DSDMAC) on the fabrics are spectrophotometric method based on formation and extraction of the colored ion pair with anionic dye, radiochemical analysis and HPLC analysis. This study presents new analytical methods based on the formation of cationic surfactant(DSDMAC)-disulfine blue complex on the cotton fabric. Test methods for determining the amount of DSDMAC-disulfine blue complex on the cotton fabrics are measuring the reflectance of the colored fabric and the absorbance of the methanol solution of DSDMAC-disulfine blue complex extracted from dyed cotton fabric. Linear relationships between the K/S value of the fabric treated with DSDMAC followed by disulfine blue and the amount of DSDMAC sorbed by cotton fabric were obtained. Thus, the amount of DSDMAC sorbed by cotton fabric can be determined by K/S value of the fabric. DSDMAC-disulfine blue complex on the cotton fabric was extracted with methanol. The amount of DSDMAC sorbed by cotton fabric was estimated by measuring the absorbance of the methanol solution extracted from dyed cotton fabric.

• Analytical Science and Technology
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• v.8 no.1
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• pp.79-84
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• 1995

Ion-selective poly(vinyl chloride) membrane electrodes for the determination of the anticholinergic drug alverine in pure substances is described. Ion-pair complex of alverine with anionic counter ion acid red 97 is investigated as electroactive compound for the electrode membrane. On the optimal composition of membrane, its slope was 55.35mV/decade, relative standard deviation was 0.61 and lower limit of linear range was $1.0{\times}10^{-5}M$. The observed potentiometric selectivity coefficient was -2.625 toward methylephedrine and -2.216 toward histidine. We can got the stable potential at pH 7.0~4.0. Response time was 20~30 seconds for solutions${\leq}10^{-4}M$, about 10 seconds for solutions ${\geq}10^{-4}M$ of these compounds.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3543-3548
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• 2010

A kinetic study on nucleophilic displacement reactions of 2-pyridyl X-substituted benzoates 1a-e with potassium ethoxide (EtOK) in anhydrous ethanol is reported. Plots of pseudo-first-order rate constants ($k_{obsd}$) vs. $[EtOK]_o$ exhibit upward curvature. The $k_{obsd}$ value at a fixed $[EtOK]_o$ decreases steeply upon addition of 18-crown-6-ether (18C6) to the reaction mixture up to [18C6]/$[EtOK]_o$ = 1 and then remains nearly constant thereafter. In contrast, $k_{obsd}$ increases sharply upon addition of LiSCN or KSCN. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ has revealed that ion-paired EtOK is more reactive than dissociated $EtO^-$, indicating that $K^+$ ion acts as a Lewis acid catalyst. Hammett plots for the reactions of 1a-e with dissociated $EtO^-$ and ion-paired EtOK result in excellent linear correlation with $\rho$ values of 3.01 and 2.67, respectively. The $k_{EtOK}/k_{EtO^-}$ ratio increases as the substituent X in the benzoyl moiety becomes a stronger electron-donating group. $K^+$ ion has been concluded to catalyze the current reaction by stabilizing the transition state through formation of a 6-membered cyclic complex.