• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.353-363
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• 1995

The purpose of this study was to investigate the intestinal and nasal absorption enhancement of cefotaxime (CTX) by ion-pairing with counterions and to design an effective oral and intranasal drug delivery system for antibiotics. Counterions for absorption promotion were cationic surfactants [cetylpyridinium chloride (CP), cetrimide (CT) and benzalkonium chloride (BA)]. In the presence of counterions, the apparent partition coefficient of cefotaxime was increased depending on the molar concentration of the counterions. Anion interference was observed for ion-pairing of cefotaxime with counterions because of the counterbalance between an anion and counterions. The present study employed the in situ simultaneous nasal and intestinal perfusion technique in rats. The apparent permeabilities $(P_{app})$ of cefotaxime were $1.43{\pm}0.04{\times}10^{-5}\;cm/sec(mean{\pm}S.E)$ in the nasal cavity and 0 in the jejunum, respectively, which indicated that the intrinsic absorptivity of cefotaxime was greater in the nasal cavity than in the jejunum. When ionupairing formers were used, the decreasing order of apparent cefotaxime permeability $(P_{app},\;10^{-5}\;cm/sec)$, corrected for surface area of absorption, was as followings: $BA\;(7.50{\pm}0.36)\;>\;CT\;(4.92{\pm}0.24)\;>\;CP\;(3.01{\pm}0.17)$ in the jejunum and $BA\;(22.31{\pm}1.36)\;>\;CP\;(18.24{\pm}0.81)\;>\;CT \;(16.22{\pm}1.87)$ in the nasal cavity. The increase in permeability of cefotaxime was about 13-fold in the rat nasal cavity and was marked in the rat jejunum for ion-pairing with counterions as compared to those without ion-pairing. The damages of jejunal and nasal mucosal membrane by counterions were observed within approximately 2hrs after removal of ion-pair of cefotaxime with counterions from the nasal cavity and jejunum. These results suggest that CP can be used as an ion-pairing former in the jejunum and CP and CT can be used as ion-pairing formers in the nasal cavity for cefotaxime, as well as for poorly absorbed drugs with a negative charge due to ionization.

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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• pp.16-18
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• 1999

• Analytical Science and Technology
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• v.10 no.5
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• pp.343-349
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• 1997

Analytical method using the reversed phase ion-pair chromatography (RP-IPC) for the determination of kasugamycin(5-amino-2-methyl-6-(2,3,4,5,6-pentahydroxy cyclohexyloxy)tetrahydropyran-3-yl-amino-${\alpha}$-imino acetic acid), pesticide as fungicide bactercide has been established. The retention behavior of kasugamycin in the RP-IPC was examined with respect to the effect of concentrations of organic modifiers, pH of eluent and types and concentrations of the counter ions as ion-pair reagent. This method developed by the optimum factors, can be used for the application of the quality control in the crude product and its formulation.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.55-59
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• 2003

This work is focused on analyzing ion-pair interactions and showing the effect of solvent induced inter-atomic attractions in various dielectric environments. To estimate the stability of ion-pairs, SCI-PCM ab initio MO calculations were carried out. We show that the solvent-induced attraction or ‘cavitation' energy of the ion-pair interactions in solution that arises mainly from the stabilization of the water molecules by the generation of an electrostatic field. In fact, even the strong electrostatic interaction characteristic of ion-pair interactions in the gas phase cannot overcome the destabilization or reorganization of the water molecules around solute cavities that arise from cancellation of the electrostatic field. The solvent environment, possibly supplemented by some specific solvent molecules, may help place the solute molecule in a cavity whose surroundings are characterized by an infinite polarizable dielectric medium. This behavior suggests that hydrophobic residues at a protein surface could easily contact the side chains of other nearby residues through the solvent environment, instead of by direct intra-molecular interactions.

• Journal of Photoscience
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• v.3 no.3
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• pp.147-151
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• 1996

Dynamics of contact ion-pair between 1, 2, 4, 5-tetracyanobenzene anion and cation of biphenyl derivatives was investigated on the picosecond time scale. Solvent effect on the electron transfer was observed and electron transfer rates were examined using Marcus equation which contains distance dependence of the electron transfer rate in the frequency factor, along with the consideration of molecular shape. From the discussion based on disk model for molecular shape, contribution of interring torsional motion of biphenyl to the inner-sphere reorganization energy is strongly suggested, which leads to the physical explanation for the observed solvent effect on the rate of electron transfer.

• YAKHAK HOEJI
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• v.37 no.2
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• pp.119-123
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• 1993

A spectrophotomertic method is proposed for the determination of antihistamines. The method is based on solvent extraction of the ion pair formed between antihistamines and colored picric acid into chloroform. The binding state of antihistamines-picric acid complexes were presumed by IR and $^{1}$H-NMR spectra as intermolecular hydrogen bonding. This method was applicable to the determination of antihistamines in the pharamaceutical preparations.

• Journal of the Korean Chemical Society
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• v.28 no.3
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• pp.163-169
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• 1984

The transport rates of $K^+$ion through CHCl$_3$ liquid membrane containing dibenzo-18-crown-6(DBC) as a carrier molecule have been determined at $25^{\circ}C$. The transport rates depend highly on the ion concentration and on the nature of anion. It is concluded that $K^+$ions are transported in the form of ion-pair. In the case of potassium picrate, however, it is found that the transport proceeds with the formation of the incomplete ion-pair in the concentration less than 1.0 ${\times}10^{-3}$M of picrate, while with the complete formation of ion-pair in the concentration more than 1.0 ${\times}10^{-3}$M of picrate. Seven steps of the transport process are suggested and they can be illustrated in terms of energy barrier model as a function of the position of ionic species in the membrane.

• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.224-230
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• 1986

Dodecyltrimethylammonium bromide (DTAB) was examined as a counter-ion in the separation of aromatic sulfonic acids on alkylmodified silica (ODS) column by reversed-phase ion-pair chromatography. The capacity factor of acids was investigated and separation was attempted. The capacity factor of samples was influenced by the several factors such as a concentration of counter-ion, concentration of methanol, kinds and concentration of electrolyte in mobile phase as well as kinds and position of functional group in samples. Some mixtures of samples were able to be separated under optimum condition.

• Bulletin of the Korean Chemical Society
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• v.21 no.3
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• pp.358-360
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• 2000

• Journal of the Korean Chemical Society
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• v.26 no.5
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• pp.326-332
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• 1982

The structure of the complex extracted from an aqueous solution containing methylene blue and tetrafluoroborate with 1,2-dichloroethane has been investigated by comparing IR spectrum of the extract with those of pure components and appeared to be an 1 : 1 contact ion-pair between monovalent ions of opposite charge. The extraction constant obtained from the absorbance data measured at 658nm in 1,2-dichlorethane has a value of 1.1${\times}$at$10^4M{-1}$ 25$^{\circ}$C in the range from 1.43${\times}10^{-2}$ to 2.86${\times}10^{-1}$M HF. In the solvent extraction with nitrobenzene, the identical experiments show that extraction constants are increased with HF concentration possibly due to dissociation of the ion-pair in nitrobenzene.