• Journal of Pharmaceutical Investigation
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• 제34권3호
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• pp.185-192
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• 2004

The objective of this study was to evaluate the effects of surfactant type and concentration upon dissolution rates of carbamazepine from an immediate-release tablet. The dissolution media used in this study were aqueous solutions containing 0.1-2% sodium lauryl sulfate, cetyltrimethylammonium bromide, or polysorbate 80. The solubility of carbamazepine in the dissolution media was determined at first. A dissolution study was then conducted by using the USP dissolution apparatus II (paddle method) with an agitation rate of 75 rpm. Aliquots of the dissolution media were taken at predetermined time intervals, and the amount of carbamazepine dissolved was measured spectrophotometrically at 285 nm. The dissolution data obtained were fitted into a biphasic exponential equation with four parameters. Excellent correlations were observed between the experimental data and the theoretical ones predicted by the equation. This equation permitted the calculation of $T_{50%}$ (the time required for dissolving 50% of carbamazepine) under various experimental conditions. Differentiation of the equation also led to the attainment of dissolution rates at dissolution time points. The addition of a surfactant to an aqueous solution led to increasing the solubility of carbamazepine by 3- to 12-folds, depending upon its type and concentration. This event also resulted in enhancing the magnitude of a sink condition during the dissolution study. As a result, the dissolution rate of carbamazepine was affected by the aqueous surfactant concentration in a proportional manner. Subsequently, $T_{50%}$ values declined rapidly, as the surfactant concentration increased. Such effects were observed in decreasing order of sodium lauryl sulfate, cetyltirmethylammonium bromide, and polysorbate 80. These results clearly demonstrated that it was possible to tailor a dissolution rate and $T_{50%}$ of carbamazepine by manipulating the type and concentration of a surfactant. Relevant information would be beneficial to setting up dissolution specifications for poorly water-soluble drug products.

• 대한화학회지
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• 제35권1호
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• pp.70-77
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• 1991

1-Benzyl-4-iodomethyl-2-azetidinone(BIMA)을 합성하여 iodomethyl기에 대한 전기화학적 환원을 direct current, differential pulse polarography, cyclic voltammetry 그리고 controlled potential coulometry 방법으로 연구하였다. BIMA의 환원과정은 1단계(-1.35 volts vs. Ag-AgCl)에서 완전비가역과 2전자이동후에 양성자가 첨가되는 EEC 반응기구로 진행되었으며 1-benzyl-4-methyl-2-azetidinone이 생성되었다. 양이온 계면활성제(cetyltrimethylammonium bromide)의 농도가 진하여질수록 양전위 이동이 있었으나 음이온 계면활성제(sodium lauryl sulfate)의 경우에는 2단계로 세분화되는 현상이 나타났다. pH변화에 따른 전극환원과정과 생성물 분석의 결과를 바탕으로 전기화학적 반응기구를 제안하였다.

• Carbon letters
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• 제13권4호
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• pp.212-220
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• 2012

Orange peel (OP) exhibits a sorption capacity towards anionic dyes such as reactive blue 19 (RB19). Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant was used to modify the surface nature of OP to enhance its adsorption capacity for anionic dyes from an aqueous solution. Four adsorbents were investigated: the OP, sodium hydroxide-treated OP (SOP), CTAB-modified OP and CTAB-modified SOP. The physical and chemical properties of these sorbents were determined using nitrogen adsorption at 77 K and by scanning electron microscope and Fourier transform infrared spectroscopy techniques. The adsorption of the RB19 dye was assessed with these sorbents at different solution pH levels and temperatures. The effect of the contact time was considered to determine the order and rate constants of the adsorption process. The adsorption data were analyzed considering the Freundlich, Langmuir, Elovich and Tempkin models. The adsorption of RB19 by the assessed sorbents is of the chemisorption type following pseudo-first-order kinetics. CTAB modification brought about a significant increase in RB19 adsorption, which was ascribed to the grafting of the sorbent with a cationic surfactant.

• 대한화학회지
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• 제32권3호
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• pp.195-202
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• 1988

Acetonitrile 용액중에서 3-phenyl-4-nitrosydnone의 전기화학전 환원을 direct current, differential pulse polarography, cyclic voltammetry 그리고 controlled potential coulometry 방법으로 연구하였다. Phenyl-N 단일 결합의 분리 이전에 nitro 기능기의 비가역적 전자 전달-화학반응(EC)기구의 진행으로 다전자 이동에 의한 amino(또한 hydroxylamino)기를 형성하고, 높은 음 전위 영역에서 2,3 비가역성 환원파의 일전자전달-화학반응에 의한 phenyl hydrazine을 생성하였다. 음극 반파 전위들은 cetyltrimethyl ammonium bromide의 억제 효과에 의해 음의 값으로 이동하였고 한편, sodium lauryl sulfate micelle은 높은 음전위 영역에서 제 2,3 환원파의 가역성산화 peaks를 보였다.

• 한국재료학회지
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• 제16권11호
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• pp.663-667
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• 2006

CTAB(cetyltrimethylammonium bromide)-capped CdSe nanoparticles were prepared by using a 4 : 1(v/v) distilled water-isopropyl alcohol mixture. The cadmium chloride and sodium selenosulfate were used as the cadmium and selenium source. By the analysis of XRD and XPS, the resultant particle was confirmed to be cubic CdSe phase. TEM image showed CdSe nanoparticles with empty core. The CTAB-capped sample showed an maximum absorption at 418nm, blue-shifting compared with bulk CdSe, which indicated stronger quantum confinement effect compared with uncapped sample. From FT-IR analysis, it was found that the presence of the new peaks in the $850{\sim}1250cm^{-1}$ range indicated the existence of chemical bonding between CTAB and surface of CdSe nanoparticles. Also TG analysis indicated that there were two weight-loss steps for the CTAB-capped CdSe nanoparticles. It was suggested that CTAB played a significant role in protecting CdSe nanoparticles.

• 한국수산과학회지
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• 제16권2호
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• pp.68-74
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• 1983

부산 수영만의 조간대 저질에서 moderate halophile인 Listeria denitrificans HB-38을 분리하여 생육에 필요한 NaCl 요구도를 조사한바, 해양환경조건의 배지에서는 $4\%$ NaCl에서 육상환경조건의 배지에서는 $10\%$ NaCl에서 최적농도였으며, 균생육 최적 온도는 $40^{circ}C$였고, 생육최적 pH는 7.5이었다. 그리고 비호염성인 E.coli, KPM 105와 protoplast안정성을 비교해본 결과, 더 높은 stabilizer의 농도를 요구하지는 않았으며, stabilizer로서 NaCl이sorbitol이나 sucrose보다 protoplast에 더 안정성을 주는 것으로 나타났다. HB-38균주의 succinic dehydrogenase 활성에는 NaCl 농도가 증가함에 따라 그 활성 이 증가하다가 $9\%$에서 최대에 달하였다. 반면에 이 호염성효소의 $(NH_4)_2\;SO_4$와 NaCl에 의한 염석은 비호염성인 E.coli 및 bovine liver 세포의 경우보다 더 높은 농도의 염에 의하는 것은 아니였다. 그리고 ethidium bromide에 의한 curing과 agarose gel 전기영동의 결과 HB-38은 extrachromosomal DNA를 가지지 않는 것으로 나타났다.

• 한국약용작물학회지
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• 제14권6호
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• pp.336-341
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• 2006

The endophytic bacteria were isolated from the rusty-root ginseng. This isolated bacteria were occurred the rusty-root ginseng with artificial inoculation. For the suppressing of rusty-ginseng, disinfectants, antibiotics, kitosan, micro-organisms and metabolites were tested to isolated endophytic bacterium. All of the isolated bacteria strains were sensitive sodium hypochlorite, however, some of isolated bacteria lines were sensitive to other tested materials. For example, D (didecyl dimethyl ammonium bromide), CIO$_2$, ODDA (octyldecyl dimethyl ammonium chloride + diocyul dimethyl ammonium chloride + alkyl diethyl benzyl ammonium chloride), GD (glutaraldehyde + dimethy cocobenzyl ammonium chloride) suppressed some of bacteria strains. Otherwise, some of antibiotics (e.g. ampicillin, chloramphenicol, erythromycin, kanamycin, neomycin, rifampin, streptomycin, tetracycline) were sensitive to the isolated bacteria strains. All of isolated bacteria strainswere inhibitive to the mixed formation with neomycin and streptomycin, and neomycin and tetracycline. Both sodium hypochlorite and antibiotic mixing of neomycin and tetracycline were effective to prevention of rusty-root ginseng of sub-merging ginseng in the ginseng field.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.32.1-32.1
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• 2009

현재 ITO를 대체할 재료로 투명 전도성 탄소나노튜브(carbon nanotube, CNT) 필름에 대한 연구가 진행 되고 있다. 이러한 연구에서 특히 CNT 필름의 투과도에 따른 전기저항을 향상시키기 위한 연구가 활발히 진행되고 있다. 본 연구에서는 단일벽 CNT (single-walled CNT)를 여러 가지 계면활성제로 최적 분산시킨 수용액으로부터 제조한 CNT 필름의 투과도에 따른 면 저항 (sheet resistance) 변화를 관찰하였다. 우선 계면활성제로 분산시킨 CNT 수용액을 알루미나 재질의 필터에서 정량적으로 진공 필터링하여 CNT 필름을 제조하였다. 알루미나 필터를 sodium hydroxide (NaOH) 수용액으로 용해시켜 제거함으로써 얻은 CNT 필름을 유리기판 위에 부착시켰다. 필름의 전기저항을 낮추기 위해 유리기판 위에 부착된 CNT 필름을 질산 (HNO3) 용액으로 처리하였다. Scanning electron microscopy, UV-Vis spectroscopy를 이용하여 각각 필름의 형상과 광 투과도를 분석하였고, 4-point probe로 면 저항을 측정하였다. 계면활성제로 분산시킨 CNT 필름 대부분의 면 저항은 질산 처리에 의해 감소하였다. 이는 CNT 표면에 코팅되어 있던 계면활성제가 질산에 의해 제거되었기 때문인 것으로 예상된다. 여러 계면활성제 중 sodium dodecyl benzenesulfonate로 분산시킨 CNT 필름이 산 처리 후에 가장 낮은 면 저항을 보였다. 그리고 Polyvinyl pyrrolidone (PVP)과 cetyltrimethylammonium bromide (CTAB)를 사용하여 제조한 CNT 필름의 면 저항이 가장 뚜렷한 감소를 보였다.

• 분석과학
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• 제32권3호
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• pp.88-95
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• 2019

This study was conducted to establish the analytical method for the determination of cyanide in blood, urine, lung and skin tissues in rats. In order to detect or quantify the sodium cyanide in above biological matrixes, it was derivatized to Pentafluorobenzyl cyanide (PFB-CN) using pentafluorobenzyl bromide (PFB-Br) and then reaction substance was analyzed using gas chromatography mass spectrometer (GC/MS)-SIM (selected ion monitoring) mode. The analytical method for cyanide determination was validated with respect to parameters such as selectivity, system suitability, linearity, accuracy and precision. No interference peak was observed for the determination of cyanide in blank samples, zero samples and lower limit of quantification (LLOQ) samples. The lowest limit detection (LOD) for cyanide was $10{\mu}M$. The linear dynamic range was from 10 to $200{\mu}M$ for cyanide with correlation coefficients higher than 0.99. For quality control samples at four different concentrations including LLOQ that were analyzed in quintuplicate, on six separate occasions, the accuracy and precision range from -14.1 % to 14.5% and 2.7 % to 18.3 %, respectively. The GC/MS-based method of analysis established in this study could be applied to the toxicokinetic study of cyanide on biological matrix substrates such as blood, urine, lung and skin tissues.

• Journal of Pharmaceutical Investigation
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• 제23권3호spc1호
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• pp.41-50
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• 1993

The iontophoretic delivery across rat skin of quaternary ammonium salts (isopropamide: ISP, pyridostigmine: PS), which are positively charged over a wide pH range, was measured ill vitro. The study showed that: (a) iontophoresis significantly enhanced delivery of ISP and PS compared to respective passive transport; (b) delivery of ISP and PS was directly proportional to the applied continuous direct current density over the range of $0-0.69\;mA/cm^2;$ (c) delivery of ISP and PS was also proportional to the drug concentration in the donor compartment over the range of $0-2{\time}l0^{-2}M:$ (d) sodium ion in the donor compartment inhibited the drug transport possibly due to decreasing the electric transference number of the drug; (e) delivery of ISP and PS increased as the pH of the donor solution increased over the pH range 2-7 suggesting permselective nature of the epidermis, and inhibition of the transference number of the drugs by hydronium ion; (f) some organic anions such as taurodeoxycholate, salicylate and benzoate which form lipophilic ion-pair complexes with ISP inhibited the delivery of ISP. The degree of inhibition by the organic anions was linearly proportional to the extraction coefficient $(K_e)$ of ISP from the partition system with each counteranion between phosphate buffer (pH 7.4) and n-octanol. For PS, however, taurodeoxycholate, but not salicylate and benzoate inhibited the iontophoretic delivery. It suggests that not only sodium ion and hydronium ion but also the counteranions which form lipophilic ion-pairs with quaternary ammonium drugs are not favorable components in formulating the donor solution of the drugs to achieve an effective iontophoretic delivery.