• Current Applied Physics
• /
• 제18권12호
• /
• pp.1553-1557
• /
• 2018

Gallium nitride (GaN) nanoparticles are synthesized by the gallium particle trapping effect in a $N_2$ nonthermal plasma with metallic Ga vapor. A proposed method has an advantage of synthesized GaN nanoparticle purity because the gallium vapor from the inductively heated tungsten boat does not contain any impurity source. The synthesized particle size can be controlled by the amount of Ga vapor, which is adjusted using the plasma emission ratio of nitrogen to gallium, owing to the particle trapping effect. The synthesized nanoparticles are investigated by electron microscopy studies. High-resolution transmission electron microscopy (HRTEM) studies confirm that the synthesized GaN nanoparticles (10-40 nm) crystallize in a single-phase wurtzite structure. Room-temperature photoluminescence (PL) measurements indicate the band-edge emission of GaN at around 378 nm without yellow emission, which implies that the synthesized GaN nanoparticles have high crystallinity.

• Journal of Pharmaceutical Investigation
• /
• 제40권2호
• /
• pp.101-107
• /
• 2010

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of N-(-4-Chlorophenyl)-6-hydroxy-7-methoxy-2-chromanecarboxamide (KAL-1120), a novel anti-inflammation agent, in the rat plasma. The method was applied to analyze the compound in the biological fluids such as bile, urine and tissue homogenates. After liquid-liquid extraction, the compound was analyzed on an HPLC system with ultraviolet detection at 275 nm. HPLC was carried out using reversed-phase isocratic elution with a $C_{18}$ column, a mobile phase of a mixture of acetonitril (40 v/v%) at a flow rate of 1.0 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma was linear over the concentration range of 0.05-50 ${\mu}g$/mL. The intra- and inter-day assay accuracies of this method ranged from 0.06% to 9.33% of normal values and the precision did not exceed 6.28% of relative standard deviation. The plasma concentration of KAL-1120 decreased to below the quantifiable limit at 1.5 hr after the i.v. bolus administration of 2-10 mg/kg to rats ($t_{1/2,({\alpha})}$ and $t_{1/2,({\beta})$ of 2.15 and 26.7 min at a dose of 2 mg/kg, 3.91 and 33.0 min at a dose of 10 mg/kg, respectively). The steady-state volume of distribution ($V_{dss}$) and the total body clearance ($CL_t$) were not significantly altered in rats given doses from 2 to 10 mg/kg. Of the various tissues tested, KAL-1120 was mainly distributed in the lung and heart after i.v. bolus administration. KAL-1120 was detected in the bile by 30 min after its i.v. bolus administration. However, the concentration in the urine after i.v. bolus administration became too low to measure, suggesting that KAL-1120 is mostly excreted in the bile. In conclusion, this analytical method was suitable for the preclinical pharmacokinetic studies of KAL-1120 in rats.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.394.2-394.2
• /
• 2002

A sensitive and selective reversed-phase LC-ESI-MS method to quantitate pseudoephedrine in human plasma was developed and validated. Phenacetin was used as an internal standard. Samples were prepared simply by acetonitrile precipitation without an evaporation step. Chromatographic separation was achieved on a XTerra MS C18 column ($150{times}2.1$ mm I.D.. 3.5 $\mu\textrm{m}$ particles). using gradient elution with 0.5% (v/v) trifluoroacetic acid (TFA) in water and 0.5% (v/v) TFA in methanol at a flow-rate of 0.1 ml/min. (omitted)

• Journal of Pharmaceutical Investigation
• /
• 제39권1호
• /
• pp.65-71
• /
• 2009

The aim of the present study was to evaluate the bioequivalence of two domperidone maleate tablets, Motilium-$M^{(R)}$ Tablet (Janssen Korea Ltd., reference product) and $Toriem^{(R)}$ Tablet (Daewon Pharm. Co., Ltd., test product). Domperidone was extracted by liquid-liquid extraction using tert-butyl methyl ether and separated in less than 3 min on $C_{18}$ reverse-phase column using an isocratic elution. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z $426.1{\rightarrow}119.1$ and the m/z $837.4{\rightarrow}158.2$ transitions for domperidone and the internal standard (roxithromycin), respectively. Calibration curves, from $0.05{\sim}50$ ng/mL of domperidone, showed correlation coefficients (r) higher than 0.9941. Intra day and inter day precision (C.V. %) for quality control were ranged from 10.04 to 16.09% and from 10.87 to 18.69%, respectively. The lower limit of quantification (LLOQ) of domperidone was 0.05 ng/mL. The method described is precise and sensitive and has been successfully applied to the study of bioequivalence of domperidone in 24 healthy Korean volunteers. Twenty-four healthy male Korean volunteers received a single dose of each medicine ($2{\times}12.72\;mg$ domperidone maleate) in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of domperidone were monitored for over a period of 24 hr after the administration. $AUC_{0-t}$ (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were within acceptable range of log 0.8 to log 1.25 (e.g., $log\;0.92{\sim}log\;1.05$ for $AUC_{0-t}$, $log\;0.81{\sim}log\;1.05$ for $C_{max}$). The major parameters, $AUC_{0-t}$ and $C_{max}$ met the criteria of KFDA for bioequivalence indicating that $Toriem^{(R)}$ tablet is bioequivalent to Motilium-$M^{(R)}$ tablet.

• 한국결정성장학회지
• /
• 제7권2호
• /
• pp.235-243
• /
• 1997

$YBa_2Cu_3O_x$ 고온 초전도체 상을 MgO 단결정위에 증착시키기 위하여 액상의 에어로 졸 입자를 저온 플라즈마의 화학증기 증착로안에 유입하였다. 플라즈마의 분포를 조절하기 위한 반응로의 설계에 따라 초전도체상의 미세구조가 변화하는 양상을 관찰하였으며, 이때 증착 기판 위에서 관찰되는 입자들의 생성원인에 대하여 고찰하였다. 입자생성의 주된 원인으로는 불안정한 플라즈마의 분포와 출발원료의 낮은 기화속도에 기인하는 것으로 나타났다. 또한 증착속도는 출발원료가 기화되는 곳으로부터 멀어질수록 급격히 감소하는 것으로 밝혀졌다.

• Journal of Pharmaceutical Investigation
• /
• 제41권5호
• /
• pp.309-315
• /
• 2011

A sensitive and specific liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the analysis of ambroxol (active moiety of acebrophylline). After acetonitrile precipitation of proteins from plasma samples, ambroxol and the domperidone (internal standard, IS) were eluted on a C18 column. The isocratic mobile phase was consisted of 10 mM ammonium acetate and methanol (10 : 90, v/v), with flow rate at 0.2 mL/min. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z 379.2${\rightarrow}$264.0 and the m/z 426.2${\rightarrow}$175.1 transitions for ambroxol and the IS, respectively. Twenty four healthy Korean male subjects received two capsules (100 mg ${\times}$ 2) of either the test or the reference formulation of acebrophylline HCl in a 2 ${\times}$ 2 crossover study, this was followed by a 1week washout period between either formulation. $AUC_{0-t}$ (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were acceptable range of log 0.8 to log 1.25 (e.g., log 0.8964 - log 0.9910 for $AUC_{0-t}$ log 0.8690 - log 1.0750 for $C_{max}$). The major parameters, $AUC_{0-t}$ and $C_{max}$ met the criteria of Korea Food and Drug Administration for bioequivalence indicating that Acephyll$^{(R)}$ capsule (test) is bioequivalent to Surfolase$^{(R)}$ capsule (reference).

• 한국어병학회지
• /
• 제20권2호
• /
• pp.139-145
• /
• 2007

인체에 널리 사용되고 있는 Aspirin (ASA)을 양식 뱀장어 (Anguilla japonica) 약욕 또는 경구 투여한 다음 혈장 중의 ASA와 salicylic acid (SA)의 양을 HPLC로 측정하였다. 뱀장어 혈장은 0.2 M HCl과 0.2 M orthophosphoric acid로 산성화시킨 다음 acetonitrile과 혼합하여 ASA와 SA를 추출하였다. 2약제의 정량은 Novapak C18과 UV detector (237 nm)가 장착된 HPLC로 측정하였다. 이 때 이동상은 740 ㎖의 증류수, 900 ㎕의 orthophosphoric acid와 180㎖의 acetonitrile을 사용하였다. ASA, SA 및 내부 표준물질로 사용한 2-methylbenzoic acid (MBA)의 retention time은 각각 4.8분, 8.4분 및 11.4분이였으며, 측정한계 농도는 ASA가 0.05 ㎍/㎖, SA는 0.01 ㎍/㎖였다. 혈장으로 부터의 평균회수율은 ASA가 70.8-99.6%, SA는 95.2-100.3%였다. 뱀장어에 ASA를 약욕 (20 ppm) 또는 경구투여 (50 ㎎/kg BW) 한 다음 채취한 혈장을 시료로 이 방법으로 ASA와 SA의 양을 측정한 결과 단지 SA만 검출되어졌고, ASA는 검출되지 않았다. 이는 ASA가 혈장내에서 신속히 SA로 분해되기 때문으로 판명되었다. 또 ASA에 약욕시킨 경우에는 약욕 후 3시간후에 혈장내의 SA양이 최고치에 도달하였으며, 경구투여 한 경우에는 7일후에 최고치에 도달하였다. 한편 ASA를 투여한 다음 ASA 무첨가 수조에 수용한 결과 2투여 경로 모두 48시간 이후에는 SA가 0.02-0.03 ㎍/㎖이 검출되어 잔류의 문제도 거의 없었다. HPLC를 이용한 혈장내의 ASA와 SA의 검출법은 신속하며 정확한 방법으로 뱀장어 이외의 어류에도 활용 가능할 것으로 생각된다.

• Mass Spectrometry Letters
• /
• 제5권2호
• /
• pp.42-48
• /
• 2014

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the simultaneous quantification of porphyrins (coproporphyrin, pentacarboxylporphyrin, hexacarboxylporphyrin, heptacarboxylporphyrin, and uroporphyrin) in human plasma and urine. Acidified plasma samples and urine samples were prepared by using liquid-liquid extraction using ethyl acetate and protein precipitation with acetonitrile, respectively. The separation was achieved onto a Synergi Fusion RP column ($150mm{\times}2.0mm$, $4{\mu}m$) with a gradient elution of mobile phase A (0.1% formic acid in 2 mmol/L ammonium acetate, v/v) and mobile phase B (20% methanol in acetonitrile, v/v) at a flow rate of $450{\mu}L$/min. Porphyrins and the internal standard (IS), coproporphyrin I-$^{15}N_4$, were detected by a tandem mass spectrometer equipped with an electrospray ion source operating in positive ion mode. Multiple reaction monitoring (MRM) transitions of the protonated precursor ions and the related product ions were optimized to increase selectivity and sensitivity. The proposed method was validated by assessing selectivity, linearity, limit of quantification (LOQ), precision, accuracy, recovery, and stability. The calibration curves were obtained in the range of 0.1-100 nmol/L and the LOQs were estimated as 0.1 nmol/L for all porphyrins. Results obtained from the validation study of porphyrins showed good accuracy, precision, recovery, and stability. Finally, the proposed method was successfully applied to clinical studies on the autism spectrum disorder (ASD) diagnosis of 203 Korean children.

• 분석과학
• /
• 제22권6호
• /
• pp.514-518
• /
• 2009

코엔자임 큐텐은 비타민과 유사한 물질로 체내 중 미토콘드리아에 주로 분포 되어 있으며 항산화 작용을 나타낸다고 알려져 있다. 본 연구는 27-44세의 건강한 성인 남 녀 24명을 대상으로 하였고 혈장내 코엔자임 큐텐의 농도를 정량 평가하기 위하여 UV 검출기가 장착된 고성능액체 크로마토그라피를 사용 하였다. 혈장 내 코엔자임 큐텐을 분리하기 위해서 메탄올로 지방단백질을 제거하였고 노말헥산을 이용하여 액체-액체 추출법으로 코엔자임 큐텐을 용해 시켰다. 그 후 원심분리를 실시하여 노말헥산과 제단백된 물질을 층분리 시키고 상층액을 다른 유리 시험관에 옮겨 담았다. 옮겨진 노말헥산 층은 질소 가스를 이용하여 증발 농축을 시켰으며 남은 잔사에 순수한 에탄올로 재용해 시켜 검사 장비 내로 주입 하였다. 이 때 사용된 컬럼은 C18 역상 컬럼이었고 275 nm의 파장이 이용되었으며 메탄올과 에탄올을 85:15로 섞은 이동상을 1.7 mL/min의 유속으로 흘렸다. 본 검사 방법의 정량한계(limit of quantitation : LOQ, N/S=10)는 0.02 mg/L로 평가 되었고 0.1-2.0 mg/L의 농도 범위에서 검량선을 작성 하였다. 대상군 24명의 혈장 중 코엔자임 큐텐의 농도는 0.41-0.98 mg/L의 범위에서 분포 하고 있었으며 평균 농도는 $0.62{\pm}0.13mg/L$ 였다. 본 연구의 결과 본 검사 방법은 특수성을 가지고 있었으며 혈장 내 $CoQ_{10}$을 분석하는데 충분한 정량한계를 가지고 있었기에 임상에 적용이 가능하고 연구 기관에서 사용하기에 적합하다고 사료 된다.

• 약학회지
• /
• 제54권4호
• /
• pp.295-299
• /
• 2010

The aim of this study was to develop and validate for determination of alibendol in human plasma by HPLC method. After precipitation of 500 ${\mu}l$ plasma samples by 50% methanol 50 ${\mu}l$ and 60% perchloric acid 30 ${\mu}l$ and the supernatant 50 ${\mu}l$ was injected into HPLC. The assay was performed isocratically using 10 mM potassium phosphate (pH 3.0) and acetonitrile (80 : 20, v/v) as mobile phase. The $C_{18}$ column (particle size $3.5{\mu}m$, $4.6{\times}50$ mm, Zorbax Eclipse) was used as a solid phase. The mobile phase was delivered at a flow-rate of 1.7 ml/min, detection was by ultraviolet absorption at 232 nm and concentrations were calculated on the basis of peak areas. In these conditions, alibendol can be separated from ethylparaben, the internal standard, and endogenous substances. The retention times of alibendol and ethylparaben were just about 2.6 and 3.5 minutes, respectively. This rapid HPLC method was validated by examining the precision and accuracy for inter- and intra-day analysis. The standard curve was linear ($R^2$=1.0000) over the concentration range of 0.05~20 ${\mu}g$/ml. The inter-day relative standard deviation (R.S.D.) and accuracy were 0.2~12.2% and 94.4~101.2% (82.7% at the lower limit of quatitation). The intra-day R.S.D. and accuracy were 0.1~11.8% and 98.8~102.5%, respectively. The method was successfully applied to the determination of alibendol in plasma for a pharmacokinetic study.