• The Korean Journal of Physiology and Pharmacology
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• v.16 no.5
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• pp.355-360
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• 2012

A simple, sensitive and reproducible high-performance liquid chromatography (HPLC) method has been validated for determining concentrations of glutamate, glycine, and alanine in human plasma. Proteins in plasma were precipitated with perchloric acid, followed by derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Simultaneous analysis of glutamate, glycine, and alanine is achieved using reversed-phase HPLC conditions and ultraviolet detection. Excellent linearity was observed for these three amino acids over their concentration ranges with correlation coefficients (r)>0.999. The intra- and inter-day precision were below 10%. This method utilizes quality control samples and demonstrates excellent plasma recovery and accuracy. The developed method has been successfully applied to measure plasma glutamate, glycine, and alanine in twenty volunteers.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.901-905
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• 2004

A rapid, sensitive and selective hydrophilic interaction liquid chromatography-tandem mass spectrometric(HILIC-MS/MS) method for the determination of tiapride in human plasma was developed. Tiapride and internal standard, metoclopramide were extracted from human plasma with dichloromethane at basic pH and analyzed on an Atlantis HILIC silica column with the mobile phase of acetonitrile-ammonium formate (190 mM, pH 3.0) (94：6, v/v). The ana-Iytes were detected using an electrospray ionization tandem mass spectrometry in the multi-ple-reaction-monitoring mode. The standard curve was linear (r＝0.999) over the concentration range of 1.00-200 ng/mL. The coefficient of variation and relative error for intra- and inter-assay at three QC levels were 6.4∼8.8％ and -2.0∼3.6％, respectively. The recoveries of tiapride ranged from 96.3 to 97.4％, with that of metoclopramide (internal standard) being 94.2％. The lower limit of quantification for tiapride was 1.00 ng/mL using 1 00 $\mu$L of plasma sample.

• Biomolecules & Therapeutics
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• v.4 no.1
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• pp.78-83
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• 1996

The pharmacokinetics and tissue distribution of DA-3285 (recombinant human erythropoietin, recently manufactured by Research Laboratories of Dong-A Pharmaceutical Company) were studied in the laboratory animals. The plasma, urine, and tissue concentration of DA-3285 were measured by a double-antibody sandwich enzyme immunoassay. After intravenous administration of DA-3285, 20, 100, 500 and 2500 units/kg to rats, the plasma concentrations declined polyexponentially with the terminal half-lives of 2.15, 2.10, 2.31, and 2.35 hr, respectively. Total body clearance (20.7∼26.6 mι/hr/kg) and apparent volume of distribution at steady state (57.2∼70.1 mι/kg) were independent of the dose and AUC increased proportionally with the dose. The renal clearance was much lower than total body clearance, suggesting that extrarenal clearance, presumably metabolism , plays a significant role in elimination of DA-3285. In all rat tissues, the tissue to plasma ratios were smaller than unity, indicating less affinity of DA-3285 to rat tissues and was proved by considerably less value of Vdss. After 3 times a week for consecutive 3 weeks i.v. administration of DA-3285, 100 units/kg to rats, the plasma concentrations and pharmacokinetic parameters of DA-3285 were not significantly different from those in a single administration. After s.c. administration to the rat, plasma concentrations of DA-3285 peaked at 6 hr and the extent of bioavailability was 26.7%. In mice, rabbits and dogs, at DA-3285 dose of 100 units/kg, the mean terminal haw-lives were 2.78, 3.05, and 4.01 hr, respectively. Compared with reported data in the literatures, DA-3285 has similar properties to rh-EPO manufactured by other companies in view of pharmacokinetics.

• The Korean Journal of Physiology
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• v.16 no.1
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• pp.57-61
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• 1982

This study was conducted to investigate the effect of ingestion of rice meal with red pepper(Capsicum annuum) as a seasoning upon the plasma gastrin concentration of normal human subjects in Korea. Thirteen normal human subjects including male and female(mean age: 21 years, range: $20{\sim}24\;years$) were studied. After an overnight(about 15 hrs) fast each subject ingested a test meal and a control meal on different days. The test meal consisted of 250 g toiled rice, 250 ml radish soup containing red pepper(dried powder, 3 g), 50 g vegetables and 200 ml barley tea, corresponding to 7.0 g protein, 9.0 g fat and 82 g carbohydrate and the control meal consisted of the same amount as the test meal except that the radish soup was supplied without red pepper. The venous blood samples were drawn before and after the ingestion of meals at the following times: -30, 0, 15, 30, 45, 60, 90, and 120 min for the measurement of plasma gastrin concentration by means of radioimmunoassay. 1) Plasma gastrin concentration in response to the ingestion of control meal without red pepper increased significantly compared with the concentration in fasting state. 2) The increase of plasma gastrin concentration after the ingestion of test meal(containing red pepper) was significantly higher than that after the control meal. It is inferred from the above mentioned results that the ingestion of red pepper as a seasoning has a stimulatory influence on gastrin release in normal human subjects.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.513-519
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• 2004

A sensitive method for quantification of pinaverium bromide in human plasma was established using liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS). Glimepiride was used as internal standard. Pinaverium bromide and internal standard in plasma sample were extracted using tert-butylmethylether(TBME). A centrifuged upper layer was then evaporated and reconstituted with mobile phase of acetonitrile-5 mM ammonium formate (80/20, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS with multiple reaction monitoring (MRM) mode, pinaverium and glimepirde were detected without severe interference from human plasma matrix. Pinaverium produced a protonated precursor ion $([M+H]^+)$ at m/z 510.3 and a corresponding product ion at m/z 228.9. Internal standard produced a protonated precursor ion $([M+H]^+)$ at m/z 491.5 and a corresponding product ion at m/z 352.0. Detection of pinaverium bromide in human plasma was accurate and precise, with limit of quantitation at 0.5 ng/ml. The method has been successfully applied to bioavailability study of pinaverium bromide tablet in Korean healthy male volunteers. Pharmacokinetic parameters such as $AUC_t,\;C_{max},\;T_{max},\;K_{el}\;and\;t_{1/2}$ were calculated.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.247-250
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• 2003

A simple and sensitive assay method was developed for cefepime in human plasma using high performance liquid chromatography (HPLC). Cefepime and cefadroxil (the internal standard) were extracted from heparinized human plasma by simple deproteination with perchloric acid. The extract was injected into an Atlantis dC18 column ($250{\times}4.6$ mm; particle size $5{\mu}m$, Waters) and the column was eluted with methanol and 0.01 M dihydrogen phosphate at pH 3.0 (15：85 v：v) as a mobile phase at a flow rate of 0.7 mL/min. Linearity was confirmed for the range 0.25 to $200{\mu}L/mL$ and the limit of quantitation was $0.25{\mu}L/mL$. The retention times were 10.2 min and 13.4 min for cefepime and cefadroxil, respectively. This method was successfully applied to a pharmacokinetic study of cefepime in plasma from bone marrow transplant patients.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.973-977
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• 2004

Carvedilol is administered as a racemic mixture of the R(＋)- and S(-)-enantiomers, although they exhibit different pharmacological effects. To investigate the stereoselective pharmacoki-netics, the enantiomeric separation of carvedilol in human plasma was undertaken using capil-lary electrophoresis (CE). Resolution of the enantiomers was achieved using 2-hydoxypropyl-$\beta$-cyclodextrin as the chiral selector. Phosphate buffer (50 mM, pH 4.0) containing 10 mM of 2-hydoxypropropyl-$\beta$-cyclodextrin was used as electrolytic buffer. Achiral separation was carried out with the same electrolytic buffer without chiral selector. Following a single oral administra-tion of 25-mg carvedilol to 11 healthy, male volunteers, stereoselective pharmacokinetic analy-sis was undertaken. The maximum plasma concentrations ( $C_{max}$) were 48.9 and 21.6 ng/mL for (R)-carvedilol and (S)-carvedilol, respectively, determined by the chiral method. The profiles of the plasma concentration of (RS)-carvedilol showed $C_{max}$ of 71.5, 72.2, and 73.5 ng/mL, as determined by the CE, HPLC/FD methods and calculations from the data of the chiral method, respectively.y.y.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.4
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• pp.281-290
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• 2003

Platelet-rich plasma which is made with the newly developed technique concentrating platelets 3-folds or more is also proven to be very effective method to stimulate and accelerate the healing of bone and soft tissue. This study is aimed to investigate the effect of platelet-rich plasma on the attachment of osteoblast. To evaluate the effect on human, human osteoblast cell line was cultured. Platelet-rich plasma was extracted from the blood of a healthy volunteer. The effect on the attachment was evaluated by MTT assay. To evaluate autocrine and paracrine effect on osteoblast, conditioned medium was made and compared with platelet-rich plasma. By western blot analysis, the expression of fibronectin and vitronectin in experimental groups was examined. The results were as following: The cellular attachment of osteoblast cell line increased depending on the concentration of platelet-rich plasma and conditioned medium. The amount of increasing was similar between two groups. The expression of fibronectin and vitronectin in platelet-rich plasma and conditioned medium is more than control group in western blot analysis. These findings imply that platelet-rich plasma enhance the cellular attachment by inducing fibronectin, vitronectin from osteoblast and maximize the cellular attachment by using the autocrine and paracrine effect of platelet-rich plasma.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.379-383
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• 2009

For an accurate risk assessment of furan, a potential human carcinogen, levels must be determined in human blood plasma using a simple and robust assay. In this study, solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) was used to analyze blood plasma levels of furan in 100 healthy individuals who consumed a normal diet. The subjects were 30 to 70 years of age and 51% were women. Ultimately, an analytical method was established for analyzing furan in human blood. The limit of quantification (LOQ) and furan recovery rate in blood were 1.0 ppb and 104%, respectively. Finally, furan was detected in 21 individuals (13 males, 8 females) with levels ranging up to 17.86 ppb (ng furan/g food).

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1681-1685
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• 2012

A sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed to determine valproic acid in human red blood cell (RBC). It is important to measure the drug concentration of the RBC as well as that of the plasma because of drug partitioning for pharmacokinetic and pharmacodynamic study. The method was linear over the dynamic range of 1-100 ${\mu}g$/mL with a correlation coefficient $r$ = 0.9997. The linearity of this method was established from 1 to 100 ${\mu}g$/mL for valproic acid in red blood cell with accuracy and precision within 15% at all concentrations. The intra-run and inter-run assay accuracy and coefficient of variations are all within 15% for all QC samples prepared in plasma and red blood human samples. Then, valproic acid amount by protein precipitation in plasma was quantified by LC-MS/MS mass spectrometry. The distribution ratio of VPA in RBC and plasma was analyzed by clinical samples. Based on measurement of the valproic acid in human red blood cell, this method has been applied to clinical research for study of distribution ratio of valproic acid in blood.