• Analytical Science and Technology
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• v.30 no.5
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• pp.221-225
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• 2017

Thioctic acid is a vitamin-like antioxidant which is prepared as tablets and injection. The Korean Pharmacopoeia (KP XI) contains monograph for the quality control of raw thioctic acid using ultra-violet visible spectrophotometry and its formulations using high performance liquid chromatography (HPLC). In British Pharmacopoeia 2013 (BP2013), another HPLC method is used for the assay test of thioctic acid material. For the international harmonization, we present an HPLC method for quantitation of thioctic acid in both raw material and tablets. Method validation was performed to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of calibration curves in the desired concentration range was high ($r^2=0.9995$), while the RSDs for intra- and inter-day precision were 0.93 ~ 1.26 % and 1.40 ~ 1.76 %, respectively. Accuracies ranged from 98.13-100.00 %. Since the system suitability, intermediate-precision and robustness of the assay were satisfactory, this method will be a valuable addition to the Korean Pharmacopoeia (KP XI).

• Food Science and Biotechnology
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• v.17 no.4
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• pp.846-849
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• 2008

This study employed high performance liquid chromatography (HPLC) coupled to an on-line $ABTS^+$ radical scavenging detection (RSD) system along with HPLC-electro spin impact/mass spectrometry (ESI/MS), to rapidly determine and identify antioxidant compounds occurring in blueberry extract. The extract was separated by HPLC, and then the radical scavenging activities of the separated compounds were evaluated by the on-line coupled $ABTS^+$-RSD system. The negative peaks of the $ABTS^+$-RSD system, which indicates the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734 nm. The active components in the blueberry extract were identified by HPLC-ESI/MS using their MS spectra and retention times. According to the data acquired from the on-line HPLC-$ABTS^+$-based assay and HPLC-ESI/MS systems, the antioxidant compounds detected in the blueberry extract were identified as chlorogenic acid and 11 anthocyanins.

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.358-363
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• 2005

We have studied the interaction of 3-nitrotyrosine with peroxynitrite using three different methods; chemiluminescence, spectrophotometry and HPLC. Peroxynitrite-induced luminol or lucigenin chemiluminescence were significantly decreased by 3-nitrotyrosine, in concentration­dependent manners. The intensity of the peroxynitrite spectrum was also markedly reduced in the presence of 3-nitrotyrosine in the spectrophometric assay. However, there was no attenuation of the 3-nitrotyrosine signal in the HPLC assay after mixing with peroxynitrite. The interaction of 3-nitrotyrosine and hypochlorous acid (HOCI) was also studied via the chemilumines-cence assay, where the HOCI-induced responses were markedly inhibited by 3-nitrotyrosine. These results suggest that caution should be taken when studying the levels or interactions of 3-nitrotyrosine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.945-949
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• 1994

Chondroitin sulfate (Chs) contents in edible snail , Achatina fulica Bowdich , andits processed meat extracts were determined by high-performance liquid chormatogrpahy(HPLC) and spectrophotometric method. Spectrophotometric method was based on the precipitation of acriflavine by ChS, and HPLC method was based on the detection of two unsaturated disaccharides, 2-acetamido-2-deoxy-3-O-($\beta$ -D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose($\Delta$Di-4S) and 2-acetamido-2deoxy-3-O-($\beta$-D-gluco-4-eepyranosyluronic acid)-6-O-sulfo-D-galactose ($\Delta$야-6S) librated from ChS byenzymeatic digestion with chondroitinase ABc. the ratio of 125$\mu$mol of sodium hydroxide to mg of ChS and 8$0^{\circ}C$ of reaction temperature were proper for alkaline hydrolysis to remove protein residue form ChS. In assay preparation for HPLC ethod, the iptimum concentration of the enzyme chondroitinase ABc was 0.15 unit per 50 $\mu\textrm{g}$ of ChS at a fixed reaction time (30 min) and pH 8.0 using Tris buffer. ChS content in edible snail was 177.6mg% by spectrophotometric method and 153.5mg% by HPLC method and those in the processed meat extract was 71.3mg% by spectrometric method ad 62.8mg% by HPLC method, respectively.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.39-45
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• 2010

The pollution of antibiotics is a major cause of spreading antibiotics resistant bacteria in the environment. Applications of ozonation, UV, and ${\gamma}-ray$ irradiations have been introduced to remove antibiotics in the effluents from wastewater treatment system. In this study, we compared the chemical (HPLC) and biological (antimicrobial susceptibility test, AMS) assays in measuring of the concentrations of residual antibiotics after ${\gamma}-ray$ and UV irradiation. Most samples were degraded by ${\gamma}-ray$ irradiation (1~2 kGy). However, lincomycin and tetracycline were not degraded by UV irradiation. The concentration of residual antibiotics, that was treated with ${\gamma}-ray$ and UV irradiation, measuring by bioassay was similar to HPLC. The concentrations of ${\gamma}-ray$ irradiated cephradine measured by AMS test were 2 times higher than that of HPLC assay, indicating AMS test is more sensitive than HPLC assay. These results indicate that ${\gamma}-ray$ irradiation technique is more useful than UV irradiation, and biological assay is more useful to detect the antibiotics and toxic intermediates in antibiotics degradation.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.1-9
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• 1994

In order to assay the human plasma concentration of nifedipine in patients with bronchopulmonary dysplasia (BPD) and pulmonary hypertension, a modified high performance liquid chromatography (HPLC) method was applied. The retention times for nifedipine and an internal standard (11-ketoprogesterone) were $10.5\;{\pm}\;0.41$ and $13.1\;{\pm}\;0.63$ min, respectively. Absolute recovery from the plasma was $102.9\;{\pm}\;7.07%$. Reproducibility was excellent and variability between the runs was small. There was a negligible degradation during the assay procedure. The calibration curve shows a good linearity in the range of the desired plasma concentrations of nifedipine. A stability test of nifedipine in the human plasma shows 8 and 13% degradation during the storage of 5 and 9 months, respectively. There were no interferences on the HPLC assay with any possible medications for the BPD. The method has been used to monitor the drug concentrations in a patient. The concentration-time curve of a patient after a single oral dose of 0.3 mg/kg shows a double-peak phenomenon that was quite different from the previous report, suggesting non-bolus administration. However the hemodynamic responses were corresponding to the plasma concentration levels of nifedipine.

• Toxicological Research
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• v.32 no.4
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• pp.269-274
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• 2016

The potency of influenza vaccine is determined based on its hemagglutinin (HA) content. In general, single radial immunodiffusion (SRID) assay has been utilized as the standard method to measure HA content. However, preparation of reagents for SRID such as antigen and antibody takes approximately 2~3 months, which causes delays in the development of influenza vaccine. Therefore, quantification of HA content by other alternative methods is required. In this study, we measured HA contents of H1N1 antigen and H1N1 influenza vaccine by reverse phase-high performance liquid chromatography (RP-HPLC) methods. The presence of HA1 and HA2 was investigated by silver staining and Western blot assay. In addition, accuracy and repeatability of HA measurement by RP-HPLC were evaluated. Comparison of HA concentration by SRID and RP-HPLC revealed a precise correlation between the two methods. Our results suggest that RP-HPLC assay can replace SRID in the event of a pandemic flu outbreak for rapid vaccine development.

• Journal of Microbiology
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• v.38 no.2
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• pp.74-79
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• 2000

For the demonstration of a novel riboflavin kinase assay method based on the bacterial bioluminescence, partially purified riboflavin kinase was prepared from bovine liver through ammonium sulfate precipitation and DEAE-cellulose ion exchange chromatography. Using bacterial luciferase from Photobacterium phosphoreum and the dithionite reduction method, and easy, safe, and fast assay method was established. The optimal temperature, pH, Km values form riboflavin and ATP of boving liver riboflavin kinase determined with this luminescence method were 35$^{\circ}C$, pH 7, 15.3${\mu}$M and 8.3.${\mu}$M, respectively. The detection limit of FMN produced by riboflavin kinase was in the range of 200 pM to 4${\mu}$M which is comparable to the HPLC-fluorescence detection method, while the detection time for each assay was less than 15 sec compared to the HPLC method which requeires at least 10 min for completion.

• Analytical Science and Technology
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• v.29 no.6
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• pp.277-282
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• 2016

British Pharmacopoeia (BP 2013), the United States Pharmacopoeia (USP 39) and the Korean Pharmacopoeia (KP XI) contain monographs for the quality control of raw diosmin using high performance liquid chromatography (HPLC). However, official monographs detailing pharmaceutical formulations for diosmin are not available in foreign pharmacopoeias. In the KP XI, ultraviolet-visible (UV-Vis) spectroscopy-which is less specific than HPLC-is reported for the testing of diosmin capsules. In this study, we present an alternative HPLC assay for such testing that is more specific than UV-Vis methods. Method validation was performed to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of calibration curves in the desired concentration range was high ($r^2$>0.999), while the RSDs for intra- and inter-day precision were 0.15-0.29 % and 1.05-1.74%, respectively. Accuracies ranged from 101.2-103.2 %, while the retention time and peak area RSDs were 0.37 % and 0.06 %, respectively. Additionally, the plate number and asymmetry factor values for diosmin were 3591.293 and 1.35, respectively. Since the intermediate-precision and robustness of the assay were satisfactory, this method will be a valuable addition to the Korean Pharmacopoeia (KP XI).

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.96-103
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• 2010

Oligosaccharyltransferase (OTase) catalyzes the transfer of a lipid-linked oligosaccharide (LLO) to the nascent polypeptide. Most eukaryotes have an OTase composed of a multisubunit protein complex. However, the kinetoplastid Leishmania major and the bacterium Campylobacter jejuni have only a single subunit for OTase activity, Stt3p and PglB, respectively. In this study, a new in vitro assay for OTase was developed by using a fluorescent peptide containing N-glycosylation sequon, Asn-Xaa-Thr/Ser, where Xaa can be any amino acid residue except Pro. L. major Stt3p and C. jejuni PglB as a model OTase enzyme demonstrated the formation of glycopeptides from a fluorescent peptide through OTase activities. For separation and measurement of the glycopeptides produced by the OTases, Tricine-SDS-PAGE, a lectin column and fluorospectrophotometer, and HPLC were applied. Comparison of these assay methods for analyzing a fluorescent glycopeptide showed HPLC analysis is the best method for separation of glycopeptides and nonglycosylated peptides as well as for quantify the peptides than other methods.