• The Korean Journal of Pesticide Science
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• v.20 no.2
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• pp.93-103
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• 2016

A simultaneous analytical method was developed for the determination of isoxaflutole and metabolite (diketonitrile) in agricultural commodities. Samples were extracted with 0.1% acetic acid in water/acetonitrile (2/8, v/v) and partitioned with dichloromethane to remove the interference obtained from sample extracts, adjusting pH to 2 by 1 N hydrochloric acid. The analytes were quantified and confirmed via liquid chromatograph-tandem mass spectrometer (LC-MS/MS) in positive-ion mode using multiple reaction monitoring (MRM). Matrix matched calibration curves were linear over the calibration ranges ($0.02-2.0{\mu}g/mL$) for all the analytes into blank extract with $r^2$ > 0.997. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates at each level. The recoveries were ranged between 72.9 to 107.3%, with relative standard deviations (RSDs) less than 10% for all analytes. All values were consistent with the criteria ranges requested in the Codex guideline (CAC/GL40, 2003). Furthermore, inter-laboratory study was conducted to validate the method. The proposed analytical method was accurate, effective, and sensitive for isoxaflutole and diketonitrile determination in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.32 no.4
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• pp.254-261
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• 2017

Determining the origin of the components in commercially available gelatin, a purified protein derived mostly from pig skin and bovine tissue, is a challenge, leading to concerns on the grounds of religious beliefs and health. Therefore, regular monitoring of labeling compliance by food control authorities is also necessary. In this study, we monitored the origin of gelatin capsules from 181 commercial dietary supplements that were available for purchase on the internet, using species-specific PCR assays. Fifty five products were labeled correctly, declaring that they used bovine-, fish- and plant-derived gelatin, whereas the other 126 capsules were labeled "gelatin" without specifying the origin. Gelatin in these capsules was obtained from cattle (n = 51), pigs (n = 31), or both (n = 44). Therefore, it is important to declare all of the raw materials used to produce gelatin capsules on the labels to best protect consumers' rights, religious beliefs, and health.

• Osong Public Health and Research Perspectives
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• v.8 no.6
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• pp.389-396
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• 2017

Objectives: To circumvent the limitations of the current golden standard method, colony-forming unit (CFU) assay, for viability of Bacille Calmette-$Gu{\acute{e}}rin$ (BCG) vaccines, we developed a new method to rapidly and accurately determine the potency of BCG vaccines. Methods: Based on flow cytometry (FACS) and fluorescein diacetate (FDA) as the most appropriate fluorescent staining reagent, 17 lots of BCG vaccines for percutaneous administration and 5 lots of BCG vaccines for intradermal administration were analyzed in this study. The percentage of viable cells measured by flow cytometry along with the total number of organisms in BCG vaccines, as determined on a cell counter, was used to quantify the number of viable cells. Results: Pearson correlation coefficients of FACS and CFU assays for percutaneous and intradermal BCG vaccines were 0.6962 and 0.7428, respectively, indicating a high correlation. The coefficient of variation value of the FACS assay was less than 7%, which was 11 times lower than that of the CFU assay. Conclusion: This study contributes to the evaluation of new potency test method for FACS-based determination of viable cells in BCG vaccines. Accordingly, quality control of BCG vaccines can be significantly improved.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.139-151
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• 2023

Sulfonylurea herbicides are widely used in agriculture because they have a long residual period and high selectivity. An analytical method was developed using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique for simultaneous determination of sulfonylurea herbicide residues in agricultural products by liquid chromatography tandem mass spectrometry and for establishment MRL (Maximum Residue Limit) of those herbicides in Korea. Extraction was performed using acetonitrile containing 0.1% formic acid with MgSO₄ (anhydrous magnesium sulfate) and NaCl (sodium chloride) and the extract was cleaned up using MgSO₄ and C₁₈ (octadecyl). The matrix-matched calibration curves were composed of 7 concentration levels from 0.001 to 0.25 mg/kg and their coefficients of determination (R²) exceeded 0.99. The recoveries of three spiking levels (LOQ, 10LOQ, 50LOQ, n=5) were in the range of 71.7-114.9% with relative standard deviations of less than 20.0% for all the five agriculture products. All validation values met criteria of the European Union SANTE/11312/2021 guidelines and Food and Drug Safety Evaluation guidelines. Therefore, the proposed analytical method was accurate, effective, and sensitive for sulfonylurea herbicide residues determination in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.124-134
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• 2019

An analytical method was developed for the determination of broflanilide and its metabolites in agricultural products. Sample preparation was conducted using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and LC-MS/MS (liquid chromatograph-tandem mass spectrometer). The analytes were extracted with acetonitrile and cleaned up using d-SPE (dispersive solid phase extraction) sorbents such as anhydrous magnesium sulfate, primary secondary amine (PSA) and octadecyl ($C_{18}$). The limit of detection (LOD) and quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. The recovery results for broflanilide, DM-8007 and S(PFP-OH)-8007 ranged between 90.7 to 113.7%, 88.2 to 109.7% and 79.8 to 97.8% at different concentration levels (LOQ, 10LOQ, 50LOQ) with relative standard deviation (RSD) less than 8.8%. The inter-laboratory study recovery results for broflanilide and DM-8007 and S (PFP-OH)-8007 ranged between 86.3 to 109.1%, 87.8 to 109.7% and 78.8 to 102.1%, and RSD values were also below 21%. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL 40-1993, 2003) and the Food and Drug Safety Evaluation guidelines (2016). Therefore, the proposed analytical method was accurate, effective and sensitive for broflanilide determination in agricultural commodities.

• Biomolecules & Therapeutics
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• v.23 no.4
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• pp.386-389
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• 2015

Sibutramine is an anorectic that has been banned since 2010 due to cardiovascular safety issues. However, counterfeit drugs or slimming products that include sibutramine are still available in the market. It has been reported that illegal sibutramine-contained pharmaceutical products induce cardiovascular crisis. However, the mechanism underlying sibutramine-induced cardiovascular adverse effect has not been fully evaluated yet. In this study, we performed cardiovascular safety pharmacology studies of sibutramine systemically using by hERG channel inhibition, action potential duration, and telemetry assays. Sibutramine inhibited hERG channel current of HEK293 cells with an $IC_{50}$ of $3.92{\mu}M$ in patch clamp assay and increased the heart rate and blood pressure ($76{\Delta}bpm$ in heart rate and $51{\Delta}mmHg$ in blood pressure) in beagle dogs at a dose of 30 mg/kg (per oral), while it shortened action potential duration (at $10{\mu}M$ and $30{\mu}M$, resulted in 15% and 29% decreases in $APD_{50}$, and 9% and 17% decreases in $APD_{90}$, respectively) in the Purkinje fibers of rabbits and had no effects on the QTc interval in beagle dogs. These results suggest that sibutramine has a considerable adverse effect on the cardiovascular system and may contribute to accurate drug safety regulation.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.318-327
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• 2015

BACKGROUND: Trinexapac-ethyl is a plant growth regulator (PGR) that inhibits the biosynthesis of plant growth hormone (gibberellin). It is used for the prevention of lodging, increasing yields of cereals, and reducing mowing of turf. The experiment was conducted to establish a determination method for trinexapac-ethyl and its metabolites trinexapac in agricultural products using LC-MS/MS.METHODS AND RESULTS: Trinexapac-ethyl and trinexapac were extracted from agricultural products with methanol/ distilled water and the extract was partitioned with dichloromethane and then detected by LC-MS/MS. Limit of detection(LOD) was 0.003 mg/kg and limit of quantification(LOQ) was 0.01 mg/kg, respectively. Matrix matched calibration curves were linear over the calibration ranges (0.01-1.0 mg/L) for all the analytes into blank extract withr²> 0.997. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, 10LOQ, 50LOQ,n=5). Recoveries of trinexapacethyl and trinexapac were within the range of 73.6-106.9%, 72.7-99.2%, respectively. The relative standard deviations (RSDs) were less than 9.0%. All values were consistent with the criteria ranges requested in the CODEX guideline(CAC/GL 40, 2003).CONCLUSION: The proposed analytical method was accurate, effective and sensitive for trinexapac-ethyl and trinexapac determination and it can be used to as an official method in Korea.

• Analytical Science and Technology
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• v.29 no.2
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• pp.94-103
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• 2016

An analytical method was developed to determine the amount of spinetoram (spinetoram J and spinetoram L) in livestock samples. The spinetoram was extracted with acetonitrile and purified through a primary secondary amine (PSA) sorbent. The spinetoram residues were then quantified and confirmed using a liquid chromatography–tandem mass spectrometer (LC-MS/MS) in the positive ion mode using multiple reactions monitoring (MRM). Matrix-matched calibration curves were linear over the calibration ranges (0.005-0.5 mg/kg) into a blank extract with r² > 0.994. The limits of detection and quantification were 0.002 and 0.01 mg/kg, respectively. The recovery results of spinetram ranged between 81.9-106.4% at different concentration levels (LOQ, 10LOQ, 50LOQ, n=5) with relative standard deviations (RSDs) less than 10%. All values were consistent with the criteria ranges requested in the Codex guidelines (CAC/GL40, 2003). An interlaboratory study was conducted to validate the method. The proposed analytical method proved to be accurate, effective, and sensitive for spinetoram determination. The method will be used as an official analytical method in Korea.

• YAKHAK HOEJI
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• v.58 no.4
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• pp.255-261
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• 2014

Poly-pharmacy has been on the rise because of aging of population and chronic disease. Most of drug metabolism happens in the liver by CYP isozymes and the metabolism by CYP450 enzymes. The Cytochrome P450 (CYP) is a superfamily of enzymes that catalyzes the oxidations of many endogenous and exogenous compounds. Primary human Hepatocytes (HH) are considered as the gold standard model for In vitro drug interaction studies. However, there are several limitations (cost, limited life span) for using HH cells. HepaRG cells are being used as a possible alternative. HepaRG cells were cultured in William E medium containing the positive control inducers (1A2: 10, 25, 50 ${\mu}M$ omeprazole, 2C9 and 2C19: 10 ${\mu}M$ rifampin, 3A4: 10, 25, 50 ${\mu}M$ rifampin) at $37^{\circ}C$, 5 % $CO_2$ in a humidified atmosphere. This study was to evaluate the induction of CYP isozymes (1A2, 2C9, 2C19 and 3A4) using LC-MS/MS. We evaluated the potential induction ability of Bosentan, as a drug of pulmonary artery hypertension, in HepaRG cells. For reference, dose of the Bosentan is determined to the basis of the $C_{max}$ (835 mg/ml) value. The enzyme activity demonstrated that CYP2C9 and 3A4 were induced up to 20 times by Bosentan. Like as In vivo, the enzyme activity of CYP2C9 and CYP3A4 is significantly induced in a dose-dependent by Bosentan.

• Analytical Science and Technology
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• v.28 no.2
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• pp.86-97
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• 2015

Recently, the consumption of dietary supplements has increased because of people’s greater interest in health. Unfortunately, the sales of dietary supplements containing unauthorized substances such as drugs have also increased. We developed a rapid, accurate method for the simultaneous determination of antihistamines using liquid chromatography tandem mass spectrometry with a multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the instrument used in this method were in the ranges 0.0003-0.3 and 0.0009-0.6 µg mL⁻¹, respectively. The linearity of the method was > 0.99. The precision levels of the method were 0.1-9.8% (intra-day) and 0.3-9.6% (inter-day), and the levels of accuracy of the method were 82.7-115.0% (intra-day) and 84.3-113.0% (inter-day). The mean of recovery of the method was in the range of 83.9-117.9% and the RSD of the stability was less than 5.9%.