• Title, Summary, Keyword: 생물학적 반감기

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Correlation between physicochemical properties and biological half-life of triazole fungicides in perilla leaf (들깻잎에서 Triazole계 살균제의 생물학적 반감기와 물리화학적 특성과의 상관관계)

  • Lee, Sang-Hyeob;Kwak, Se-Yeon;Hwang, Jeong-In;Kim, Hyo-Jung;Kim, Tae-Hwa;Kim, Jang-Eok
    • Journal of Applied Biological Chemistry
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    • v.62 no.4
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    • pp.407-415
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    • 2019
  • The biological half-life of pesticides applied on crops is the key indicator for ensuring the safety of agricultural products. The biological half-life is affected by the several factors like growing conditions of the crop, climate, application method, and physicochemical properties of pesticides. In this study, the biological half-life was calculated and the degradation rates of six triazole fungicides sprayed on perilla leaves were evaluated. Moreover, the statistical analysis confirmed the correlation between the biological half-life and physicochemical properties of six triazole pesticides. The recoveries of the six pesticides were between 84.8-104.9%, which satisfied the residual pesticide analysis criteria. The biological half-life of six pesticides sprayed on perilla leaves, calculated using the first-order kinetics model, ranged between 6.4-15.1 days. When the biological half-life and the physicochemical properties were correlated using the principal component analysis: pKa and Log P, the biological half-life was found to be affected by PC1. The correlation coefficient between biological half-life and physicochemical properties (pKa), calculated by Spearman rank-order correlation, was R2 = -0.928 (p <0.01). Biological half-life has been shown to correlate with pKa. In conclusion, it can be used as a database for the relationship between biological half-life and physicochemical properties and will contribute to ensure safe supply of agricultural products.

Pharmacokinetic profiles of norfloxacin after intravenous and oral administration in the rabbits (토끼에서 norfloxacin의 경구 및 정맥 투여시 체내 동태)

  • Park, Seung-chun;Yun, Hyo-in;Oh, Tae-kwang;Cho, Joon-hyoung
    • Korean Journal of Veterinary Research
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    • v.35 no.4
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    • pp.683-689
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    • 1995
  • 임상적으로 건강한 New Zealand White 종인 수컷 토끼에서 항생제 norfloxacin(NFX)의 체내 동태를 조사하기 위하여 체중 kg당 5mg을 정맥 및 경구 투여하였다. 그 결과 빠른 분포기와 소실기를 갖는 2-콤파트먼트 모델 양상으로 나타났다. 혈장에서의 약물분석은 HPLC로 실시하였는데, 이동상은 acetonitrile/0.01M phosphate buffer/ 10% citric acid 1mM heptane sulfonic acid(10/70/20)이었고, 흡수 파장은 274nm에서 실시하였다. 정맥 투여후, 생물학적 반감기는 3.14시간으로 나타났으며, 분포반감기는 0.38시간으로 빠른 분포를 보여주었다. 최고 혈중농도는 $24.27{\mu}g/ml$로 계산되었으며 청소율은 0.68ml/kg/h로 분석되었다. 경구 투여후, 최고 혈중 농도와 최고 혈중 도달 시간은 $0.86{\mu}g/ml$과 0.43시간으로 각각 계산되었다. 이때의 생물학적 반감기는 3.61시간으로 정맥 투여시와 유의성 있는 차이는 없었으며, 흡수 반감기는 0.17시간으로 빠른 흡수를 보여주었다. 생체이용율은 30%로 나타났으며, 0.2-1.6g/ml인 치료혈중 농도 범위에서 혈장 결합율은 26%로 나타나, 토끼에서 항생요법은 구강 투여시 초기 투여량은 2.71mg/kg이며, 유지 투여량은 12시간마다 2.54mg/kg이 적당한 것으로 분석되었다.

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Residue Patterns and Biological Half-lives of Pyridalyl and Fluopicolide in Watermelon (수박 중 및 Pyridalyl 및 Fluopicolide의 잔류 특성 및 생물학적 반감기 산출)

  • Park, Ji-Su;Yang, Seung-Hyun;Choi, Hoon
    • Korean Journal of Environmental Agriculture
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    • v.36 no.1
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    • pp.50-56
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    • 2017
  • BACKGROUND: The present study was carried out to identify the residue patterns of insecticide pyridalyl and fungicide fluopicolide in watermelon and calculate the biological half-lives for establishing the pre-harvest residue limits (PHRLs). METHODSANDRESULTS:The watermelon samples for residue analysis were harvested 7 times during 0~10 days (Field 1) and 0~20 days (Field 2) after treatment of pesticides on watermelon in two different fields at the recommended dose, respectively. The residue analysis was conducted with HPLC/UVD. The method limit of quantitation (MLOQ) were set at 0.05 and 0.02 mg/kg, respectively, and overall mean recoveries were 81.2~90.5% for pyridalyl and fluopicolide. The residues in sample were stable for 43~47 days. The initial residue amount in field 1 and 2 were 0.12~0.16 mg/kg for pyridalyl and 0.23~0.24 mg/kg for fluopicolide, which were below maximum residue limit (MRL). The biological half-lives in field 1 and 2 were 26.9 and 17.9 days for pyridalyl and 16.6 and 94.2 days for fluopicolide, respectively. CONCLUSION: The PHRL for watermelon were estimated as 0.21 and 1.03 mg/kg for pyridalyl and flopicolide at 10 days before harvesting. The residue patterns of pyridalyl and fluopicolide were characterized by a very slow decrease of residue levels in watermelon.

Dissipation Pattern of Fungicides Boscalid and Pyraclostrobin in Jujube (대추 중 살균제 boscalid와 pyraclostrobin의 잔류 소실 특성)

  • Jo, Hyeong-Wook;Sohn, Sang-Hyun;Kim, Kyoung-Jin;Hwang, Gi-Jun;Jo, Beom-Haeng;Gil, Seok-Ju;Kwon, Chan-Hyeok;Moon, Joon-Kwan
    • The Korean Journal of Pesticide Science
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    • v.21 no.1
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    • pp.17-25
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    • 2017
  • Dissipation pattern and biological half-lives of fungicides boscalid and pyraclostrobin were calculated on jujube. The pesticides were sprayed on jujube in two different field at the standard rate, respectively. The raw agricultural commodities were harvested at 0 (2 hr), 1, 3, 5, 7, 10 and 14 days after treatment, and analyzed by HPLC/DAD. The method limit of quantification (MLOQ) was $0.02mg\;kg^{-1}$ for boscalid and pyraclostrobin. The recovery ranged 101.8~109.3% with below 5% of CV (Coefficient of variation) for boscalid and 104.2~115.4% with below 5% of CV for pyraclostrobin. An average initial deposit at field 1 and field 2 samples were observed 0.40 and $0.48mg\;kg^{-1}$ for boscalid and, 0.76 and $0.57mg\;kg^{-1}$ for pyraclostrobin, respectively. The biological half-lives of field 1 and field 2 were 11.0 and 13.2 day for boscalid, and 6.1 and 12.7 days for pyraclostrobin.

Residual Patterns of Acaricides, Etoxazole and Flufenoxuron in Apples (살응애제 Etoxazole 및 Flufenoxuron의 사과 중 잔류양상)

  • Hwang, Jeong-In;Kim, Jang-Eok
    • The Korean Journal of Pesticide Science
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    • v.18 no.2
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    • pp.61-68
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    • 2014
  • Dissipation constants and half-lives of acaricides etoxazole and flufenoxuron in apples were calculated to establish their pre-harvest residue limits (PHRLs). The acaricides were sprayed on apples with single and triple doses based on safe use guidelines, and their residual patterns in the apple were interpreted using first order kinetics equation. The residual amounts of acaricides during the experimental period were below their maximum residue limits (MRL) for apple. The dissipation constants of acaricides in the apples were calculated at 0.0788 for etoxazole and 0.0319 for flufenoxuron corresponding to their biological half-lives; 8.8~21.7 days for etoxazole and 21.7~23.1 days for flufenoxuron. The PHRLs of acaricides in the apple showed the residual amounts of etoxazole and flufenoxuron at the harvesting date would be below their MRLs if their residual amounts were less than 0.87 and 0.88 mg/kg, respectively, at 7 days prior to harvesting the apples.

Residue Patterns of Fungicides, Flusilazole and Myclobutanil in Apples (살균제 Flusilazole 및 Myclobutanil의 사과 중 잔류양상)

  • Hwang, Jeong-In;Kim, Jang-Eok
    • Current Research on Agriculture and Life Sciences
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    • v.31 no.4
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    • pp.272-279
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    • 2013
  • The dissipation patters of the triazole fungicides flusilazole and myclobutanil in apples were investigated to establish the biological half-lives and pre-harvest residue limits (PHRLs). The residual amounts of the fungicides sprayed with single or triple doses were below the maximum residue limits (MRL) for apples established by Ministry of Food and Drug Safety. The dissipation constants of the fungicides in the apples were 0.0513 for flusilazole and 0.0244 for myclobutanil meaning their biological half-lives were calculated as 6.2-6.7 days for flusilazole and 13.3-24.8 days for myclobutanil. The PHRLs calculated using the dissipation constants indicated that the residual amounts of flusilazole and myclobutanil in the apples at the harvesting date would be below the MRLs if their residual amounts were 0.43 and 0.59 mg/kg, respectively, at 7 days prior to harvesting the apples.

Field tolerance of pesticides in the strawberry and comparison of biological half-lives estimated from kinetic models (Kinetic models에 의한 딸기 중 농약의 생물학적 반감기 비교와 생산단계잔류허용기준 설정)

  • Park, Dong-Sik;Seong, Ki-Young;Choi, Kyu-Il;Hur, Jang-Hyun
    • The Korean Journal of Pesticide Science
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    • v.9 no.3
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    • pp.231-236
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    • 2005
  • This study was conducted to determine the amounts of pesticide residues after treatment of criterion dose with 4 pesticides(tolclofos-m, folpet, procymidone, and triflumizole) under cultivated period and to compare the biological half-life of pesticides with 6 kinetic models(first, zero and second order kinetics, power function, elovich and parabolic model) and to establish proposed field tolerance using biological half-lives. Recovery of 4 pesticides form strawberry was ranged from 85.1 to 105.5%. For all of 4 pesticides, dissipation rate was over 73% at 5 days after application. Among 6 kinetic models, first order kinetic model (FO) was best fit to describe the relationship between residual pattern of pesticides and time. Therefore, half-lives were calculated by FO for establishing the field tolerance. These results showed that half-life should be calculated by comparative best fit kinetic model and field tolerance can help to prevent unacceptable agricultural products from marketing. It is good for both consumers and farmers having safe agricultural products and financial benefits, respectively.

Residual Pattern of Chlorothalonil, Indoxacarb, Lufenuron, Metalaxyl and Methomyl during the Cultivation Periods in Chinese Cabbage (얼갈이배추의 재배기간 중 Chlorothalonil, Indoxacarb, Lufenuron, Metalaxyl 및 Methomyl의 잔류량 변화)

  • Ko, Kwang-Yong;Kim, Sung-Hun;Jang, Young-Hee;Lee, Kyu-Seung
    • The Korean Journal of Pesticide Science
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    • v.12 no.1
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    • pp.34-42
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    • 2008
  • In order to know the residual pattern of some pesticides and predict to the degradation period until below MRL, we experimented chlorothalonil, indoxacarb, lufenuron, metalaxyl and methomyl for Chinese cabbage. They were frequently detected pesticides in Chinese cabbage by NAQS (National Agricultural product Quality management Service) monitoring survey. In this experiment, we sprayed those pesticides 10days before harvest and analyzed 0, 1, 2, 3, 5, 7, 10 day samples to establish logical equation and to calculate $DT_{50}0$. During the cultivating period, the residue amount of chlorothalonil was changed from $55.58\;mg\;kg^{-1}$ (0 day) to $20.08\;mg\;kg^{-1}$ (10 day), $DT_{50}$ was 7.45 days, indoxacarb was $7.85\;mg\;kg^{-1}$ (0 day) to $1.46\;mg\;kg^{-1}$ (10 day), and 4.2 days, lufenuron was $1.57\;mg\;kg^{-1}$ (0 day) to $0.49\;mg\;kg^{-1}$ (10 day), and 5.85 days, metalaxyl was $8.12\;mg\;kg^{-1}$ (0 day) to $0.10\;mg\;kg^{-1}$ (10 day), and 175 days, and methomyl was $11.51\;mg\;kg^{-1}$ (0 day) to $0.80\;mg\;kg^{-1}$ (10 day), and 2.42 days at single dose application, respectively. The $DT_{50}$ of double amount in those pesticides were 9.05 days in chlorothatonil, 7.09 days in indoxacarb, 8.82 days in lufenuron, 3.32 days in metalaxyl, and 2.72 days in methomyl, respectively.

Establishment of Pre-Harvest Residue Limits of Clothianidin and Thiacloprid in Ginseng (인삼 중 Clothianidin 및 Thiacloprid의 생산단계 농약잔류허용기준 설정)

  • Na, Eun-Shik;Lee, Yong-Jae;Kim, Kyoung-Ju;Kim, Seong-Soo;Lee, Kyu-Seung
    • The Korean Journal of Pesticide Science
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    • v.17 no.3
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    • pp.155-161
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    • 2013
  • The residue patterns of clothianidin and thiacloprid, insecticides registered in the ginseng, were investigated to predict pre-harvest residues limits (PHRL). Pesticides were treated under Korea GAP (Good Agricultural Practices) with the recommended dose (single dose) and twice of recommended dose (double dose). Samples were collected 11 times over 42 days (each 0, 2, 5, 8, 12, 16, 20, 24, 28, 33, 42 days after treatment). Residues of clothinidin and thiacloprid were analyzed by UPLC/TQD. Biological half-life of clothinidin in single dose and double dose were 14.6 days and 10.2 days and that of thiacloprid were also 9.7 days and 11.2 days, respectively. The PHRL of ginseng on 10 days before harvest was 0.3 mg/kg in clothianidin and 0.18 mg/kg in thiacloprid.

Dissipation Patterns of Triazole Fungicides Estimated from Kinetic Models in Apple (Triazole계 살균제의 사과 중 잔류양상의 Kinetic Model 적용)

  • Kim, Ji-Hwan;Hwang, Jeong-In;Jeon, Young-Hwan;Kim, Hyo-Young;Ahn, Ji-Woon;Kim, Jang-Eok
    • Journal of Applied Biological Chemistry
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    • v.55 no.4
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    • pp.235-239
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    • 2012
  • While cultivating crops, it is important to predict the biological half-lives of applied pesticides to ensure the safety of agricultural products. Dissipation patterns of the triazole fungicides, such as diniconazole and metconazole, during the cultivation of apple were established by utilizing the dissipation curve. As well as, the biological half-lives of the pesticides in apples were calculated using the residue amounts of them. The apples were harvested from 0 to 14 days after spraying diniconazole (WP) and metconazole (SC) at a recommended and three times of the recommended dose. Initial concentrations of diniconazole in apple were 0.09 and 0.15 mg/kg at a recommended and three times of the recommended dose, respectively, which were below MRL 1.0 mg/kg established by KFDA. The equations of biological half-life were $C_t=0.0811e^{-0.179x}$(half life: 3.9 days) and $C_t=0.1451e^{-0.148x}$ (half life: 4.7 days), respectively. In case of metconazole, initial concentrations in apple were 0.10 and 0.25 mg/kg, below MRL 1.0mg/kg, and biological half-life equations were $C_t=0.0857e^{-0.055x}$ (half life: 12.6 days) and $C_t=0.2304e^{-0.052x}$ (half life: 13.3 days), respectively. Therefore, when triazole fungicides were applied during the cultivation of apple, the biological half-life need to be calculated with the optimal equation model.