• 제목/요약/키워드: Half Life ($t_{1/2}$)

검색결과 250건 처리시간 0.029초

노르플록사신의 체내동태에 대한 신장해의 영향 (Effect of Renal Failure on Pharmacokinetics of Norfloxacin in Rabbits)

  • 이종기
    • Journal of Pharmaceutical Investigation
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    • 제25권3호
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    • pp.265-270
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    • 1995
  • The pharmacokinetics of norfloxacin (100 mg/kg, oral) in renal failure rabbits was studied. Renal failure rabbits were induced by the i.v. injection of folate (50,100 and 150 mg/kg). These produced significant increases of serum creatinine concentration $(S_{cr})$ and blood urea nitrogen (BUN). Plasma concentration and AUC of norfloxacin significantly increased. Elimination rate constant $(K_{el})$ of norfloxacin significantly decreased, and half-life $(t_{1/2})$ of norfloxacin significantly increased. Correlation between serum creatinine concentration $(S_{cr})$ and half-life $(t_{1/2})$ of norfloxacin, and correlation between BUN and AUC of norfloxacin have linear relationship respectively. These results suggest that adjustment or the dosage regimen of norfloxacin is desirable, and serum creatinine concentration $(S_{cr})$ as well as BUN can be used an index for adjusting the dosage regimen of norfloxacin in renal failure.

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Novel AGLP-1 albumin fusion protein as a long-lasting agent for type 2 diabetes

  • Kim, Yong-Mo;Lee, Sang Mee;Chung, Hye-Shin
    • BMB Reports
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    • 제46권12호
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    • pp.606-610
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    • 2013
  • Glucagon like peptide-1 (GLP-1) regulates glucose mediated-insulin secretion, nutrient accumulation, and ${\beta}$-cell growth. Despite the potential therapeutic usage for type 2 diabetes (T2D), GLP-1 has a short half-life in vivo ($t_{1/2}$ <2 min). In an attempt to prolong half-life, GLP-1 fusion proteins were genetically engineered: GLP-1 human serum albumin fusion (GLP-1/HSA), AGLP-1/HSA which has an additional alanine at the N-terminus of GLP-1, and AGLP-1-L/HSA, in which a peptide linker is inserted between AGLP-1 and HSA. Recombinant fusion proteins secreted from the Chinese Hamster Ovary-K1 (CHO-K1) cell line were purified with high purity (>96%). AGLP-1 fusion protein was resistant against the dipeptidyl peptidase-IV (DPP-IV). The fusion proteins activated cAMP-mediated signaling in rat insulinoma INS-1 cells. Furthermore, a C57BL/6N mice pharmacodynamics study exhibited that AGLP-1-L/HSA effectively reduced blood glucose level compared to AGLP-1/HSA.

아테놀올의 체내동태에 대한 신장해의 영향 (Effect of Renal Failure on Pharmacokinetics of Atenolol in Rabbits)

  • 이종기;조삼상
    • 한국임상약학회지
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    • 제8권1호
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    • pp.23-28
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    • 1998
  • The pharmacokinetics of atenolol (25 mg/kg, i.v.) in the folate-induced renal failure rabbits was studied. Renal failure was induced by the i.v. injection of folate (50, 100, and 200 mg/kg). At folate dose of 100 and 200 mg/kg, the serum creatinine concentration (Scr) and blood urea nitrogen (BUN) increased significantly compared with control rabbits. Plasma concentrations and AUC of atenolol increased significantly at folate dose of 100 and 200 mg/kg. The elimination rate constant $(K_{el})$ and total body clearance $(CL_t)$ of atenolol decreased significantly, and half-life ($t_{1/2}$) and mean residence time (MRT) of atenolol increased significantly at folate dose of 100 and 200 mg/kg. The serum creatinine concentration $(S_{cr})$ correlated well (p<0.05) with half-life $(t_{1/2})$ and elimination rate constant $(K_{el})$ of atenolol, as well as BUN with AUC and total body clearance $(CL_t)$ of atenolol.

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Pharmacokinetics of PEG-Hemoglobin SB1, a Hemoglobin-Based Oxygen Carrier, after Its Intravenous Administration in Beagle Dogs

  • Kwon, Oh-Seung;Chung, Uoo-Tae;Chung, Youn-Bok
    • Archives of Pharmacal Research
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    • 제27권2호
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    • pp.259-264
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    • 2004
  • The purpose of the present study was to investigate the pharmacokinetics of PEG-hemoglobin SB 1, a modified bovine hemoglobin with polyethylene glycol, after its single and multiple administration in beagle dogs. For this purpose, the analytical method of free hemoglobin in the plasma was developed and validated. Excellent linearity ($r^2$=0.999) was observed in the calibration curve data, with the limit of quantification of 0.005 g/dL. The precision and the deviation of the theoretical values for accuracy were always within $\pm$15% in both the between-and the within-day results. The method was tested by measuring the plasma concentrations following intravenous administration to beagle dogs and was shown to be suitable for pharmacokinetic studies. In a single dose study, the plasma half-life (t$_{1}$2/) increased and the total body clearance (Cl$_{t}$) decreased with the dose (i.e., 0.017 to 0.75 gHb/kg as PEG-hemoglobin SB1) in both sexes. The volume of distribution at steady-state (Vd$_{ss}$ ) showed no difference with the dose. In contrast, the values of t$_{1}$2/, CL$_{t}$ and the area under the plasma concentration-time curve (AUC) after the multiple dose were significantly different from those of the single dose administration. The values of t$_{1}$2/ in the multiple administration were about two times higher-than that of the single dose. As a result, t$_{1}$2/ of hemoglobin after the administration of PEG-hemoglobin SB1 was about 15-30 h, indicating the PEG modification of the hemoglobin lead to a prolongation of plasma concentration of the protein. Therefore, these observations suggested that the PEG modification of hemoglobin is potentially applicable in the hemoglobin-based therapeutics.tics.

Alteplase와 pamiteplase에 의한 MMPs 조절 효과 비교 (Comparison of Effects between Alteplase and Pamiteplase on MMPs Regulation)

  • 정재창;이선령
    • 생명과학회지
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    • 제17권7호통권87호
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    • pp.1019-1022
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    • 2007
  • 뇌졸중 환자에 사용되는 tPA치료법은 혈전을 용해시키고 혈액의 흐름을 용이하게 해 주기 때문에 매우 중요하게 사용되고 있다. 동물 실험모델을 이용한 이전의 실험결과에 따르면 tPA뿐 아니라 tPA의 일종인 pamite-plase 역시 30분 이내 탁월한 혈전 용해의 효과를 보여주었다. 그러나 fPA치료법은 단시간 처리와 출혈, 부종과 같은 여러 가지 부작용이 수반될 수 있으며 이들은 MMP-9의 활성 조절과 깊은 관련이 있는 것으로 보고되고 있다. 본 연구에서는 임상에 사용되는 tPA의 한 종류인 alteplase와 이러한 부정적인 효과를 극복하기 위해 개발된 pamiteplase의 MMP-9활성에 미치는 효과를 비교 분석하였다. 랫트의 뇌로부터 추출한 신경세포에서 alteplase의 처리는 농도의존적으로 MMP-9의 발현을 촉진시켰고 활성화된 형태의 MMP-2역시 증가되는 양상을 보였다. 반면, pamiteplase의 경우 MMP-2와 MMP-9의 발현양상에 영항을 미치지 않았다. 유사한 효과는 뇌신경계를 구성하는 다른 세포인 성상세포에서도 관찰되었다. 즉 대뇌의 성상세포를 분리, 배양하여 이들의 효과를 확인한 결과 신경세포에서와 마찬가지로 alteplase의 경우 농도의존적으로 증가하였고 pamiteplasse의 경우 변화를 나타내지 않았다. Pamiteplase는 뇌신경구성세포에서 출혈과 부종을 유도하는 데 관련이 있는 것으로 보고된 MMP-9의 활성에 영향을 미치지 않는 것으로 보아 alteplase에 비해 보다 효과적인 치료제로서의 가능성을 보여주고 있다.

돼지호흡기세균에 대한 oxytetracycline과 tiamulin의 시험관내 상승작용 및 돼지에서의 약물동태학 (Synergistic effects of oxytetracycline and tiamulin against swine respiratory bacteria and their pharmacokinetics in the pigs)

  • 박승춘;윤효인;이근우
    • 대한수의학회지
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    • 제42권1호
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    • pp.45-54
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    • 2002
  • The study was carried out to characterize the pharmacokinetics after intravenous (iv, 20 mg/kg) and oral (p.o. 100 mg/kg) administration as oxytetracycline (OTC) and tiamulin (TIA) mixture in swine and to determine interaction between OTC and TIA against various pig pathogenic bacteria. The antibacterial effects of OTC in combination with TIA in vitro showed synergistic effect against Salmonella typhimurium 1925, Pasteurella multocida Type A, P. multocida Type D, Krebsiella Pneumoniae 2001, K. Pneumoniae 1560, K. Pneumoniae 2208, Haemophillus pleuropneumonia S 2, and H. pleuropneumonia S 5, but against additive effect E. coli K88ab and S. choleraesuis on the basis of fractional inhibitory concentration (FIC) index. On the while, after i.v. and p.o. administration of OTC and TIA mixture, each OTC and TIA concentrations in plasma were fitted to an open two-compartment model. After i.v. administration of OTC-TIA mixture, the mean distribution half-life ($T_{1/2{\alpha}}$) of OTC and TIA in plasma showed 0.29 h and 0.17 h, and the mean elimination half-life ($T_{1/2{\beta}}$) of those was 4.36 h and 6.64 h, respectively. The mean volume of distribution at steady state ($Vd_{ss}$) of OTC and TIA was $0.85{\ell}/kg$ and $2.44{\ell}/kg$, respectively. After oral administration of OTC and TIA mixture, the mean maximal absorption concentrations ($C_{max}$) of OTC and TIA were $0.60{\mu}g/m{\ell}$ at 1.07 h ($T_{max}$) and $1.68{\mu}g/m{\ell}$ at 1.85 h ($T_{max}$), respectively. The mean elimination half-life ($T_{1/2{\beta}}$) of those showed 6.84 h and 6.36 h. In conclusion, we could suggest in this study that the combination of OTC and TIA may be recommended for the antibacterial therapy against polymicrobial infections, and both OTC and TIA showed large distribution to tissues and high $C_{max}$ after p.o. administration.

초음파 위배출 측정과 한의설문 간의 상관성 분석 (Correlation Analysis between Gastric Emptying Measurement by Ultrasonography and Korean Medical Questionnaires)

  • 조수호;이재홍;고석재;김진성;박재우
    • 대한한방내과학회지
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    • 제39권4호
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    • pp.570-591
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    • 2018
  • Objective: This study was designed to investigate the correlation between gastric emptying measurement by ultrasonography and the findings of various questionnaires of functional dyspepsia (FD) or in Korean medicine to explore the possibility of quantification of questionnaires. Methods: Eighty-eight patients (44 patients with FD and 44 healthy controls) were recruited from October 2016 to November 2017. Gastric emptying half-time (T1/2) was measured by ultrasonography at fasting, and at 0, 15, 30, 45, 60, 90, and 120 min after meals (apple juice, 500 ml, 224 kcal). The average half-time (average T1/2) was calculated by averaging all measured half-times. A visual analogue scale (VAS), food retention questionnaire (FRQ), damum questionnaire (DQ), cold and heat questionnaire (CHQ), deficiency and excess questionnaire (DEQ), spleen-qi deficiency questionnaire (SQDQ), Nepean dyspepsia index-Korean version (NDI-K), and quality of life of NDI (NDI-QoL) were filled out by all participants. Correlation between the average T1/2 and questionnaires were analyzed for 79 patients (37 patients with FD and 42 healthy controls) after excluding missing and erroneous data. Results: The FRQ, DEQ, SQDQ, NDI-K, and NDI-QoL scores, especially for some gastrointestinal symptoms and general weakness-related symptoms, showed statistically significant correlations with average T1/2. Conclusions: Our results suggest that gastric emptying measurement by ultrasonography may be a quantitative substitute method for some Korean medical questionnaires or for some dyspepsia-related and deficiency-related items among them. However, further studies using various measurements of gastric emptying will be needed.

Mass Interception Fractions and Weathering Half-lives of Iodine-131 and Radiocesium in Leafy Vegetables Observed after the Fukushima Daiichi Nuclear Power Plant Accident

  • Tagami, Keiko;Uchida, Shigeo
    • Journal of Radiation Protection and Research
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    • 제46권4호
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    • pp.178-183
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    • 2021
  • Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions (FBs) and weathering half-lives (Tws) of 131I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. FB is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq·kg-1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq·m-2). Tw values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated FB and Tw values for 131I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of FBs between 131I and radiocesium by t-test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m2·kg-1 FW, respectively. Geometric mean Tw value of 131I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between Tw values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between 131I and radiocesium for FBs and Tws. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of 131I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.

에토석시미드의 HPLC 분석법 및 한국인에서의 약동학적 특징 (HPLC Determination and Pharmacokinetic Profile of Ethosuximide in Korean Subjects)

  • 배정우;김지홍;양상인;김현경;장춘곤;한혜원;박영서;손의동;이석용
    • 약학회지
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    • 제47권6호
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    • pp.444-459
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    • 2003
  • Ethosuximide is an oral anticonvulsantic agent used in the first choice anti-absence seizure drug. The purpose of this study was to assess the pharmacokinetic profile of the ethosuximide in healthy Korean volunteers and to develop the efficient assay method of ethosuximide in human plasma. The pharmacokinetics of ethosuximide administered orally was evaluated after a dose of 500 mg. Ethosuximide was assayed from plasma by a specific HPLC method reading absorbance at 195 nm. AUC was 1222$\pm$160 $\mu\textrm{g}$/$m\ell$$.$hr, $C_{max}$ 14.2l$\pm$1.74 $\mu\textrm{g}$/$m\ell$, $T_{max}$ 1.06$\pm$0.62 hr and half-life 77.83$\pm$12.46 hr. The half-life in Korean was longer than, in Caucasian (53∼56 hr).).).

오메프라졸과 메글루민의 복합체 형성과 안정성 (Complexation of Omeprazole with Meglumine and its Stability)

  • 이계주;김성욱;도기찬;박종범;황성주
    • Journal of Pharmaceutical Investigation
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    • 제27권4호
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    • pp.253-263
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    • 1997
  • To investigate the interaction of omeprazole (OMP) and meglumine (MEG), a complex was prepared by freeze-drying method in ammoniacal aqueous medium at room temperature and subjected to IR, DSC, and 1H NMR analysis. In addition, the stability of the complex was tested by accelerated stability analysis, and the dissolution rate of both powder and enteric coated was determined pellet by paddle method. The results are as follows; i) IR, DSC, and $^{1}H$ NMR studies indicate the formation of inclusion complex between OMP and MEG probably by electrostatic forces as $[OMP]\;[MEGH]^+$ form in a stoichiometric ratio (1:1) of OMP : MEG. ii) The dissolution rate of enteric coated OMP-MEG complex pellet in simulated enteric fluid was 90.6% in 10 minutes, which may satisfy the requirement for the regulation of dissolution. iii) OMP-MEG complex were decomposed according to pseudo 1st order kinetics: while the decomposition of OMP showed a rate constant $(k_{25^{\circ}C})$ of $5.13{\times}10^{-4}{\cdot}\;day^{-1}$, a half-life$(t_{1/2})$ of 1,350 days, a shelf-life$(T_{90%})$ 205 days and an activation energy of 23.53 kcal/mole. OMP-MEG complex inhibited a rate $(k_{25})$ of $2.92{\times}10^{-4}{\cdot}\;day^{-1}$, a half-life$(t_{1/2})$ of 2,373 days, a shelf-life $(T_{90%})$ of 306 days and an activation energy of 20.18 kcal/mole. iv) OMP was stabilized markedly by the formation of OMP-MEG complex between OMP and MEG, and the humidity increased the stability of OMP-MEG complex by decreasing the decomposition rate$(k_{50^{\circ}C})$ from $1.27{\times}10^{-2}{\cdot}\;day^{-1}$ at 31% R.H. to $2.54{\times}10^{-2}{\cdot}\;day^{-1}$ at 90% R.H.

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