• Title/Summary/Keyword: Half-life(t1/2)

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Effect of Hepatic Cirrhosis on the Pharmacokinetics of Theophylline in Rats

  • Nam, Bang-Hyun;Sohn, Dong-Hwan;Ko, Geonil;Kim, Jae-Baek
    • Archives of Pharmacal Research
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    • v.20 no.4
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    • pp.318-323
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    • 1997
  • The experimental hepatic cirrhosis was induced either by bile duct ligation (BDL) or by pretreatment with dimethyinitrosamine (DMNA). The pharmacokinetics of theophylline were studied after a single intravenous or a single oral administration. Using the ultrafiltration method, protein-drug binding experiments were also carried out. The bilirubin level was several-fold increased by BDL, but not by DMNA treatment. The albumin content was decreased in both cirrhotic groups. The total clearance (Clt, ml/kg/hr) of theophylline in both hepatic cirrhosis groups significantly decreased and the terminal half-life $(t_{1/2})$ in the cirrhotic rats was increased about two-fold after intravenous and oral administration. The volume of distribution at steady state (Vdss, ml/kg) was increased slightly in the cirrhotic groups. Protein binding in BDL $(8.67{\pm}4.85%)$ decreased about four-folds, but in DMNA $(73.00{\pm}9.85%)$ similar result war observed as compared with the control. Increased free fraction of theophylline did not increase the volume of distribution in BDL. Therefore decreased total body clearance of theophylline was mainly due to decreased intrinsic clearance of theophylline in the liver. The absolute bioavailability of theophylline in these experiments was between 63.8 and 72.8%(66.1% in BDL, 63.8% in Sham operated and Control, 72.8% in DMNA). These results suggest that in the experimental hepatic cirrhosis model, administration route does not affect the disposition of theophylline.

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The Effect of Temperature on the Corrosion of Mild Steel in H3PO4 Containing Halides and Sulfate Ions

  • Chandrasekaran, V.;Kannan, K.;Natesan, M.
    • Corrosion Science and Technology
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    • v.4 no.1
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    • pp.8-14
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    • 2005
  • The corrosion behaviour of mild steel in phosphoric acid solution in the presence and absence of pollutants viz. Chloride, Fluoride and Sulfate ions at 302K-333K was studied using mass loss and potentiostatic polarization methods. The addition of chloride and sulfate ions inhibits the mild steel corrosion in phosphoric acid while fluoride ions stimulate it. The effect of temperature on the corrosion behaviour of mild steel indicated that inhibition of chloride and sulfate ions decreased with increasing temperature. The adsorption of these ions (Chloride and sulfate) on the mild steel surface in acid has been found to obey Langmuir adsorption isotherm. The values of activation energy (Ea) and free energy of adsorption ($\Delta$) indicated physical adsorption of these ions (chloride and sulfate) on the mild steel surface. The plot of $logW_{f}$ against time (days) at 302K gives a straight line, which suggested that it obeys first order kinetics and also calculate the rate constant k and half-life time $t_{1/2}$.

Effect of Renal Failure on Pharmacokinetics of Carbamazepine in Rabbits (카르바마제핀의 체내동태에 대한 신장해의 영향)

  • Lee, Chong Ki;Park, Hyun Jin;Cho, Heng Nam
    • Korean Journal of Clinical Pharmacy
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    • v.9 no.2
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    • pp.92-96
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    • 1999
  • The pharmacokinetics of carbamazepine(100 mg/kg, oral) in the folic acid-induced renal failure rabbits was studied. Renal failure was induced by the i.v. injection of folic acid (50, 100, and 200 mg/kg). At folic acid 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 area under the plasma level-time curve (AUC) of carbamazepine increased significantly at folic acid dose of 100 and 200 mg/kg. The elimination rate constant (Kel) of carbamazepine decreased significantly, and half-life $(t_{1/2})$ of carbamazepine increased significantly at folic acid dose of 100 and 200 mg/kg. The serum creatinine concentration (Scr) correlated well with AUC and elimination rate constant (Kel) of carbamazepine, as well as BUN with AUC and elimination rate constant (Kel) of carbamazepine. These results suggest that adjustment of the dosage regimen of carbamazepine is desirable, and serum creatinine concentration (Scr) as well as BUN can be used for adjusting the dosage regimen of carbamazepine in renal failure.

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Drug Interaction between Flavone and Paclitaxel in Rats (프라본과 파크리탁셀과의 약물상호작용)

  • 최준식;이진환
    • YAKHAK HOEJI
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    • v.47 no.2
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    • pp.98-103
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    • 2003
  • The purpose of this study was to investigate the effect of flavone (20 mg/kg) on the pharmacokinetic parameters and the bioavailability of paclitaxel (40 mg/kg) orally coadministered in rats. The plasma concentration of paclitaxel in combination with flavone was increased significantly (coadministration p<0.05, pretreatment p<0.0l) compared to that of control. Area under the plasma concentration-time curve (AVC) of paclitaxel with flavone was significantly (coadministration p<0.05, pretreatment p<0.0l) higher than that of control. Peak concentration (Cmax) of paclitaxel with flavone were significantly increased (coadministration p<0.05, pretreatment p<0.01) compared to that of control. Time to peak concentration (Tmax) of paclitaxel with flavone decreased significantly (p<0.05) than that of control. The total body clearance (CLt) and elimination rate constant ($\beta$) of paclitaxel with flavone were significantly reduced (p<0.05) compared to those of control. Half-life (t$_{1}$2/) of paclitaxel with flavone was significantly prolonged (p<0.05) compared to that of control. Based on these results, it might be concluded that flavone may enhance bioavailability of paclitaxel through the inhibition of cytochrome P450 and P-glycoprotein, which are engaged in paclitaxel absorption and metabolism in liver and gastrogintestinal mucosa, respectively.

Pharmacokinetic and Pharmacodynamic Characterization of Gliclazide in Healthy Volunteers

  • Kim, Ho-Soon;Yun, Min-Hyuk;Kwon, Kwang-Il
    • Archives of Pharmacal Research
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    • v.26 no.7
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    • pp.564-568
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    • 2003
  • Pharmacokinetic and pharmacodynamic properties of gliclazide were studied after an oral administration of gliclazide tablets in healthy volunteers. After an overnight fasting, gliclazide tablet was orally administered to 11 volunteers; Additional 10 volunteers were used as a control group (i.e., no gliclazide administration). Blood samples were collected, and the concentration determined for gliclazide and glucose up to 24 after the administration. Standard pharmacokinetic analysis was carried out for gliclazide. Pharmacodynamic activity of the drug was expressed by increase of glucose concentration ($\Delta$PG), by area under the increase of glucose concentration-time curve ($AUC_{$\Delta$PG}$) or by the difference in increase of glucose concentration ($D_{$\Delta$PG}$) at each time between groups with and without gliclazide administration. Pharmacokinetic analysis revealed that $C_{max}, T_{max}$, CL/F (apparent clearance), V/F (apparent volume of distribution) and half-life of gliclazide were $4.69\pm1.38 mg/L, 3.45\pm1.11 h, 1.26\pm0.35 L/h, 17.78\pm5.27 L, and 9.99\pm2.15 h$, respectively. When compared with the no drug administration group, gliclazide decreased significantly the $AUC_{$\Delta$PG}$ s at 1, 1.5, 2, 2.5, 3 and 4 h (p<0.05). The $\Delta$PGs were positively correlated with $AUC_{gliclazide}$ at 1 and 1.5 h (p<0.05), and the correlation coefficient was maximum at 1 h (r = 0.642) and gradually decreased at 4 h after the administration. The $AUC_{$\Delta$PG}$s were positively correlated with $AUC_{gliclazide}$ at 1, 2, 3 and 4 h (p<0.05), and the maximum correlation coefficient was obtained at 2 h (r=0.642) after the administration. The $D_{$\Delta$PG}$ reached the maximum at 1 h, remained constant from 1 h to 3 h, and decreased afterwards. Therefore, these observations indicated that maximum hypoglycemic effect of gliclazide was reached at approximately at 1.5 h after the administration and the effect decreased, probably because of the homeostasis mechanism, in health volunteers.

Bioavailability of Tripotassium Dicitrato Bismuthate by ICP-MS in Human Volunteers (ICP-MS를 사용한 구연산비스마스칼륨 (Tripotassium dicitrato bismuthate)의 생체이용률 측정)

  • Kwon, Oh-Seung;Kwon, Jee-Young;Yoon, Ae-Rin;Park, Kyung-Soo
    • Journal of Pharmaceutical Investigation
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    • v.37 no.2
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    • pp.79-84
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    • 2007
  • This study was aimed to establish analytical method of Bi to develop a guideline of the bioequivalence test of tripotassium dicitrato bismuthate (TDB). For this purpose, a simple, specific and sensitive inductively coupled plasma-mass spectrometry (ICP/MS) method were developed and validated in human plasma. Various concentrations of bismuth standard solution (0-25ng/mL) were prepared with distilled water and human blank plasma. To 10mL of the volumetric flasks, 2mL of blank plasma was added with 8ml of distilled water. Bi standard solution was added to prepare the calibration samples and injected into ICP-MS. The plasma samples obtained from volunteers given 3 tablets of bismuth (total 900mg as TDB) were analyzed as described above. As a result, the coefficients of variation were <20% in quantitation limit (0.2 ng/mL) and <15% at the rest of concentrations. The stability test by repeated freezing-thawing cycles showed that the samples were stable only for 24hr. The stability tested for samples with a short-term period of storage at room temperature and pre-treatment prior to the analysis showed very stable over 24hr. In 8 healthy Korean subjects received Denol tablets at the dose of 900mg bismuth, AUC, $C_{max},\;T_{max}$ and half-life $(t_{1/2})$ were determined to be $198.33{\pm}173.78 ng{\cdot}hr/mL,\;64.48{\pm}27.06 ng/mL,\;0.52{\pm}0.21 hr,\;and\;5.15{\pm}2.67 hr$, respectively, from the plasma bismuth concentration-time curves. In conclusion, the method was suitable for the determination of bismuth in human plasma samples and could be applied to bioequivalence test of bismuth tablet.

Physicochemical Characteristics of Liquid Fertilizer made from Pig Manure in Korea (국내 돼지분뇨의 액비성분 특성 비교조사)

  • Jeon, Sang-Joon;Kim, Soo-Ryang;Rho, Kyung-Sang;Choi, Dong-Yoon;Kim, Dong-kyun;Lee, Myung-Gyu
    • Journal of Animal Environmental Science
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    • v.18 no.3
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    • pp.221-228
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    • 2012
  • Physicochemical properties of liquid fertilizer samples of resource organization, which are domestically produced and distributed, are analyzed. Major contents of the research results are as follows. 1. The ratio of complete decomposition for liquid fertilizer is 49% at Public Resource Center and 33% at Liquid Fertilizer Supply Center. The combined ratio of both half-decomposed and un-decomposed liquid fertilizers is over 50% at both centers. 2. The ratio of complete decomposed liquid fertilizer, 67%, is the highest in Gangwon and Gyeonggi-do area. The ratio of un-decomposed liquid fertilizer is high in Chungbuk and Chungnam area. The sum of ratios of the half- and un-decomposed is over 60% in the areas except Gyeonnggi-do and Gangwon-do. 3. As a result of regional comparison of the physicochemical properties of liquid fertilizers, concentration variation in most of the items are large, and the degree of uniformity is found to be considerably low. In particular, concentration variation in T-N and $NH_4$-N is the most noticeable. 4. The items that physicochemically correlated to the degree of decomposition of liquid fertilizer are appeared to be T-N, $NH_4$-N, $NO_3$-N, EC, $SCOD_{Mn}$, and ORP. 5. The physicochemical average values of the liquid fertilizer estimated as "complete decomposed" are appeared to be T-N 829 mg/L,$NH_4$-N 517 mg/L, $NO_3$-N 151 mg/L, $SCOD_{Mn}$ 1,205 mg/L, EC 10.32 mS/cm, ORP -117.12 mV.

A Comparative Study on Sexual Life between Women and Their Spouses after Hysterectomy (자궁적출술 후 여성과 배우자의 성생활 비교 연구)

  • Lim, Heoyn-Suk;Yoo, Eun-Kwang
    • Women's Health Nursing
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    • v.9 no.2
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    • pp.189-200
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    • 2003
  • The purpose of this comparative study is to find out women and their spouses' sexual life and the factors affecting on their sexual life after women's hysterectomy. The data were the 110 questionaires which were collected from the participants, the 55 women who had undergone a hysterectomy due to gynecologic disease or benign tumor of genital organs and their spouses from January 1, 1999 to January 30, 2002 in one general hospital located in Seoul, Korea. Questionnaires were mailed to couples, who agreed to participate on the study and self reported questionnaires returned in the pre-stamped envelopes. And personal visits were made for those couples who did not respond. Tools for Sexual life and characteristics of sexual activities were reconstituted by the author based on Kim(1996) and Chang(1988)'s tools and were reviewed by a nurse specialist. Data analysis was done by SPSS 10.0 program using frequency, percentage, mean, S.D. Pearson correlation coefficient, t-test, oneway ANOVA and multiple regression. The results of this study are as follows; 1. Of all female subjects, 80% had experienced hysterectomy below the age of 50. 2. 72.8% of female subjects and 67.3% of male subjects did not receive any sexual education & counseling before and after the surgery. More than 60% of both female and male subjects answered that it was necessary to have a sexual counseling. And 40% wanted to receive sexual counseling from a professional sexual counselor. 3. More than half of couples started their first coitus within 4 weeks after the surgery. And 88.9% of females and 85.2% of males answered that they were experiencing orgasms with their sexual relationship. 4. Influencing factors on the satisfaction level of sexual life were couple's intimacy and sexual discomfort in women and couple's intimacy and sexual knowledge in spouses. These factors explained the 33% and 24% of total variance respectively. In conclusion, the result suggests that it is necessary for couples to receive a professional sexual education and counseling to improve couples' quality of life. It is also necessary for institutions to use prepared nurses by receiving sexual counseling and education program as a professional sexual counselors or educators so as to provide individualized sexual education and counseling for their clients.

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Influences of Forest Fire on Forest Floor and Litterfall in Bhoramdeo Wildlife Sanctuary (C.G.), India

  • Jhariya, Manoj Kumar
    • Journal of Forest and Environmental Science
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    • v.33 no.4
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    • pp.330-341
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    • 2017
  • Tropical forests play a key role for functioning of the planet and maintenance of life. These forests support more than half of the world's species, serve as regulators of global and regional climate, act as carbon sinks and provide valuable ecosystem services. Forest floor biomass and litterfall dynamics was measured in different sites influenced by fire in a seasonally dry tropical forest of Bhoramdeo wildlife sanctuary of Chhattisgarh, India. The forest floor biomass was collected randomly placed quadrats while the litterfall measured by placing stone-block lined denuded quadrat technique. The seasonal mean total forest floor biomass across the fire regimes varied from $2.00-3.65t\;ha^{-1}$. The total litterfall of the study sites varied from $4.75-7.56t\;ha^{-1}\;yr^{-1}$. Annual turnover of litter varied from 70-74% and the turnover time between 1.35-1.43 years. Monthly pattern of forest floor biomass indicated that partially decayed litter, wood litter and total forest floor were differed significantly. The seasonal variation showed that leaf fall differed significantly in winter season only among the fire regimes while the wood litter was found non significant in all the season. This study shows that significant variation among the site due to the forest fire. Decomposition is one of the ecological processes critical to the functioning of forest ecosystems. The decomposing wood serves as a saving account of nutrients and organic materials in the forest floor. Across the site, high fire zone was facing much of the deleterious effects on forest floor biomass and litter production. Control on such type of wildfire and anthropogenic ignition could allow the natural recovery processes to enhance biological diversity. Chronic disturbances do not provide time for ecosystem recovery; it needs to be reduced for ecosystem health and maintaining of the high floral and faunal biodiversity.

Enhanced Bioavailability of Paclitaxel by Bamboo Concentrate Administration

  • Kang Keon Wook;Choi Jun Shik
    • Archives of Pharmacal Research
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    • v.28 no.4
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    • pp.469-475
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    • 2005
  • The purpose of this study was to investigate the effect of a cotreatment of bamboo concentrates (Jukcho solution; 0.75, 1.5, and 3.0 mL/kg) with the chemotherapeutic agent paclitaxel on the bioavailability of orally administered paclitaxel (50 mg/kg) in rats. The effect of a pretreatment of bamboo concentrates (1.5 and 3.0 mL/kg for 1.0 h or a consecutive 3 day) was also examined. The paclitaxel plasma concentrations of rats orally administered paclitaxel plus bamboo concentrates (coadministration, 3.0 mL/kg and pretreatment, 1.5 and 3.0 mL/kg) were significantly higher than those of rats treated with paclitaxel alone. Plasma concentrations of paclitaxel in groups pretreated with bamboo concentrates for 3 day were markedly higher than those of a paclitaxel control group at the measured time points. The areas under plasma concentration-time curves (AUCs) of paclitaxel in groups pretreated with bamboo concentrates were elevated and the absolute bioavailability ($AB\%$) and relative bioavailability ($RB\%$) of paclitaxel were also significantly higher than those in the control group. The peak concentration ($C_{max}$), half-life ($t_{1/2}$), and the elimination rate constant ($K_{el}$) of paclitaxel after 3 day of pretreatment with bamboo concentrates were also significantly higher than those in the control, but the time required to reach the maximum plasma concentration ($T_{max}$) of paclitaxel was unaffected by the bamooo concentrates. Western blot analyses demonstrated that the level of CYP3A4 was increased in the livers of rats treated orally with paclitaxel, but this was reversed by pretreating with bamboo concentrates. These results show that bamboo concentrates enhance the bioavailability of orally administered paclitaxel and this effect may be associated with a diminished expression of CYP3A4 in the liver.