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State Volume (state + volume)
Kinds of State Volume Selected AbstractsA valid equation for the well-stirred perfusion limited physiologically based pharmacokinetic model that consistently accounts for the blood,tissue drug distribution in the organ and the corresponding valid equation for the steady state volume of distributionJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2010Leonid M. Berezhkovskiy Abstract A consistent account of the assumptions of the well-stirred perfusion limited model leads to the equation for the organ tissue that does not coincide with that often presented in books and papers. The difference in pharmacokinetic profiles calculated by the valid and the commonly used equations could be quite significant, particularly due to contribution of the organs with relatively large perfusion volume, and especially for drugs with small tissue,plasma partition coefficient and high blood,plasma concentration ratio. Application of the valid equation may result in much faster initial drop of drug plasma concentration time curve and significantly longer terminal half-life, especially for low extraction ratio drugs. An equation for the steady state volume of distribution consistent with the well-stirred model described by the valid equation is provided. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:475,485, 2010 [source] Pharmacokinetics and dose proportionality of BMS-204352 after intraarterial administration to ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 6 2002Rajesh Krishna Abstract BMS-204352 is a novel maxi-K channel opener that is being developed for the treatment for stroke. The current study was designed to evaluate the dose proportionality and pharmacokinetics of BMS-204352 in rats. In an open, parallel fashion, sixteen rats per gender received a single intraarterial dose of BMS-204352 as a 3-min infusion into the carotid artery at 0.4, 2.0, 5.0 and 10.0 mg/kg dose levels. Serial blood samples were collected for up to 24 h post-dose and plasma samples were analyzed for the concentrations of intact BMS-204352 using a validated liquid chromatographic mass spectrometric (LC/MS) method. Pharmacokinetic analysis was performed using a non-compartmental method. Results revealed a gender difference in the pharmacokinetics of BMS-204352 in rats at all doses excluding the first (i.e., 0.4 mg/kg) dose panel. BMS-204352 peak plasma concentration (Cmax) and area under the plasma concentration,time curve (AUC) values increased in a proportion greater than the increment in dose. Specifically, as dose increased in the ratio 1:5:12.5:25, Cmax increased in the ratio 1:7:18:31 in male rats and 1:7:22:51 in female rats. The respective AUC ratios were 1:6:20:42 in male rats and 1:12:29:77 in female rats. Mean total body clearance (CLT) values for BMS-204352 ranged from 879,3242 ml/h/kg over the four dose levels and generally decreased with increase in dose. Similarly, steady state volume of distribution (VSS) values ranged from 3621,8933 ml/kg over the four dose levels and generally decreased with increase in dose. However, mean residence time (MRT) and elimination half-life (T1/2) values for BMS-204352 were independent of dose and ranged from 2.42,4.54 to 2.08,4.70 h, respectively. In conclusion, BMS-204352 appears to exhibit dose-dependent pharmacokinetics in rats. In addition, there appeared to be some evidence of gender related differences in the pharmacokinetics of BMS-204352. Copyright © 2002 John Wiley & Sons, Ltd. [source] Platinum pharmacokinetics in sulphur-crested cockatoos (Cacatua galerita) following single-dose cisplatin infusionAUSTRALIAN VETERINARY JOURNAL, Issue 6 2000LJ FILIPPICH Objective To determine the pharmacokinetics of platinum (Pt) in cockatoos. Design A pharmacokinetic study of Pt, following a single IV infusion of cisplatin, was done in six healthy sulphur-crested cockatoos (Cacatua galerita). Procedure Birds were hydrated for 1 h before and 2 h after a 1-h cisplatin infusion (1 mg/kg, IV). Serial blood samples were collected for 96 h after initiation of the infusion and urine was collected for 2 h during the hydration period after cisplatin administration. Tissue samples from 10 organs were obtained at necropsy, 96 h after cisplatin infusion. Total Pt and filterable Pt in plasma, urinary Pt and tissue Pt concentrations were assayed by inductively coupled plasma-mass spectrometry. A noncompartmental pharmacokinetic analysis was performed on the plasma and urine data. Results For total Pt and filterable Pt, the respective mean systemic clearances were 0.373 and 0.699 L/kg hourly, the steady state volumes of distribution were 4.19 and 0.356 L/kg, and the mean residence times were 111 and 0.512 h. Total plasma Pt displayed a bi-exponential decay profile with average half-lives of 0.398 and 79.0 h, while filterable Pt had a monoexponential decay with mean half-life of 0.413 h. The renal clearance during the 2-h postinfusion period was 0.167 L/kg hourly. The kidneys had the highest Pt accumulation (4.54 u.g/g DM). Conclusions and Clinical Relevance Cisplatin infusion in cockatoos was well tolerated and Pt plasma concentrations were similar to those measured during treatment of solid tumours in human patients. Despite anatomical, physiological and biochemical differences among animal species, the pharmacokinetic disposition of Pt in the cockatoo shares some features with the kinetics reported previously in rodents, dogs and human beings. 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