Kinetics administration

T. W. Newton, The Kinetics of the Oxidation Reduction Reactions of Uranium, Neptunium, Plutonium, andMmericium inMqueous Solution, TlD-26506, U.S. Energy, Research, and Development Administration (ERDA) Technical Information Center, Washington, D.C., 1975. 

Perminks et al. (1987) reported that 80% of a single oral dose of dioctyltin dichloride at 2 mg/kg body weight was excreted in the faeces within 2 days. After 3 days, excretion of radioactivity followed first-order kinetics, with a half-life of 8.9 days. After intravenous administration, 66% of the radioactivity was excreted in the faeces, and a half-life value of 8.3 days was obtained, roughly similar to that of oral administration. Percentages of radioactivity excreted in the urine were 11% and 22% following intravenous and oral dosing, respectively. 

Figure 3). Except for the first two days following administration, the clearance of activity from the body followed apparent first order rate kinetics. The half-life for clearance, ti/2, was 17.4 dt 5.6 days. As previously indicated, it was assumed that the relatively large amount excreted during the first 2 days had not been absorbed therefore, these values were not used in calculating the clearance rate. 

T. Teorell, Kinetics of distribution of substances administered to the body. 1. The extravascular modes of administration. Arch. Int. Pharmacodyn., 57 (1937) 205-225. II. The intravascular modes of administration. Arch. Int. Pharmacodyn., 57 (1937) 226-240. 

Lartigue-Mattei, C., Chabard, J.L., Ristori, J.M., Bussiere, J.L., Bargnoux, H., Petit, J., and Berger, J.A., Kinetics of allopurinol and it s metabolite oxypurinol after oral administration of allopurinol alone or associated with benzbromarone in man. Simultaneous assay of hypoxanthine and xanthine by gas chromatogra-phy-mass spectrometry, Fund. Clin. Pharm., 5,621,1991. 

M Rowland, S Riegelman, PA Harris, SD Sholkoff. Absorption kinetics of aspirin in man following oral administration of an aqueous solution. J Pharm Sci 61 379-385, 1972. 

Campbell BC, Meredith PA, Moore MR, et al. 1984. Kinetics of lead following intravenous administration in man. Toxicol Lett 21 321-235. 

A direct in vivo assessment was carried out with the single-pass perfusion approach in the human jejunum by using the Loc-I-Gut technique with R/S-verapamil (log D6 5 2.7, octanol/water pH 7.4 MW 455 Da) as the model compound for CYP 3A4 and P-gp-mediated local intestinal kinetics [2, 34, 35, 122] (see Figs. 7.7 and 7.9). The Peff for both enantiomers at each of the concentrations (4.0, 40, 120, and 400 mg L-1) was 2.5 x 10 4, 4.7 x 105.5 x 104 and 6.7 x 104 cm s-1, respectively (Fig. 7.15) [34, 35], A luminal concentration of 400 mg L 1 is expected to be achieved in the upper part of the small intestine after oral administration of a 100-mg dose of verapamil in an immediate-release dosage form [1, 34, 35], The three other perfusate concentrations represent fractions of the dose when 30%, 10%, and 1%, respectively are left to be absorbed [34, 35], The increased in vivo jejunal Peff of R/S-vcrapamil, along with its increased luminal perfusate concentration, is in accordance with a saturable efflux mechanism mediated by... 

Fletcher et al. [123] used a sensitive and specific gas chromatography-mass spectrometry method for the assay of primaquine in plasma and urine for studying the plasma kinetics. Preliminary studies on the effects of single and multiple oral doses were carried out. In both cases, the drug was completely removed from plasma in 24 h. The concentration of primaquine in plasma usually reached a peak 1-2 h after oral administration. The plasma elimination half-life was about 4 h. 

Prasad et al. [126] developed and used a sensitive and specific spectropho tome trie method for the estimation of primaquine to study the plasma kinetics of primaquine in Rhesus monkeys. It was observed that the drug completely disappeared from the plasma in 24 h after a single oral dose. Its concentration in the plasma reached a peak at 2 h of administration. The mean absorption and elimination half-lives were 0.36 0.08 and 3.44 0.37 h, respectively. 

Excretion kinetics of chlordane are complex, and different isomers exit through different pathways (USEPA 1980, 1988). In rats, chlordane elimination was almost complete 7 days after receiving single oral doses up to 1 mg/kg body weight (BW) 24 hours after treatment, 70% of the r/. v-chlordane and 60% of the trans-chlordane had been excreted (WHO 1984). In rodents, chlordane and its metabolites were usually excreted in feces, regardless of the administration route the cis-isomer was excreted slightly faster than the trans-isomer, although identical metabolites seemed to be formed (Menzie 1969, 1980 USEPA 1980 WHO 1984 Nomeir and Hajjar 1987). In rabbits, however, up to 47% of the administered dose was voided in the urine, and cis- and /ran.v-chlordanc were excreted at the same rate (Nomeir and Hajjar 1987). 

Peak plasma levels are reached about 1.5 h after oral ingestion, the maximum concentrations being in the order of 2 - 3 ng equivalents/ml (parent drug + metabolites) for an oral 1 mg dose. The elimination from the plasma is biphasic and proceeds with mean half-lives of 6 h (a-phase) and 50 h ((3-phase). Similar elimination half-lives are obtained from the urinary excretion. The cumulative renal excretion is practically the same after oral and intravenous administration and amounts to 6 - 7 % of the radioactivity dosed. The main portion of the dose, either oral or intravenous, is eliminated by the biliary route into the faeces. The kinetics of bromocriptine has been demonstrated to be linear in the oral dose range from 2.5 to 7.5 mg. 

J. M. Irache, M. Berrabah, P. Verite, and S. Menager, Phenobarbitone-loaded poly-curly epsilon-caprolactone nanocapsules In vitro kinetics and in vivo behaviour by the oral route, in Formulation of Poorly-Available Drugs for Oral Administration, Paris, 1996, pp. 334-337. 

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