Absorption excretion

There is no available information on the absorption, excretion, or tissue distribution of TCDD in animals. Therefore, this study was done... 

Tesoriere, L et al., Absorption, excretion, and distribution of dietary antioxidant betalains in LDLs potential health effects of betalains in humans. Am. J. Clin. Nutr., 80, 941, 2004. 

Krantz, C., Monier, M., and Wahlstrom, B., Absorption, excretion, metabolism and cardiovascular effects of beetroot extract in the rat. Food Cosmet. Toxicol, 18, 363, 1980. 

Measurement of exposure can be made by determining levels of toxic chemicals in human serum or tissue if the chemicals of concern persist in tissue or if the exposure is recent. For most situations, neither of these conditions is met. As a result, most assessments of exposure depend primarily on chemical measurements in environmental media coupled with semi-quantitative assessments of environmental pathways. However, when measurements in human tissue are possible, valuable exposure information can be obtained, subject to the same limitations cited above for environmental measurement methodology. Interpretation of tissue concentration data is dependent on knowledge of the absorption, excretion, metabolism, and tissue specificity characteristics for the chemical under study. The toxic hazard posed by a particular chemical will depend critically upon the concentration achieved at particular target organ sites. This, in turn, depends upon rates of absorption, transport, and metabolic alteration. Metabolic alterations can involve either partial inactivation of toxic material or conversion to chemicals with increased or differing toxic properties. 

Ohzawa et al. [113] studied the absorption, excretion, and metabolism of miconazole after a single oral administration of 14C miconazole at a dose of 10 mg/kg to male dogs. After administration of 14C miconazole, the blood concentration of radioactivity reached the maximum level at 4 h, and then declined slowly with a half-life of about 26 h. The plasma concentration reached the maximum level at 5 h and then declined slowly with a half-life of 30 h. After the administration of miconazole, the plasma concentration of the unchanged form reached the maximum level at 3 h and then rapidly declined with half-life of about 4.3 h. Within 168 h after administration of 14C miconazole, urinary and fecal excretion amounted to about 6% and 66% of the administration radioactivity, respectively. After administration of 14C miconazole, the plasma concentration of the unchanged form rapidly declined, but the plasma level of two major metabolites reached maximum at 5 and 12 h, respectively and then declined. 

Miller, J. K. and Byrne, W. F. (1970). Absorption, excretion and tissue distribution of orally and intravenously administered radiocerium as affected by EDTA, J. Dairy Sci. 53, 171. 

In pharmocokinetic C14-labelled studies of its absorption, excretion, distribution and metabolism, Ge-132 administered orally was absorbed about 30%, distributed evenly, with... 

The absorption, excretion, and biotransformation of valproic acid were studied by Kukino and Matsumoto (14). 

Table V. Absorption, Excretion, and Retention of Phosphorus as Affected by Calcium and Orthophosphates...

However, PCP is the second heaviest used pesticide in the United States, although it has been mostly used for the purpose of wood preservation(1). Under such circumstances, an international symposium on "Pentachlorophenol" convened by K. Ranga Rao(University of West Florida) was held in Pensacola, Florida, June 27-29, 1977, concerning the chemistry, pharmacology, and environmental toxicology of PCP. At the symposium, I presented a paper(2) on the metabolism of PCP in fishes, mostly reviewing the works on the absorption, excretion and detoxification of PCP in fish and shellfish, which were done in our laboratory. 

After determining a concentration of test compound which elicits no visually detectable response or effect in the aquatic species over a period of 48 hours (Step 1), fresh animals are placed in the chamber, exposed to known concentrations of test chemical (usually 14C-labelled), and the uptake rate and major metabolites determined (Step 2). Depuration rate from the dosed animals also can be estimated at this point by transfer to untreated water. Fresh animals also can be exposed to a constant flow of test solution until an absorption-excretion equilibrium (steady state) has been established, dosed briefly with labelled compound, and release (turnover) rate determined (Step 3). 

Approved clinical investigations follow three phases. In Phase 1, about 100 to 200 people are exposed to the drug to determine the tolerance, absorption, excretion, half-life, and other pharmacologic reactions the preferred route of administration and the safe dosage. In Phase 2, initial trials are conducted on 500 to 1000 patients to assess the treatment or prevention of the specific disease. Additional animal studies to indicate safety may be conducted concurrently. If these preliminary studies demonstrate sufficient promise. Phase 3 clinical trials are performed with several thousand patients. 

In rats, isometamidium is poorly absorbed from the gastrointestinal tract, approximately 99% of an oral dose being excreted in the feces. A similar absorption/excretion profile is exhibited by homidium, one of the four major impurities of the commercial product that normally contains about 70% of pure... 

Mullen W, Edwards CA, Crozier A. 2006. Absorption, excretion and metabolic profiling of methyl-, glucuronyl-, glucosyl and sulpho-conjugates of quercetin in human plasma and urine after ingestion of onions. Brit J Nutr 96 107-116. 

Sano S, Fujimori R, Takashima M, et al. 1982. Absorption, excretion and tissue distribution of silver sulphadiazine. Burns 8 278-285. 

R. Albert, Accumulation of toxic metals with special reference to their absorption, excretion and biological half times. Environ. Physiol. Biochem. 3 65, 1978. 

Despite several decades of clinical experience and animal study, the pathophysiology of brain encephalopathy is far from understood. One of the main reasons for the complexity of the research on Al is the difficult interaction with molecules found in biological systems. In most natural systems, a small fraction of Al is found as the simple Al3+ aquo ion. Thus Al absorption, excretion, tissue retention, and deposition will all depend on the properties of the Al3+ complexes formed with biological ligands. Unfortunately, the search for an accurate description of Al complexation equilibria and kinetics has been consistently frustrated by the tendency of both free Al3+ ion and simple Al complexes to hydrolyze at or below neutral pH. 

Children may also be more sensitive to harmful environmental chemicals because of differences in absorption, excretion, and metabolism (see also Chapter 2). Immaturity of some systems (e.g., immune, nervous systems) also contributes to children s vulnerability to chemicals. 

As mentioned previously BjSrn-Rasmussen and Lykken both reported a relationship between post-absorptive excretion of iron and serum ferritin The higher the subject s serum ferritin the greater the body iron stores and the more post-absorptive excretion which was observed For uniformity we have defined FAE-9 as the percentage of the dose of isotope which was excreted more than 9 days after the dose Nine days comprise three 3-day stool collection periods Bjorn-Rasmussen used a 10-day cutoff point (29) ... 

Figure 6 Relationship between serum Iron and post-absorptive excretion (PAE-9) of iron.

Fost-ahsorptive excretion of zinc and copper has not previously been reported Presumably the same or similar mechanisms are involved in the excretion of iron, zinc, and copper, since the excretion of the three metals appears to be synchronous in most subjects Post- absorptive excretion of iron goes on for four to five weeks after an oral dose of (29). Using stable isotopes of Fe, Zn, and Cu, we have observed post-absorptive excretion of all three metals for up to six weeks after the isotope dose. 

Post-absorptive excretion of zinc may involve zinc which has entered the enteropancreatic circulation, since not all of the zinc in pancreatic secretions is reabsor d (33). 

ReisseU P, Manninen V. Effect of administration of activated charcoal and fibre on absorption, excretion and steady state blood levels of digoxin and digitoxin. Evidence for intestinal secretion of the glycosides. Acta Med Scand Suppl 1982 668 88-90. 

Strauss I, Erhardt F. Ethambutol absorption, excretion and dosage in patients with renal tuberculosis. Chemotherapy 1970 15(3) 148-57. 

Tumlund, J. R., Keyes, W. R., and Peiffer, G. L. (1995). Molybdenum absorption, excretion, and retention studied with stable isotopes in young men at five intakes of dietary molybdenum. Am.. Clin. Nutr. 62, 790-796. 

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