Fecal elimination

Calcium Adequate intake (Table 3-1) in divided doses Absorption-predominantly active transport with some passive diffusion, fractional absorption 10-60%, fecal elimination for the unabsorbed and renal elimination for the absorbed calcium... 

Transcellular Shift Enhanced Renal Excretion Enhanced Fecal Elimination... 

In rats exposed by intratracheal instillation to radiolabeled phenol, elimination was 95% complete after 72 hours, with the primary elimination route being through the urine (Hughes and Hall 1995). Fecal elimination was slower and accounted for less overall. 

Both urinary and fecal excretion of 14C was determined in rats administered an oral dose of 1.2 mg/kg of [14C]-labeled phenol (Edwards et al. 1986). Rats excreted 80.3 11.2% in the urine and 1.8 1.6%inthe feces in 24 hours. In rats exposed orally to radiolabeled phenol, elimination was 95% complete after 72 hours, with the primary elimination route being through the urine (Hughes and Hall 1995). Fecal elimination was slower and less overall. 

Excretion - Of the 99% of the total abacavir dose recovered, 1.2% was excreted unchanged in the urine as abacavir. Fecal elimination accounted for 16% of the dose. In single-dose studies, the observed elimination half-life was approximately 1.54 hours. 

CSF concentratons are less than 1% of plasma concentrations. Half-life ranged from 67 to 77.6 hours following the suspension. The long half-life is caused by presumed enterohepatic cycling and eventual fecal elimination. There is indirect evidence that atovaquone may undergo limited metabolism however, a specific metabolite has not been identified. 

Hassler E, Eind B, Nilsson B, et al. 1983. Urinary and fecal elimination of nickel in relation to airborne nickel in a battery factory. Ann Clin Eab Sci 13 217-224. 

Urine is the primary route of elimination for both inorganic As(III) and inorganic As(V) in most common laboratory animals. With the exception of the rat, which exhibits slower overall elimination of arsenic, 50 % or more of a single oral dose of arsenic is usually eliminated in urine within 48 hours. Urine is also the primary route of elimination in species, such as the marmoset, which do not methylate arsenic (Vahter et al., 1982). Comparison of urinary and fecal elimination in mice that have been given the same... 

Once mobilized in the hepatocyte, chemicals can contact and interact with biotransformation enzymes (Chapter 7). These enzymes generally increase the polarity of the chemical, thus reducing its ability to passively diffuse across the sinusoidal membrane back into the blood. Bio transformation reactions also typically render the xenobiotics susceptible to active transport across the canalicular membrane into the bile canaliculus and, ultimately, the bile duct (Figure 10.3). The bile duct delivers the chemicals, along with other constituents of bile, to the gall bladder that excretes the bile into the intestines for fecal elimination. 

Limited quantitative and qualitative evidence of the metabolic fate of white phosphorus after acute oral exposure was located. In an acute oral study in rats with 32P-labeled white phosphorus, Lee et al. (1975) determined that urinary and fecal elimination routes respectively accounted for 17.1% and 2%, 34.5% and 16.6%, and 46.7% and 33.0% of the administered dose at 4 hours, 1 day, and 5 days post-dosing, respectively. White phosphorus is insoluble in water, and about 96% of the phosphorus bound in urine is inorganic phosphate (Latner 1975). Based on this, it is reasonable to conclude that -20% of... 

Lee et al. (1975) measured urinary and fecal elimination of 32P in rats after oral administration of labeled white phosphorus. The total radioactivity excreted in urine and feces was assessed in three different groups of rats sacrificed at 4 hours or 1 or 5 days after dosing. Total excretion of 32P was far higher via the urinary route by 4 hours postdosing. Excretion of 32P via the fecal route increased rapidly between 4 hours and 5 days post-dosing. By 5 days post-dosing, combined urinary and fecal excretion accounted for -80% of the administered dose of 32P. 

The clearance of radioactivity after oral exposure to labeled 2,3,7,8-TCDD followed first-order kinetics in most studies. Fecal elimination was the major route, though excretion in the urine, expired air, and milk was also reported. 

Humans exposed to a single dose of 30 mg DEHP excreted 11 to 15% of the dose as metabolites in the urine over 48 hours (Schmid and Schlatter 1985). When a smaller dose (10 mg) was given for each of 4 sequential days, 15-25% of the dose was recovered in the urine. No measurements of fecal elimination of DEHP or its metabolites were made. 

Fig. 9.3 The proposed four steps of the mechanism of particulate mucoadhesion. Step 1, administration. Step 2, initial adsorption of the particles. Step 3, mucoadhesion of particles and further transit in the lumen. Step 4, detachment of particles, further transit and further fecal elimination. Adapted from Ponchel et al. (1998)...

Dermal application of 14C-labeled 4-nitrophenol to dogs resulted in 11% of the dose (radioactive label) excreted in the urine over a period of 7 days. Fecal elimination was negligible. In rabbits, 78% of an absorbed dermal dose of C-labeled 4-nitrophenol appeared in the urine in 1 day. As in dogs, fecal elimination accounted for less than 1% of the absorbed dose (Snodgrass 1983). 

Rats injected intravenously with a dose of 8.3 mg/kg of 4-nitrophenol excreted 35% of the dose as sulfate conjugate and 40% as glucuronide over a period of 24 hours (Meerman et al. 1987). No differences were noticed between males and females. Dogs given an intravenous dose (0.06 mg/kg) of C-labeled 4-nitrophenol excreted 92% of the dose (labeled C) in the urine in the first day (Snodgrass 1983). Radioactivity in the feces accounted for approximately 1% over a 7-day period. Snodgrass (1983) used the same protocol in rabbits and found that 78% of the dose (0.12 mg/kg) was recovered in the urine within day 1 excretion was essentially complete by day 4. Fecal elimination accounted for less than 1% of the dose. 

The calculated half-lives for the renal elimination amounted to a mean of 12.2 h (oral dose) and 9.0 h (intravenous dose). The fecal elimination took place with mean half lives of 10.3 h and 8.8 (oral and intravenous dosing). 

The data are finally drawn together for detailed discussion and evaluation with special attention to known results from other radiokinetic studies such as the mass balance study and the obtained fecal elimination or the quantitative whole body autoradiography. 

Mice received a single oral dose of either 10 or 200 mg/kg radiolabeled benzene (McMahon and Bimbaum 1991). Radioactivity was monitored in urine, feces, and breath. At the low dose, urinary excretion was the major route of elimination. Hydroquinone glucuronide, phenylsulfate, and muconic acid were the major metabolites at this dose, accounting for 40%, 28%, and 15% of the dose, respectively. At 200 mg/kg, urinary excretion decreased to account for 42-47% of the administered dose, while respiratory excretion of volatile components increased to 46-56% of the administered dose. Fecal elimination was minor and relatively constant over both doses, accounting for 0.5-3% of the dose. 

Poorly absorbed lOti decreasing to zero with food or beverage intake-long T p (renal elimination (of absorbed) and fecal elimination (unab sorbed)... 

The rat pancreatic hyperplasia may be due to the ability of high concentration of HP-p-CD to increase the fecal elimination of bile salts indirectly causing a... 

The physiological mechanisms by which phenylbutazone is cleared from the body in the horse have not been well described. In one study, renal clearance accounted for only 25% of the total drug administered (Lees et al 1985). It has been hypothesized that biliary excretion with subsequent fecal elimination represents the primary clearance mechanism of phenylbutazone in the horse (Lees et al 1985). Renal excretion, of an as yet unidentified phenylbutazone metabolite, may also account for a proportion of total body clearance of the compound. 

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