Urine unhydrolyzed

There have been studies of the metabolism of DEHP in humans after oral exposures as reflected by its urinary excretory products. In two volunteers exposed to 30 mg DEHP, metabolites I, II, III, IV, V, VI, VII, and VIII were identified in the urine by mass spectroscopy (Schmid and Schlatter 1985). MEHP accounted for 6-12% of the measured metabolites. Metabolite VI was approximately 20% of the excreted material, Metabolite IX approximately 30% and Metabolite V approximately 30%. The remaining metabolites were each less than 5% of the excreted material. Based on a comparison of the metabolites in the hydrolyzed urine as compared to the unhydrolyzed urine, approximately 65% of DEHP metabolites are excreted as glucuronide conjugates in humans. Each of these major metabolites is the product of oxidation of a different carbon in the 2-ethylhexyl substituent. 

Nitrophenol is excreted in urine entirely as glucuronide and sulfate conjugates (Fatiadi 1984). The sequential analysis of hydrolyzed (enzymatically or by acid) and unhydrolyzed urine provides a measure of the conjugated and unconjugated levels of the compound. Derivatization subsequent to acid hydrolysis of urine and quantification by gas chromatography with electron capture detection provides one of the most sensitive methods for 4-nitrophenol (Fatiadi 1984). 

Figure 2. Distribution according to polarity (extractability of Aa-TIIC) of in vivo metabolites in hydrolyzed and unhydrolyzed Rhesus urine nonpolar neutrals = extractable with hexane at natural pH weakly polar neutrals = extractable with ether at pH 12 weakly polar acids — extractable with ether at pH 2 moderately polar acids = extractable with ethyl acetate at pH 2 highly polar acids = extract-...

Figure 12. Effect of pH on ether extractability of h -THC in vivo metabolites from unhydrolyzed Rhesus urine...

Figure 14. Confirmation-mode ts -THC-ll-oic acid/TMS analysis of same sample as Figure 13 showing 174 ng/5 mh of unhydrolyzed urine with K — 44 at a retention time of 225 sec. Only 9 lines were scanned and 5 of these were contaminated.

Free), unhydrolyzed urine and (X---------X, Total), hydrolyzed urine. 

D-Fructose in the human diet derives mainly from sucrose, fruits, and honey. Sucrose is /I-D-fructofuranosyl a-D-glucopyranoside, and, after hydrolysis by invertase (EC 3.2.1.26), to D-glucose and D-fructose, can be absorbed from the small intestine. In the human intestine, invertase, as well as a-D-glucosidases, is developed very early in fetal life, and even appears much earlier than lactase (EC 3.2.1.23). There is no significant, intestinal transport of unhydrolyzed sucrose, and, in animal experiments, sucrose administered by injection is quantitatively excreted in the urine.1 Intestinal invertase is produced by mucosal cells localized in the brush-border membrane of the mucosal epithelia. Invertase is not secreted,1-4 and little or no invertase (sucrase) has been found in the intestinal lumen.1 The specific localization of sucrase at the mucosal, luminal interface is thought to be of functional importance in coupling sucrose digestion to transport.1... 

Sample preparation Condition a 300 mg Bond Elut Certify SPE cartridge with 2 mL MeOH and 2 mL water. 5 mL Urine -i- 1 mL concentrated HCl, vortex, heat at 120° for 30 min, cool, adjust pH to between 7.0 and 8.0 with 10 M KOH. 5 mL Urine or hydrolyzed urine + nalorphine, add to the SPE cartridge, wash with 2 mL water, wash with 1 mL pH 4 acetate buffer, wash with 2 mL MeOH, elute with 2 mL dichloromethane isopro-pemol 80 20 containing 2% ammonia. Evaporate the eluate to dryness imder a stream of nitrogen, reconstitute the residue in 0.5-1 mL pentane dichlorometheine 90 10. (Use unhydrolyzed urine to determine diamorphine and unconjugated compoimds.)... 

Esters that are sterically hindered are hydrolyzed more slowly and may appear unchanged in the urine. For example, approximately 50% of a dose of atropine appears unchanged in the urine of humans. The remainder appears to consist of unhydrolyzed biotransformed products. 

Benzidine methods make use of the very low solubility of benzidine sulfate which can be isolated and titrated as an add as in the method of Rosenheim and Drummond (79), or determined by means of a color reaction such as that with hydrt en peroxide and ferric chloride (91), or sodium fi-naphthoquinone-4-sulfonate(59),orbydiazotizationandcoupling(33,55,72). The colorimetric methods are claimed to be very sensitive. The benzidine method provides a rapid method for estimating ethereal sulfate but since, like the Folin (43) method, it is a difference method it becomes less reliable as the inorganic. ethereal sulfate ratio increases. The precipitation of benzidine sulfate by the original method, especially from hydrolyzed urines, may occasionally be capricious, even to the extent that less benzidine sulfate is precipitated from hydrolyzed urine than from unhydrolyzed urine. This difficulty can be largely overcome by preliminary removal of phosphates and precipitation under conditions recommended by Fiske (42). Under experimental conditions dietary control may serve to ensure that the excretion of phosphate is so low as not to interfere with precipitation of benzidine sulfate (e. g.. Maw (63)). 

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