Drug Metab Dispos
October 1999
Telmisartan 1-O-acylglucuronide, the principal metabolite of telmisartan in humans, was characterized in terms of chemical stability and the structure of its isomerization products was elucidated. In addition, pharmacokinetics of telmisartan 1-O-acylglucuronide were assessed in rats after i.v.
View Article and Find Full Text PDFIn humans, meloxicam is metabolized mainly by cytochrome P-450 (CYP)-dependent hydroxylation of the 5'-methyl group. The predominant P-450 enzyme involved in meloxicam metabolism is CYP 2C9, with a minor contribution of CYP 3A4. Quinidine, a CYP 3A4 substrate commonly used as a selective in vitro inhibitor of CYP 2D6, was found to markedly increase the rate of meloxicam hydroxylation during in vitro experiments with human liver microsomes.
View Article and Find Full Text PDFA sensitive and selective high-performance liquid chromatographic assay has been developed for a new hypoglycaemic agent AG-EE 388 ZW (I) in human plasma. Plasma samples containing I were acidified with 0.2 M hydrochloric acid, directly injected into C2 reversed-phase pre-columns, and cleaned up on-line.
View Article and Find Full Text PDFArzneimittelforschung
April 1988
Since its introduction into the market in 1952, bisacodyl has been successfully used worldwide as a laxative. In discussions on the kinetics and the laxative effect, it is often neglected that results obtained after the administration of the pure compound bisacodyl cannot be transferred to distinctive bisacodyl formulations. The aim of the present investigation is therefore to study the absorption and the plasma level profile and to correlate plasma level profile and laxative effect after the administration of various dosage forms.
View Article and Find Full Text PDFA fully-automated liquid chromatograph based on alternated pre-column enrichment technique has been developed for routine drug monitoring of body fluids using a column switching technique. Advantages of the method include the facility of direct injection of the body fluid onto the chromatograph and the simultaneous detection of both polar and non-polar metabolites under isocratic or gradient elution conditions.
View Article and Find Full Text PDFA new fully automated high-performance liquid chromatography is described which detects drugs from directly injected plasma (urine, saliva) without sample pretreatment. The apparatus consists of a programmable automatic sampling unit, which is connected via two alternating working pre-columns to an analytical column ("alternating pre-column sample enrichment"). The new device is able to operate with directly injected body fluids like an auto-analyzer and is especially useful for pharmacokinetic and clinical studies, where drug concentrations have to be determined from plasma, urine or saliva.
View Article and Find Full Text PDFArzneimittelforschung
October 1979
The HPLC (high-performance liquid chromatography) is applicable for all biochemical analyses, because of the wide variety of separation principles (adsorption-, partition-, ion-exchange- and steric exclusion-chromatography). Of exceptional importance is the reversed phase technique, a special case of partition chromatography. The sensitivity of detectors depends upon the structure of the respective substance, but is ordinarily lower -- apart from fluorescence detection -- than GLC-detectors.
View Article and Find Full Text PDF15 mg trans-4-[2-amino-3,5-dibromo-benzyl)-amino]-cyclohexanol-hydrochloride (ambroxol, NA 872) was administered i.v. and orally to healthy volunteers.
View Article and Find Full Text PDFArzneimittelforschung
November 1975
After both oral and rectal administration in humans (4,4'-diacetoxy-diphenyl)-(pyridyl-2)-methane (bisacodyl, Dulcolax) and 4,4'-(2-pyridyl-methylene)-diphenol-disulfuric acid semiester disodium (sodium picosulfate, Laxoberal) are hydrolyzed to bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM). In both cases BHPM is responsible for the laxative action. Experiments in rats and guinea pigs have shown that the hydrolysis of picosulfate, in contrast to that of bisacodyl, is attributable to the microorganisms of the intestinal flora.
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