Metabolism of caffeine to 6-amino-5-[N-methylformylamino]-1,3-dimethyluracil in the isolated, perfused liver from control or phenobarbital-, beta-naphthoflavone- and 3-methylcholanthrene-pretreated rats.

Caffeine metabolism to 6-amino-5-[N-methylformylamino]-1,3-dimethyluracil was studied in the isolated, perfused rat liver. The [2-14C]-labelled drug and metabolites were separated by thin-layer chromatography or high-pressure liquid chromatography. The chemical structure of 6-amino-5-[N-methylformylamino]-1,3-dimethyluracil was confirmed by mass spectrometry and it was quantitatively determined by liquid scintillation counting.

Studies on 5,5-diphenylhydantoin irreversible binding to rat liver microsomal proteins.

5,5-Diphenylhydantoin irreversibly binds to rat liver microsomes and the process requires NADPH and O2. Proteins binding was significantly enhanced when experiments were carried out with liver microsomal preparations from beta-naphthoflavone and 3-methylcholanthrene pretreated animals whereas pretreatment with phenobarbital significantly reduced it. Carbon monoxide, beta-diethylaminoethyl-diphenylpropylacetate and glutathione inhibited drug covalent binding to microsomal proteins.

Possible relevance of N-trifluoroacetyladriamycin (AD 41) in the antitumoral activity of N-trifluoroacetyladriamycin-14-valerate (AD 32) in tumor-bearing mice. I. Pharmacokinetic evidence.

N-Trifluoroacetyladriamycin-14-valerate (AD 32) is an analog of doxorubicin whose chemico-physical characteristics are nontypical compared to the parent compound. Its most interesting feature is the lack of capacity to intercalate with DNA; thus, its mechanism of action as an antitumoral drug is still unknown. The N-trifluoroacetyl bond on the glycoside moiety is very stable and does not easily undergo enzymatic hydrolysis.

Quantitative thin-layer chromatographic measurement of n-trifluoroacetyladriamycin-14-valerate (AD 32) and trifluoroacetyladriamycin (AD 41) in blood and tissues.

A thin-layer chromatographic method has been developed for the detection and measurement of N-trifluoroacetyladriamycin-14-valerate (AD 32) and its major metabolite trifluoroacetyladriamycin (AD 41). The procedure gives satisfactory linearity over a large range of concentrations. The coefficient of variability is about 10% over the entire range of usable concentrations, giving good reproducibility; sensitivity is 25 ng for both AD 32 and AD 41.