Noninvasive in vivo 13C-NMR spectroscopy in the rat to study the pharmacokinetics of 13C-labeled xenobiotics.

Noninvasive NMR methodology has been developed to enable monitoring of 13C-labeled xenobiotics in the rat in vivo. 2,2-Dichloro-1-(2-chlorophenyl)-1-(4-chlorophenyl)-[3-13C]-propane can be detected in the liver of intact rats by in vivo 13C surface coil NMR spectroscopy after ip administration of the compound. The experiments were performed at 1.

Proton relaxation enhancement by means of serum albumin and poly-L-lysine labeled with DTPA-Gd3+: relaxivities as a function of molecular weight and conjugation efficiency.

A series of poly-L-lysine chains, with molecular weight ranging from 3300 up to 102,000 Da, were labeled with DTPA-Gd3+. No significant differences in longitudinal and transversal relaxivity, could be demonstrated as a function of the chain length. The R1 and R2 relaxivities were respectively 2.

Rapid method for the analysis of red blood cell fatty acids by reversed-phase high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for a rapid qualitative and quantitative analysis of p-bromophenacyl esters of red blood cell fatty acids in humans. Both free and bound fatty acids, extracted with hexane-2-propanol (3:2) from packed red blood cells were derivatized with p-bromophenacyl bromide and analysed. Ten identical samples taken from a mixed pool of packed red blood cells from healthy subjects were analysed on two different columns.

Direct liquid introduction LC/MS microbore experiments for the analysis of nucleoside material present in human urine.

In order to obtain detection limits low enough for the analysis of nucleoside material in biological samples, a direct liquid introduction (liquid chromatographic/mass spectrometric DLI) system was upgraded by inserting a self-built desolvation chamber between the DLI probe and the ion source and by switching to microbore high-performance liquid chromatography (HPLC) on a C-18 column. The system was evaluated for the analysis of pure nucleoside and 2'-deoxynucleoside compounds in CH3OH + H2O (80/20) and for the analysis of nucleoside mixtures which were separated using 0.01 M ammonium formate + methanol (97:3) as eluant.