Aromatic amino acid ammonia-lyases and aromatic amino acid 2,3-aminomutases contain the post-translationally formed prosthetic 3,5-dihydro-4-methylidene-5H-imidazol-5-one (MIO) group. MIO enzymes catalyze the stereoselective synthesis of α- or β-amino acid enantiomers, making these chemical processes environmentally friendly and affordable. Characterization of novel inhibitors enables structura...

The actions of the optical enantiomers of BAY K 8644 and Sandoz 202,791 were studied on barium inward currents recorded using the whole-cell configuration of the patch clamp technique from enzymatically isolated smooth muscle cells from the rabbit ear artery. The enantiomers were applied by bath perfusion or rapidly by a concentration jump technique, which enabled the study of drug action under...

The entactogen, 3,4-methylenedioxy-methamphetamine (MDMA), is a chiral drug that is mainly metabolized by N-demethylation and demethylenation. The involvement of cytochrome P450 (P450) isozymes in these metabolic steps has been studied by inhibition assays with human liver microsomes and, in part, with heterologously expressed human P450 isozymes. However, a comprehensive study on the involveme...

The distribution coefficients and enantioseparation of cyclopentolate were studied in an extraction system containing d-tartaric acid ditertbutyl ester in organic phase and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous phase. Various parameters involved in the enantioseparation such as the type and the concentration of chiral selectors, pH value and a wide range of organic solvents were i...

Objective: The influence of the number of active CYP2D6 alleles on enantiomeric plasma levels of tramadol (T) and its M1 metabolite O-desmethyltramadol (ODT) and the response to postoperative tramadol analgesia was investigated. Methods: After abdominal surgery the plasma levels of T and ODT enantiomers were measured after an intravenous bolus application of tramadol of 3 mg/kg body weight. Sub...

11 A fast and simple method for authenticating raspberry flavors from food products was developed. The two enantiomers 12 of the compound (E)-α-ionone from raspberry flavor were separated on a chiral gas chromatographic column. Based on 13 the ratio of these two enantiomers the naturalness of a raspberry flavor can be evaluated due to the fact that a natural 14 flavor will consist almost exclus...

The present study was undertaken to evaluate the possibility of chiral discrimination in the release of enantiomers of ketoprofen (KT) in tablet form and, in turn, the bioavailability of the individual enantiomers, using the rabbit as a model. The enantiomeric concentration of KT in plasma was determined using a customized chiral HPLC analysis. First the plasma concentration-time profile was es...

The stereoselective hydrolysis of esmolol in whole blood and in its separated components from rat, rabbit and human was investigated. Blood esterase activities were variable in different species in the order of rat>rabbit>human. Rat plasma showed the high esterase activity and had no stereoselectivity to enantiomers. Rabbit red blood cell (RBC) membrane, RBC cytosol and plasma all hydrolyzed es...

The D enantiomers of three naturally occurring antibiotics--cecropin A, magainin 2 amide, and melittin--were synthesized. In addition, the D enantiomers of two synthetic chimeric cecropin-melittin hybrid peptides were prepared. Each D isomer was shown by circular dichroism to be a mirror image of the corresponding L isomer in several solvent mixtures. In 20% hexafluoro-2-propanol the peptides c...

The effect of rifampicin on the pharmacokinetics of fexofenadine enantiomers was examined in healthy subjects who received fexofenadine alone or with single or multiple doses of rifampicin (600 mg). A single coadministered dose of rifampicin significantly decreased the oral clearance (CLtot/F) and renal clearance (CLr) of Sand R-fexofenadine by 76 and 62%, and 73 and 62%, respectively. Even aft...