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The separation of R,R‐, S,S‐, and meso‐Koga bases on derivatized amylose chiral stationary phases (CSP) has been studied using different alcohol and alcohol‐hexane mixtures as eluant. Straight‐chain and branched alcohols with carbon numbers from one to four were investigated. The carbon number and geometry of the alcohol impacts the separation of Koga bases. The optimal separations were obtained using...
A survey of linalool enantiomers in kiwifruit (Actinidia) flowers was conducted to determine their potential as sources of these valuable floral fragrances, and revealed a wide range of enantiomeric ratios. While flowers of A. polygama and A. chrysantha contained almost exclusively one enantiomer, most species contained significant amounts of both (R) and (S) isomers. In some species enantiomeric...
The pharmacokinetics of (−)‐N‐(trans‐4‐isopropylcyclohexanecarbonyl)‐D‐phenylalanine (nateglinide) and its enantiomer (L‐enantiomer) was studied in Goto‐Kakizaki (GK) rats after intravenous administration of nateglinide or L‐enantiomer at a dose of 40 μmol/kg body weight. Nateglinide, its L‐enantiomer and their metabolites in serum, bile and urine were determined. The total clearance (CLtot) and the...
The acetylcholinesterase inhibition by enantiomers of exo‐ and endo‐2‐norbornyl‐N‐n‐butylcarbamates shows high stereoselelectivity. For the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(−)‐exo‐2‐norbornyl‐N‐n‐butylcarbamates, the R‐enantiomer is more potent than the S‐enantiomer. But, for the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(−)‐endo‐2‐norbornyl‐N‐n‐butylcarbamates, the...
The binding of the (R)‐ and (S)‐enantiomers of amlodipine to bovine serum albumin (BSA), human serum albumin (HSA), α1‐acid glycoprotein (AGP), and human plasma (HP) was studied by equilibrium dialysis over the concentration range of 75–200 μM at a protein concentration of 150 μM. Unbound drug concentrations were determined by enantioselective capillary electrophoresis using 50 mM phosphate buffer,...
The purpose of this study was to investigate whether CYP2C19 activity can be estimated from plasma concentrations of lansoprazole enantiomers 4 h (C4h) after single administration by oral and enteral routes. Sixty‐nine subjects, 22 homozygous extensive metabolizers (homEMs), 32 heterozygous EMs (hetEMs), and 15 poor metabolizers (PMs), participated in the study. After a single oral or enteral dose...
The female Sprague‐Dawley (SD) and Dark Agouti (DA) rats are considered the animal counterparts of the human extensive and poor metabolizer cytochrome P450 (CYP) 2D6 phenotypes, respectively. The aim of this work was to study possible rat strain differences in the steady‐state pharmacokinetics of the (+)‐(S)‐ and (−)‐(R)‐enantiomers of citalopram and its demethylated metabolites. A chronic drug treatment...
Solvent‐induced chirality control in the enantioseparation of 1‐phenylethylamine 1 by N‐(p‐toluenesulfonyl)‐(S)‐phenylalanine 2 via diastereomeric salt formation was studied. (S)‐1·(S)‐2 was preferentially crystallized as a less‐soluble salt from aqueous alcohol, while (R)‐1·(S)‐2 salt was mainly obtained by addition of solvents with a six‐membered ring such as dioxane, cyclohexane, tetrahydropyran,...
There are several approaches to produce enantiomerically pure drug substances, such as recrystallization, catalytic process (ligand and enzyme), indirect chromatographic resolution, and direct chromatographic resolution. However, the use of preparative chromatography with chiral stationary phases seems to be most effective for early phase projects, where the time and resources on the developments...
Mori's synthetic works on bioactive natural products in general and pheromones in particular started about 40 years ago to establish their absolute configurations and also to clarify their stereochemistry–bioactivity relationships. Results indicate that bioactive natural products are not always enantiomerically pure, and the stereochemistry–bioactivity relationships are not simple but complicated...
Porous and nonporous supported liquid crystalline membranes were produced by impregnating porous cellulose nitrate supports with cholesteric liquid crystal (LC) materials consisting of 4‐cyano‐4′‐pentylbiphenyl (5CB) mixed with a cholesterol‐based dopant (cholesteryl oleyl carbonate [COC], cholesteryl nonanoate [CN], or cholesteryl chloride [CC]). The membranes exhibit selectivity for R‐phenylglycine...
Besifloxacin hydrochloride is a novel chiral broad‐spectrum fluoroquinolone developed for the treatment of bacterial conjunctivitis. R‐besifloxacin hydrochloride is used in clinics as a consequence of its higher antibacterial activity. To establish an enantiomeric impurity determination method, some chiral stationary phases (CSPs) were screened. Besifloxacin enantiomers can be separated to a certain...
The purpose of this study was to elucidate the pharmacokinetics of terazosin enantiomers in healthy Chinese male subjects. After a single oral dose of 2‐mg terazosin, the plasma concentrations of terazosin enantiomers were measured over the course of 48 h in 12 healthy subjects. The plasma concentrations of (+)‐(R)‐terazosin at all time points were higher than those of (−)‐(S)‐terazosin. The area...
Enantioselective liquid–liquid extraction of zopiclone was conducted by employing a series of (R)‐mandelic acid esters as chiral extractants. The effects of concentration of extractant, concentration of zopiclone, type of organic solvent, pH value, and temperature on the extraction efficiency were investigated. (R)‐o‐chloromandelic acid propyl ester was demonstrated to be an efficient chiral extractant...
Pipecolic acid naturally occurs in microorganisms, plants, and animals, where it plays many roles, including the interactions between these organisms, and is a key constituent of many natural and synthetic bioactive molecules. This article provides a review of current knowledge on the natural occurrence of pipecolic acid and the known and potential significance of its L‐ and D‐enantiomers in different...
Decontamination of polluted soils using plants is based on the ability of plant species (including transgenic plants) to enhance bioavailability of pollutants in the rhizosphere and support growth of pollutant‐degrading microorganisms via root exudation and plant species‐specific composition of the exudates. In this work, we review current knowledge of enantiomers of low‐molecular‐weight (LMW) organic...
The binary phase diagrams of hydrogen halides salts of medetomidine (Med.HX, X:Br,I) and hydrogen oxalate salt of medetomidine (Med.Ox) were determined based on thermogravimetric/differential thermal analysis (TGA/DTA) and their crystal structure behavior was confirmed by comparison of the X‐ray diffractometry and FT‐IR spectroscopy of the racemate and pure enantiomer. All hydrogen halide salts presented...
Vinclozolin is a chiral fungicide with potential environmental problems. The chiral separation of the enantiomers and enantioselective degradation in soil were investigated in this work. The enantiomers were separated by high‐performance liquid chromatography (HPLC) on Chiralpak IA, IB, and AZ‐H chiral columns under normal phase and the influence of the mobile phase composition on the separation was...
The enantioselective pharmacokinetics of TJ0711 hydrochloride were studied in rats given different doses of rac‐TJ0711 hydrochloride via intravenous and oral routes. R‐ and S‐TJ0711 hydrochloride were both rapidly absorbed, and the average AUC0‐∞ of R‐TJ0711 hydrochloride was greater than that of S‐TJ0711 hydrochloride after intragastric administration, with an R/S AUC ratio 1.11 and 1.35 for 30 and...
Permethrin (PM), cypermethrin (CP), and cyfluthrin (CF) are three important synthetic pyrethroids, which contain two, four, and four enantiomeric pairs (diastereomers) and thus have four, eight, and eight stereoisomers, respectively. In this study, the stereo‐ and enantioselective degradation of PM, CP, and CF in a Shijiazhuang alkaline yellow soil and a Wuhan acidic red soil were studied in detail...
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