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Chiral molecules are of great importance in the life science since individual enantiomers may differ in biological activity, mechanism, and toxicity, making it necessary to explore efficient chiral analysis methods. Chromatography approaches are often used to differentiate enantiomers while mass spectrometry (MS) was thought to be blind in chiral analysis. With the development of MS technique, it...
Fluoxetine (FLX) is one of the most widely prescribed selective serotonin reuptake inhibitors. Although FLX is used as racemate in the clinic, the clinical pharmacokinetics of FLX and its N‐demethylation metabolite norfluoxetine (NFLX) show obvious cytochrome P450 (CYP) polymorphism dependency and exhibit marked stereoselectivity. However, the kinetic profiles of CYP variants to FLX remain unclear...
The stereoselective uptake of propranolol enantiomers was investigated by using the K562 and K562 adriamycin‐resistant cell line (K562/ADR) as a model. An enantioselective RP‐HPLC method was applied to determine the accumulation of propranolol (PPL) stereoisomers in K562 and K562/ADR cells. The concentration, time and temperature dependent studies showed that the accumulation of S‐(−)‐PPL was higher...
Tetrahydropalmatine (THP), with one chiral center, is an alkaloid that possesses analgesic and many other pharmacological actives. The aim of the present study is to investigate stereoselective metabolism of THP enantiomers in human liver microsomes (HLM) and elucidate which cytochrome P450 (CYP) isoforms contribute to the stereoselective metabolism in HLM. Additionally, the inhibitions of THP enantiomers...
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...
Tetrahydropalmatine (THP), with one chiral center, is an active alkaloid ingredient in Rhizoma Corydalis. The aim of the present paper is to study whether THP enantiomers are metabolized stereoselectively in rat, mouse, dog, and monkey liver microsomes, and then, to elucidate which Cytochrome P450 (CYP) isoforms are predominately responsible for the stereoselective metabolism of THP enantiomers in...
(1R, 3R)‐1‐(1, 3‐Benzodioxol‐5‐yl)‐2‐(chloroacetyl)‐2, 3, 4, 9‐tetrahydro‐1H‐pyrido[3, 4‐b]indole‐3‐carboxylic acid methyl ester ((1R, 3R)‐Cpe) is a key intermediate used in the synthesis of tadalafil, a highly selective phosphodiesterase type‐5 inhibitor. In the present study, a chiral high‐performance liquid chromatography method was developed for the simultaneous determination of diastereoisomeric...
Mandelic acid (MA) is generally used as a biological indicator of occupational exposure to styrene, which is classified as a class of hazardous environmental pollutants. It was found to undergo one‐directional chiral inversion (S‐MA to R‐MA) in Wistar and Sprague‐Dawley rats in vivo. This study was aimed to explore the metabolic mechanism of chiral inversion of S‐MA in vitro. S‐MA was converted to...
The aim of this study was to explore potential transport mechanisms of cetirizine enantiomers across Caco‐2 cells. Cetirizine displayed polarized transport at concentrations ranging from 4.0 to 80.0 μM, with the permeability in the secretory direction being 1.4‐ to 4.0‐fold higher than that in the absorptive direction. Cetirizine enantiomers were transported distinctively different from each other...
Stereoselective metabolism of propranolol side‐chain glucuronidation was studied for two recombinant human uridine diphosphate glucuronosyltransferases (UGTs), UGT1A9 and UGT2B7. The S‐ and R‐propranolol side‐chain glucuronides produced in the incubation mixtures were assayed simultaneously by RP‐HPLC with fluorescent detector. The excitation and emission wavelengths were set at 310 nm and 339 nm,...
The transport and uptake of individual propranolol (PPL) enantiomers were studied in human intestinal Caco‐2 cell monolayers, and a reversed‐phase HPLC‐UV assay was used for quantitative analysis. S‐PPL and R‐PPL across Caco‐2 cell monolayers was determined in the concentrations range of 10–500 μM in both apical (AP) to basolateral (BL) and BL to AP directions. S‐PPL exhibited greater permeability...
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