Microbial degradation of the chiral 2-phenylbutyric acid (2-PBA), a metabolite of surfactant linear alkylbenzene sulfonates (LAS), was investigated using both racemic and enantiomer-pure compounds together with quantitative stereoselective analyses. A pure culture of bacteria, identified as Xanthobacter flavus strain PA1 isolated from the mangrove sediment of Hong Kong Mai Po Nature Reserve, wa...

stereoselectivity of mefloquine enantiomers were studied in rats after oral administration of a single 50mg/kg dose of the racemate. pharmacokinetic parameters of (+)-(rs)-mfq in blood and plasma showed no significant difference. the concentration, auc , clif and vdlf of (+)-(rs)-enantiomerin blood were significantly higher than those for the (-)-(sr)-enantiomer. tlie results obtained from this...

An accurate, simple and reproducible high-performance liquid chromatographic (HPLC) method has been developed and validated for the direct separation of individual enantiomers of Abacavir sulfate, a nucleoside reverse transcriptase inhibitor for the treatment of HIV, in pharmaceutical bulk drugs. The enantiomers were resolved by normal phase chromatography, on Chiralpak IA column by using a mob...

Of the numerous mechanisms that have been postulated to explain the origin of biological homochirality, asymmetric autocatalysis coupled with mutual inhibition is often cited as a plausible route to abiotic symmetry breaking. However, in a system closed to mass flow, the constraint of microscopic reversibility ensures that this far-from-equilibrium phenomenon can at best provide a temporary exc...

Short and high-yielding syntheses of enantiomerically pure (S)-(+) and (R)-(-)-abscisic acid are described. The syntheses proceed through key intermediates that preferentially recrystallise as single diastereoisomers for each enantiomer. This route allows the preparation of either enantiomer of abscisic acid in ca. 30% overall yield, and as demonstrated, gives access to an enantiomerically pure...

Chiral pesticides are important contaminants affecting the health and functioning of aquatic systems. The combination of stable isotope and enantiomer analysis techniques has been recently proposed to better characterize the fate of these contaminants in natural and engineered settings. We introduce a modeling approach with the aim of unifying and integrating the interpretation of isotopic and ...

The aims of this study were to develop a transdermal patch for selective controlled delivery of the active S-enantiomer from racemic propranolol, and to evaluate its performance in vivo using Wistar rats. A molecularly imprinted polymer (MIP) thin-layer composited cellulose membrane with selectivity for S-propranolol was employed as the enantioselective-controlled release system. The effect of ...

The ability of optically pure (+)- and (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to initiate skin tumors in mice was determined with a two-stage tumorigenesis system. A single application of 50 to 200 nmoles of (+)- or (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to the backs of CD-1 mice followed by twice-weekly applications of 12-O-tetradecanoyl-phorbol-13-acetate revealed that t...

Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant which has been listed in Annex A of the Stockholm Convention for elimination of production and use. It has been reported to persist in the environment and has the potential for enantiomer-specific degradation, accumulation, or both, making enantioselective analyses increasingly important. The six main stereoisomers of tech...