mefloquine (mfq), as a racemic mixture is used for the prophylaxis and treatment of malaria. stereoselective pharmacodynamic and pharmacokinetic differences have been observed for mfq. in the present study, the human blood was spiked with racemic mfq. the concentration of mfq enantiomers in various blood fractions including packed erythrocyte layer, platelet rich plasma and platelet poor plasma...

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...

Practical stereoselective synthetic routes to the antihistaminic drug olopatadine and its E-isomer have been developed, the key steps being a trans stereoselective Wittig olefination using a nonstabilized phosphorus ylide and a stereoselective Heck cyclization. The stereoselectivity of the Wittig reaction depends on both the phosphonium salt anion and the cation present in the base used to gene...

A practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2-substituted 6-oxocyclohexenepropionates 2 with (R)-phenylglycinol, the stereoselective hydrogenation of the resulting unsaturated tricyclic lactams, and the stereoselective reductive cleavage of the oxazolidine ring.

The stereoselective synthesis of D-fagomine, D-3-epi-fagomine, and D-3-epi-fagomine analogs starting from readily available D-glyceraldehyde acetonide has been achieved. The synthesis involves diastereoselective anti-vinylation of its homoallylimine, ring-closing metathesis, and stereoselective epoxidation followed by regioselective ring-opening or stereoselective dihydroxylation. The lack of a...

many properties of chemicals depend on their stereochemistry. among these, the effects of stereoisomerism on percutaneous absorption of drugs are not well studied. we have previously shown that permeation of tretinoin and isotretinoin (two geometric isomers) through hydrophilic enhancers-treated rat skin is stereoselective. as, depending on their lipophilicity, penetration enhancers can change ...

BACKGROUND Metabolism and clearance of racemic methadone are stereoselective and highly variable, yet the mechanism remains largely unknown. Initial in vitro studies attributed methadone metabolism to cytochrome P4503A4 (CYP3A4). CYP3A4 was also assumed responsible for methadone clearance in vivo. Nevertheless, recent clinical data do not support a primary role for CYP3A4 and suggest that CYP2B...

A stereoselective approach to the 8b-azaacenaphthylene ring system is described. This new route features a dichloroketene-enol ether [2 + 2] cycloaddition, a vinylogous Mannich reaction, and an aza-Prins cyclization as key stereoselective transformations.

Methadone is administered as a racemate, although opioid activity resides in the R-enantiomer. Methadone disposition is stereoselective, with considerable unexplained variability in clearance and plasma R/S ratios. N-Demethylation of methadone in vitro is predominantly mediated by cytochrome P450 CYP3A4 and CYP2B6 and somewhat by CYP2C19. This investigation evaluated stereoselectivity, models, ...

Carvedilol is administered as a racemic mixture of the R(+)- and S(-)-enantiomers, although it was demonstrated that the two enantiomers exhibit different pharmacological effects and stereoselective pharmacokinetics. The aim of this study was the evaluation of several native and derivatized cyclodextrines as chiral selectors for the separation of carvedilol enantiomers. Stereoselective interact...