Determination of diltiazem hydrochloride enantiomers in dog plasma using chiral stationary-phase liquid chromatography

Direct enantiomeric separation of cis-(+/-)diltiazem in plasma by high-performance liquid chromatography with ovomucoid column

A method is proposed for the direct enantiomeric separation of cis-(+/-)diltiazem in plasma. The method is based on a commercial Ultron ES-OVM column with a mobile phase of different mixtures of ethanol-phosphate buffer. The degree of extraction of the enantiomers was more than 86%. The detection limit of the method used was 5 ng of racemic mixture on column (coefficient of variation = 13%), corresponding to 3.2 ng for cis-(+/-)diltiazem and 1.8 ng for cis-(+/-)diltiazem.

Mirror images: the analysis of pharmaceutical enantiomers

Pharmaceutical enantiomers often exhibit different pharmacodynamic and pharmacokinetic properties. Stereospecific chromatographic assays are available to separate these stereoisomers. Therapeutic agents often contain chemical functional groups (e.g. amino, hydroxyl, carbonyl, and carboxylic acid). These can be reacted with enantiomerically pure reagents to give diastereoisomers suitable for analysis on achiral gas chromatographic (GC) and high performance liquid chromatographic (HPLC) columns. Alternatively, derivatized or underivatized drugs may be resolved on chiral chromatographic phases. A wide variety of GC (e.g. amino acid, cyclodextrin, and metal-complex) and HPLC (mobile phase additive, crown ether, pi-pi interaction and related phases, protein, cyclodextrin, polysaccharide, methacrylate and amide polymer, and ligand exchange) columns are commercially available. This article reviews the chromatographic separation of enantiomers.