A. Van Overbeke

Comparative Study on the Enantiomeric Separation of Several Non-Steroidal Anti-Inflammatory Drugs on Two Cellulose-Based Chiral Stationary Phases

Two cellulose-based chiral stationary phases were compared on their feasibility to resolve a representative number of 2-arylpropionic acids : a new experimental phase (Tolylcellulose, EXP B101) manufactured by Bio-Rad RSL and the Chiralcel OJ phase by Daicel. Both columns were tested under normal phase conditions, applying a n-hexane:isopropanol mobile phase. The Bio-Rad column was also assayed under reversed phase conditions using a methanol and perchlorate buffer system. Enantiomeric separation without prior derivatization of most 2-arylpropionic acids was far better on the Chiralcel OJ column than on the Bio-Rad column, the latter performing somewhat better under reversed phase conditions. Prior derivatization of the carboxylic acid group with an amine (naphthylmethylamine, (2-methyl)benzylamine) or an alcohol (benzylalcohol) permitted to separate the tested drugs to different extents on both columns.

Direct enantiomeric HPLC separation of several 2-arylpropionic acids, barbituric acids and benzodiazepines on chiralcel OJ-R chiral stationary phase

SummaryA newly developed reversed-phase chiral stationary phase, cellulose tris(4-methylbenzoate), known as Chiralcel OJ-R, has been successfully applied to the direct resolution of the enantiomers of several nonsteroidal anti-inflammatory drugs belonging to the profen group. Among the five barbituric acids tested, the chiral resolution of mephobarbital is especially high. The Chiralcel OJ-R column also proved quite efficient for the enantiomeric resolution of a few representatives of the benzodiazepine group.Variations of mobile phase conditions based on acetonitrile and/or methanol were tested. The results obtained are briefly compared with separations performed using a Chiralcel OJ column under normalphase conditions.

Separation of 2-arylpropionic acids on a cellulose based chiral stationary phase by RP-HPLC.

The enantiomers of eight 2-arylpropionic acids, a group of chiral non steroidal antiinflammatory drugs, were resolved as their benzylamide derivatives on a high-performance liquid chromatographic chiral stationary phase consisting of a covalently bound tris (4-methylbenzoate) cellulose layer on silica gel. The column was used under reversed-phase conditions using methanol as the main mobile phase component, with a perchlorate buffer pH 2.0. A compromise for derivatization with a water soluble carbodiimide and 1-hydroxybenzotriazole of a group of eight analytes was obtained. The derivatives were identified by IR- and MS-spectroscopy.

Quantitative Fourier transform infrared/attenuated total reflectance analysis of ketoprofen in some pharmaceutical formulations

Abstract An overhead attenuated total reflectance system was used to quantify ketoprofen in some pharmaceutical formulations (capsules and injection ampoules). No extensive sample pretreatment was needed. The ampoules were analysed as such and a simultaneous quantification of ketoprofen and arginine base was performed. A partial least-squares software package (PLS1) was applied to the calibration and prediction for a limited number of standard solutions.

Chemiluminescence determination of tiopronin and its metabolite 2-mercaptopropionic acid in human urine by HPLC coupled with flow injection

SummaryIn previous pharmacokinetic studies tiopronin, a drug used for effective treatment of cystinuria and rheumatoid arthritis, and its metabolite 2-mercaptopropionic acid were analysed by conventional liquid chromatography with pre- and post-column derivatization and UV detection. Now a novel HPLC-coupled chemiluminescence-flow-injection analysis (CL-FIA) method has been developed for the determination of tiopronin and 2-mercaptopropionic acid in urine. The method is based on chemiluminescence from a Ce(IV) oxidation system sensitized by quinine, as proposed earlier by this group, and flow-injection analysis. The method, which has the advantages of high sensitivity and selectivity, simple sample treatment and prompt production of results, has also been preliminarily adapted for pharmacokinetic study of tiopronin in urine.

Enantiomeric separation of six 2-arylpropionic acids after pre-column derivatization with various amines and alcohols on a cellulose-based chiral stationary phase

A large number of mono-, bi- and tricyclic amines and alcohols were used for the derivatization of six 2-arylpropionic acids. The effect of the bonded aromatic portion on the enantiomeric separation using a tris(4-methylbenzoate)cellulose column was studied. Small modifications of the bonded groups close to the chiral centre pointed out their predominant steric effect to the chiral recognition process rather than electronic influence. Varying ratios of methanol and perchlorate buffer composing the mobile phase were applied to elute the different series within comparable analysis times.