Enantioselective HPLC analysis of propafenone and of its main metabolites using polysaccharide and protein-based chiral stationary phases.

HPLC on chiral stationary phases has been used for the enantioselective assay of propafenone (PPF), 5-hydroxypropafenone (PPF-50H) and N-despropylpropafenone (PPF-NOR) enantiomers. The results obtained on Chiralpak AD column showed that it is useful for the resolution of PPF and of its main metabolites, although the peaks obtained for PPF-NOR were not symmetrical under the conditions investigated. This column and circular dichroism-based detection system were used to determine the absolute configuration of the eluates. Furthermore, the influence of the mobile phase composition on the resolution of PPF and of its main metabolites was investigated on cellulose derivatives (Chiralcel OD-H and Chiralcel OD-R) and protein (Chiral AGP and Ultron ES-OVM)-based chiral stationary phases. The enantiomers of PPF were resolved on all the columns, except for the Ultron ES-OVM. This column, the Chiralpak AD and the Chiralcel OD-H columns were suitable for the resolution of the PPF-50H enantiomers. The PPF-NOR enantiomers were resolved on the Chiralpak AD, Chiral AGP and Chiralcel OD-R columns.

Heparan sulfates and heparins: similar compounds performing the same functions in vertebrates and invertebrates?

The distribution and structure of heparan sulfate and heparin are briefly reviewed. Heparan sulfate is a ubiquitous compound of animal cells whose structure has been maintained throughout evolution, showing an enormous variability regarding the relative amounts of its disaccharide units. Heparin, on the other hand, is present only in a few tissues and species of the animal kingdom and in the form of granules inside organelles in the cytoplasm of special cells. Thus, the distribution as well as the main structural features of the molecule, including its main disaccharide unit, have been maintained through evolution. These and other studies led to the proposal that heparan sulfate may be involved in the cell-cell recognition phenomena and control of cell growth, whereas heparin may be involved in defense mechanisms against bacteria and other foreign materials. All indications obtained thus far suggest that these molecules perform the same functions in vertebrates and invertebrates.

Simultaneous determination of propafenone and 5-hydroxypropafenone enantiomers in plasma by chromatography on an amylose derived chiral stationary phase.

An enantioselective liquid chromatography method was developed for the simultaneous determination of propafenone (PPF) and 5-hydroxypropafenone (PPF-5OH) enantiomers in plasma. After liquid liquid extraction with dichloromethane, the enantiomers were resolved on a Chiralpak AD column using hexane-ethanol (88:12, v/v) plus 0.1% diethylamine as the mobile phase and monitored at 315 nm. Under these conditions the enantiomeric fractions of the drug and of its metabolite were analysed within 20 min. The extraction procedure resulted in absolute recoveries of 62.9 and 61.3% for (R)- and (S)-PPF, respectively, and of 57.6 and 56.5% for (R)- and (S)-PPF-5OH, respectively. This procedure was efficient in removing endogenous interferents as well the interference of an other PPF metabolite, N-despropylpropafenone (PPF-NOR). The calibration curves were linear over the concentration range 25-1250 ng/ml. Low values of the coefficients of variation were demonstrated for both within-day and between day assays. The method described in this paper allows the determination of PPF and PPF-5OH enantiomers at plasma levels as low as 25 ng/ml and can be used in clinical pharmacokinetic studies.