Electrochemical Oxidation of Different Therapeutic Classes of Pharmaceuticals Using Graphite-PVC Composite Electrode

This study reports electrochemical treatment of different therapeutic classes of pharmaceuticals (caffeine, prazosin, enalapril, carbamazepine, nifedipine, levonorgestrel, and simvastatin) in a mixture. The electrochemical process was investigated using graphite-PVC anode at different applied voltages (3, 5, and 12 V), initial concentrations of studied pharmaceuticals in aqueous solution (5 and 10 mg/L), and concentrations of sodium chloride (1 and 2 g/L). The % removal of pharmaceuticals increased with the applied voltage, and was found higher than 98% after 50 min of electrolysis at 5 V. Energy consumption ranged between 0.760 and 3.300 Wh/mg using 12 V being the highest value compared to 3 and 5 V. The formation of chlorinated by-products from four selected pharmaceuticals, simvastatin (C11H13Cl3O5, and C10H12Cl4O3), prazosin (C13H12Cl3N5O3 and C10H11Cl4N2O2), carbamazepine and caffeine (C15H11N2O2Cl and C8H9N4O2Cl) was identified and elucidated using liquid chromatography-time of flight mass spectrometry (LC-TOF/MS).

[Analysis of 37 drugs in whole blood by HPLC after solid phase extraction]

OBJECTIVE

To develop a specific, sensitive, reproducible SPE-HPLC method for the determination of 37 drugs in whole blood.

METHODS

With the doxapram as internal standard, Oasis column was used to extract drugs from whole blood. Two kinds of mobile phases were used in this study. Separations were achieved by a LiChrospher 100 RP-C18 (250 mm x 4.0 mm x 5 microm) column kept at 50 degrees C, the DAD detector was set at 230 nm and 250 nm.

RESULTS

The limit of detection were 1-30 ng/mL. The method showed excellent linearity and the linear correlation coefficient was > or =0.997 98. The relative standard deviation for between-day and within-day assay were <10%.

CONCLUSION

The method is effective, simple, reliable and has been used in real cases.

[Chiral separation and preparation of three new antagonists of alpha 1-adrenoceptors by chiral mobile phase HPLC]

AIM

To establish new methods for the chiral separation and preparation of three new drugs, alfuzosin, terazosin and doxazosin.

METHODS

By optimizing factors which affect the chiral separation, modifier of solvent, chiral additive, pH of mobile phase, modifier of organic base and stationary phase, the optimum condition for chiral separation were selected. The preparation of enantiomers was carried out on semi-preparative reverse phase column (7.8 mm x 250 mm C4 5 microns). Acetonitrile-water modified by the addition of carboxymethyl-beta-cyclodextrin (2%-5%, w/v) was applied as chiral mobile phase.

RESULTS

The enantiomers of three new drugs were base-line-separated and milligram-scale samples of enantiomer were obtained.

CONCLUSION

The newly established method can be used in research and development of the enantiomers of three new drugs.