KCS

Carbomylated derivatives of two antibiotics, namely, clindamycin phosphate (CLIP) and erythromycin (ERY) were successfully employed as co-precursors, in combination of zirconium tetrabutoxide as a precursor, to prepare chiral organic-zirconia hybrid monoliths (i.e., CLIP-ZHMs and ERY-ZHMs, respectively) via a single-step in-situ sol-gel approach in our previous works [1,2]. Their superiority over chiral organic-zirconia/silica monoliths, prepared by post-modification approach, in terms of better enantioresolution and enhanced stability inspired us to prepare ZHMs based on an another antibiotic, azithromycin (i.e., AZI-ZHMs). Monolithic columns were employed for capillary electrochromatographic enantioseparation of acidic chiral drugs in mobile phases consisting of acetonitrile (ACN) and methanol (MeOH) as organic modifiers and, acetic acid (AcOH) and triethylamine (TEA) as electrolytes. The effects of composition of mobile phase and applied voltage on chiral separation were investigated by using ketoprofen as a representative analyte. Baseline resolutions (i.e., Rs >1.5) were obtained for six acidic drugs (namely, ketoprofen, suprofen, carprofen, flurbriprofen, ibuprofen and warfarin) using a mobile phase consisting of 70/30 (v/v) ACN/MeOH with 240 mM AcOH and 20 mM TEA. The relative standard deviations for resolution values regarding column to column and batch to batch repeatability were less than 2.5% (for n=3) under optimized conditions indicating satisfactory stability of columns and reproducibility of column preparation process. [1] Dixit, S., Park, J. H., J. Chromatogr. A 2015, 1416, 129-136. [2] Tran, L. N., Dixit, S., Park, J. H., J. Chromatogr. A 2014, 1356, 289-293.