Enantiomeric Separation of Ofloxacin by Nano-Liquid Chromatography Using a Sulfated-β-Cyclodextrin as a Chiral Selector in the Mobile Phase

Abstract

The S-(-)-enantiomer of ofloxacin, a chiral fluoroquinolone antibiotic, exhibits an antibacterial activity 8-128 times higher than that of the R-(+)-isomer. A new stereospecific nano-LC method for the enantioseparation of the ofloxacin racemic mixture was developed using an achiral reversed phase column (Pinnacle II Phenyl 3 μm, 15 cm x 100 μm ID) and heptakis-(2,3-diacetyl-6-sulfo)--cyclodextrin (HDAS--CD) as a mobile phase chiral additive. Best enantioresolution was achieved using a mobile phase containing acetonitrile, 50 mM sodium acetate buffer pH 3 (30:70, v/v) and 5 mM of HDAS--CD. The flow rate thorough the capillary column was estimated in 620 nL/min and the wavelength for the UV detection was set at 290 nm. Good separation of the enantiomers was obtained is less than 10 min with a resolution and selectivity factor of 1.66 and 1.88, respectively. The effect of several experimental parameters on the chiral separation was also evaluated and the method was successfully validated in terms of linearity, accuracy and precision, showing the enantiorecognition capability of the employed sulfated -CD toward the ofloxacin chiral drug.

Chiral separation of quinolones by liquid chromatography and capillary electrophoresis

“…Rosales‐Conrado et al. developed a nano‐HPLC method to resolve ofloxacin enantiomers using heptakis‐(2,3‐diacetyl‐6‐sulfo)‐β‐cyclodextrinβ as a chiral additive to the mobile phase made of acetonitrile and 50 mM sodium acetate buffer (30:70, v/v). The separation was performed on a Pinnacle II Phenyl (15 cm × 100 μm id) capillary column and took not more than 8 min.…”

“…Additionally, the cost of operation is very low and discharging less hazardous waste: eco‐friendly. There are only few examples of the use of these techniques in the enantioseparation of fluoroquinolones , but certainly they will find more and more applications as the respective equipment is becoming commercially available and researchers are becoming familiar with these new techniques. Again, as shows the comparison of nano‐ and usual methods (Table ), an increase in sensitivity would be necessary for nano‐HPLC/CE to compete with HPLC/CE.…”

Chiral Separations using Miniaturized Techniques: State of the Art and Perspectives

“…The addition of a methylated β‐CD in the MP employing a C 18 silica phase allowed the enantiomeric separation of some compounds of pharmaceutical interest, e.g., nonsteroidal anti‐inflammatory drugs (acidic analytes), also including the calculation of association constants for a CD‐drug . In another work by our group, sulfated‐β‐cyclodextrin was added to the MP for the chiral resolution of ofloxacin having a Pinnacle II Phenyl 3 µm SP . This approach was very economical, and we could even use more expensive CDs due to the reduced volumes of MP.…”

Chiral Separations Using Nano-Liquid Chromatography

“…The separated enantiomers were R and S-1,1'-binaphtyl-2-2'-dihyl hydrogen phosphate [13] . Our group was also interested in this topic studying the enantiomers separation of different compounds of pharmaceutical interest such as non-steroidal antiinflammatory drugs or fluoroquinolone antibiotics [14][15][16] utilizing nano-LC with packed capillaries of 100 mm I.D. and different CDs (trimethylated-, sulphated-, dimethylated-or hydroxy-propyl-g-CD) added to the mobile phase.…”