Chromatographic behavior of selected antibiotic drugs supported by quantitative structure-retention relationships

- The applied multiple linear regression (MLR) was based on a variety of theoretical molecular descriptors selected by the stepwise variable procedure of subset selection.
- The geometry of all drugs was optimized by the semi-empirical method AM1 and used to calculate different molecular descriptors.
- The prediction results were in good agreement with the experimental values.

As antibiotic drugs have a wide variety of applications, there is a growing demand for their selective determination, a task for which chromatographic methods seem to be appropriate. With this end in view, chromatographic measurements were performed with the use of six different HPLC columns (ACE 5C18, IAM.PC.DD.2, octadecyl, phenyl, alkylamide and cholesteryl-alkylamide) to determine the logkw of selected antibiotic drugs (amoxicillin, cefatoxime, ciprofloxacin, fluconazole, gentamicin, clindamycin, linezolid and metronidazole). The retention behavior of the analytes was investigated as a function of different binary hydro-organic mobile phases containing 10-45% (v/v) acetonitrile. The studied compounds were separated under isocratic conditions. The best results of separation of the tested biologically active compounds were obtained on the commercially available C18 column. Special attention was dedicated to the study of interactions among the stationary phase, mobile phase and the analytes. Another goal was to selecting the best column for separation of the tested biologically active compounds. Finally, QSRR models together with stationary phase characterization provided reliable information on the properties and characteristics of studied columns.