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

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 logk_w 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.