HPLC Retention Control of Antibiotics (Metronidazole and Norfloxacine) in Toothpaste

Commercially available toothpaste has been known to include antibiotics. To demonstrate the retention control on the mixed-mode column Primesep 100, toothpaste was spiked with the antibiotics metronidazole and norfloxacin. In a 13 minute method, retention of the antibiotics was controlled by adjustment in ratio of organic in the mobile phase. This method demonstrates the flexibility of using mixed-mode columns such as Primesep 100.