Sinus tissue concentration of moxifloxacin after a single oral dose

Moxifloxacin is a new fluoroquinolone antimicrobial approved for the treatment of acute bacterial rhinosinusitis. In order to assess its distribution pattern into the paranasal sinuses, and specifically to evaluate how the histopathologic changes associated with chronic inflammation affect its tissue penetration, we conducted the present investigation, a randomized, open-label, single dose, sinus-tissue pharmacokinetic study with oral moxifloxacin. Twenty adult subjects, selected for surgery because of recalcitrant chronic rhinosinusitis, were preoperatively randomly allocated to receive a tablet of 400 mg moxifloxacin 3 or 4 hours before the procedure. During the operation, tissue samples were collected at specific sinonasal sites, and the concentration levels of the antimicrobial in the different parts of the paranasal sinuses were assayed. Simultaneously, the degree of inflammation at each site was evaluated. We found that moxifloxacin was distributed extensively throughout the sinuses, in both inflamed and noninflamed mucosae, but tended to be concentrated in maxillary sinus cysts. The tissue-to-blood ratios exceeded 4:1 at most sites, with mucosal concentration levels well above the MIC90 values of the drug against a wide range of microorganisms. We concluded that the oral moxifloxacin tissue kinetics provides an extremely potent antimicrobial activity in all parts of the sinuses, regardless of the inflammatory status of the mucosa.