The Pharmacokinetics And Pharmacodynamics Of Moxifloxacin In Human Peritoneal Exudates

OBJECTIVE To investigate the pharmacokinetics of moxifloxacin in the peritoneal exudates in surgical patients and evaluate the phamacodynamics and antimicrobial effect against the common bacteria encountered in patients with intra-abdominal infections.METHODS Patients (number 9) with a high risk of infection received a single intravenous infusion of moxifloxacin400 mg, over 1.5 h, the peritoneal exudates samples were obtained at 1,2,3,4,6,10,24h, and concentrations of moxifloxacin were measured by HPLC with fluorescence detection. The software DAS 2.0 was used for the determination of Cmax,AUC,t1/2,MRT and CL, then the antibiotic effect of moxifloxacin was evaluated according to the PK/PD results.Results:Concentrations in peritoneal exudates were highest at 3 h after the start of the infusion, reaching a geometric mean of 1.69μg/ml, which is lower than the concentration in the plasma, and declined to a geometric mean of 0.52 mg/L at 24 h., which is a little higher than the concentration in the plasma, The area under the concentration-time curve (AUC0-24) in peritoneal exudates was also smaller than the AUC0-24 in the plasma, the time to peak concentrations (Tmax) was longer in exudates than in plasma, suggesting that there was a time interval for moxifloxacin to penetrate into the peritoneal exudates.CONCLUSION According to the result of the study, the PK/PD of moxifloxacin was low, and the bactericidal effect of moxifloxacin was significantly lower than the susceptibility rate by CLSI. However, moxifloxacin was still effective against more than 90% of the E coli and Klebsiella oxytoca that were the most commonly seen bacteria in cIAI, and effective against more than 50% other G-bacteria. For G+bacteria, moxifloxacin was bactericidal to more than 90% and more than 50% of the MSSA and MRSA respectively. It was effective against less than 50% of the Enterobacter faecalis, and the vast majority of the MRSE and E faecium were resistant to moxifloxacin.If stains of these two resistant bacteria were cultured with no progress in the patient's clinical condition, antibacterial agents such as vancomycin should be added. Moxifloxacin was less effective than 3rd fluroquinolones agais facultative anaerobic bacteria, it was necessary to change to other regimen when this kind o bacteria was cultured. For all the anaerobic bacteria, moxifloxacin was only effective agains less than 50% of them. And as a result of the resistance of anaerobic bacteria tc moxifloxacin,it was suggested that metronidazole be added as a combination to treat cIAI.