A PK/PD approach on the effects of clarithromycin against oral and nasal microbiota of healthy volunteers

Abstract

Objective: To assess the pharmacokinetics of clarithromycin (CLR) and its effects oil oral and nasal microbiota in healthy volunteers in an open, randomized, two-period crossover design. Methods: A single 500 mg oral dose of CLR (Group 1: Merck Group 2: Klaricid) was administered observing a 1-week interval between doses. Blood samples were collected from pre-dose to 24 h. plasmatic concentrations of CLR were quantified by the LC-MS-MS method. Saliva and nasal mucosa swabs were obtained previously and after 1.33, 2, 6 and 12 11 of drug administration. Pharmacokinetics and PK/PD (t>MIC, %t>MIC and AUC(0-24)/MIC ratio) parameters were estimated. The microogranism counts were obtained on different Culture media. Results: No statistically significant differences were observed between the two formulations (p>0.05) regarding the pharmacokinetic parameters. Total microorganisms, staphylococci and streptococci counts did not show statistical differences (p>0.05) between the two groups during each sampling time. Considering the microorganisms of each group, no statistically significant differences were found after drug administration, but all differed from pre-dose Counts (p<0.05). The observed t>MIC ranged from 14.45 h (+/- 1.69) to 1.19 h (+/- 2.17) considering MICs of 0.25 mu g/ml and 2.0 mu g/ml, respectively. There was no correlation between any t>MIC %t>MIC or AUC(0-24) and bacterial reduction (between 0- and 12-h periods), However, the profile or reduction Of Microorganisms in both saliva and nasal samples were compatible with high values of %t>MIC verified for both clarithromycin formulations. Conclusion: Both formulations of clarithromycin had similar pharmacokinetics and efficacy.