Pharmacokinetic/pharmacodynamic comparison between generic and brand-name levofloxacin based on Monte Carlo simulation

Objective: Generic medications are widely used because of their low cost. However, some generic medications show lower quality and clinical efficacy compared with brand-name medications, especially for antimicrobial drugs. Levofloxacin is a fluoroquinolone antimicrobial drug with excellent antimicrobial activity and wide antimicrobial spectrum, while it is susceptible to drug resistance. Our study aims to evaluate the bioequivalence of generic and brand-name levofloxacin.Methods: The pharmacokinetic (PK) parameters (C max , AUC 0 similar to 24 , T max , and t 1/2 ), pharmacodynamic (PD) parameters (in vitro antibacterial activity and the inhibition of resistant mutation), and PK/PD analysis (the probability of target attainment; the cumulative fraction of response) calculated by Monte Carlo simulation were investigated.Results: Our results demonstrated that compared with generics, brand-name levofloxacin not only had higher drug content, it also showed higher antimicrobial susceptibility, higher resistance to mutation ability, and higher percentage of each dosage interval wherein plasma concentration of antimicrobial agents exceeded the MPC 90 (mutant prevention concentration to prevent the mutation of 90% strains) against various clinical isolates. Although the differences in AUC 0 similar to 24 between brand-name levofloxacin and generics were not statistically significant ( P > 0.05, F test), Monte Carlo simulation results showed cumulative fraction of response values for PK/PD of brand-name medications were higher than generics.Conclusion: Our results indicated that PK or PD equivalence did not imply therapeutic equivalence; thus, we suggest including PK/PD analysis in the bioequivalence evaluation system, which benefits prediction of clinical outcome with high application value.(c) 2023 The Authors. Published by Elsevier Ltd on behalf of International Society for AntimicrobialChemotherapy.This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )