A study of the pharmacokinetics of moxifloxacin by the dynamics of its distribution in the blood plasma and saliva of healthy volunteers: a comparative analysis and possible extrapolation methods

Abstract

Abstract Objectives The pharmacokinetics of moxifloxacin in plasma and saliva was investigated in this study. Methods The pharmacokinetics of two specialty drugs of moxifloxacin – reference (Ref) and test (Test) preparation – was studied in 18 healthy volunteers after a single oral dose of 400 mg. Results It was found that the concentration of moxifloxacin in saliva 3–24 h after taking the drugs was statistically significantly higher than that in plasma. A high correlation was observed between the concentration of moxifloxacin in plasma and saliva of volunteers after taking of Ref and Test. Some pharmacokinetic parameters, calculated by the concentration of moxifloxacin in saliva and plasma, are statistically different. A technique is proposed for extrapolating the concentration of moxifloxacin in plasma according to its concentration in saliva using the established linear relationship between the moxifloxacin in plasma and saliva of volunteers in time interval of 3–24 h after taking Ref. Based on the obtained extrapolated concentration of moxifloxacin, the pharmacokinetic parameters were calculated for two studied drugs and did not statistically differ from the parameters calculated according to the data in plasma. Conclusions The developed method of concentration extrapolation allows the use of saliva for pharmacokinetic studies of the tablet preparations of moxifloxacin.