Effect of Salbutamol on the Disposition Kinetics of Levofloxacin in the Plasma and Lung of Rats.

Background: Antibiotics and bronchodilator drugs can be used together in respiratory distress caused by bacterial infections. Levofloxacin (LVX) and Salbutamol (SLB) can be used simultaneously in respiratory distress. However, there have been no investigations on how the concurrent use of SLB can affect the pharmacokinetics of LVX in rats.

Objective: The purpose of this study was to investigate the influence of SLB on the plasma and lung pharmacokinetics of LVX in rats.

Methods: A total of 132 rats were randomly assigned to two groups: LVX (n=66) and LVX+SLB (n=66). LVX (intraperitoneal) and SLB (oral) were administered to rats at doses of 50 and 3 mg/kg, respectively. The concentrations of LVX in the plasma and lungs were determined through the utilization of high-performance liquid chromatography along with UV. Pharmacokinetic parameters were assessed by non-compartmental analysis.

Results: The area under the curve from 0 to 16 h (AUC_0-16), terminal elimination half-life, volume of distribution, total body clearance, and peak concentration of LVX in the plasma were 42.57 h*μg/mL, 2.32 h, 3.91 L/kg, 1.17 L/h/kg, and 23.96 μg/mL, respectively. There were no alterations observed in the plasma and lung pharmacokinetic parameters of LVX when co-administered with SLB. The AUC_0-16 lung/AUC_{0-16 plasma} ratios of LVX were 1.60 and 1.39 after administration alone and co-administration with SLB, respectively.

Conclusion: The concentration of LVX in lung tissue was higher than that in plasma. SLB administration to rats did not affect the plasma and lung pharmacokinetics and lung penetration ratio of LVX. There is a need to reveal the change in the pharmacokinetics of LVX after multiple administration of both drugs and after administration of SLB by different routes.