Pharmacokinetics and bioavailability assessment of Miltefosine in rats using high performance liquid chromatography tandem mass spectrometry.

Miltefosine (MFS) is the first effective oral drug for treatment of visceral, mucosal and cutaneous leishmaniasis. In this study, liquid chromatography coupled mass spectrometry (LC-MS/MS) method of MFS was validated in rat plasma and its practical utilization to pharmacokinetic studies in rats for the first time. A rapid, selective and sensitive LC-MS/MS method for MFS in rat plasma was linear over the calibration range of 1-500ng/mL. MFS and Phenacetin (internal standard) were separated on Phenomenex Luna 3μ HILIC 200A (150×4.6mm) column under isocratic condition using methanol: 0.1% formic acid in triple distilled water, 90:10 (v/v) mobile phase at a flow rate of 0.8mL/min. The total chromatographic run time was 4.0min. The intra- and inter-day assay accuracy was observed between 99.45-102.88% and 99.92-101.58%, respectively. The intra- and inter-day assay precision was observed between 2.68-5.54% and 2.35-5.94%, respectively. The validated assay was practically applied to determine the plasma concentrations after oral and intravenous administration of MFS to rats. After oral administration, MFS showed Cmax (3200.00±95.39ng/mL) was observed at 12.00h (tmax) and t1/2 was 102.36±16.65h. The absolute bioavailability of MFS was 60.33±2.32%.