Abstract
A simple, sensitive, and specific reverse phase high performance liquid chromatography (RP-HPLC) method was developed and validated for the quantification of Milnacipran HCl in rabbit plasma. Milnacipran HCl and internal standard (IS, Venlafaxine HCl) were extracted by protein precipitation method with chloroform. The separation was performed on a HiQ sil C18 column (250 mm × 4.6 mm i.d., 5 µm). The wavelength was set at 220 nm. The mobile phase was a mixture of potassium dihydrogen phosphate buffer (0.0125 M) and acetonitrile (72:28%, v/v) with 0.20% triethylamine at a flow rate of 1.0 mL/min. The pH of the solution was adjusted to 3.65 with 0.1 M orthophosphoric acid. The calibration curve was linear over the concentration range 0.1–25 µg/mL. The intra-day and inter-day precision was ranged from 3.9 to 7.3% and 5.2 to 10.8%, respectively. Finally, this proposed method was successfully applied to rabbit pharmacokinetics study and yielded the most comprehensive data on systemic exposure of Milnacipran HCl to date.