Pharmacokinetic study of HS061, a new human insulin, in non-diabetic rat using ultra performance liquid chromatography–tandem mass spectrometry

HS061, a new structure analogue of human insulin, was investigated for the treatment of diabetes. In this study, we developed a simple and accurate UPLC-MS/MS method for the pharmacokinetic studies of HS061 in non-diabetic rats followed by a full method validation. Following a simple protein precipitation with acetonitrile, the analyte and internal standard (Levemir, IS) were separated on a Waters XBridge™ BEH300 C4 column (100 mm × 4.6 mm i.d., 3.5 μm) with a gradient elution using acetonitrile and 0.2% aqueous formic acid. The method was operated under pseudo-multiple reaction monitoring (pseudo-MRM) in the positive electrospray ionization mode. The monitored transitions were set at m/z 1563.4→1563.4 for HS061 by pseudo-MRM and m/z 1184.7→454.5 for IS by MRM. Linear calibration curves were obtained over the concentration ranges of 10-1000 ng/mL and no interfering peaks were detected at the retention time of HS061 and IS in blank rat plasma. The mean extraction recoveries of HS061 at three concentrations of 20, 100, 800 ng/mL were greater than 95.17%. Stability was assessed under different conditions and no significant degradations were found. The validated method was then successfully applied in measuring HS061 following subcutaneous (0.5, 1.0, 3.0 U/kg) and intravenous (1.0 U/kg) injection in rat plasma to support the pre-clinical pharmacokinetic study. Maximum plasma concentration (Cmax) and area under the curve (AUC) for the subcutaneous doses of HS061 was approximately dose proportional while other pharmacokinetic parameters showed no significant differences among the three doses (p>0.05). The absolute bioavailability of HS061 after subcutaneous administration at 1.0 U/kg was estimated to be 70.40%.