Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications

A rapid, sensitive and selective pseudo MRM（p MRM）-based method for the determination of solutol HS15（SHS15） in rat plasma was developed using liquid chromatography/tandem mass spectrometry（LC–MS/MS）. The most abundant ions corresponding to SHS15 free polyethyleneglycol（PEG）oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for p MRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector（ELSD）. Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community,where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities（NCEs） to address the spiky plasma concentration profiles.