Development of HPLC-CAD stability indicating assay method for polyethylene glycol-conjugated phospholipid (DMPE-PEG...

The study introduces first report on a liquid chromatographic method for the quantification of 1,2-Dimyristoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] ammonium salt (DMPE-PEG 2000), which is an important constituent of lipid-based nanoparticles. It involves an HPLC-CAD stability-indicating assay method development for DMPE-PEG 2000 and structure elucidation of its degradation products. Hypersil Gold™ PFP column (150 mm × 4.6 mm, 3.0 μm) was used to achieve the separation among DMPE-PEG 2000 and its degradation products using 0.0025% formic acid in water: methanol (80:20 v/v) as mobile phase A and methanol: acetonitrile (60:40 v/v) as mobile phase B in a gradient elution mode. The method was validated for precision, linearity, sensitivity, solution stability and robustness. Relative standard deviations for the intra-day precision, inter-day precision and sensitivity were 1.6%, 0.6% and 3.8%, respectively. The method was linear in the range from 210 μg/mL to 390 μg/mL with R² value of 0.996. Further, the solution stability of DMPE-PEG 2000 was evaluated under different stressed and storage conditions to understand the impact of any excursion to its regular storage temperature of -20 °C. The observed degradation products were identified through liquid chromatography high resolution mass spectrometry and a tentative pathway was proposed for the generation of these degradants.