Separation of polyethylene glycols and maleimide‐terminated polyethylene glycols by reversed‐phase liquid chromatography under critical conditions

Abstract

The separation of polyethylene glycols and maleimide-substituted polyethylene glycol derivatives based on the number of maleimide end-groups under critical liquid chromatography conditions has been investigated on a reversed-phase column. The critical solvent compositions for nonfunctional polyethylene glycols and bifunctional maleimide-substituted polyethylene glycols were determined to be identical at about 40% acetonitrile in water on a reversed-phase octadecyl carbon chain-bonded silica column using mixtures of acetonitrile and water of varying composition as the mobile phase at 25°C. The maleimide-functionalized polyethylene glycols were successfully separated according to maleimide functionality (with zero, one, two, or three maleimide end-groups, respectively) under the critical isocratic elution conditions without obvious effect of molar mass. The separation was mainly due to the hydrophobic interaction between the maleimide end-groups and the column packing. Off-line matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify the repeating units and, especially, the end-groups of the maleimide-substituted polyethylene glycols. Liquid chromatography analysis at critical conditions could provide useful information to optimize the synthesis of functional polyethylene glycols. To our knowledge, this is the first report of the baseline separation of maleimide-functionalized polyethylene glycols based on the functionality independent of the molar mass without derivatization by isocratic elution.

Separation and characterization of benzaldehyde-functional polyethylene glycols by liquid chromatography under critical conditions

“…34 The critical compositions for non-functional PEGs were obtained at 40% acetonitrile in water from an XB-C18 column at 25 °C. 35 The effect of the composition of the mobile phase ( percentage of acetonitrile in water) on the retention of PEGs and benzaldehyde-substituted PEGs due to the interaction between PEGs and XB-C18 column packing was investigated and is shown in Fig. 3.…”

Ultra‐high‐performance liquid chromatography with tandem mass spectrometry method for cellular toxicity and pharmacokinetic study of PEG1K polymers

“…Due to their non‐immunogenic and non‐antigenic properties, PEG polymers have been approved by the Food and Drug Administration (FDA) for pharmaceutical applications [6–8]. The favorable properties of PEG polymers have facilitated their applications in drug delivery systems to improve their water solubility and prolong their half‐life in vivo [9–13]. Investigations of the cellular toxicity and pharmacokinetic behavior of PEG are needed and helpful for revealing the efficiency and toxicity of PEGylated drug delivery systems in preclinical and clinical applications.…”

Recent advances in the bioanalytical methods of polyethylene glycols and PEGylated pharmaceuticals

“…One of the major benefits of PEGylation is to prolong the in vivo circulation time of the modified pharmaceuticals, shielding them from biological inactivation by proteolysis or metabolism, which means dosage reduction and improvement of the patients’ compliance by reducing the times of injections [16–20]. Moreover, PEGylation can also enhance the aqueous solubility of the modified therapeutic agents as well as reduce the risk of immunogenicity of some biopharmaceuticals [1,19,21–26].…”