Liposomes are an important class of colloidal drug delivery systems, yet the clinical applications of conventional liposomes can be hampered by poor colloidal and biological stabilities. In this work, a sugar-based, PEGylated amphiphilic macromolecule (AM) was evaluated for its ability to stabilize dipalmitoyl phosphatidylcholine (DPPC)-based liposomes. Compared to unmodified liposomes, AM-stabilized liposomes exhibited enhanced colloidal stability, maintaining relatively constant particle sizes for 5 weeks without aggregation. AM-stabilized liposomes also showed significantly decreased membrane permeability, even in the presence of serum. Finally, AM-stabilized liposomes displayed improved biological stability, significantly inhibiting phagocytosis by macrophages. Overall, the effectiveness of AM to stabilize liposomes was comparable to a conventional stabilizing agent, PEG-modified phosphatidylethanolamine. Based upon these results, AM is a promising stabilizing agent for colloidal drug delivery applications and currently being optimized. (C) 2014 Elsevier Inc. All rights reserved.