Cationic Liposome Colloidal Stability in the Presence of Guar Derivatives Suggests Depletion Interactions May be Operative in Artificial Tears

• Published in: Biomacromolecules Vol. 11; no. 9; pp. 2460 - 2464
• Main Authors: Khanal, Anil, Cui, Yuguo, Zhang, Liang, Pelton, Robert, Ren, Yuanyuan, Ketelson, Howard, Davis, James
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13.09.2010
• Subjects: Anions; Applied sciences; Biological and medical sciences; Borates - chemistry; Borates - metabolism; Colloids - chemistry; Electrolytes - chemistry; Electrolytes - metabolism; Exact sciences and technology; Fatty Acids, Monounsaturated - chemistry; Fatty Acids, Monounsaturated - metabolism; Flocculation; General pharmacology; Liposomes; Medical sciences; Natural polymers; Ophthalmic Solutions - chemistry; Ophthalmic Solutions - metabolism; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Physicochemistry of polymers; Polysaccharides - chemistry; Polysaccharides - metabolism; Quaternary Ammonium Compounds - chemistry; Quaternary Ammonium Compounds - metabolism; Starch and polysaccharides; Tear film; Liquid solid adsorption; Liposome; Boron polymer; Experimental study; Quaternary ammonium compound; Polyelectrolyte; Boric acid; Biomimetics; Ionic strength; Flocculation; Guar gum; Oside polymer; Polyacid; Aqueous solution
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm100655j

The colloidal stability of cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) liposomes was measured in the presence of guar, carboxymethyl guar, hydroxypropyl guar (HPG), and in mixtures of HPG with boric acid. Carboxymethyl guar induced DOTAP aggregation, presumably by bridging flocculation. The interaction with HPG−borate, an anionic polyelectrolyte with labile charge groups, depended on ionic strength. Without added salt, HPG−borate (pH 9.2) adsorbed on the liposomes and destabilized them. In contrast, in 0.1 M NaCl, HPG−borate did not adsorb onto the liposomes. HPG, HPG−borate, and guar induced depletion flocculation of the liposomes at high polymer concentration. Depletion flocculation may be an important mechanism when HPG is employed in artificial tear formulations.