Controls on Polymer Molecular Weight May Be Used To Control the Size of Palmitoyl Glycol Chitosan Polymeric Vesicles

For the first time, to our knowledge, it has been demonstrated that polymeric vesicle size may be controlled by controls on polymer molecular weight. A direct relationship exists between the square root of the palmitoyl glycol chitosan molecular weight and sonicated polymeric vesicle z -average mean diameter ( r = 0.95). Glycol chitosan samples of varying molecular weight were prepared by hydrolysis with 4 M hydrochloric acid and palmitoyl glycol chitosan samples of varying molecular weight synthesized by reacting glycol chitosan with palmitic acid N -hydroxysuccinimide ester. Polymer characterization was carried out by gel permeation chromatography/laser light scattering and 1 H NMR. Vesicles produced from the various palmitoyl glycol chitosan samples by probe sonication in the presence of cholesterol were sized and imaged by transmission electron microscopy. Palmitoyl glycol chitosan samples of MW 276 000, 134 000, 89 000, 28 000, and 31 000 produced unilamellar polymeric vesicles with a z -average mean diameter of 481, 429, 384, 221, and 206 nm, respectively. In addition palmitoyl glycol chitosan vesicles could be prepared from the low molecular weight polymer (MW 28 000) alone in the absence of cholesterol.