Physicochemical properties and blood compatibility of acylated chitosan nanoparticles

Chitosan was N-acylated with butanoic, hexanoic and benzoic anhydride under homogeneous conditions in the presence of methanol. The degree of substitution of N-acyl chitosans was determined by H-1-NMR. The N-acyl chitosan nanoparticles were prepared by the addition of tripolyphosphate anions. Freeze-dried N-acyl chitosan nanoparticles were then analyzed for particles size, zeta potential, and blood compatibility. The N-acyl chitosan nanoparticles were in the range of 200-360 nm and positively charged (10-20 mV) in a saline solution after freeze-drying. It was found that long and bulky acyl groups hinder hydrogen bonding and prevent aggregation. Hemolysis and thromboelastography showed that the N-acyl chitosan nanoparticles were blood compatible. (C) 2004 Elsevier Ltd. All rights reserved.