Characterization of polymer micelles with hemocompatibility based on N-succinyl-chitosan grafting with long chain hydrophobic groups and loading aspirin

Blood compatibility exerts an essential role in designing medical materials. The negative surface charge possessed by N-succinyl-chitosan (SCCS) has the benefit of being nonthrombogenic. To enhance the self-aggregation of SCCS, 2-hydroxy-3-(octadecyloxy) propyl groups (HOP) were employed as hydrophobic groups on SCCS to synthesise amphiphilic chitosan derivatives (HOPSCCS). The degree of succinyl substitution (DS) significantly influenced the water solubility of SCCS. Due to the intermolecular electrostatic attraction, SCCS (H-DS39.1) was water-insoluble, while SCCS (HDS67.51, 78.6) were water-soluble. The substitution degree of HOP was 0.99-4.05%. The size of HOPSCCS micelles mainly ranged from 117 nm to 194 nm, and their critical micelle concentrations (CMC) were in the range of 1.42-4.24 x 10(-3) mg mL(-1), and their surface had a negative charge ranging from -27.0 mV to -35.6 mV, suggesting that they possessed excellent stability and dispersion stability which was beneficial to prolong their circulation half-life and reduce the frequency of drug use. Aspirin was encapsulated into HOPSCCS, and the value of maximum drug loading capacity (LC) reached 18.5%, indicating that it can be an effective vehicle for aspirin and a good strategy for the use of aspirin. (1)H NMR confirmed the aggregation behaviour of the micelles. Aspirin-loaded HOPSCCS, HOPSCCS/aspirin mixture and the influence of DS of SCCS on order structure were measured by FTIR. Thermal behaviour was determined by DTA/TG. Anticoagulant assays indicated that HOPSCCS had a slight anticoagulant property. Cell toxicity assessment, anticoagulant assays and hemolysis test suggested that HOPSCCS possessed low cytotoxicity and excellent hemocompatibility as a potential drug carrier for systemic administration and therapy of some blood diseases.