OBJECTIVE To investigate the effect of deacetylation degree (DD) and molecular weight (Mr) of chitosan (CS) on the properties
of CS
nanoparticles (CS-NP) in vitro in order to optimize the formulation of CS-NP. METHODS CS-NP was prepared by ionic crosslinkage process using different chitosan with various DD and Mr, and norcanthardin (NCD) was used as a model drug. The properties of CS-NP, such as the appearance, average size, Zeta potential, encapsulation efficiency (EE), loading capacity (LC) and the drug release rate in vitro, were detected,respectively. RESULTS All CS-NP were spherical with narrow size distribution. With the decrease of DD of CS, the average size of CS-NP was increased while the Zeta potential, the EE and LC of NCD were all decreased. With the decrease of Mr of CS, the average size of the CS-NP was reduced correspondingly while the zeta potential, the EE and LC were not changed significantly. Both decrease of DD and MW of CS rendered the speed-up of the release rate of NCD from the CS-NP in vitro. . CONCLUSION Both DD and Mr of CS no-lablely affected on the properties of the CS-NP in vitro. By the adjustment of the two
molecular parameters, CS-NP with various average size and drug release rate could be obtained.