Effect of molecular weight of chitosan on quercetin-loaded chitosan nanoparticles

The widespread use of quercetin is limited by its instability, low solubility and poor oral bioavailability. Encapsulation of quercetin using a nanoparticle delivery system is an effective way to overcome these drawbacks.

The effect of the molecular weight (M_w) of chitosan (CS) (100, 200, 500 and 1000 kDa) on quercetin-loaded chitosan nanoparticles (QCNPs) was investigated. The structure, stability, release properties and antioxidant activities of the nanoparticles (QCNP-10, QCNP-20, QCNP-50 and QCNP-100) were assessed. Particle size of QCNPs decreased and polydispersity index increased with the increasing M_w of CS. The main forces involved in the formation of QCNPs were hydrogen bonding and hydrophobic interaction. X-ray diffraction verified that quercetin was loaded into CS nanoparticles. The photostability and thermal stability of QCNPs increased with increasing M_w of CS. QCNP-100 exhibited the lowest release rate in a mixture of water and anhydrous ethanol. The antioxidant activities of QCNPs were enhanced with increasing M_w of CS, and QCNP-100 possessed the highest antioxidant activities, which might be relevant to its smallest particle size.

Overall, these results revealed that the M_w of CS affected the properties of QCNPs, and QCNP-100 possessed the smallest particle, best stability, lowest release rate and highest antioxidant activities. © 2024 Society of Chemical Industry.