Low Molecular Weight Palmitoyl Chitosan: Synthesis, characterization And Nanoparticle Preparation

Abstract

Low molecular weight chitosan (LMWC) exhibits higher water solubility and produces nanoparticles of fairly low particle size. However, poor drug loading and shorter circulation time in body limits its application in preparation of nanoparticles. Acylation of LMWC ensures extended circulation of nanoparticles in body and hence enhanced bioavailability of the drug. We therefore synthesized the acylated LMWC using palmitoyl chloride and confirmed its synthesis by FTIR and NMR spectroscopy. The nanoparticles of LMWC and low molecular weight palmitoyl chitosan (LMWPC) were prepared by miniemulsion and chemical crosslinking method using glutaraldehyde and 5-fluorouracil (5FU) as a model drug. The nanoparticles were evaluated for particle size, zeta potential, morphology, drug loading and drug release. TEM analysis revealed nanosize and spherical nature of the particles. The palmitoyl chain of LMWPC increased particle size from 83.2±2.5 nm to 93.4±3.2 nm whereas zeta potential of nanoparticles decreased from 12.5±2.2 mV to 4.2±1.1 mV due to diminished amino groups of LMWPC as a result of acylation. The drug loading in nanoparticles was increased from 13.8±0.95% to 30.2±1.9%. LMWC showed 80±2.08% as maximum drug released in 10 h while only 52.3±2.14% was released in 24 h for LMWPC. Hence, LMWPC nanoparticles ensure increased drug loading capacity and sustained drug release profile without significant change in particle size.