PREPARATION AND PHYSIOCHEMICAL CHARACTERIZATION OF CHITOSAN NANOPARTICLES FOR CONTROLLED DELIVERY OF OXYTOCIN

This study aimed to characterize and evaluate chitosan nanoparticles (CSNPs) as a carrier system for the hormone, oxytocin. Ionotropic gelation was the technique used to synthesize the CSNPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed narrow particle size distribution of 30-50 nm and spherical particle shape. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), thermal gravimetric / differential thermal analysis (TGA / DTA) and Fourier Transform Infrared Spectroscopy (FTIR) were used to evaluate possible drug-polymer interactions. Data obtained from X-ray diffraction (XRD) showed a decrease in crystallinity due to the disruption of the intramolecular / intermolecular chitosan network and a molecular level of oxytocin dispersion in the O-CSNP matrix. Differential scanning calorimetry (DSC) exhibited further evidence of drug-polymer interaction through observed endothermic shifts. Fourier-transform-infrared (FT-IR) spectra obtained confirmed the presence of oxytocin within the CSNP matrix as well as further proof of the intermolecular interactions existing between oxytocin and chitosan. Loading and release profiles of the O-CSNPs were conducted using LC/MS. The effect of nanoparticle size and oxytocin concentration was shown to affect drug loading capabilities and the release behaviour of the O-CSNPs under physiological conditions. In vitro release studies were also performed on the O-CSNPs, which exhibited an initial burst effect followed by first-order rate kinetics of oxytocin release from the system. In this work, CSNPs are presented as a potential carrier system for the extended release of oxytocin, thereby improving the efficacy of the hormone in the treatment of neurological disorders.