Formation of positively charged poly(butyl cyanoacrylate) nanoparticles stabilized with chitosan

To investigate the formation of positively charged nanoparticles (NP) stabilized with chitosan, positively charged poly(butyl cyanoacrylate) (PBCA) NP were prepared by emulsion polymerization in the presence of chitosan as a polymeric stabilizer at low pH. The effect of physicochemical factors such as the pH, the concentration and the volume of the chitosan solution, the chitosan molecular weight and the temperature on the mean particle size and the turbidity of PBCA-NP was investigated. Particle size was determined using a transmission electron microscope. The chemical interaction between chitosan and PBCA was identified by Fourier transform infrared (FT-IR) spectroscopy and the grafting percentage at various pH values was determined. The zeta potential of PBCA-NP coated with chitosan was determined from the electrophoretic mobility in 10 mM NaCl. The pH, the concentration and the volume of the chitosan solution and the molecular weight of chitosan were shown to be important factors in controlling the mean particle size of NP in the range 10-100 nm. FT-IR spectra indicated that chitosan was covalently linked to PBCA and the maximum grafting percentage reached about 120% w/w at pH 2.0. Nimodipine as a model drug was successfully incorporated into chitosan-stabilized PBCA-NP with a mean particle diameter of 31.6 nm. PBCA-NP coated with chitosan carried a positive charge. The results indicate that positively charged NP may be produced in the presence of cationic polysaccharide chitosan and might increase their potential use as a targeting drug delivery system.