Preparation and characterization of acetylated starch nanoparticles as drug carrier: Ciprofloxacin as a model.

The objective of this study was to characterize in-vitro the potential of acetylated corn starch (ACS) particles as a matrix for the delivery of ciprofloxacin (CFx). ACS was successfully synthesized and optimized by the reaction of native corn starch using acetic anhydride and acetic acid with low and high degrees of substitution (DS). The nanoprecipitation method was applied for the formation of the ACS-based nanoparticles, by the dropwise addition of water to acetone solution of ACS under stirring. The effects of acetylation and nanoprecipitation on the morphology and granular structure of ACS samples were examined by the FT-IR, XRD, DSL and SEM techniques. The efficiency of CFx loading was also evaluated via encapsulation efficiency (EE) in ACS nanoparticles. The average degree of acetyl substitution per glucose residue of corn starch was 0.33, 2.00, and 2.66. The nanoparticles size of the ACS and ACS-loaded with CFx were measured and analyzed relative to the solvent:non-solvent ratio. Based on the results, ACS nanoparticles with DS of 2.00 and water:acetone of 3:1 had 312nm diameter. Increasing DS in starch acetate led to increase in the EE from 67.7 to 89.1% and with increasing ratio of water/acetone from 1:1 to 3:1, the EE raised from 48.5 to 89.1%. X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation.