Nanoparticles Obtained from Zein for Encapsulation of Mesalazine.

We encapsulated MSZ in zein nanoparticles (NP-ZN) using a desolvation method followed by drying in a mini spray dryer. These nanoparticles exhibited a size of 266.6 ± 52 nm, IPD of 0.14 ± 1.1 and zeta potential of -36.4 ± 1.5 mV, suggesting colloidal stability. Quantification using HPLC showed a drug-loaded of 43.8 µg/mg. SEM demonstrated a spherical morphology with a size variation from 220 to 400 nm. A FTIR analysis did not show drug spectra in the NPs in relation to the physical mixture, which suggests drug encapsulation without changing its chemical structure. A TGA analysis showed thermal stability up to 300 °C. In vitro release studies demonstrated gastroresistance and a sustained drug release at pH 7.4 (97.67 ± 0.32%) in 120 h. The kinetic model used for the release of MSZ from the NP-ZN in a pH 1.2 medium was the Fickian diffusion, in a pH 6.8 medium it was the Peppas-Sahlin model with the polymeric relaxation mechanism and in a pH 7.4 medium it was the Korsmeyer-Peppas model with the Fickian release mechanism, or "Case I". An in vitro cytotoxicity study in the CT26.WT cell line showed no basal cytotoxicity up to 500 μg/mL. The NP-ZN showed to be a promising vector for the sustained release of MSZ in the colon by oral route.