Development of Drug Delivery Systems from Vegetal Proteins: Legumin Nanoparticles

Abstract Legumin (storage protein from Pisum sativum L.) nanoparticles of about 250 nm were prepared by means of a pH-coacervation method and chemical cross-linking with glutaraldehyde. This preparative method enabled to avoid the use of organic solvents but only yielded about 27% of protein added as nanoparticles. No significant differences in size, percentage yield, and surface charge were obtained between legumin nanoparticles cross-linked with different glutaraldehyde concentrations. Legumin nanoparticles were quite stable in phosphate-buffered saline (PBS). They follow a zero-order degradation, and by increasing glutaraldehyde concentration, a longer half-life (t50) was obtained. The amount of methylene blue (MB), used as a model of hydrophilic drug, loaded was about 6.2% of the initial dye. Its release from the nanoparticles consisted of a rapid initial phase followed by a slower second period. The rates in this second phase were inversely related to the degree of cross-linking.