chitosan and plga microspheres as drug delivery ... - UniCA Eprints

7. RFP Loaded PLGA Coated Chitosan Microspheres Obtained by WSD Methodcoating particles. The highest cellular viability was found for particles more concentrated inchitosan while the lowest for the uncoated PLGA particles. Therefore chitosan reducedtoxicity effects of plain PLGA as a consequence of its deposition on the surface of PLGAmicrospheres.10080Viability60402000,1 0,25 0,5 EmptyNo Chit 0,1% Chit 0,25% Chit 0,5% Chit 0,75% Chit RFP SolutionFigure 7.8: Viability Studies of RFP-Loaded PLGA Coated Chitosan Microsferes withA549 Cells7.3. ConclusionPLGA microspheres coated with mucoadhesive polymer were successfully prepared by theemulsion solvent diffusion methods in water (WSD). The surface coating of microsphereswith chitosan, was confirmed by the change in zeta potential. The excellent mucoadhesionproperties of chitosan-coated PLGA microspheres were proved by their significant adsorptionto the mucin solution mainly due to the electrostatic attraction between the amino groups ofchitosan and the negatively charged mucin. The chitosan-coated PLGA microspheres, whichimproved the RFP loading, were applied to improve the pulmonary delivery of the drug bynebulization. The particle diameter of the aqueous dispersion of the microspheres was animportant factor to enclose the particles in the aerosolized aqueous droplets produced with thenebulizer.The elimination rate of chitosan-modified microspheres from the lungs can decreasesignificantly due to the mucoadhesive property after pulmonary administration compared tothat of the unmodified microspheres. Furthermore, it was supposed that chitosan on thesurface of the microspheres enhances the drug absorption by opening the intercellular tightjunctions in the lung epithelium. These findings demonstrated that the chitosan-modified116