Chitosan microparticles for the controlled delivery of fluoride

Abstract Objectives To manufacture and characterise chitosan/fluoride microparticles prepared by spray drying and assess their utility as controlled release vehicles for fluoride. Methods Microparticles were manufactured from dispersions containing 1.0% and 2.0% (w/v) chitosan and 0.20% or 0.40% (w/v) NaF in the absence/presence of glutaraldehyde. Particle size distributions were determined using laser diffraction; fluoride loading and release were determined by ion-selective electrode. Release profiles were studied in isotonic media (pH 5.5) over 360 min; microparticles exhibiting greatest cumulative fluoride release were further evaluated at pH 4.0 and 7.0. Particle morphology was investigated using environmental scanning electron microscopy. Bioadhesion parameters were determined with a texture-probe analyser. Results Microparticles exhibited low polydispersity and volume mean diameters (VMDs)