Salicylic acid release from chitosan pellets coated with polylactide

The aim of the study was to prepare a bi-polymer drug carrier composed of chitosan pellets (CS) coated with polylactide shell (PLA) providing prolonged model drug – salicylic acid (SA) release into phosphate buffer of pH = 7.2. Pellets were obtained through a coacervation followed by a freeze-drying process. In a terms of model drug loading, porous pellets were impregnated with a SA solution under vacuum. Afterwards, loaded and dried beads were coated with PLA films through their dipping in a PLA organic solution. FTIR spectroscopy was implemented to analyse the efectiveness of SA loading process. The UV-Vis spectrophotometry kinetic studies of a model drug release from PLA coated and non-coated pellets into phosphate buffer were conducted. Increasing time of CS pellets impregnation with SA solution resulted in decrease of salicylic acid release rate.This tendency was more evident for the SA release from pellets coated with an additional layer of PLA. Model drug release kinetic points were well approximated with first order kinetics model.