INFLUENCE OF CROSS-LINKING ON THE ACID STABILITY AND PHYSICOCHEMICAL PROPERTIES OF CHITOSAN MICROSPHERES

The aim of the present study was to improve the acid stability of chit osan microspheres and to investigate the influence of chemical crossli nking on essential physicochemical properties. For this purpose, previ ously manufactured microspheres were crosslinked by glutardialdehyde. The influence of glutardialdehyde concentration and crosslinking time on the microsphere size, surface charge, drug loading (with prednisolo ne sodium phosphate), acid stability, raid influenced by the concentra tion of glutardialdehyde and the process time. Size and acid stability increased with increasing influenced by the concentration of glutardi aldehyde and the process time. Size and acid stability increased with increased glutardialdehyde concentrations whereas drug loading was red uced. Acid stability as well as loading efficacy also decreased with i ncreasing reaction time. Size was not influenced by reaction time. The surface charge was not changed by the crosslinking process. Non-cross linked as well as crosslinked microspheres caused no haemolytic effect , indicating good biocompatibility.