A multiple emulsion method to entrap a lipophilic compound into chitosan microspheres

A new method for preparation of chitosan microspheres loaded with an hydrofobic drug, ketoprofen, was developed. It is an emulsification/solvent evaporation process carried out in mild conditions and particularly useful for thermally sensitive drugs. This method should be additionally combined wit chemical and physical cross-linking in order to modulate drug release. Physical cross-linking was carried out by dry heating chitosan miscrospheres at fixed temperature and for different times. Glutaraldheyde at different concentrations was used as chemical cross-linking agent using microspheres constituted by different theoretical ketoprofen/chitosan ratios (1:2, 1:4, 1:6 w/w). Chitosan microspheres were morphologically characterized for shape, surface characteristics and size distribution.; chitosan/ketoprofen interactions inside the microspheres were investigated by DSC and powder X-ray difractometry. Ketoprofen contents inside the microspheres and in vitro drug release profiles were also determined.