Characterization and in vivo evaluation of ketotifen-loaded chitosan microspheres

Ketotifen (KT)-loaded chitosan microspheres (MS) were prepared for controlled release of the antihistaminic drug, and their use as delivery systems in the intraperitoneal cavity of rats was investigated. Microspheres were prepared by a spray-drying method followed by treating with glutaraldehyde solutions in methanol as cross-linker. Results showed that very small spherical microspheres (1.0–1.3 μm) with a high load of KT (92 ± 6 μg KT/mg) were obtained. KT loading decreased with cross-linking (52 ± 2–46 ± 7 μg KT/mg). Interactions between KT and chitosan avoided total KT release from cross-linked MS. After intraperitoneal (i.p.) administration, microsphere aggregations were adhered to muscle subjacent to the tegument and to adipose tissue, and there were no evident sings of rejection; KT was detected in blood stream (0.37–0.25 μg/mL) at 24 h, which was longer than the i.p. administration of the drug in solution (39.4 μg/mL at 2.4 h).