Colon targeting of fluticasone propionate inclusion complex: a novel approach in inflammatory bowel disease

Abstract

Purpose of the present research was to present fluticasone propionate, a glucocorticoid, as a novel formulation exhibiting improved aqueous solubility, and targeting the drug directly to colon for the treatment of inflammatory bowel disease. Inclusion complex of the drug with hydroxypropyl betacyclodextrin were prepared by solvent evaporation and subsequently the granules of the inclusion complex were coated with Eudragit S100, in order to achieve colon targeting. Inclusion complex was characterized by FTIR, DSC, XRD and 1H-NMR studies. In vitro drug release from coated granules and the drug transport across excised rat colon using modified Ussing chamber were also attempted. The drug was found to be present in amorphous form, when included in HPβCD cavities. Furthermore, intrinsic dissolution of the drug was found to increase by ~18 times. Coated granules exhibited no drug release in 0.01 N HCl as dissolution medium, indicating gastro-resistance, while 92 % of the drug was released in 120 min, in phosphate buffer (pH 7.4) as dissolution medium. The drug transport studies with rat colon led to more drug transport and concentration in target tissue, when presented as inclusion complex. The formulation releases the drug with improved aqueous solubility in colonic region, and thus concentrating the drug at the target tissue itself.