USP DISSOLUTION-APPARATUS-III (RECIPROCATING CYLINDER) FOR SCREENING OF GUAR-BASED COLONIC DELIVERY FORMULATIONS

The reciprocating cylinder dissolution apparatus (USP Dissolution Appa ratus III) was used to evaluate performance of several colonic deliver y systems. Its dissolution tubes move between successive rows of vesse ls, allowing delivery systems to release drug in different media seque ntially, i.e. simulated gastric fluids, simulated intestinal fluids, a nd simulated colonic fluids (SCF). The objective of this study was to assess USP dissolution apparatus III using formulations based on guar gum, a galactomannan polysaccharide. Drug (dexamethasone or budesonide ) release in SCF was markedly increased at galactomannanase concentrat ions >0.01 mg/ml. The galactomannanase concentration and dipping speed s in the SCF were adjusted to produce dexamethasone release profiles s imilar to those estimated from absorption data in vivo. Thus, this dis solution setup may have predictive value for in vivo colonic delivery using guar gum-based colonic dosage forms.