Development of a novel tablet-in-capsule formulation of mesalamine for inflammatory bowel disease

Objective: The objective of the present work was to develop a tablet-in-capsule type of multiunit system, which releases the drug in a controlled manner at pre-programmed time intervals.Methods: The system consists of an enteric-coated hydroxypropyl methylcellulose capsule filled with four units of mesalamine minitablets, each of which was further coated with different ratios of Eudragit® E100 and Eudragit® RS100.Results: In vitro evaluation of tablets coated with Eudragit® E100 and Eudragit® RS100 at different pH conditions revealed that at lower pH levels (2.0, 3.6 and 5.5 pH), the drug release is mainly governed by the dissolution of Eudragit® E100 from the Eudragit® E100 and Eudragit® RS100 coat. In vitro evaluation of capsules enteric coated with Eudragit® L100 and Eudragit® S100 revealed that a maximum lag time of 3 h and 4 h was obtained, respectively. In vivo roentgenographic evaluation in rabbits revealed that the developed system remained intact until it reaches the targeted region of the gastro...