Design, development and optimization of a novel time and pH-dependent colon targeted drug delivery system.

The aim of present study was to develop a time- and pH-dependent system for delivering mesalamine to the colon. The system consists of the core tablet of mesalamine which is compression coated with hydroxypropyl methylcellulose (HPMC K4M) (time-dependent factor). This is then coated with pH-dependent polymer Eudragit L100.