Targeted delivery of drugs to the colon has been employed to achieve one or more of four objectives. The desired outcomes can be (i) sustained delivery to reduce dosing frequency; (ii) to delay delivery to the colon to achieve high local concentrations in the treatment of diseases of the distal gut; (iii) to delay delivery to a time appropriate to treat acute phases of disease (chronotherapy or chronopharmaceutics) and historically, (iv) to deliver to a region that is less hostile metabolically, e.g., to facilitate absorption of acid and enzymatically labile materials, especially peptides. Further commercial benefits are the extension of patent protection and the ability to promote new claims centered on the provision of patient benefits such as increased effectiveness and the optimization of dosing frequency.