Examples of the Prodrug Approach

There have been numerous examples of the application of the prodrug approach to improve the oral bioavailability of drugs subject to extensive presystemic metabolism, with varying degrees of success. Some selected examples of prodrugs and the results observed are summarized in Table 1 and are discussed below. Also included in Table 1 are some examples of peptides for which the prodrug approach was utilized to potentially improve oral or transmucosal delivery by reducing metabolic degradation....

Application to Functional Groups

There are four functional groups found in drug molecules for which the greatest number of promoieties have been designed, synthesized, characterized (solubility, stability, purity), and evaluated in diffusion cell experiments. These four functional groups are the amide or imide (O C-NH), the thioamide (S C-NH), the hydroxy group (OH) substituted on aliphatic or aromatic carbons, and the carboxylic acid (O C-OH) mentioned above. For each functional group there are two general types of...