Prodrugs components

DI Friedman, GL Amidon. Passive and carrier-mediated intestinal absorption components of two angiotensin converting enzyme (ACE) inhibitor prodrugs in rats Enalapril and fosinopril. Pharm Res 6(12) 1043-1047, 1989. 

Overall, the prodrug approach is a well-established strategy to improve the bioavailability and targeting of pharmacophores, and is a vital component in the development of therapeutics and drug-delivery strategies. 

AstraZeneca also entered a molecule (AZD-3409) (Fig. 4) into phase I/II studies [180]. AZD-3409 is a double prodrug inhibiting both FTase and GGTase I. AZD-3409 is converted in vivo into a prodrug, the main component in plasma of dosed animals, which is further metabolized in cells to the active drug. Recently published phase I data indicate that AZD-3409 was well... 

Because the mechanism of action of sulfasalazine is not related to the sulfapyridine component, and since sulfapyridine is believed to be responsible for many of the adverse reactions to sulfasalazine, mesalamine alone can be used. Mesalamine can be used topically as an enema for the treatment of proctitis, or given orally in slow-release formulations that deliver mesalamine to the small intestine and colon (Table 34—5 and Fig. 34-1). Slow-release oral formulations of mesalamine such as Pentasa release mesalamine from the duodenum to the ileum, with about 75% of the drug passing into the colon. Olsalazine is a dimer of two 5-aminosalicylate molecules linked by an azo bond. Mesalamine is released in the colon after colonic bacteria cleave olsalazine. Balsalazide is a mesalamine prodrug that is enzymatically cleaved in the colon to produce mesalamine. The recommended daily doses of the oral mesalamine derivatives are intended to approximate the molar equivalent of mesalamine present in 4 g of sulfasalazine. At present, snlfasalazine is nsed in preference to oral mesalamine derivatives, mainly becanse it costs mnch less. However, it is not tolerated as well as the mesalamine altematives. Becanse the oral mesalamine formulations are coated tablets or grannies, they should not be crushed or chewed. 

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