Efficient Intestinal Digestion and on Site Tumor‐Bioactivation Are the Two Important Determinants for Chylomicron‐Mediated Lymph‐Targeting Triglyceride‐Mimetic Docetaxel Oral Prodrugs

Abstract The oral absorption of chemotherapeutical drugs is restricted by poor solubility and permeability, high first‐pass metabolism, and gastrointestinal toxicity. Intestinal lymphatic transport of lipophilic prodrugs is a promising strategy to improve the oral delivery efficiency of anticancer drugs via entrapment into a lipid formulation and to avoid first‐pass metabolism. However, several basic principles have still not been clarified, such as intestinal digestibility and stability and on‐site tumor bioactivation. Herein, triglyceride‐mimetic prodrugs of docetaxel (DTX) are designed by conjugating them to the sn‐2 position of triglyceride (TG) through different linkage bonds. The role of intestinal digestion in oral absorption of TG‐like prodrugs is then investigated by introducing significant steric‐hindrance α‐substituents into the prodrugs. It is surprisingly found that poor intestinal digestion leads to an unsatisfactory bioavailability but efficient intestinal digestion of TG‐like prodrugs with a less steric‐hindrance linkage (DTX‐S‐S‐TG) facilitating oral absorption. Moreover, it is found that the TG‐like reduction‐sensitive prodrug (DTX‐S‐S‐TG) has good stability during intestinal transport and blood circulation, and on‐demand release of docetaxel at the tumor site, leading to a significantly improved antitumor efficiency with negligible gastrointestinal toxicity. In summary, the chylomicron‐mediated lymph‐targeting triglyceride‐mimetic oral prodrug approach provides a good foundation for the development of oral chemotherapeutical formulations.