Visualized triglyceride mimetic prodrugs: Preparation, effect evaluation and mechanistic investigation of lymphatic transport

Triglyceride-mimetic prodrugs are prepared by conjugating a triglyceride moiety to the parent drug, which promotes lymphatic transport, reduces hepatic first-pass metabolism, and enhances the oral bioavailability of the parent drug. To verify its lymphatic transport propensity, this study used 20-hydroxyprogesterone as the model parent drug. Fluorescent dyes were virtually screened via molecular docking, and the candidate dyes were stably conjugated to the linker of the triglyceride-mimetic prodrug by chemical synthesis. A fluorescently labeled, in vivo visualizable triglyceride-mimetic prodrug was prepared, and its in vivo fate was traced using fluorescence imaging combined with cellular and protein-level assays. The visualized prodrug was specifically absorbed in the duodenum and preferentially accumulated in mesenteric lymph node, thereby reducing hepatic first-pass metabolism. Using a Caco-2 cell monolayer model, it was further confirmed that the prodrug was taken up by intestinal epithelial cells through macropinocytosis, and then participated in the assembly of chylomicrons (CM) under the synergistic effect of the endoplasmic reticulum and Golgi apparatus, before being secreted out of the cells loaded in CM. The strategy of this study enables the visualization of the biotransformation process without encapsulating drugs or fluorescent probes in particulate delivery systems. It provides a practical example for the fluorescent labeling of triglyceride-mimetic prodrugs, and offers a replicable methodological reference for investigating the in vivo fate of similar drugs with strong first-pass effects.