Nanocrystals with different stabilizers overcome the mucus and epithelial barriers for oral delivery of multicomponent Bufadienolides.

Using nanocrystals (NCs) technology may be a promising drug delivery strategy for oral administration of multicomponent anticancer drugs. However, the intestinal epithelium and the mucus layer on the intestine extremely limited drug transport and absorption by orally. In this study, we selected multicomponent inartificial compound Bufadienolides (BU) with broad spectrum antitumor activity as the model drug to prepare BU NCs with different stabilizers by wet grinding, and explored the efficiency of penetrating through the mucus layer and transporting intestinal epithelial cells in vitro and ex vivo. Results revealed that BU NCs can dramatically improve dissolution behavior synergistically and the efficiency of mucus permeation. Besides, we found that BU NCs with different stabilizers enhanced cellular uptake, which was mainly attributed to increasing or changing the endocytosis pathway and plasma membrane/Endoplasmic reticulum (ER) pathway involved in the transmembrane transport of NCs. Furthermore, BU NCs could definitely improve intestinal absorption efficiency and change the absorption site of BU ex vivo. This multi-angle exploration will provide reference for the development of BU oral delivery formulations.