Improvement of oral bioavailability of n-251, a novel antimalarial drug, by increasing lymphatic transport with long-chain fatty acid-based self-nanoemulsifying drug delivery system

Purpose The objective of this study was to improve the absorption behavior of N-251, a novel antimalarial drug, by preparing an appropriate self-nanoemulsifying drug delivery system (SNEDDS). Methods Two different types of SNEDDS formulations, medium-chain fatty acid-based SNEDDS (MC-SNEDDS) and long-chain fatty acid-based SNEDDS (LC-SNEDDS), were prepared based on pseudo-ternary phase diagram, and examined for their in vivo oral absorption behavior in rats. Results Oral dosing of MC-SNEDDS formulations significantly improved the bioavailability (BA) of N-251 compared with N-251 powders. However, its high hepatic extraction limited the BA of N-251 to only 0.49 for MC-SNEDDS B, the best formulation of MC-SNEDDS. LC-SNEDDS formulations, especially LC-SNEDDS F provided the highest BA, 0.65, and successfully attenuated the inter-individual difference in the absorption behavior. Furthermore, it was confirmed that lymphatic transport of N-251 for LC-SNEDDS F was significantly increased up to around 3.19 times larger than that for MC-SNEDDS B. Simulation study suggested that 20 to 39% of N-251 uptaken by the small intestine would be delivered to lymphatic system after oral administration of LC-SNEDDS F. Conclusions SNEDDS formulations significantly improved the absorption behavior of N-251 and long-chain fatty acid-based lipid further improved it by avoiding the hepatic first-pass elimination.