12 13 Lymphatic transport allows extraordinary gains in bioavailability and efficacy through avoidance of first-pass hepatic metabolism and drug preservation in lymphatic tissues, mainly mesenteric lymph nodes (MLNs), which have proven critical in the improvement of oral bioavailability by SMEDDS. 8вЂ“11 The effectiveness of SMEDDS is highlighted by several successful, marketed products, such as Sandimmune Neoral. 4вЂ“7 Self-microemulsifying drug delivery systems (SMEDDS), which are considered ideal alternative oral drug delivery carriers, have attracted increasing attention owing to their potential to promote drug transport into the intestinal lymphatics. To overcome this challenge, various nanocarriers, including nanoparticles, micelles, liposomes, and nanoemulsions, have been designed for targeted delivery of immunomodulators to the lymph nodes. 3 However, because of the structure and anatomy of lymph nodes as well as the distinct localization and migration of the different cell types within them, it is challenging to access the lymphatics via traditional drug delivery routes via the blood circulation. 2 Therefore, strategies that deliver immunomodulators directly to lymph nodes provide an opportunity to modify the adaptive immune response, thereby improving cancer immunotherapeutic outcomes. 1 Lymph nodes play a critical role in the adaptive immune system, which organizes lymphocyte (LYM) accumulation, activation, and proliferation.

Cancer immunotherapeutic strategies require engagement with immune cells, which are unevenly distributed in the body and concentrated in the lymph nodes and lymphoid organs. An ever-growing understanding of immune system regulation and activation in tumors has driven the exploration of targeted and immune-based cancer therapies.

Abdominal lymph nodes