Optimizing drug delivery to the lymphatic system is essential for effective cancer treatment, as lymph node (LN) metastasis is a critical factor influencing patient prognosis.

A research team led by Professor Tetsuya Kodama from the Graduate School of Biomedical Engineering at Tohoku University has published groundbreaking findings that clarify how the physicochemical properties of therapeutic formulations govern lymphatic and vascular flow dynamics.

The study, published in Biomedicine & Pharmacotherapy, on January 13, 2026, is the first to comprehensively demonstrate how the osmolarity and viscosity of solvents influence drug behavior during and after administration via a Lymphatic Drug Delivery System (LDDS). In LDDS, anticancer drugs are injected directly into sentinel LNs to reach downstream nodes, serving as an innovative complement to traditional systemic chemotherapy.

To achieve this, the researchers employed MXH10/Mo/lpr mice, a unique animal model characterized by macroscopically enlarged LNs similar in size to those of humans. By precisely controlling the solvent conditions, the team analyzed real-time changes in lymphatic and blood flow.

"We determined that increasing solvent osmolarity promotes blood inflow into the injected LN, leading to the expansion of the lymphatic sinus, which serves as the drug pathway in the LN" explains Kodama. Furthermore, the team clarified that solvent viscosity is the dominant factor determining drug retention and the extent of delivery within the vascular and lymphatic systems.

These findings provide clear guidelines for "tailor-made solvent design" based on specific clinical cases and therapeutic goals. This research directly supports the validity of ongoing Phase I clinical trials currently being conducted at Iwate Medical University and Tohoku University Hospital. This discovery is expected to accelerate the clinical application of LDDS as a next-generation platform for cancer treatment.