Computed tomographic mesenteric lymphography by oral iohexol liposomes

Lymphography is a useful technique in the diagnosis of lymphatic diseases. Conventional lymph node imaging methods, such as subcutaneous and footpad injections, are invasive and unable to visualize mesenteric lymph nodes. Liposomes have the potential to increase the oral bioavailability of poorly bioavailable hydrophilic drugs and promote their lymphatic transport in the intestinal lymph. In this study, the iohexol liposome was prepared using cholesterol, soybean lecithin, and iohexol by the reverse-phase evaporation method. It had an encapsulation efficiency of 70.26%, an average particle size diameter of 185.7 nm, a polydispersity index of 0.275, and a zeta potential of -7.697 mV. The iohexol liposomes were stable for five days at 4 °C under static conditions. The iohexol content in the lymph nodes of mice after oral iohexol liposomes initially increased and then gradually decreased over time, with the absorption peak occurring around 50-70 minutes and a peak iohexol content of 5.09 mg/g. After oral administration of iohexol liposomes, mild enhancement (12.46-12.92 HU) was observed in the mesenteric lymph nodes of dogs through CT scanning after a certain period. These results indicate that iohexol liposomes, when administered orally, can effectively achieve imaging of the mesenteric lymph nodes. Overall, we provide a novel noninvasive imaging modality based on liposomes for evaluating mesenteric lymph nodes via lymphography.