Oral in vivo biodistribution of fluorescent labelled nano lipid carrier system of erlotinib using real time optical imaging technique

This study investigates the biodistribution of a nano lipid carrier system (NLCs) containing the hydrophobic drug erlotinib (ERL-NLCs). The system was labelled with the fluorescent dye IR-780 for real-time dynamic imaging. ERL-NLCs were initially developed using the ultrasonication method with oleic acid and stearic acid. In vitro and ex vivo studies were performed to confirm the formation and penetration of NLCs within the intestine. Subsequently, the biological distribution of ERL-NLCs was monitored using a fluorescent dye through the IVIS® fluorescent optical imaging technique in whole live animals. Mice were orally administered blank IR 780 dye solution, ERL suspension, and IR 780 labelled NLCs. Fluorescence images were acquired at different time intervals up to 24 h and then total radiant efficiency was calculated through the region of interest (ROI) of the whole animal at each interval of time for all three groups. To validate the results obtained from in vivo imaging, various organs including lungs, heart, liver, both kidneys, stomach, and intestine were subsequently extracted and examined after 24 h. The ROI was found to be higher in the blank IR 780 dye solution, followed by the drug suspension and IR 780 labelled NLCs. These results confirm that the plain ERL suspension distributes across the body, and its encapsulation in NLCs facilitates passage through the lymphatic intestinal pathway, effectively avoiding first-pass metabolism. The remarkable results indicated that the NLCs formulation effectively circumvents first-pass metabolism by adopting the intestinal lymphatic pathway, thereby enhancing the oral bioavailability of the drug. This observed behaviour underscores the potential of NLCs in optimizing drug delivery and minimizing adverse effects associated with gastrointestinal and metabolic processes.