Preparation and Antitumor Activity Evaluation of Folic Acid-Modified Phospholipid–Gambogic Acid Nanocrystals

Background: Liver cancer is a complex malignant tumor; gambogic acid (GA) has significant anti-cancer potential, but poor water solubility and low bioavailability limit its clinical application. In this paper, by integrating nanocrystal (NC) technology and an active targeting strategy, a new nanoagent—folic acid-modified phospholipid–gambogic acid nanocrystals (GA-NCs@FA)—was developed to improve the delivery efficiency and therapeutic effect of GA in the treatment of liver cancer. Methods: GA-NCs@FA was prepared by the CO2-assisted precipitation method and the thin-film hydration method. The in vitro anti-tumor activity of GA-NCs@FA was evaluated by cytotoxicity, as well as a scratch and uptake test. A HepG2 tumor-bearing nude mouse model was established to investigate the in vivo distribution and tumor targeting of GA. The in vivo anti-tumor activity was evaluated by the tumor inhibition rate, and the pathological changes of organs in each group were observed by H&E staining. Results: GA-NCs@FA significantly reduced HepG2 cell viability (IC50: 0.50 μg·mL−1) and migration ability (48 h healing rate: 11.50%) and enhanced intracellular fluorescence intensity. In vivo analysis showed that GA-NCs@FA significantly increased the accumulation of drugs in tumor tissues by active targeting and achieved a tumor growth inhibition rate of 70.9%. Histopathology confirmed that GA-NCs@FA induced the most obvious nuclear pyknosis and necrosis in tumor tissues while maintaining good biosafety. Conclusions: GA-NCs@FA significantly prolongs the systemic circulation time of the drug and enhances intratumoral accumulation; therefore, it is a method that can be considered for active targeting and treatment of liver cancer.