Preparation of camptothecin micelles self-assembled from disodium glycyrrhizin and tannic acid with enhanced antitumor activity

Natural compounds as carriers for hydrophobic drugs have been increasingly used in drug delivery systems . In this study, disodium glycyrrhizin (Na 2 GA), tannic acid (TA) and camptothecin (CPT) were firstly used to prepare the camptothecin solid dispersion (CPT SD). When dissolved in a solution medium, Na 2 GA self-assembled to form micelles and CPT was encapsulated in micelles, meanwhile, TA connected with Na 2 GA through hydrogen bonds to form a contract shell. The average diameter of the CPT-loaded micelles is 80  nm with the critical micellar concentration of 0.303 mg/mL, the zeta potential of −33 mV, the PDI of 0.25 and drug loading 6.22%. In vitro experiments confirmed that the drug-loaded micelles exhibited excellent stability and permeability in the intestinal environment. Furthermore, the formulation showed excellent anti-tumor activity in vitro and in vivo . These findings imply that this nano-micelles provide a more potential and efficacious oral drug formulation for chemotherapy.