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 (Na2GA), tannic acid (TA) and camptothecin (CPT) were firstly used to prepare the camptothecin solid dispersion (CPT SD). When dissolved in a solution medium, Na2GA self-assembled to form micelles and CPT was encapsulated in micelles, meanwhile, TA connected with Na2GA 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.