Encapsulation of 10-hydroxy camptothecin in supramolecular hydrogel as an injectable drug delivery system

10-Hydroxy camptothecin (HCPT) has been proven to be a cell cycle-specific chemotherapeutic agent, which is a necessary choice to inhibit tumor residue growth and prevent tumor metastasis after surgery. But it suffers from light decomposition, poor solubility, relatively low bioavailability, and some side effects, which are the major obstacles toward its clinical use. Integration of hydrophobic HCPT with hydrophilic hydrogel is a facile approach to change the disadvantageous situation of HCPT. In this study, a novel supramolecular hydrogelator with improved synthetic strategy was triggered by chemical hydrolysis, and then self-assembled to hydrogel. Taking advantage of the high-equilibrium solubility of HCPT in hydrogelator solution, this hydrogel was utilized to load HCPT via encapsulation as an effective carrier. HCPT hydrogels were characterized by several techniques including transmission electronic microscopy, rheology, and UV spectroscopy. In vitro release experiment indicated HCPT hydrogel could maintain long term and sustained release of HCPT at high accumulated rate. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that HCPT hydrogel had an optimized anticancer efficacy. Besides, with prominent physical properties of carrier, HCPT hydrogel possessed satisfactory stability, syringeability, and recoverability, demonstrating itself as a potential localized injectable drug delivery system.