Preparation and in Vitro Evaluation of Reduction-responsive Methotrexate/Hydroxycamptothecin Nanoparticles

OBJECTIVE To synthesize drug-polymer conjugate hyaluronic acid-disulfide bond-methotrexate-linoleic acid (HA-SS-MTX-LA), prepare nanoparticles(NPs)(HA-SS-MTX-LA@HCPT NPs) with it as a carrier by encapsulating hydroxycamptothecin(HCPT), and investigate its in vitro drug release behavior and in vitro antitumor activity.METHODS The drug-polymer conjugate HA-SS-MTX-LA was synthesized by amidation reaction under the catalysis of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide and N-hydroxy succinimde, and its structure was confirmed by hydrogen nuclear magnetic spectroscopy and Fourier transform infrared spectroscopy. HA-SS-MTX-LA NPs were prepared by ultrasound method. The critical aggregation concentration and particle size were used as indicators to optimize the feeding ratio of LA to HA-SS-MTX. Using HCPT as a model drug, HCPT-loaded HA-SS-MTX-LA NPs(HA-SS-MTX-LA@HCPT) were prepared by emulsifying solvent evaporation method to investigate the drug co-loading property. The reduction responsiveness of HA-SS-MTX-LA@HCPT NPs was evaluated by in vitro release test. The anti-tumor activity in vitro of drug-loaded nanoparticles was assessed by MTT assay. RESULTS HA-SS-MTX-LA NPs was prepared successfully. The optimal feeding ratio of LA to HA-SS-MTX was 1∶1, the critical aggregation concentration was 60.50 mg×mL^-1, and the particle size was (226.6±2.5)nm with PDI of 0.180±0.036. The particle size of HA-SS-MTX-LA@ HCPT NPs was (257.59±1.41)nm with PDI of 0.132±0.009. The encapsulation efficiency and drug loading of HCPT were (72.46±0.73)% and (11.51±0.32)%, respectively. The in vitro release results showed that the drug could be rapidly released under high concentration of glutathione. The results of MTT experiment indicated that HA-SS-MTX-LA@HCPT NPs had a significant inhibitory effect on the growth of HepG2 liver cancer cells and Bel-7402 liver cancer cells. CONCLUSION The HA-SS- MTX-LA@HCPT NPs have uniform particle size, with high encapsulation efficiency and drug loading, good drug co-loading ability, good reduction responsiveness and anti-cancer activity. The anti-tumor effect of HCPT and MTX in vitro is further improved.