Background: Quercetin (QE) is one of the flavonoids with various biological functions such as anti-oxidation, anti-inflammatory and antitumor. However, the low aqueous solubility and short half-life in the body reduce its in vivo efficacy. Therefore, the appropriate delivery techniques to solve those problems have drawn much attention. In the present study, methoxypolyethylene glycol- poly-DL-lactic acid (MPEG-PLA) nanoparticles loaded with quercetin (QE), called NP, were prepared, and their antitumor characteristics were investigated in vitro and in vivo.
Method: NPs were produced by evaporating organic solvent from the organic solvent-water mixture in four formulations. The particle characteristics and in vitro release were examined for the obtained preparations (NP1 – NP4). The antitumor features were investigated in vivo with different administration schedules using mice inoculated subcutaneously with murine Sarcoma 180. In addition, the efficacy of co-administration of NP with a strong antitumor chemotherapeutic agent, irinotecan hydrochloride (CPT-11), was examined. Biodistribution studies were performed using the same animal models.
Result: The NP with the higher drug content (0.58 % (w/w)) and gradual release profile, Preparation NP4, were chosen and used as NP in the in vivo studies. NP suppressed tumor growth better than QE solution in various dosing schedules (total dose = 2 mg/kg). In the combination therapy with CPT-11, NP exhibited antitumor efficacy in a nearly additive manner. No decrease in body weight observed with any administration. NP markedly enhanced the systemic distribution and tumor localization.
Conclusion: These results indicated that the present NP should promote the efficacy of QE, and might have useful therapeutic potential in the treatment of solid tumors.