Characterization of Chitosan-Carboxymethyl Dextran Nanoparticles as a Drug Carrier and as a Stimulator of Mouse Splenocytes

Abstract

The in vitro drug-release behavior of chitosan-carboxymethyl dextran nanoparticles (CDNP) containing cefmetazole, 5-fluorouracil (5-FU) or indocyanine green (ICG), and the in vitro effect of CDNP on mouse B16 melanoma cell proliferation and in vivo modulation effect of CDNP on serum cytokines and spleen lymphocytes in mice were evaluated in this study. Drug-loaded CDNP were prepared by embedding (for cefmetazole or 5-FU) and absorption (for ICG), and the particle size was increased with increased drug association efficiency (AE) and decreased surface amino group content. Prolonged release of cefmetazole (540 min) or 5-FU (360 min) from CDNP was observed when compared to that of nanoparticle-free cefmetazole (210 min) or 5-FU (50 min), and the release of cefmetazole or 5-FU from CDNP98 (CDNP made with 98% degree of deacetylation (DD) chitosan) was slower than from CDNP78 (CDNP made with 78% DD chitosan). High AE (72.0-98.6%), undetectable surface amino group content and dramatically increased particle size (1076.9-1506.0 nm) of ICG-loaded CDNP with undetectable release of ICG within 48 h revealed the good affinity between ICG and CDNP. Twenty-five to 100 μg/ml of CDNP elicited dose-dependent inhibitory effects on B16 tumor cell proliferation, and CDNP98 was more effective than CDNP78. CDNP78 regulated serum IL-17 level in up-regulating IL-4, IL-6, IL-10, IL-23 and TGF-β within 3 h; on the other hand, CDNP98 significantly down-regulated TGF-β and had no induction effect on IL-23 within 24 h. In addition, reduced IL-17 was observed in CDNP at 24 h. CDNP98 was more effective than CDNP78 in stimulating mouse splenic T CD4+, TCD8+ and NK cell proliferation within 24 h, while CDNP78 was superior to CDNP98 in stimulating B CD19+ cells. The ability of CDNP to be the drug carrier and to enhance both humoral and cell-mediated immune response in this study demonstrated its promising potential to be applied as biomedical material.