RESUMO
With matrine(MAT) as the model drug, to prepare nano graphene oxide(NGO)-based MAT in situ gel(MAT-NGO-gel), a kind of drug for tumor treatment in combination with phototheraphy, and investigate the physicochemical properties and anti-tumor effects in vivo of MAT-NGO-gel. First, HPLC method was established to measure the content of MAT in the gel. The ultrasonic method was used to load MAT onto the surface of NGO, and then poloxamer 188 and poloxamer 407 were chosen as the main materials to prepare MAT-NGO-gel. The optimum prescription was selected with the gelation temperature as the index. Finally, the drug loading rate, micromorphology, phototherrmal conversion characteristics and drug release in vitro of MAT-NGO-gel were characterized. In the optimized prescription, the concentration of poloxamer 188 and poloxamer 407 was 2% and 20% respectively, and the mass ratio of NGO and MAT was 1â¶1. The gelation temperature and drug loading rate of MAT-NGO-gel prepared by the optimal prescription process was 37.5 â and 16.7%. Under 808 nm laser irradiation, MAT-NGO-gel showed obvious concentration-and time-dependent photothermal conversion characteristics. In vitro release experiments showed that MAT-NGO-gel had temperature-dependent release characteristics. The pharmacodynamics of MAT solution, NGO-gel and MAT-NGO-gel were studied by using S180 tumor-bearing mice and 808 nm laser. The relative tumor volume and body weight of the tumor-bearing mice were plotted over time. After the experiment, the tumor tissues of each group were taken and the histopathological changes were observed by HE staining. The results of pharmacodynamic studies demonstrated that when compared with NS group and NGO-gel group, the body weights of mice in MAT-NGO-gel group and MAT-NGO-gel + laser group were higher, and the relative tumor volume growth was slower. The results of HE stained pathological sections showed that the tumor cells count for the mice in MAT-NGO-gel group and MAT-NGO-gel + laser group was significantly reduced, with obvious nuclear fragmentation and nucleolysis in these two groups. These results suggested that MAT-NGO-gel, especially combined with 808 nm laser, had stronger anti-tumor activity in vivo. The prescription process of MAT-NGO-gel in this experiment was stable and feasible. As compared with MAT solution, MAT-NGO-gel showed obvious sustained and temperature-dependent drug release characteristics. MAT-NGO-gel had much more obvious anti-tumor activity in vivo when combined with 808 nm laser irradiation. This study could provide certain theoretical basis for the therapy of malignant tumor with multiple mechanisms.
