Formulation optimization of emodin nanostructured lipid carriers by Box-Behnken response surface method and in vitro quality evaluation / 中国中药杂志

Emodin nanostructured lipid carriers(ED-NLC) were prepared and their quality was evaluated in vitro. Based on the results of single-factor experiments, the ED-NLC formulation was optimized by Box-Behnken response surface method with the dosages of emodin, isopropyl myristate and poloxamer 188 as factors and the nanoparticle size, encapsulation efficiency and drug loading as evaluation indexes. Then the evaluation was performed on the morphology, size and in vitro release of the nanoparticles prepared by emulsification-ultrasonic dispersion method in line with the optimal formulation, i.e., 3.27 mg emodin, 148.68 mg isopropyl myristate and 173.48 mg poloxamer 188. Under a transmission electron microscope(TEM), ED-NLC were spherical and their particle size distribution was uniform. The particle size of ED-NLC was(97.02±1.55) nm, the polymer dispersion index 0.21±0.01, the zeta potential(-38.96±0.65) mV, the encapsulation efficiency 90.41%±0.56% and the drug loading 1.55%±0.01%. The results of differential scanning calorimeter(DSC) indicated that emodin may be encapsulated into the nanostructured lipid carriers in molecular or amorphous form. In vitro drug release had obvious characteristics of slow release, which accorded with the first-order drug release equation. The fitting model of Box-Behnken response surface methodology was proved accurate and reliable. The optimal formulation-based ED-NLC featured concentrated particle size distribution and high encapsulation efficiency, which laid a foundation for the follow-up study of ED-NLC in vivo.

[Preparation and pharmacodynamics in vivo of nano graphene oxide-based matrine in situ gel].

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 1∶1. The gelation temperature and drug loading rate of MAT-NGO-gel prepared by the optimal prescription process was 37.5 ℃ 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.

Preparation and characterization of glycyrrhetinic acid-modified nano graphene oxide drug delivery system / 中国中药杂志

In this study,a nano drug delivery system GA-DTX-NGO which could be used for liver tumor photothermal and chemotherapy was prepared and characterized,with docetaxel(DTX) as model drug,glycyrrhetinic acid(GA) as the target molecule,and nano graphene oxide(NGO) as the photosensitizer. Firstly,GA-NGO nanocomposites were synthesized by the amidation reaction,and then GA-DTX-NGO was prepared by ultrasonic dispersion method. The encapsulation efficiency and drug loading ratio were determined by high performance liquid chromatography(HPLC) and ultracentrifugation; the morphology was observed by transmission electron microscopy(TEM). The photothermal conversion test was carried out by laser irradiation at 808 nm and the drug release test in vitro was performed using reverse dialysis. Finally,the effect of GA-DTX-NGO on SMMC-7721 liver tumor cells proliferation was determined by using MTT assay. The results showed that GA-DTX-NGO had good water dispersibility,and TEM results showed a lamellar structure with about 200 nm in diameter. The encapsulation efficiency and drug loading ratio of GA-DTX-NGO were(98. 89 ± 0. 07) % and(64. 74±0. 26) %,respectively. GA-DTX-NGO had strong photothermal conversion performance under 808 nm of laser irradiation. The drug release test in vitro results showed GA-DTX-NGO had obvious sustained-release effects and temperature-dependent release characteristics. The results of cell assay showed that GA-DTX-NGO could effectively inhibit the proliferation of SMMC 7721 cells in a concentration-and time-dependent manner,and the inhibitory effect was enhanced after combination with the near-infrared therapy. In conclusion,the preparation process of GA-DTX-NGO nano drug delivery system is feasible,which could provide some theoretical basis for further study of photothermal and chemotherapy on liver tumor.