Monodisperse magnetic iron oxide nanoparticles (MNPs), coated with PEG at different molecular weight, were prepared via self-assembly method. The particle diameters were measured by dynamic light scattering and transmission electron microscope. Increasing the molecular weight of PEG in the coating polymer increased the overall particles diameter. As coating thickness increased, the saturation magnetization (Ms) and T2 relaxivity decreased. The interactions of these MNPs with macrophage cells were also investigated. The results showed that cellular uptakes of MNPs depended on nanoparticle concentration and surface chemistry. The results of this study will have implications on the chemical design of nanomaterials for bio-imaging and bio-detection.
Breviscapine is a Traditional Chinese Medicine treating cardiovascular diseases by promoting blood circulation and removing blood stasis. The major active component of breviscapine has low aqueous solubility, poor chemical stability, short biological half-life and rapid elimination rate from the plasma. The use of a lipid emulsion formulation containing breviscapine might improve chemical stability, increase drug loading, exhibit sustained release profile. In the present study, we developed an optimized formulation and technological method for the preparation of sterile and stable breviscapine lipid emulsion (Bre-LE) for intravenous infusion. The average particle size, polydispersity index, zeta potential, stability constant (Ks) value and content of final product were (225.3±8.8) nm, 0.221±0.020, (−29.6±1.5) mV, (24.3±2.9)% and (94.5±0.6)% respectively (n=3). The results of in vitro release experiment suggest that lipid emulsion as breviscapine carrier showed a desirable sustained release profile. Dilution stability and long-term stability were also researched in the present paper. The results show the carrier could protect drug from degradation after dilution by phosphate buffered saline and fetal calf serum. And Bre-LE was stable for up to 6 months at room temperature storage condition. The biodistribution of drug in heart of mice increased dramatically after encapsulation into lipid emulsion which was beneficial to heart disease therapy.
Breviscapine lipid emulsions were prepared by a high speed dispersion-homogenization method with optimal formulation and technological method. The proportion of liposomes in breviscapine lipid emulsions, an important character for determining the behavior of drug in vivo belongs to which carriers, was less than 5%. Loading breviscapine into lipid emulsions did increase the breviscapine concentrations in plasma, retarded the clearance, and exhibited the properties of sustained-release concluded by pharmacokinetic parameters: after bolus administration, the elimination phase (t1/2(β) = 99.535) of lipid emulsions was 5.4-times longer than that of Injectio Breviscapine. The AUC0→∞ (14.453-times), k10 (0.047-times), Cls (0.147-times), and MRT0→∞ (17.766-times) values also confirmed this trend. The amount of drug in every tissue increased at different levels after intravenous administration of breviscapine lipid emulsions compared with Injectio Breviscapine. The relative exposure value of breviscapine lipid emulsions for plasma and lungs were 29.59 and 5.81, respectively, indicating that the exposure of breviscapine to plasma and lungs was significantly increased by entrapment in lipid emulsions. Other targeting evaluation indexes also proved the superiority of lipid emulsions carrier to deliver drug to the targeting region of vascular and lung diseases therapy.
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