OBJECTIVE:To prepare Coenzyme Q10 long-circulating liposomes,establish the determination method of content and entrapment efficiency,and prepare it into lyophilized preparation to improve its stability. METHODS:Coenzyme Q10 long-cir-culating liposomes were prepared by film dispersion method. Particle size and Zeta potential of liposomes were determined,and HPLC assay was used to determine the content of coenzyme Q10. Free drugs and liposomes were separated using protamine aggre-gation method,and the encapsulation efficiency was calculated. Lyophilized preparation was prepared by coenzyme Q10 long-circu-lating liposomes,and the changes of content and encapsulation efficiency of drugs were determined 0,30 and 90 days after lyophi-lization. RESULTS:The liposomes were homogeneous in size with mean diameter of(166.0±5.3)nm and Zeta potential of(-22.2± 1.4)mV. Average content(the percentage of content accounted for labeled amount)and entrapment efficiency of 3 batches of sam-ple were 98.2%(RSD=2.8%) and 93.2%(RSD=4.6%),respectively. Compared with 0 d after lyophilization,coenzyme Q10 long-circulating liposomes had no obvious change in the content and encapsulation efficiency 90 d after lyophilization. CONCLU-SIONS:Coenzyme Q10 long-circulating liposomes with high quality and entrapment efficiency and lyophilized preparation being stored stably for 90 d have been prepared successfully.

OBJECTIVE To prepare lipid-coated mesoporous silica nanoparticles （CLMSNs） co-loaded with doxorubicin （DOX） and siRNA （CLMSNs-SS-NH2@DOX/siRNA），and to characterize it and study anti-multidrug-resistant tumor cells. METHODS MSNs-SS-NH2@DOX was prepared on the basis of mesoporous silica （MSNs），covered with cationic liposomes （CLs） to synthesize CLMSNs-SS-NH2@DOX，and then obtain CLMSNs-SS-NH2@DOX/siRNA by co-loading with siRNA. The particle size and Zeta potential of the preparation were determined，and its micromorphology was observed； differential scanning calorimetry，X-ray diffraction，infrared spectroscopy and physical adsorption analysis were conducted. The in vitro release of DOX from the preparation was determined under different pH conditions （pH5.0，pH7.4） and different glutathione concentrations （0，2，5， 10 mmol/L）. The effects of this preparation on the uptake，migration，apoptosis，cycle and P-glycoprotein （P-gp） expression of MCF-7/ ADR in DOX-resistant breast cancer cells were investigated. RESULTS CLMSNs-SS-NH2@DOX/siRNA had a clear core-shell structure，obvious lipid membrane layer，particle size of （197.63±3.75） nm，Zeta potential of （20.64±0.98） mV，and with good physical and chemical properties. In vitro release results showed that CLMSNs-SS-NH2@DOX/siRNA possessed good pH/reduction double-response. The results of cell experiment showed that after intervened with CLMSNs-SS-NH2@DOX/siRNA，the fluorescence intensity of MCF-7/ADR cells was significantly enhanced，the migration rate and P-gp expression level were significantly reduced， while total proportion of apoptosis and that of G0/G1 phase were significantly increased （P＜0.05）. CONCLUSIONS In this study， DOX and siRNA co-loaded CLMSNs-SS-NH2@DOX/siRNA is prepared successfully， which has good physical and chemical properties， pH/reduction double-response properties. It can reverse the multidrug resistance of MCF-7/ADR cells by down-regulation of P-gp expression.