Preparation of curcumin-loaded long-circulating liposomes and its pharmacokinetics in rats / 中国中药杂志

Curcumin has a wide spectrum of pharmaceutical properties such as antitumor, antioxidant, antiamyloid, and anti-inflammatory activity. However, poor aqueous solubility and low bioavailability of curcumin are major challenge in its development as a useful drug. To overcome many of these problems, curcumin-loaded long-circulating liposomes (Cur-LCL) were prepared by the ethanol injection method. Morphology of Cur-LCL was observed by transmission electron microscope, mean particle size and Zeta potential were detected by laser particle size analyzer, entrapment efficiency and drug loading were evaluated by ultracentrifugation. The drug release behavior in vitro and pharmacokinetic behavior in rats of Cur-LCL were investigated with curcumin (Cur) and curcumin liposomes (Cur-Lips) as control. The results showed that the mean diameter of Cur-LCL was 110 nm, the Zeta potential was -5.8 mV. The entrapment efficiency and drug loading of Cur-LCL was 80.25%, 2.06%, respectively. The release behavior in vitro studied by dialysis in PBS buffer showed significant sustained release profile that 48.95% Cur were released from Cur-LCL in 7 h, 88.92% in 24 h. The pharmacokinetic parameters showed that compared with Cur and Cur-Lips, the t(1/2beta) of Cur-LCL was extended to 13 and 1.8-fold, respectively. Besides, the AUC values was significantly increased (P < 0.01), and the clearance was evidently decreased (P < 0.01). These results from in vitro and in vivo indicated that Cur-LCL were able to realize controlled drug release and increase circulation time.

Analysis on the metabolites of mesaconitine in the rat urine by liquid chromatography and electrospray ionization mass spectrometry / 药学学报

The mesaconitine and its major metabolites in the rat urine were identified by liquid chromatography and electrospray ionization tandem mass spectrometry. The rat urine was collected for consecutive 24 hours from the rat following intragastric infusion of mesaconitine, subsequently which were enriched and purified using solid phase extraction. The metabolites of mesaconitine in the rat urine were analyzed by the liquid chromatography and electrospray ionization tandem mass spectrometry. It is shown that the parent drug mesaconitine and its metabolites were found in the rat urine, such as hypo-mesaconitine glucuronic acid conjugate, 10-hydroxy-mesaconitine, 1-O-demethyl mesaconitine, deoxy-mesaconitine and hypo-mesaconitine. Among the five of metabolites, the hypo-mesaconitine glucuronic acid conjugate (m/z 766) was first discovered as the aconitine in rats phase II metabolites, which revealed a new way of mesaconitine metabolism in rats.