Aim The objectives of the present study were to prepare stealthy vincristine plus quinacrine liposomes and evaluate the pharmacokinetics in Sprague-Dawley rats. Methods Anti-resistant stealthy liposomes were prepared by incorporating vincristine with quinacrine together using the ammonium sulfate gradient loading procedure. For the pharmacokinetic study, Sprague-Dawley rats were divided into two groups： each rat in the Group Ⅰwas administered intravenously via tail vein as stealthy liposomal vincristine plus quinacrine, and the Group Ⅱ similarly given as a mixture solution of free vincristine plus free quinacrine. The concentrations of vincristine and quinacrine in plasma were measured by HPLC with diode array detection and fluorescence detection, respectively. Results The mean particle size of stealthy liposomes was 135.9 ±7.1 nm and the encapsulation efficiencies of stealthy liposomes were 〉 90% for vincristine, and 〉 85% for quinacrine, respectively. Administered as the stealthy vincristine plus quinacrine liposomes, the plasma exposures of both vincristine and quinacrine were significantly extended, and the mean concentrations of both vincristine and quinacrine were significantly higher compared to those given as the mixture solution of free vincristine plus free quinacrine. The Cmax, t1/2, AUC0-24 h values of vincristine for stealthy liposomal group were significantly increased, but the total clearance Cl values decreased, as compared to those of free drug group, respectively. Similarly, the Cmax, t1/2 and AUC0-24 h values of quinacrine for the stealthy liposomal group were significantly increased, but the total clearance C1 values decreased, as compared to those of free quinacrine. Conclusion The anti-resistant stealthy liposomes are successfully prepared by incorporating vincristine with quinacrine, and the liposomes extend significantly the duration in blood circulation and improve evidently the plasma concentrations of both vincristine and quinacrine.
The objective of the present study is to examine cardiovascular protective action of a newly developed transdermal patch by incorporating bisoprolol and isosorbide dinitrate in spontaneously hypertensive rats. As the combination therapy with these two synergistic drugs at low doses through a suitable form of administration could provide optimal therapeutic benefit, we further evaluated the effects of a 42 d period of anti-hypertensive treatment in spontaneously hypertensive rats. Rats were divided into the following five groups： control （blank patch）, bisoprolol fumarate tablets （BP-FT, 20.0 mg/kg, i.g.）, bisoprolol transdermal patch （BP-TP, 20.0 mg/kg）, isosorbide dinitrate transdermal patch （ISDN-TP, 20.0 mg/kg）, and the combination of BP and ISDN in a transdermal patch at low doses （8 and 12 mg/kg, respectively）. The effects of treatment were evaluated via biochemical indicators related to cardiovascular protection, structure and function. The combination therapy had synergistic anti-hypertensive effects and significantly reduced blood pressure with the benefit of controlling blood pressure variability compared to BP-FT and BP-TP. The combined treatment also reduced heart rate as well as BP-FT and BP-TP, while ISDN-TP had no evident effects on blood pressure, heart rate, and cardiovascular protection. Combination therapy was superior to BP-TP and BP-FT at increasing blood atrial natriuretic peptide and nitric oxide, while also reducing cardiac hydroxyproline and endothelin-1 with no difference in blood endothelin-1 and cardiac malondialdehyde levels. Cardiovascular remodeling differed among the groups, with the combination therapy reducing cardiac hypertrophy and the aortic media/lumen ratio. The consequential improvements in relaxation in response to cumulative concentrations of acetylcholine may explain the associated improvement in endothelial function. Combi- nation treatment with a transdermal patch exhibited a synergistic therapeutic effect. Such favorable cardiovascular effects wit
