Lin Jiahao, Wang Xiuli, Wu Qing, Dai Jundong, Guan Huida, Cao Weiyi, He Liangying, Wang Yurong
Department of Chinese Pharmaceutics, School of Chinese Materia Medica, Eastern Campus, Beijing University of Chinese Medicine, Beijing 100102, PR China.
Department of Chinese Pharmaceutics, School of Chinese Materia Medica, Eastern Campus, Beijing University of Chinese Medicine, Beijing 100102, PR China.
Int J Pharm. 2014 Feb 28;462(1-2):11-8. doi: 10.1016/j.ijpharm.2013.12.040. Epub 2013 Dec 27.
The aim of this study was to systematically optimize and characterize the co-encapsulation process of Salvianolic acid B (Sal B), Tanshinone II A (TSN) and Glycyrrhetinic acid (GA) into liposomes. The liposomes (GTS-lip) were prepared using film hydration method combined with probe sonication to encapsulate two hydrophobic components (TSN and GA), and using pH gradient method to load hydrophilic component Sal B. The concentration of encapsulated drugs was measured by a reversed phase high performance liquid chromatography (RP-HPLC) method. Systematic optimization of encapsulation process was performed using single factor test, orthogonal test in combination with Box-Behnken Design. Optimum conditions are as follows: ratio of GA to lipid (w/w)=0.08, ratio of Sal B to lipid (w/w)=0.12 and pH of buffer=3.3. Based on the conditions mentioned above, encapsulation efficiency of Sal B, TSN and GA reached target levels: (96.03 ± 0.28)%, (80.63 ± 0.91)% and (88.56 ± 0.17)%, respectively. The GTS-lip had a unimodal size-distribution and a mean diameter of 191.3 ± 6.31 nm. Morphology determination of the GTS-lip indicated that the liposomes were spherical, and there was no free drug crystal in the visual field of transmission electron microscopy. Also, the ζ potential of GTS-lip was detected to be -11.6 ± 0.35 mV. In vitro release investigation of GTS-lip suggested that the release rate of GTS-lip significantly decreased compared to drug solution. The accumulative release percentage of TSN, GA and Sal B were 10% in 36 h, 4% in 36 h and 77% in 24 h. Meanwhile, GTS-lip exhibited definite activity on proliferative inhibition of hepatic stellate cells (HSC). GTS-lip decreased the viability of the HSC to higher than 75% at two high drug concentration groups in 24h. At the same time, GTS-lip of two low drug concentration groups increased the inhibition rates by 2.3 folds and 1.9 folds separately at 48 h compared to 24h. By contrast, inhibition activity of G-T-S solution group showed less change between 48 h and 24 h. The prolonged and enhanced activity in 48 h which GTS-lip group manifested might contribute to its sustained release effect.
本研究旨在系统优化并表征将丹酚酸B（Sal B）、丹参酮II A（TSN）和甘草次酸（GA）共包封于脂质体中的过程。采用薄膜水化法结合探头超声处理制备脂质体（GTS-脂质体）以包封两种疏水性成分（TSN和GA），并采用pH梯度法载入亲水性成分Sal B。采用反相高效液相色谱（RP-HPLC）法测定包封药物的浓度。通过单因素试验、正交试验结合Box-Behnken设计对包封过程进行系统优化。最佳条件如下：GA与脂质的比例（w/w）=0.08，Sal B与脂质的比例（w/w）=0.12，缓冲液pH=3.3。基于上述条件，Sal B、TSN和GA的包封率达到目标水平：分别为（96.03±0.28）%、（80.63±0.91）%和（88.56±0.17）%。GTS-脂质体具有单峰尺寸分布，平均直径为191.3±6.31 nm。GTS-脂质体的形态学测定表明脂质体呈球形，在透射电子显微镜视野中无游离药物晶体。此外，检测到GTS-脂质体的ζ电位为-11.6±0.35 mV。GTS-脂质体的体外释放研究表明，与药物溶液相比，GTS-脂质体的释放速率显著降低。TSN、GA和Sal B的累积释放率在36小时内分别为10%、在36小时内为4%以及在24小时内为77%。同时，GTS-脂质体对肝星状细胞（HSC）的增殖抑制表现出一定活性。在两个高药物浓度组中，GTS-脂质体在24小时内使HSC的活力降低至75%以上。同时，两个低药物浓度组的GTS-脂质体在48小时时与24小时相比，抑制率分别提高了2.3倍和1.9倍。相比之下，G-T-S溶液组在48小时和24小时之间的抑制活性变化较小。GTS-脂质体组在48小时时表现出的活性延长和增强可能归因于其缓释效果。
