Gaetil Marilisa P N, Benfica Polyana L, Mendes Livia P, Vieira Marcelo S, Anjos Jorge L V, Alonso Antônio, Rezende Kênnia R, Valadares Marize C, Lima Eliana M
J Nanosci Nanotechnol. 2015 Jan;15(1):838-47. doi: 10.1166/jnn.2015.9188.
Liposomes containing 4-nerolidylcatechol (4-NC), the major metabolite isolated from Pothomorphe umbellata, were obtained and characterized. Influence of liposomal encapsulation on chemical stability of 4-NC and on cytotoxicity profile of this drug was evaluated. Soybean phosphatidylcholine liposomes were prepared by lipid film hydration followed by extrusion. Entrapment efficiency for 4-NC was approximately 92%. Mean diameter of liposomes was 100 nm with a polydispersity index below 0.13. Liposomal 4-NC (L4-NC) and free drug (F4-NC) were submitted to forced degradation assays, monitored by HPLC. Photodegradation assay followed ICH Guidelines, using a photostability chamber equipped with both UV and white light sources. Liposomal encapsulation was able to markedly reduce 4-NC degradation rates under all the conditions tested. L4-NC showed a half-live approximately 15% higher than F4-NC under light exposure. After 72 hours, acid and base hydrolysis of F4-NC lead to 13 and 16% of degradation, respectively. However, no degradation was observed in L4-NC. EPR spectra of liposomal membrane showed that greatest changes in membrane properties were obtained when 5-doxyl stearic acid was used as the spin label, indicating a marked decrease in the fluidity of the bilayer. Following incubation with K562 cells, 4-NC showed a concentration-dependent cytotoxicity profile, while L4-NC exhibited a time and concentration-dependent profile, consistent with a controlled drug release system. F4-NC induced extensive hemolysis under isotonic conditions; conversely liposomal encapsulation protected erythrocytes from 4-NC induced lysis. Liposomal 4-NC resulted in a hemocompatibility and stable formulation, representing a viable drug delivery system to further investigate in vivo performances of 4-NC in pre clinical studies.
制备并表征了含有从伞形波叶大黄中分离出的主要代谢产物4-橙花叔醇儿茶酚（4-NC）的脂质体。评估了脂质体包封对4-NC化学稳定性及其细胞毒性特征的影响。采用脂质膜水化法并通过挤压制备大豆磷脂酰胆碱脂质体。4-NC的包封率约为92%。脂质体的平均直径为100 nm，多分散指数低于0.13。脂质体4-NC（L4-NC）和游离药物（F4-NC）进行强制降解试验，通过高效液相色谱法监测。光降解试验遵循国际协调会议指南，使用配备紫外线和白光源的光稳定性试验箱。在所有测试条件下，脂质体包封能够显著降低4-NC的降解速率。在光照下，L4-NC的半衰期比F4-NC高约15%。72小时后，F4-NC的酸水解和碱水解分别导致13%和16%的降解。然而，L4-NC未观察到降解。脂质体膜的电子顺磁共振光谱表明，当使用5-硬脂酰基-二茂铁酸作为自旋标记时，膜性质发生了最大变化，表明双层流动性显著降低。与K562细胞孵育后，4-NC呈现浓度依赖性细胞毒性特征，而L4-NC呈现时间和浓度依赖性特征，这与控释药物系统一致。F4-NC在等渗条件下诱导广泛溶血；相反，脂质体包封可保护红细胞免受4-NC诱导的裂解。脂质体4-NC具有血液相容性且制剂稳定，是一种可行的药物递送系统，可在临床前研究中进一步研究4-NC的体内性能。
