包裹阿霉素的新型载药微泡制备及体外缓释实验研究

摘要

Objective To combine the active poly lactic co-glycolic acid (PLGA) nanosperes with adriamycin in side (ADM-NP) on the surface of ultrasound micrbubbles in covalent bonding and to prepare a novel drug-loading ultrasound micrbubble,and observe the physicochemical property.To quantify drug encapsulation efficiency and drug-loading amounts and drug-release properties in vitro and the effect of tumor imaging.Methods ADM-NP were prepared with double emulsification method,The surface carboxyl of ADM-NP was activated with carbodiimide method.Amino ultrasound microbubbles (MB-NH2) were prepared with mechanical shaking.The carboxyl of ADM-NP and the MB-NH2 could take place condensation reaction under a certain condition.Light microscope was used to observe the shape and distribution of the novel micrbubble.High performance liquid chromatography (HPLC) was used to quantify drug encapsulation efficiency and drug loading amounts.This novel microbubbles were put in 2 dialysis bag to observe the releasing properties of ADM in vitro,and one of the bag was using low frequency ultrasound irradiation for 120 s.The effect of tumor imaging using this novel microbubble was observed.Results After 48 hours,a number of ADM-NP attacted to the MB-NH2 like a gar land.Determination of entrapment efficiency and drug loading of it by HPLC weare (86.11 ± 6.76)％ and (8.71 ± 0.46)％.The sustained release in vitro can last for more than 48 hours.More than 90％ of ADM encapsulated in the 2 groups was sustained released for 48 hours.And the release characteristics of the 2 groups in vitro was in accord with Higuchi equation,and no difference was observed in the 2 groups (P ＞0.05).The tumor showed typical enhancement pattems of "quick wash-in and quick wash-out".Conclusions To combine the nanospheres to the surface of microbubbles with covalent bonding,it could prepare a novel efficient drug-loading microbubbles for a original technique of ultrasound-targeted microbubble destruction(UTMD).%目的 将包裹阿霉素(ADM)的乳/羟基乙酸共聚物(PLGA)纳米缓释药物微球(ADM-NP)通过共价结合方式连接于带正电氨基脂质超声微泡(MB-NH2)表面,制备包裹ADM的新型载药微泡,并观察其基本理化特性、载药量、包封率、体外缓释特性及显影效果.方法 采用双乳化法,制备ADM-NP,并通过碳二亚胺法活化ADM-NP表面的羧基,在一定条件下,使ADM-NP以共价结合的方式,连接于MB-NH2表面.用光镜观察连接情况、微泡形态并检测其粒径大小.用高效液相色谱法(HPLC)检测其包封率及载药量,观察该新型载药微泡的体外缓释药特性以及对兔VX2肝癌的显像效果.结果 48 h后光镜观察,可见大量ADM-NP连接于MB-NH2表面,呈花环状,分布较为均匀,其平均最大径为(2.68±0.98)μm.该新型载药微泡的载药量为(8.71±0.46)％,包封率为(86.11±6.76)％.两组体外释药均符合Hignch方程,其结果无明显差异性(P＞0.05),48 h体外累积释药量达90％以上.经兔耳缘静脉注射该微泡后,兔肝实质明显持续增强,肝癌呈“快进快退”显像表现.结论 采用碳二亚胺法可将ADM-NP通过共价结合方式连接于MB-NH2表面,提高微泡载药量,延长药物的持续作用时间,并且在兔VX2肝癌肿瘤中显影效果好,为采用超声靶向爆破微泡进行药物定位释放技术提供了一种新型高效的载药微泡系统.