布比卡因脂质体对大鼠坐骨神经的神经阻滞作用

Sciatic Nerve Block by Liposomal Bupivacaine in Rats

目的制备布比卡因脂质体,研究其对大鼠坐骨神经的局麻作用。方法以蛋黄卵磷脂、胆固醇、α-生育酚和布比卡因粉剂为原料,采用薄膜分散法制备布比卡因脂质体;分别在电镜和光镜下观察脂质体的形态,计算其粒径;用紫外线分光光度仪检测布比卡因脂质体的包封率。40只SD大鼠(200～225g)坐骨神经周围置管后随机分为4组,通过导管分别注射0.9%氯化钠溶液(N1组)、空白脂质体(N2组)、0.5%布比卡因(BP组)和0.5%布比卡因脂质体(BP-L组)各0.4mL,以形态学、机械痛阈的变化评价麻醉效果。结果光镜下观察可见脂质体呈大小不等的圆形或多球团块状;电镜下观察可见脂质体的形态大小不等,呈包膜透明的圆球状。其粒径介于150～2000nm,包封率为43.6%。N1和N2组未见明显的麻醉作用。BP-L组坐骨神经周围给药后不同麻醉阶段的麻醉时间t1、t2、t3以及麻醉总时间t总均显著大于BP组。结论以蛋黄卵磷脂、胆固醇、浕-生育酚和布比卡因粉剂为原料,采用薄膜分散法可制备布比卡因脂质体;布比卡因被脂质体包裹后,其大鼠坐骨神经阻滞时间明显延长。

Objective To prepare liposomal bupivacaine and study the local anesthetic effect by injection around sciatic nerve in rats. Methods 0.5 % liposomal bupivacaine was prepared with egg yolk phosphatidylcholines, cholesterol, α-tocopherol and bupivacaine using film dispersion method. Its size was calculated by light microscope and electron microscope. The encapsulation efficiency was measured by ultraviolet spectrophotometer. Forty SD rats were randomly divided into 4 goups ： N1 （injected with saline ）, N2 （injected with blank liposomes ）, BP （injected with 0.5% bupivacaine）, BP-L （injected with 0. 5% liposomal bupivacaine ）. Appearance and mechanical pain threshold were evaluated after injecting around sciatic nerve, respectively. Results The morphology of liposomal bupivacaine was like sphere, its size was 150 - 2 000 nm, and the encapsulation efficiency was 43.6%. No local anesthetic effect was observed in ether group N1 or N2. The duration of liposomal bupivacaine（ t1, t2, t3 and ttotal ） was longer than bupivacaine. Conclusion Liposomal bupivacaine can be prepared successfully with egg yolk phosphatidylcholines, cholesterol, α-tocopherol and bupivacaine by using film dispersion method. The duration of sciatic nerve block by bupivacaine encapsulated in liposomes can be prolonged.