目的 制备麻黄碱壳聚糖修饰脂质体凝胶剂，考察其粒径分布、包封率及体外透皮特性。方法 采用薄膜蒸发法制备麻黄碱脂质体混悬液，在麻黄碱脂质体混悬液中缓慢滴加pH值为5～6的0.35%壳聚糖溶液，制成麻黄碱壳聚糖修饰脂质体凝胶剂。激光粒度仪测定修饰脂质体的粒径分布，反透析法测定包封率，Franz扩散装置考察其体外透皮特性。结果 麻黄碱壳聚糖修饰脂质体的平均粒径在1 400～1 900 nm；平均包封率达（41±0.94）%；修饰脂质体中麻黄碱能缓慢透过大鼠皮肤，与普通剂型相比累积透过量随时间变化差异较明显，缓释效果显著。结论 该制剂制备工艺简单，性质稳定，药物包封率较高，定量测定方法简便、准确；药物透皮速率缓慢，释药稳定。

Objective To prepare the ephedrine chitosan-modified liposomes gels, detect the particle diameter and the entrapment efficiency, and investigate the transdermal diffusion characteristics in vitro. Methods Ephedrine liposomes suspensions were prepared using thin film evaporation and slowly dropped by 0.35% chitosan solution with pH values 5—6 in order to prepare the chitosan-modified liposomes gels. The particle diameter of the modified liposomes was detected by Laser Scattering Particle Size Distribution Analyzer. The entrapment efficiency was determined by reverse dialysis method with HPLC. Using Franz Diffusion Cell to investigate transdermal diffusion characteristics of the modified liposomes gels in vitro. Results The mean particle diameter of the modified liposome prepared was from 1 400 to 1 900 nm. The average entrapment efficiency of the modified liposomes was up to (41 ± 0.94)%. Ephedrine in the modified liposomes could penetrate rat skin. The results of the transdermal diffusion test showed the cumulative penetration amount of the ephedrine chitosan-modified liposomes gels was lower than that in the ephedrine solutions with time variation. Conclusion This preparatiom is prepared with simple technology and stable character. The entrapment efficiency of the ephedrine is higher and the assay method is simple and accurate. The penetrating rate of ephedrine is slow and the drug releasing is stable.

武警部队资助项目（WYD-2006-18）