亚微乳处方因素对亲脂性药物细胞处置的影响

Effects of sub-micro emulsion composition on cellular disposition of incorporated lipophilic drug

目的:探讨亚微乳处方组成对亲脂性药物细胞摄取和胞内传递过程的影响。方法:以6-香豆素为模型药物,制备亚微乳。考察油相种类、表面活性剂构成、表面电荷对HeLa细胞摄取的影响,并研究阴离子亚微乳和阳离子亚微乳药物摄取及消除动力学规律,对药物入胞机制进行初步考察。结果:油相成分和吐温类表面活性剂对细胞摄取无显著影响;司盘类表面活性剂可增加细胞摄取,其中以HLB值为8.6的司盘20效果最好;亚微乳的阳离子修饰可显著增加细胞摄取,加快细胞消除。其摄取速率常数和消除速率常数分别为阴离子亚微乳的4.0倍和1.5倍。6-香豆素主要通过被动扩散方式入胞,阳离子亚微乳细胞摄取增效作用主要通过增加细胞膜接触机会实现。结论:亚微乳表面特性如乳化剂HLB值及电位可影响亲脂性药物在细胞内的摄取及消除过程。

Objective：To investigate the effects of sub-micro emulsion composition on cellular uptake and disposition of incorporated lipophilic drug.Methods：Sub-micro emulsions containing 10％ oil,1.2％ lecithin and 2.25％ glycerol were prepared,and the fluorescent agent coumarin 6 was used as a model drug.The effects of oil types,co-surfactants and cationic lipid on uptake and elimination kinetics of 6-coumarin in HeLa cells were studied.The uptake mechanism of sub-micro emulsions was further investigated.Results：Oil type and Tweens had no influence on the cellular uptake.Modifications of surfactants with Span series increased the cellular influx,among which Span 20 with hydrophiliclipophilic balance （HLB） value of 8.6 was the best enhancer.The intracellular drug level reached up to （46.09 ± 1.98） ng/μg protein which had significant difference with control group [（38.54 ± 0.34） ng/μg protein].The positively charged emulsions significantly increased the uptake rate constant and elimination rate constant which were 4 times and 1.5 times of those in anionic groups,respectively.The uptake enhancement was also observed in cationic emulsions,cellular concentrations at plateau were （42.73 ±0.84） ng/μg protein,which was about 3 times of that in anionic emulsions [（15.71 ±0.74）ng/μg protein],when extracellular drug concentration kept at 100 ng/ml.Cationic emulsions delivered the payload mainly by direct drug transfer to contacted cells,while the negative ones depended on both drug passive diffusion and clathrin-mediated endocytosis of drug containing oil droplets which accounted for 20％ of the intracellular drug.Conclusion：Interfacial characteristic of sub-micro emulsions such as co-surfactants HLB as well as zeta potentials can influence lipophilic drug both in cellular uptake and elimination.