Inhibitive Effect of Cremophor RH40 or Tween 80-based Self-microemulsiflying Drug Delivery System on Cytochrome P450 3A Enzymes in Murine Hepatocytes

This study examined the effect of self-microemulsiflying drug delivery system (SMEDDS) containing Cremophor RH40 or Tween 80 at various dilutions on cytochrome P450 3A (CYP3A) enzymes in rat hepatocytes, with midazolam serving as a CYP3A substrate.The particle size and zeta potential of microemulsions were evaluated upon dilution with aqueous medium.In vitro release was detected by a dialysis method in reverse.The effects of SMEDDS at different dilutions and surfactants at different concentrations on the metabolism of MDZ were investigated in murine hepatocytes.The cytotoxicity of SMEDDS at different dilutions was measured by LDH release and MTT technique.The effects of SMEDDS on the CYP3A enzymes activity were determined by Western blotting.Our results showed that dilution had less effect on the particle size and zeta potential in the range from 1:25 to 1:500.The MDZ was completely released in 10 h.A significant decrease in the formation of 1’-OH-MDZ in rat hepatocytes was observed after treatment with both SMEDDS at dilutions ranging from 1:50 to 1:250 and Cremophor RH 40 or Tween 80 at concentrations ranging from 0.1% to 1% (w/v), with no cytotoxicity observed.A significant decrease in CYP3A protein expression was observed in cells by Western blotting in the presence of either Cremophor RH40 or Tween 80-based SMEDDS at the dilutions ranging from 1:50 to 1:250.This study suggested that the excipient inhibitor-based formulation is a potential protective platform for decreasing metabolism of sensitive drugs that are CYP3A substrates.

cremophor RH40及labrafil M 1944 CS的鼻黏膜毒性考察

目的:考察乙醇-油酸聚乙二醇甘油酯(labrafil M 1944 CS)和聚氧乙烯氢化蓖麻油40(cremophor RH40)的鼻黏膜毒性,探讨其在鼻腔给药系统中应用的可行性。方法:以山梨糖醇酐油酸酯(span-80)和聚山梨酯-80(tween-80)为参比,采用在体蟾蜍上腭模型,光学显微镜下观察纤毛持续运动时间,考察cremophor RH40和labrafil M 1944 CS的纤毛毒性作用;运用家兔血细胞溶血试验,考察cremophor RH40和labrafil M 1944 CS对细胞膜完整性的影响。结果:体积分数为1%时,4种表面活性剂对纤毛运动的影响顺序为cremophor RH40<labrafil M 1944 CS<tween-80<span-80;cremophor RH40的细胞膜毒性最小,tween-80和span-80次之,而labrafil M 1944 CS的影响最大;cremophor RH40对细胞膜完整性无影响用量为tween-80和span-80的15倍。结论:在一定体积分数下cremophor RH40的鼻黏膜毒性作用较小,可应用于鼻腔给药制剂的研制。

粒径法筛选微乳固体型表面活性剂

目的:建立粒径法筛选微乳表面活性剂的方法。方法:表面活性剂的浓度在达到临界胶束浓度(CMC)时,体系的粒径会发生显著的变化。将达到CMC前体系的粒径定义为S1,达到CMC后,体系的粒径定义为S2。其变化值表示形成胶束能力的强弱,该值用E表示,为S1与S2的比值。通过比较表面活性剂的E,对微乳固体表面活性剂进行筛选。将筛选出的微乳固体表面活性剂制成微乳,并利用激光粒度仪测定该种微乳的粒径和Zeta电位,通过透射电镜观察其形态,设计家兔眼部刺激性试验评价其刺激性。结果:固体表面活性剂的乳化能力相对强弱依次为聚氧乙烯氢化蓖麻油RH40(cremophor RH40)>Kollicoat IR>聚乙烯醇(PVA)>β-环糊精(β-CD)>聚乙二醇4000(PEG4000)>十二烷基硫酸钠(SLS)>泊洛沙姆407>泊洛沙姆188>阿拉伯胶>PEG-CHO改性明胶B>骨制明胶B。以cremophor RH40为表面活性剂制备的微乳的粒径38.50 nm,Zeta电位-18.13 m V,透射电镜结果显示其形态圆整、分布均匀。该微乳对雄性家兔眼睛无刺激性,统计结果无显著性差异。结论:利用粒径法对微乳固体型表面活性剂进行筛选的方法合理、可行。