Gradauer Kerstin, Nishiumi Ayano, Unrinin Kota, Higashino Haruki, Kataoka Makoto, Pedersen Betty L, Buckley Stephen T, Yamashita Shinji
†Faculty of Pharmaceutical Sciences, Setsunan University, Osaka 573-0101, Japan.
‡Global Research, Novo Nordisk A/S, DK-2760 Måløv, Denmark.
Mol Pharm. 2015 Jul 6;12(7):2245-53. doi: 10.1021/mp500776a. Epub 2015 Jun 23.
The purpose of the present study was to investigate the interaction of intestinal permeation enhancers with lipid and surfactant components present in the milieu of the small intestine. Maltosides of different chain lengths (decyl-, dodecyl-, and tetradecyl-maltoside; DM, DDM, TDM, respectively) were used as examples of nonionic, surfactant-like permeation enhancers, and their effect on the permeation of FD4 across Caco-2 monolayers was monitored. To mimic the environment of the small intestine, modified versions of fasted and fed state simulated intestinal fluid (FaSSIFmod, FeSSIFmod6.5, respectively) were used in addition to standard transport media (TM). Compared to the buffer control, 0.5 mM DDM led to a 200-fold permeation enhancement of FD4 in TM. However, this was dramatically decreased in FaSSIFmod, where a concentration of 5 mM DDM was necessary in order to elicit a moderate, 4-fold, permeation enhancement. Its capacity to promote permeation was diminished further when FeSSIFmod6.5 was employed. Even when cells were exposed to a concentration of 5 mM, no significant permeation enhancement of FD4 was observed. Analogous effects were observed in the case of DM and TDM, with slight deviations on account of differences in their critical micelle concentration (CMC). This observation was corroborated by calculating the amount of maltoside monomer versus micellar bound maltoside in FaSSIFmod and FeSSIFmod6.5, which demonstrated a reduced amount of free monomer in these fluids. To evaluate the in vivo significance of our findings, DDM solutions in TM, FaSSIFmod, and FeSSIFmod6.5 were used for closed intestinal loop studies in rats. Consistent with the results found in in vitro permeation studies, these investigations illustrated the overwhelming impact of sodium taurocholate/lecithin micelles on the permeation enhancing effect of DDM. While DDM led to a 20-fold increase in FD4 bioavailability when it was applied in TM, no significant permeation enhancement was seen in FaSSIFmod/FeSSIFmod6.5. Collectively, these investigations highlight the importance of using biorelevant media when evaluating the potency of permeation enhancers. In doing so, this ensures improved correlations between in vitro and in vivo studies and thus enables an early and more accurate assessment of promising permeation enhancers.
本研究的目的是调查肠道渗透促进剂与小肠环境中存在的脂质和表面活性剂成分之间的相互作用。使用不同链长的麦芽糖苷（分别为癸基麦芽糖苷、十二烷基麦芽糖苷和十四烷基麦芽糖苷；分别为DM、DDM、TDM）作为非离子型、表面活性剂样渗透促进剂的示例，并监测它们对FD4跨Caco-2单层细胞渗透的影响。为了模拟小肠环境，除了标准转运介质（TM）外，还使用了禁食和进食状态模拟肠液的改良版本（分别为FaSSIFmod、FeSSIFmod6.5）。与缓冲液对照相比，0.5 mM DDM使TM中FD4的渗透增强了200倍。然而，在FaSSIFmod中这种增强作用显著降低，在该介质中需要5 mM DDM的浓度才能引起适度的、4倍的渗透增强。当使用FeSSIFmod6.5时，其促进渗透的能力进一步降低。即使细胞暴露于5 mM的浓度下，也未观察到FD4的显著渗透增强。在DM和TDM的情况下也观察到了类似的效果，由于它们的临界胶束浓度（CMC）不同而略有偏差。通过计算FaSSIFmod和FeSSIFmod6.5中麦芽糖苷单体与胶束结合麦芽糖苷的量，证实了这一观察结果，结果表明这些流体中游离单体的量减少。为了评估我们研究结果的体内意义，将TM、FaSSIFmod和FeSSIFmod6.5中的DDM溶液用于大鼠的闭合肠袢研究。与体外渗透研究的结果一致，这些研究表明牛磺胆酸钠/卵磷脂胶束对DDM的渗透增强作用具有压倒性影响。当DDM应用于TM时，它使FD4的生物利用度提高了20倍，但在FaSSIFmod/FeSSIFmod6.5中未观察到显著的渗透增强作用。总的来说，这些研究突出了在评估渗透促进剂效力时使用生物相关介质的重要性。这样做可以确保体外和体内研究之间有更好的相关性，从而能够对有前景的渗透促进剂进行早期和更准确的评估。
