Experimental and Computational Studies of Epithelial Transport of Mefenamic Acid Ester Prodrugs
作者:Kamonthip Wiwattanawongsa、Vimon Tantishaiyakul、Luelak Lomlim、Yon Rojanasakul、Sirirat Pinsuwan、Sanae Keawnopparat
DOI:10.1007/s11095-005-2587-6
日期:2005.5
A series of ester derivatives of mefenamic acid were synthesized with the aim of suppressing local gastrointestinal toxicity of mefenamic acid. A computational method was used to assist the design of the prodrug and to gain insights into the structure relationship of these compounds as P-glycoprotein (P-gp) substrates. The prodrugs were studied for their enzymatic stability, bidirectional permeability across Caco-2 monolayer, and their potential as transporter modulators Bidirectional transport studies were performed using Caco-2 cells. Compounds exhibiting an efflux ratio of ≥2 were further examined for their potential interaction with P-gp and multidrug resistance–associated protein (MRP) using verapamil and indomethacin. Calcein efflux inhibition studies were conducted to investigate the efflux mechanism of these compounds. Geometry optimization of the esters was performed, and the spatial separation of two electron donor groups of each prodrug was measured. Morpholinoethyl ester (3) and pyrrolidinoethyl ester (4) of mefenamic acid showed evidence of efflux mechanism. Inhibition by verapamil had a pronounced effect on the transport of 3 and 4. Indomethacin, however, completely inhibited the apical efflux of 3 but enhanced the efflux ratio of 4. Both compounds increased the ratio of cellular calcein accumulation by 3- to 5-fold over control. Consistent with the experimental data, the computational results suggest the involvement of P-gp or its interaction in 3 and 4 transport. Apical efflux of 3 is associated with P-gp and MRP, but the efflux of 4 involves P-gp and/or MRP. The computational approach used in this study provided the basis for P-gp substrates of compounds 3 and 4 from their electron donor subunits spatial separation.
为了抑制甲灭酸的局部胃肠道毒性,我们合成了一系列甲灭酸的酯类衍生物。研究人员利用计算方法协助设计原药,并深入了解这些化合物作为 P 糖蛋白(P-gp)底物的结构关系。利用 Caco-2 细胞进行了双向转运研究。使用维拉帕米和吲哚美辛进一步检测了流出率≥2的化合物与 P-gp 和多药耐药性相关蛋白(MRP)的潜在相互作用。为研究这些化合物的外流机制,还进行了钙黄绿素外流抑制研究。对酯的几何形状进行了优化,并测量了每种原药的两个电子供体基团的空间间隔。甲灭酸的吗啉基乙酯(3)和吡咯烷基乙酯(4)显示了外流机制的证据。维拉帕米的抑制对 3 和 4 的转运有明显的影响。而吲哚美辛则完全抑制了 3 的根尖外流,但提高了 4 的外流比率。两种化合物都使细胞钙素积累比率比对照组提高了 3 至 5 倍。计算结果与实验数据一致,表明 P-gp 或其相互作用参与了 3 和 4 的转运。3 的顶端外流与 P-gp 和 MRP 有关,但 4 的外流涉及 P-gp 和/或 MRP。本研究采用的计算方法为化合物 3 和 4 的 P-gp 底物从其电子供体亚基空间分离提供了依据。