Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand.
AAPS PharmSciTech. 2010 Jun;11(2):497-508. doi: 10.1208/s12249-010-9399-7. Epub 2010 Mar 24.
The aim of this study was to investigate the effects of a type of hydrophobic moiety, extent of N-substitution (ES), and degree of quaternization (DQ) of chitosan (CS) on the transepithelial electrical resistance and permeability of Caco-2 cells monolayer, using fluorescein isothiocyanate dextran 4,400 (FD-4) as the model compound for paracellular tight junction transport. CS was substituted with hydrophobic moiety, an aliphatic aldehyde (n-octyl) or aromatic aldehyde (benzyl), for the improved hydrophobic interaction with cell membrane, and they were quaternized with Quat-188 to render CS soluble. The factors affecting the epithelial permeability have been evaluated in the intestinal cell monolayers, Caco-2 cells. Cytotoxicity was evaluated by using the trypan blue and MTT viability assay. The results revealed that at pH 7.4 CSQ appeared to increase cell permeability in dose-dependent manner, and this effect was relatively reversible at the lower doses of 0.05-1.25 mM. The higher DQ and ES caused the higher permeability of FD-4. Cytotoxicity of CSQ was concentration, %DQ, and %ES dependent. Substitution with hydrophobic moiety caused decreasing in permeability of FD-4 and cytotoxicity by benzyl group had more effect than octyl group. These studies demonstrated that these novel modified chitosan derivatives had potential for using as absorption enhancers.
本研究旨在探讨壳聚糖（CS）的疏水性基团类型、N-取代度（ES）和季铵化程度（DQ）对 Caco-2 细胞单层跨上皮电阻和通透性的影响，采用荧光素异硫氰酸酯葡聚糖 4400（FD-4）作为细胞旁紧密连接转运的模型化合物。CS 被疏水性基团（脂肪醛（正辛基）或芳香醛（苄基）取代，以改善与细胞膜的疏水相互作用，并被 Quat-188 季铵化以增加 CS 的水溶性。通过 Caco-2 细胞的肠细胞单层评估了影响上皮通透性的因素。通过使用台盼蓝和 MTT 活力测定法评估细胞毒性。结果表明，在 pH 7.4 时，CSQ 似乎以剂量依赖性方式增加细胞通透性，并且在较低剂量（0.05-1.25 mM）下，这种作用相对可逆。较高的 DQ 和 ES 导致 FD-4 的通透性更高。CSQ 的细胞毒性与浓度、DQ 和 ES 百分比有关。疏水性基团的取代会降低 FD-4 的通透性，而苄基的细胞毒性比辛基的影响更大。这些研究表明，这些新型改性壳聚糖衍生物具有作为吸收增强剂的潜力。
