Mahmud Foyez, Jeon Ok-Cheol, Al-Hilal Taslim A, Kweon Seho, Yang Victor C, Lee Dong Soo, Byun Youngro
†Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, South Korea.
‡Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea.
Mol Pharm. 2015 Jun 1;12(6):1911-20. doi: 10.1021/mp500626a. Epub 2015 May 4.
Currently, oral administration of insulin still remains the best option to avoid the burden of repeated subcutaneous injections and to improve its pharmacokinetics. The objective of the present investigation was to demonstrate the absorption mechanism of insulin in the physical complexation of deoxycholyl-l-lysyl-methylester (DCK) for oral delivery. The oral insulin/DCK complex was prepared by making a physical complex of insulin aspart with DCK through ion-pair interaction in water. For the cellular uptake study, fluorescein-labeled insulin or DCK were prepared according to a standard protocol and applied to Caco-2 or MDCK cell lines. For the PK/PD studies, we performed intrajejunal administration of different formulation of insulin/DCK complex to diabetic rats. The resulting insulin and DCK complex demonstrated greatly enhanced lipophilicity as well as increased permeation across Caco-2 monolayers. The immunofluorescence study revealed the distribution of the complex in the cytoplasm of Caco-2 cells. Moreover, in the apical sodium bile acid transporter (ASBT) transfected MDCK, the insulin/DCK complex showed interaction with ASBT, and also demonstrated absorption through passive diffusion. We could not find that any evidence of endocytosis in relation to the uptake of insulin complex in vitro. In the rat intestine model, the highest absorption of insulin complex was observed in the jejunum at 1 h and then in the ileum at 2-4 h. In PK/PD study, the complex showed a similar PK profile to that of SC insulin. Overall, the study showed that the effect of DCK on enhancing the absorption of insulin resulted from transcellular processes as well as bile acid transporter activity.
目前，口服胰岛素仍是避免重复皮下注射负担并改善其药代动力学的最佳选择。本研究的目的是证明用于口服给药的脱氧胆酰-L-赖氨酰甲酯（DCK）物理络合物中胰岛素的吸收机制。通过在水中使门冬胰岛素与DCK通过离子对相互作用形成物理络合物来制备口服胰岛素/ DCK络合物。对于细胞摄取研究，根据标准方案制备荧光素标记的胰岛素或DCK，并应用于Caco-2或MDCK细胞系。对于PK/PD研究，我们对糖尿病大鼠进行了不同配方的胰岛素/ DCK络合物的空肠内给药。所得的胰岛素和DCK络合物表现出大大增强的亲脂性以及跨Caco-2单层的通透性增加。免疫荧光研究揭示了该络合物在Caco-2细胞胞质中的分布。此外，在顶端钠胆汁酸转运体（ASBT）转染的MDCK中，胰岛素/ DCK络合物显示与ASBT相互作用，并且还通过被动扩散表现出吸收。我们在体外未发现任何与胰岛素络合物摄取相关的内吞作用证据。在大鼠肠道模型中，在空肠1小时时观察到胰岛素络合物的最高吸收，然后在回肠2 - 4小时时观察到最高吸收。在PK/PD研究中，该络合物显示出与皮下注射胰岛素相似的PK曲线。总体而言，该研究表明DCK对增强胰岛素吸收的作用是由跨细胞过程以及胆汁酸转运体活性引起的。
