Transport of Insulin in Modified Valia-Chien Chambers and Caco-2 Cell Monolayers

ABSTRACT

The transport characteristics of insulin were investigated using two different absorption models. Using the modified Valia-Chien chambers, permeability coefficients of insulin in the duodenum, jejunum, and ileum were 0.71 × 10⁻⁷, 7.11 × 10⁻⁷ and 9.45 × 10⁻⁷ cm/s, respectively. In the Caco-2 cell monolayers, the bidirectional transepithelial fluxes of insulin across Caco-2 cell line showed symmetry. Confocal laser scanning microscopy visualized that FD-4 and FITC-insulin were mainly located in the paracellular route. It is evident that the lower intestine might be an advantageous region, and absorption enhancer that helps open tight junctions between cells should be used for oral delivery of insulin.

KEYWORDS:

• Insulin
• Transport
• Valia-Chien chamber
• Protein adsorption
• P‐glycoprotein
• Paracellular pathway