Encapsulation of hydrophobically ion-paired teduglutide in nanoemulsions: Effect of anionic counterions

This study presents a novel method for encapsulating the bioactive peptide teduglutide to enhance its oral bioavailability using O/W nanoemulsion (NE). Recombinant teduglutide (rTGT), produced in E. coli with 93 % purity, was hydrophobically modified through ion-pairing with phytic acid (PA) and sodium dodecyl sulfate (SDS). This approach increased encapsulation efficiency from 48.5 % to 87.5 % and 88.3 %, respectively. rTGT/SDS was incorporated within the core of lipid particles, whereas rTGT/PA was likely oriented on the surface. rTGT/SDS_NE exhibited smaller particle size, greater stability, and low cytotoxicity across all tested concentrations in HT-29 cells. Additionally, rTGT/SDS_NE achieved the highest upregulation of genes associated with intestinal function (VIL1, SGLT1, and GLUT2), although the differences were not statistically significant. These findings highlight the potential of the hydrophobic ion-pairing of rTGT with SDS and its encapsulation in nanoemulsion for efficient delivery of rTGT, suggesting promise for advancing oral peptide therapeutics.