Insulin-bile salt nanocomplex achieved 6.44% pharmacological availability via jejunal administration by exploiting the ASBT bile acid transporter for active intestinal absorption.
6.44%pharmacological availability of oral insulin via bile acid transporter-mediated jejunal absorption
What the researchers found
Insulin-SGDC nanocomplexes achieved 6.44% pharmacological availability via jejunal administration through ASBT-mediated active transport. Jejunal delivery was 17.89-fold more effective than colonic. Caco-2 permeability improved 6.36-fold vs. insulin solution.
Why it matters
Replacing insulin injections with oral formulations would transform diabetes management for millions of patients. Exploiting an existing active transport system rather than trying to force passive absorption is an innovative strategy.
The numbers in context
HIP of insulin + SGDC; markedly improved intestinal absorption via bile acid transporters vs free insulin.
How the study worked
Hydrophobic ion-pairing of insulin with sodium glycodeoxycholate. Optimization and characterization. Caco-2 permeability studies with endocytosis inhibitors. ASBT-transfected MDCK cells for transport confirmation. In vivo intrajejunal and intracolonic administration in rats.
Who was studied
Preclinical models testing oral insulin HIP-nanocomplex absorption
What this study cannot tell us
Rat intrajejunal delivery doesn't replicate oral administration with gastric transit. 6.44% bioavailability, while improved, may not be sufficient for clinical use. Manufacturing scalability and stability need assessment. Human ASBT capacity and variability could affect performance.
How to read the evidence
Proof-of-concept with both in vitro mechanistic confirmation and in vivo pharmacological data. Promising but requires optimization for practical oral delivery.
When this study was published
Published in 2021. Oral insulin delivery continues to be one of the most active areas of peptide drug delivery research.
The bigger picture
Oral peptide delivery has been limited by the assumption that large molecules can't cross the intestinal wall. By leveraging existing biological transport systems (bile acid transporters), this approach opens a new paradigm for oral delivery of peptide drugs beyond insulin.
Questions still open
- Can this bile acid transport approach achieve clinically useful oral insulin bioavailability?
- Would enteric coating allow oral capsule delivery targeting the jejunum?
- Could this platform be applied to other peptide drugs like GLP-1 agonists?
Common questions
Why can't insulin be taken as a pill currently?
What is the ASBT transporter?
Read the original research
Bile acid transporter-mediated oral absorption of insulin via hydrophobic ion-pairing approach.
Journal of controlled release : official journal of the Controlled Release Society, 338, 644-661
Citation
Bashyal, Santosh; Seo, Jo-Eun; Choi, Young Wook; Lee, Sangkil. (2021). Bile acid transporter-mediated oral absorption of insulin via hydrophobic ion-pairing approach.. Journal of controlled release : official journal of the Controlled Release Society, 338, 644-661. https://doi.org/10.1016/j.jconrel.2021.08.060