The Quest for Oral Insulin and GLP-1 Pills: Delivery Strategies Reviewed
Nanocarrier systems show the most promise for delivering insulin and GLP-1 drugs orally, overcoming the twin barriers of stomach acid destruction and poor gut absorption.
Quick Facts
What This Study Found
The review evaluated multiple strategies for oral delivery of antidiabetic peptides (insulin, GLP-1, and GLP-1 analogs), identifying two main barriers that must be overcome: degradation by proteolytic enzymes in the gastrointestinal tract and poor absorption through the intestinal wall.
Among all approaches reviewed — including absorption enhancers, enzyme inhibitors, chemical modifications, and various carrier systems — nanocarrier systems emerged as the most promising platform. These include polymeric nanoparticles, solid lipid nanoparticles, liposomes, and micelles, each with distinct advantages for protecting peptides from degradation and enhancing their absorption. However, the authors noted that no FDA-approved oral antidiabetic peptide delivery system existed at the time of publication, and further development was needed.
Key Numbers
Strategies reviewed: nanoparticles, solid lipid NPs, liposomes, micelles · Targets: insulin, GLP-1, GLP-1 analogs · Key barriers: enzymatic degradation + poor GI absorption
How They Did This
This was a narrative review that surveyed the published scientific literature on strategies for oral delivery of antidiabetic peptide drugs. The authors evaluated the advantages and limitations of each approach, including nanocarrier systems, absorption enhancers, enzyme inhibitors, mucoadhesive systems, and chemical modification strategies, with a focus on insulin, GLP-1, and GLP-1 analogs.
Why This Research Matters
Diabetes affects over 500 million people worldwide, and many require injectable peptide drugs. The inconvenience, pain, and needle phobia associated with injections reduce adherence and delay treatment initiation. Converting these drugs to oral pills would be transformative for patient quality of life and could improve diabetes outcomes on a population level. This review captures the state of the field just before oral semaglutide (Rybelsus) became the first oral GLP-1 drug to reach the market.
The Bigger Picture
This review was published in 2017, just two years before oral semaglutide (Rybelsus) received FDA approval in 2019 — using a different approach (SNAC absorption enhancer) than the nanocarrier systems highlighted here. The field has continued to evolve rapidly, with oral insulin and next-generation oral GLP-1 formulations in clinical trials. The nanocarrier approaches reviewed here remain active areas of research and may eventually produce products that surpass current technology, particularly for oral insulin delivery which has still not achieved widespread commercial success.
What This Study Doesn't Tell Us
This review predates the approval of oral semaglutide (Rybelsus, 2019), which used an absorption enhancer approach rather than nanocarriers. The nanocarrier strategies highlighted as most promising have not yet produced FDA-approved products. As a narrative review, it does not systematically assess study quality. The field has advanced significantly since 2017.
Questions This Raises
- ?Will nanocarrier-based oral insulin formulations eventually reach the market, or will absorption enhancer approaches (like SNAC in Rybelsus) dominate?
- ?Can oral peptide delivery achieve the same bioavailability and dose precision as injectable formulations for insulin-dependent patients?
- ?How will next-generation oral GLP-1 formulations compare to the first-generation oral semaglutide in terms of absorption efficiency and patient outcomes?
Trust & Context
- Key Stat:
- Nanocarriers: most promising strategy Among all oral peptide delivery approaches reviewed, nanocarrier systems showed the best potential for protecting insulin and GLP-1 from degradation and enhancing absorption
- Evidence Grade:
- Rated 'moderate' because this is a comprehensive narrative review published in a respected pharmaceutics journal, but it generates no new data, predates major developments in the field (oral semaglutide), and the highlighted nanocarrier approaches have not yet achieved clinical approval.
- Study Age:
- Published in 2017 in the European Journal of Pharmaceutics and Biopharmaceutics. Notably, oral semaglutide (Rybelsus) was approved in 2019 using an absorption enhancer approach. The nanocarrier strategies reviewed here remain in development but have not yet produced approved products.
- Original Title:
- Novel strategies in the oral delivery of antidiabetic peptide drugs - Insulin, GLP 1 and its analogs.
- Published In:
- European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 115, 257-267 (2017)
- Authors:
- Ismail, Ruba(2), Csóka, Ildikó(2)
- Database ID:
- RPEP-03331
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Why can't you just swallow an insulin pill?
Insulin is a peptide — a chain of amino acids that your stomach acid and digestive enzymes quickly break apart, just like the proteins in food. Even if some insulin survived digestion, it's a large molecule that can't easily pass through the intestinal wall into the bloodstream. Oral delivery systems must solve both problems: protect the peptide from destruction and help it get absorbed.
Has an oral insulin pill been approved?
As of the review's publication in 2017, no oral insulin had been approved. While oral semaglutide (a GLP-1 drug) was approved in 2019, a true oral insulin pill for widespread clinical use remains elusive. Several companies continue to work on oral insulin formulations using nanoparticles and other delivery technologies.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-03331APA
Ismail, Ruba; Csóka, Ildikó. (2017). Novel strategies in the oral delivery of antidiabetic peptide drugs - Insulin, GLP 1 and its analogs.. European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 115, 257-267. https://doi.org/10.1016/j.ejpb.2017.03.015
MLA
Ismail, Ruba, et al. "Novel strategies in the oral delivery of antidiabetic peptide drugs - Insulin, GLP 1 and its analogs.." European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 2017. https://doi.org/10.1016/j.ejpb.2017.03.015
RethinkPeptides
RethinkPeptides Research Database. "Novel strategies in the oral delivery of antidiabetic peptid..." RPEP-03331. Retrieved from https://rethinkpeptides.com/research/ismail-2017-novel-strategies-in-the
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Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.