Nanomedicine Strategies for Delivering Peptide Drugs to the Colon via Oral Route | Research

The takeaway

Nanomedicine-based delivery systems can protect therapeutic peptides through the harsh upper gut and deliver them to the colon, where lower enzyme activity and longer retention times improve absorption.

Colon
The distal GI segment with lower proteolytic activity and longer retention — making it a prime target for oral peptide delivery

What the researchers found

The review establishes that the colon offers significant advantages for oral peptide delivery compared to upper GI segments: lower proteolytic enzyme activity, enhanced retention time, and conditions more favorable for peptide absorption. Nanomedicine strategies — including nanoparticles, liposomes, and other carrier systems — can protect peptides through the harsh upper GI environment and enable colon-specific release.

The authors classify therapeutic peptides and map them to appropriate nanomedicine delivery strategies, while also addressing the regulatory hurdles that currently slow clinical translation of these systems.

Why it matters

Most therapeutic peptides must be injected, which limits patient compliance and quality of life. Cracking the oral delivery problem — especially for colon-targeted peptides — could transform treatment for conditions like inflammatory bowel disease, colorectal cancer, and metabolic disorders. Nanomedicine is one of the most promising approaches to making this feasible.

How the study worked

This is a state-of-the-art review that surveys the published literature on nanomedicine approaches for oral delivery of peptides to the colon. The authors compile and categorize peptide classification systems, nanomedicine delivery strategies, and regulatory considerations for clinical translation.

What this study cannot tell us

This is a review article and presents no new experimental data. The abstract does not quantify the comparative performance of different nanomedicine strategies or provide specific bioavailability numbers. Many of the described approaches remain preclinical, and the gap between laboratory results and clinical translation for oral peptide delivery systems remains substantial.

How to read the evidence

This is a narrative review of the existing literature, not a systematic review or meta-analysis. It provides a useful overview of the field but does not generate new evidence or quantitatively compare strategies.

When this study was published

Published in 2022, this review covers the state of the art at that time. The oral peptide delivery field is evolving rapidly, so some newer nanomedicine approaches may not be included.

The bigger picture

Oral peptide delivery is one of the biggest unsolved challenges in pharmaceutical science. While injectable GLP-1 agonists and insulin analogs dominate the peptide drug market, the push toward oral formulations is accelerating. Colon-targeted nanomedicine represents a specialized approach within this broader effort, with particular relevance for GI-specific conditions where local delivery could improve efficacy while reducing systemic side effects.

Questions still open

Which specific nanomedicine strategy shows the most promise for clinical translation of colon-targeted peptide delivery?
How do colon-targeted nanomedicine systems perform compared to emerging permeation enhancer approaches for oral peptide delivery?
What are the key regulatory milestones needed to bring nanoparticle-based oral peptide formulations to market?

Common questions

Why can't most peptide drugs be taken as a pill?

The stomach's acid and the small intestine's digestive enzymes rapidly break down peptides before they can be absorbed into the bloodstream. The peptide molecules are also often too large to cross the intestinal wall efficiently. This is why most peptide drugs like insulin and semaglutide are given by injection, though oral formulations are an active area of research.

Why is the colon a better target for peptide delivery than the stomach or small intestine?

The colon has significantly lower levels of the digestive enzymes (proteases) that destroy peptides, and material stays in the colon for a longer time, giving peptides more opportunity to be absorbed. The challenge is getting the peptide safely past the harsh upper digestive tract, which is where nanomedicine delivery systems come in — they act as protective carriers.

Read the original research

Nanomedicine based potentially transformative strategies for colon targeting of peptides: State-of-the-art.

Colloids and surfaces. B, Biointerfaces, 219, 112816

View on PubMed ↗Publisher’s paper ↗

Citation

Vambhurkar, Ganesh; Amulya, Etikala; Sikder, Anupama; Shah, Saurabh; Famta, Paras; Khatri, Dharmendra Kumar; Singh, Shashi Bala; Srivastava, Saurabh. (2022). Nanomedicine based potentially transformative strategies for colon targeting of peptides: State-of-the-art.. Colloids and surfaces. B, Biointerfaces, 219, 112816. https://doi.org/10.1016/j.colsurfb.2022.112816