Intranasal Peptide Therapeutics - MDPI
/MDPI/2026
Why It Matters
This caught my attention because the blood-brain barrier is the main reason most promising neurological treatments fail in humans. If peptides can reliably reach the brain through nasal spray, it opens possibilities for treating conditions like Alzheimer's, Parkinson's, and depression without invasive procedures. The challenge is that most current evidence comes from animal studies, and what works in rat noses doesn't always translate to human anatomy.
Key Findings
- Peptides delivered intranasally can reach the brain via olfactory and trigeminal nerve pathways, achieving CNS concentrations within 15-30 minutes
- Intranasal delivery avoids first-pass metabolism in the liver and degradation in the GI tract — major problems that destroy peptides taken orally
- Key limitations include small nasal cavity surface area in humans, rapid mucociliary clearance (nose clears substances within 15-20 minutes), and high variability in absorption between individuals
- Formulation strategies like mucoadhesive polymers, permeation enhancers, and nanoparticle carriers can improve peptide stability and brain uptake, but add manufacturing complexity
- Clinical applications being explored include insulin for Alzheimer's disease, oxytocin for autism spectrum disorders, and various neuropeptides for mood and cognitive disorders — though most remain in early-phase trials