What Is Intranasal Administration?

Intranasal delivery uses nasal spray devices to deposit peptide solutions onto the highly vascularized nasal mucosa, where absorption occurs through the epithelial cell layer into systemic circulation. A unique advantage of intranasal delivery is the nose-to-brain pathway: peptides can travel along the olfactory and trigeminal nerve pathways to reach the brain directly, bypassing the blood-brain barrier. This makes intranasal delivery particularly relevant for neuroactive peptides like Selank, Semax, and VIP. Bioavailability is lower than injection (typically 10-30%) but the route avoids needles and hepatic first-pass metabolism. Proper technique; clearing nasal passages, holding the head slightly forward, and alternating nostrils, improves absorption consistency.